Engineering Metrology Pune University MCQs
Engineering Metrology Pune University MCQs
This set of Engineering Metrology Interview Questions and Answers focuses on “Tool Maker’s Flats and High Precision Surface Plates”.
1. What is the shape of the tool maker’s flats?
a) Circular
b) Rectangular
c) Square
d) Triangular
Answer: a
Explanation: Tool maker’s flats are small circular surface plates which are used for the high precision measurement work.
2. Which of the following is not true about tool maker’s flats?
a) Tool maker’s flats should be free from inclusions
b) Tool maker’s flats are of less hardness
c) Working surfaces are produced by lapping
d) Should be located in a stirred atmosphere
nswer: b
Explanation: Tool maker’s flats should be free from inclusions which after proper heat treatment gives a high hardness. Working surfaces are finished by lapping to possess a high degree of accuracy and uniformity.
3. Why are shallow grooves provided in larger flats?
a) To minimize the possibilities of uneven hardening
b) For design purpose
c) To maintain high accuracy for a longer period
d) To make them lighter
Answer: a
Explanation: A shallow groove is provided around the periphery of larger flats to avoid uneven hardening and for easy handling.
4. Which of the following is not true about the requirements of material selection for tool maker’s flats?
a) Suitable surface for the wringing purpose
b) High degree of rigidity
c) Wear resistance
d) Absorb radiant heat
Answer: d
Explanation: Material should have a proper surface so that gauges can be wrung on to it and it should have a high degree of rigidity and freedom from warping. Material should reflect radiant heat.
5. What is the tool maker’s flat size which generally uses both the faces as a working surface?
a) 30 to 45 mm
b) 50 to 75 mm
c) 75 to 100 mm
d) 100 to 200 mm
Answer: b
Explanation: Both the faces are highly finished in the range of 50-75 mm size and both are used as working surface and above this range it has only one face finished as working surface.
6. Which of the following hardness is given by Solid steel tool maker’s flats?
a) 93HRC
b) 83HRC
c) 73HRC
d) 63HRC
Answer: a
Explanation: Solid steel tool maker’s flats after proper heat treatment gives a hardness of 93HRC or 850HV as high hardness is a desirable property for precision flats.
7. What is the minimum thickness of top in a high precision surface plate?
a) 20 mm for 350 mm dia
b) 25 mm for 250 mm dia
c) 30 mm for 250 mm dia
d) 20 mm for 250 mm dia
Answer: d
Explanation: Minimum thickness of top in a high precision surface plate is 20 mm for 250 mm dia, 25 mm for 300 mm dia and 30 mm for 350 mm dia.
8. What is the advantage of granite over cast iron in making surface plates?
a) Reflects radiant heat
b) Won’t rust by moisture
c) Strength for given weight is high
d) No need of inserts and fasteners
Answer: b
Explanation: Granite absorbs radiant heat which is a disadvantage. Granite won’t rust by moisture but may distort. Strength of cast iron is more than granite for a given weight.
9. Which of the following is true regarding high precision surface plates?
a) The top of high precision plate projects about 32 mm beyond the framing
b) The top of high precision plate projects about 32 mm below the framing
c) The top of high precision plate projects about 12 mm beyond the framing
d) The top of high precision plate projects about 12 mm below the framing
Answer: c
Explanation: The top of high precision plates is machined around the sides and generally projects approx 12 mm beyond the framing.
10. What is the minimum total depth in high precision surface plates for 300 mm dia ?
a) 60
b) 70
c) 80
d) 90
Answer: c
Explanation: Minimum total depth for 250, 300, 350 mm dia is 70, 80, 90 mm respectively.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Angle Plates”.
1. What is the angle between the two surfaces of an angle plate?
a) 45 degree
b) 120 degree
c) 90 degree
d) 180 degree
Answer: c
Explanation: Angle plate is an accessory used for measurement purpose along with surface plates and two surfaces of angle plate are at 90 degrees to each other.
2. Which of the following is correct about the hardness of angle plates?
a) Minimum hardness of 100 HB
b) Minimum hardness of 180 HB
c) Maximum hardness of 180 HB
d) Maximum hardness of 100 HB
Answer: b
Explanation: Angle plates are generally made of cast iron and have 180 HB minimum hardness. Angle plates are available in various designs.
3. What is the purpose of baffle plates?
a) Support angle plates
b) Protect casting from direct flame heat
c) Used as an accessory with surface plates
d) Support surface plates
Answer: b
Explanation: Baffle plate creates a barrier between flames and casting, and protects casting from direct heat generated by flames.
4. Which of the following is incorrect about angle plates?
a) Plates are given heat treatment after being finished
b) Angle plates can be used for inspection purposes
c) Box squares can be used instead of angle plates
d) Surfaces of angle plates are scraped
Answer: a
Explanation: Heat treatment is given to the angle plates before being finished to relieve internal stresses. Angle plates are widely used for inspection purposes. Surface of angle plates are scraped to give them a smooth finish and flatness.
5. How many faces are there in multipurpose angle plate?
a) About 50 faces
b) About 40 faces
c) About 30 faces
d) About 10 faces
Answer: d
Explanation: A multipurpose angle plate generally has 10 faces. All faces are at 90 degrees to each other and also perfectly and accurately ground.
6. What is the accuracy of the working surfaces of multipurpose angle plates?
a) 0.002 mm in 25 mm length
b) 0.005 mm in 25 mm length
c) 0.005 mm in 50 mm length
d) 0.002 mm in 50 mm length
Answer: a
Explanation: Working surfaces and end surfaces of plates should be square within the accuracy of 0.002 mm in 25 mm length and 0.005 mm in 25 mm length respectively.
7. Which of the following is true for threaded hole position?
a) Threaded holes are provided only on the sides of angle plates for handling purpose
b) Threaded holes are provided only on the faces of angle plates so that it can be used as fixture
c) Angle plates have threaded holes on the sides and faces so that it can be used as fixture
d) No threaded holes are present in angle plates
Answer: c
Explanation: Sometimes angle plates are used as fixture and for this threaded holes are made on sides and faces of plates. Fixture is a work locating and holding a device.
8. What is the accuracy of surface straightness in angle plates?
a) ±0.001 mm in 25 mm length
b) ±0.01 mm in 25 mm length
c) ±0.04 mm in 25 mm length
d) ±0.004 mm in 25 mm length
Answer: a
Explanation: High accuracy of straightness is needed as straight planes are the basis for measurement works. Angle plates have ±0.001 mm in 25 mm length surface straightness.
9. Which option is correct about these two following statements regarding outer faces of angle plates?
Statement 1: Casting strains are eliminated by natural ageing.
Statement 2: Outer faces of angle plates have recessed grooves.
a) Only statement 1 is true
b) Both statements are false
c) Only statement 2 is true
d) Both statements are true
Answer: d
Explanation: Strain produced in the casting process is eliminated by either natural ageing or artificial seasoning. In natural ageing metal is kept at room temperature to gain its full strength. Outer faces of these plates have grooves for holding and locating purposes.
10. Which of the following option is correct about given statements?
S1: Clamping pallets allows easy fixing of workpieces.
S2: In annealing furnace, angle plates are heating up to 10 degree Celsius.
S3: Straight edges can be used for checking the straightness of the parts.
a) T, T, F
b) F, T, F
c) F, F, T
d) T, F, T
Answer: d
Explanation: In heat treatment operation, angle plates are placed in annealing furnaces where it is heated up to 55 o C . It should be maintained at this temperature for about 3 hours or more which depends upon the mass of casting.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “V-Block”.
1. What is the use of V-Blocks?
a) For checking only squareness of square work pieces
b) For checking roundness
c) Only for the support purposes
d) To support triangular surfaces only
Answer: b
Explanation: V-Blocks are generally used for cylindrical workpieces to check their roundness and for marking centres. V-blocks are like precision metalworking jigs which are used to hold workpieces. These are available in market with wide range of varieties.
2. What is the bearing area of V-Blocks?
a) 5%
b) 10%
c) 15%
d) 20%
Answer: d
Explanation: Vee-Blocks have bearing area of greater than or equal to 20%. V-blocks are used for inspection and workshop purposes. A small groove is present at the bottom of the ‘V’. They are used with screw clamps for holding the work.
3. What is the symmetrization accuracy of vees in V-Blocks?
a) 0.002 mm per 20 mm length
b) 0.001 mm per 20 mm length
c) No effect of symmetry
d) 0.02 mm per 20 mm length
Answer: a
Explanation: V blocks have symmetrization accuracy of 0.002 mm per 20 mm length in Vs and straightness accuracy is ±0.01 mm per 20 mm length.
4. Which of the following is incorrect about V-Blocks?
a) V-Blocks should be checked periodically for accuracy
b) V-Blocks are used to establish centre axis of a cylindrical piece precisely
c) First check the V-Blocks visually before using
d) V-Blocks cannot be used with clamps
Answer: d
Explanation: V-blocks should be checked periodically for accuracy and also checked for scratches and dents. Sometimes clamps are used with V-Blocks to secure the work.
5. Which V block is used for checking triangle effect?
a) V block with 120-degree angle is used
b) V block with 90-degree angle is used
c) V block with 60-degree angle is used
d) V block with 30-degree angle is used
Answer: a
Explanation: V-blocks with 120-degree vee angle are available for some special purposes like checking triangle effect or taps. V-blocks with 90-degree angle are general purpose V-Blocks.
6. Which of the following grades is specified by IS: 2494-1964?
a) Two grades of vee Blocks, viz. Grade A and B
b) Four grades of vee Blocks, viz. Grade A, B, C and D
c) Two grades of vee Blocks, viz. Grade 1 and 2
d) Four grades of vee Blocks, viz. Grade 1, 2, 3 and 4
Answer: c
Explanation: Depending upon the accuracy there are two grades are specified by IS: 2494-1964. Vee blocks should check periodically to correct inaccuracies in blocks if any.
7. Which of the following option is correct for the given statements about working surface of V blocks?
Statement 1: V-Blocks have only one working surface i.e. flanks of vees.
Statement 2: Side faces of V-blocks are not working surfaces.
a) Both statements are true
b) Statement 1 is correct
c) Statement 2 is correct
d) Both statements are false
Answer: d
Explanation: V-blocks generally have four working faces. These working faces are flanks of vees, base end faces, top and sides faces of V-blocks. They are generally supplied as matched pairs in which 2 V-blocks are of almost same size with the same grade of accuracy.
8. Which of the following option is correct for the given statements related to V-blocks?
Statement 1: V-blocks can be used as a magnetic work holding device.
Statement 2: V-blocks with internal magnets help in milling operation.
a) T, T
b) T, F
c) F, T
d) F, F
Answer: a
Explanation: Some V-blocks also has an internal magnet which can be used for holding magnetic work. V-blocks are widely used work holding device which can be used for many operations like drilling, grinding and milling.
9. Which of the following is correct for departure from flatness in Vees?
a) Any departure from flatness in vees should be a concavity
b) Any departure from flatness parallel to the vee axis should be a concavity
c) Any departure from flatness parallel to the vee axis should be a convexity
d) Any departure from flatness in vees can be a concavity or convexity
Answer: b
Explanation: Any departure from flatness on surfaces other than vees should be a concavity and from vees should be convexity. Any departure from flatness parallel to the vee axis should be a concavity.
10. Which of the following is incorrect about V blocks?
a) Cylindrical piece should be placed on the vee sides
b) Cylindrical piece should be placed on the edges of the vees
c) V-Blocks generally sold in pairs
d) V-blocks can support square, round and rectangular pieces
Answer: b
Explanation: Cylindrical pieces should not be placed on the edges; it should be on the vee sides otherwise there is an inaccuracy in marking centres. V-blocks are mostly used to hold cylindrical work pieces but it can also support square and rectangular pieces.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Bench Centres”.
1. What is the material of the bench center’s base?
a) Copper
b) Wood
c) Cast Iron
d) Steel
Answer: c
Explanation: The base of Bench centre is generally made from close-grained cast iron and should be free from any casting defect. Defects may cause error and failure of materials.
2. Why T- slots are provided on the base of bench centres?
a) To reduce its weight
b) For the attachment of centre holders
c) For the attachment of base to table
d) For easy loading and unloading
Answer: b
Explanation: For the attachment of centre holder, T-slots are provided at the base of bench centre. A spring loaded centre is present for easy loading and unloading.
3. What is the range in which distance between the centres varies?
a) 100 to 200 mm
b) 200 to 400 mm
c) 300 to 400 mm
d) 500 to 1500 mm
Answer: d
Explanation: Distance between the centres in centre bench depends upon the centre height and varies between 500 to 1500 mm with centre height accordingly.
4. Which of the following is incorrect about bench centre’s physical characteristics?
a) Centre holders may be located in any position
b) Box type straight edges have a rigid cross section for minimum deflection
c) Minimum hardness of bench centre’s base is 180 HB
d) Male or female centres are non-adjustable on bench centres
Answer: d
Explanation: Along the vees of the centre holders, male or female centres can be adjusted and locked in any desired position.
5. What will happen due to out-of-straightness of a part?
a) Less finished surface of part
b) No error in roundness
c) Failure of a part
d) Doubling run out effect
Answer: d
Explanation: A doubling run out effect and roundness error is caused by out-of-straightness of the part. Run out is also called as out-of true running.
6. What are the centre heights that available for Bench centres?
a) 125 mm
b) 125, 160 mm
c) 125, 250 and 300 mm
d) 125, 160, 200, 250 and 300 mm
Answer: d
Explanation: 125, 160, 200, 250 and 300 mm heights of centres are available in bench centres and according to these heights, centre distance is decided.
7. Match the following apparatus with the function they perform.
A) Straight Edges 1) Checking Eccentricity
B) V-Blocks 2) Checking Flatness
C) Bench Centres 3) Small angle measurement
D) Spirit Level 4) Checking Roundness
a) A-2, B-4, C-1, D-3
b) A-1, B-2, C-3, D-4
c) A-3, B-1, C-4, D-2
d) A-4, B-3, C-2, D-1
Answer: a
Explanation: Straight edges are used with surface plates to check straightness and flatness. V-blocks are used to check roundness of cylindrical pieces. Bench centres are used for rotary components to check eccentricity. Spirit levels are used to measure small inclination.
8. How much deviation is permitted in parallelism of centres axis w.r.t. guideways for 125-160 mm center height?
a) 0.01 mm/200 mm
b) 0.01 mm/300 mm
c) 0.1 mm/300 mm
d) 0.001 mm/300 mm
Answer: b
Explanation: This permissible deviation in parallelism is specified by IS: 1980-1978.
9. Which option is correct for given statements about out of roundness of V blocks?
Statement 1: Shafts can be out-of-roundness due to improper centre alignment.
Statement 2: Adjustable V-Blocks can be used to show out-of-roundness.
a) T, T
b) T, F
c) F, T
d) F, F
Answer: a
Explanation: Many factors affects the roundness of shafts like angle of centres, alignment of centres, centre holes, run-out of piece etc. Adjustable V-Blocks can be used to measure correct roundness.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Spirit Level”.
1. What is the use of Spirit Levels?
a) Angular measurements only
b) Static leveling only
c) Static leveling of equipment and angular measurement
d) Finding roundness of rotating parts
Answer: c
Explanation: Spirit level is the device which is used to measure small inclination or angle of tilt and also used for the static leveling of machineries. It has a sealed glass tube and a scale is engraved on it.
2. How sensitivity of spirit level is expressed?
a) Angle in seconds/1 division of tube
b) Angle in minutes/2 divisions of tube
c) Angle in minutes/1 division of tube
d) Angle in seconds/2 divisions of tube
Answer: a
Explanation: Sensitivity of a spirit level is the angle of tilt in seconds to the 1 division of tube i.e. bubble will move by 1 division of the tube. One division = about 2.5 mm.
3. Where the bubble rests on the scale when spirit level is placed horizontally?
a) Left most
b) Centre
c) Right most
d) Bottom
Answer: b
Explanation: A scale is engraved on the glass of spirit level tube and bubble rests at centre position. When the spirit level is tilted through a small angle then this bubble will always try to remain at the highest position.
4. What is the range of base length of type-1 spirit level?
a) 20-90 mm
b) 100-200 mm
c) 200-300 mm
d) 200-500 mm
Answer: b
Explanation: 3 types of spirit level are specified by BS-1958 in which type-1 spirit level has base length in the range of 100-200 mm and type-2 has base length between 200-500 mm.
5. If angle of tilt is equal to 10 seconds of arc and length of one division is equal to 2.5 mm in a spirit level then what is radius of tube?
a) 51.5 m
b) 51.5 mm
c) 25.5 m
d) 25.5 mm
Answer: a
Explanation: If radius of tube is R then, arc l is equal to Rα where α is taken in seconds. 1 radian is approximately equal to the 206,265 seconds of arc. 10 sec. = 0.0000485 radian. Tilt = 2.5 mm/R. By this, R = 51.5 m approximately.
6. Which of the following is used as a replacement of spirit vial in electrical level?
a) Steel rule
b) Protractor
c) Square block
d) Pendulum
Answer: d
Explanation: In an electrical level, a pendulum is present in place of spirit vial. Displacement of a pendulum is amplified by electrical means or electrically. A separate meter is used to show the readings.
7. What is the length of electronic precision levels?
a) 100 mm
b) 200 mm
c) 300 mm
d) 400 mm
Answer: b
Explanation: Electronic precision level is of about 200 mm length with 0.01 mm/m numerical division. Measuring range of electronic precision level is ±1.99 mm/m. It shows the stability of the indication after 3 seconds.
8. What is the maximum measuring error in electronic precision level?
a) ≤ ± 5% of indicated measuring value
b) ≥ ± 10% of indicated measuring value
c) ≤ ± 20% of indicated measuring value
d) ≥ ± 15% of indicated measuring value
Answer: b
Explanation: Electronic precision level has an LCD digital display with maximum measuring error of less than or equal to ±5% of indicated measuring value. Electronic precision level are used to obtain high accuracy. Measuring range is large.
9. Which of the following given statement is true/false about the sensitivity of spirit level?
Statement 1: Sensitivity of the spirit level increases as the radius of tube increases.
Statement 2: Spirit levels are insensitive to the temperature variation.
a) F, F
b) F, T
c) T, F
d) T, T
Answer: c
Explanation: Sensitiveness of the spirit level is decided by its tube radius. Variation in temperature will cause change in tension of ether vapours in the tube of a spirit level. So, spirit levels are very sensitive to temperature change.
10. Which of the following is true for spirit level?
a) The tube is completely filled with the liquid
b) The Liquid almost fills the tube
c) One-fourth part of the tube is filled with liquid
d) One-tenth part of the tube is filled with liquid
Answer: b
Explanation: The glass tube of spirit level is almost filled by liquid, there is a bubble at the highest position of the tube. The movement of the bubble along the tube radius depends upon the angle of tilt.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Combination Set”.
1. Which type of instrument is a combination set?
a) Used for highly precision works
b) A non-precision instrument
c) Used to check flatness only
d) A simple ruler with graduations on it
Answer: b
Explanation: Combination set is a non-precision instrument which can be used to determine flatness, measuring angles, inspection and layout work etc. It is the most adaptable instrument.
2. Which of the following is not correct about combination set?
a) A squaring head is permanently fixed on the scale
b) Combination set can be used for layout work
c) Interchangeable heads are present in a combination set
d) Can be used in metalworking
Answer: a
Explanation: Combination set has a scale on which heads are attached these heads are interchangeable which can slide along its length. They are not permanently fixed. They can be used for metalworking also.
3. Where the spirit level is present in a combination set?
a) Centre head
b) Squaring head
c) Scale
d) There is no spirit level on combination set
Answer: b
Explanation: A combination set has scale, centre and square head, protractor, spirit level etc. A spirit level is present at the squaring head of the combination set which is used to check the parallelism of surface.
4. What is the angle of one surface of squaring head to the scale in combination set?
a) 105 degree
b) 60 degree
c) 75 degree
d) 90 degree
Answer: d
Explanation: One surface of the squaring head is always at 90 degrees to the scale which is adjustable by a locking bolt and nut arrangement. There is a heavy scale in combination set which is grooved along its length.
5. What is the use of the centre head attachment with the scale?
a) Height measurement
b) Depth measurement
c) Locating centre of bar stock
d) Squaring operations
Answer: c
Explanation: Scale and squaring head are used for measuring depth and height, and squaring operations. Scale and centre head are used for locating the centre. Part to be centred should place beneath the scale and against the sides of centre head for locating the centre.
6. Which of the following option is correct for the given statements about protractor in combination set?
Statement 1: A protractor is permanently fixed on the scale of combination set.
Statement 2: The protractor head of combination set contains a spirit level.
a) F, T
b) T, T
c) F, F
d) T, F
Answer: a
Explanation: The protractor is not permanently fixed but can slide along the scale. And for checking an inclination plane a spirit level is present on protractor head.
7. What is incorrect about the combination set?
a) A non-reversible type protractor head can be used
b) Cast iron heads have a black wrinkle finish
c) Protractor scale is graduated from 0-360 degree
d) Centre of a round block can be located by centre head
Answer: c
Explanation: Protractor scale has 0-90 degree graduation on either side of centre or has 0-180 degree graduations. In some combinations sets, non-reversible types of protractor heads are also present.
8. Which of the following option is correct for given statements about combination set?
1) Combination set can be used as a simple ruler or scale.
2) Square head of combination head with scale can be used as a tri-square.
a) Statement 1 is true
b) Statement 2 is true
c) Both the statements are true
d) Both the statements are false
Answer: c
Explanation: By detaching all the heads from a combination set, it can be used as simple ruler. Square head has 90 and 45 degrees edge so that it can be used as a tri-square.
9. Match the following apparatus with their suitable option:
A) Combination set 1) Digital display
B) Electronic precision level 2) Comparator
C) Johansson mikrokator 3) Extremely flat surface
D) Optical flats 4) Sliding heads
a) A-4, B-1, C-2, D-3
b) A-2, B-3, C-1, D-4
c) A-1, B-2, C-3, D-4
d) A-3, B-4, C-1, D-2
Answer: a
Explanation: Combination set is a multipurpose instrument with a scale and one or more sliding heads on it. Electronic precision level has an LCD display. Optically flats are extremely flat surfaces which are used to check flatness of other surfaces.
10. Which is not a part of the combination set?
a) Scriber point
b) Spirit level
c) Centre head
d) Slip gauge
Answer: d
Explanation: Scriber point is present in combination set for scribing. Spirit level is present on centre head and projector head. Slip gauges are the rectangular blocks and are not a part of combination set.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Radius Gauges”.
1. Which of the following is another name of radius gauge?
a) Ring gauge
b) Planer gauge
c) Fillet gauge
d) Plug gauge
Answer: c
Explanation: Fillet gauge is another name of radius gauge. Fillet gauges are used to check the radius of an object. Radius gauges can also be used for inspection work.
2. Why a radius is provided at the meeting point of two surfaces?
a) To reduce material
b) To avoid collision
c) To increase stability
d) To avoid stress concentration
Answer: d
Explanation: Sharp corners are subjected to more stress. So, to avoid stress concentration, radius is provided.
3. Which of the following option is incorrect with respect to radius gauges?
a) Concave radius is an internal radius
b) Radius gauges are used for final inspection
c) If the curved surface is external then this radius is known as female radius
d) Radius gauges are suitable for both fillet and radius measurement
Answer: c
Explanation: If the curved surface is external then it is called male radius or simply radius. Term Female radius is used for internal curved surface.
4. Match the following:
A) Precision polygons - 1) Indexing
B) Radius gauge - 2) Checking known angles
C) Dividing head - 3) Measure concave surfaces
D) Sine bar - 4) Calibration of rotary table
a) A-1, B-3, C-2, D-4
b) A-4, B-3, C-1, D-2
c) A-3, B-2, C-4, D-1
d) A-2, B-1, C-3, D-4
Answer: b
Explanation: Precision polygons are used to calibrate dividing heads and rotary tables. Radius gauges are used to measure and check concave and convex surfaces. Sine bars are used to locate work at a given angle. Sine bars are also used to measure known and unknown angles.
5. Which of the following option is true for given statement?
Statement 1: For gauging the radius, a light source is used with radius gauge.
Statement 2: Pitch of the threads can be measured by radius gauge.
a) T, F
b) T, T
c) F, T
d) F, F
Answer: a
Explanation: A light source is used with radius gauges. Work is placed between light source and eye. It is the light passage due to which work can be gauged properly. To determine thread pitch, pitch screw gauge are used.
6. What is another name of blades of radius gauge?
a) Leaf
b) Petal
c) Cutter
d) Scale
Answer: a
Explanation: Each radius gauge has a number of blades. These blades are also known as leaves. Leaves can be used in any position to measure radius.
7. Which of the following is not a type of radius gauge?
a) Acrylic
b) Guitar
c) Digital
d) Planer
Answer: d
Explanation: Planer gauge is a measuring instrument which is used to measure slot width and setting tool height. It has two triangular blocks whose sides can be clamped.
8. What is the measuring range for radius gauge?
a) 0.00075-0.025 m
b) 0.0075-0.5m
c) 0.075-5m
d) 0.75-5m
Answer: a
Explanation: Measuring range of radius gauge is generally 0.00075 to 0.025 meter. The blades are specially shaped and can be used to measure fillets and radius against shoulders or corners.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Feeler Gauges”.
1. What is the use of feeler gauge?
a) To find the thickness of work piece
b) To measure the gap width
c) To check straightness
d) To check flatness
Answer: b
Explanation: Feeler gauges are used to measure gap width between two parallel faces e.g. finding clearance between two parallel surfaces.
2. What is the tensile strength of blade of feeler gauge with thickness up to 0.5 mm?
a) 170 kgf/mm 2
b) 270 kgf/mm 2
c) 50 kgf/mm 2
d) 70 kgf/mm 2
Answer: a
Explanation: The blades of feeler gauges are made of heat treated tool steel. For thickness up to 0.5 mm, the tensile strength of blades is 170 kgf/mm 2 and for 0.5 mm or above thickness it is 70 kgf/mm 2 .
3. Which of the following is incorrect about feeler gauge?
a) Feeler gauge can be used to check spark plug gaps
b) A Feeler gauge has number of blades of equal thickness
c) Blades are hinged in a sheath
d) Each thin blade is inter-leaved between two thick blades
Answer: b
Explanation: A feeler gauge is used to check gaps and clearance between two surfaces like spark plugs and tappet clearance. A feeler gauge has a number of blades of different grades and thicknesses. For maximum protection, blades are assembled in a protective sheath.
4. How much overall length is available for feeler gauge blades?
a) 50 mm
b) 30 mm
c) 70 mm
d) 100 mm
Answer: d
Explanation: The overall length available for the blades is 100 mm. and thickness of blades generally varies from 0.03 to 1 mm.
5. Which if the following option is correct for given statements?
Statement 1: Feeler gauge can be used to check clearance between cylinder and piston.
Statement 2: The working of feeler gauges is completely depended on the sense of feel.
a) Statement 1 is true but statement 2 is not true
b) Statement 2 is true but statement 1 is not true
c) Both the statements are not true
d) Both the statements are true
Answer: d
Explanation: The feeler gauge is not forced in the gap and it should not slide freely. For a perfect working, gauge should give a ‘’gauge fit’’ type of feel.
6. Match the set number with number of blades in the set as per BIS.
Set number - No. of blades
A) 2 - 1) 8
B) 6 - 2) 9
C) 3 - 3) 11
D) 1 - 4) 16
a) A-2, B-3, C-4, D-1
b) A-1, B-2, C-3, D-4
c) A-3, B-4, C-1, D-2
d) A-4, B-1, C-2, D-3
Answer: a
Explanation: 7 sets of feeler gauge are recommended by Bureau of Indian Standard. These sets are to furnish maximum utility with minimum number of blades.
7. What is the maximum variation in thickness of a feeler gauge blade of 0.3 mm thick blade?
a) 0.04
b) 0.05
c) 0.06
d) 0.07
Answer: a
Explanation: Maximum variation in thickness for feeler gauge blades up to the thickness of 0.03 mm including 0.03 should not exceed 0.04 mm. For blades over 0.3 mm, this variation is 0.006 mm.
8. According to BIS, What is the thickness of feeler gauge blades for set number 1?
a) 0.3 to 0.1
b) 0.03 to 0.1
c) 0.05 to 0.3
d) 0.5 to 0.3
Answer: b
Explanation: Set number 1 has 8 blades in the set with a thickness of blades from 0.03 to 0.1 in steps of 0.01.
9. Which of the following option is correct for given statements?
Statement 1: The series of feeler gauge blades are of thicknesses from 0.03 to 1 mm.
Statement 2: Feeler gauge blades are non-removable and are assembled in a protective sheath.
a) T, F
b) F, T
c) T, T
d) F, F
Answer: a
Explanation: Feeler gauge blades are hinged on a screw and nut. So, they are removable in nature. They are assembled in a protective sheath which protects the blades when they are not in use.
10. What is the width of feeler gauge blades at heel and tip respectively?
a) 12, 6
b) 5, 11
c) 20, 15
d) 15, 25
Answer: a
Explanation: Blades are 6 mm wide at tip and width at the heel is 12 mm. Width is less at the tip because they are tapered for the outer part of their length.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Angle Gauges”.
1. Which of the following option is incorrect with respect to angle gauges?
a) Sine bar is better than angle gauges
b) Angle gauges are made of high carbon high chromium steel
c) Angle gauges can measure the angle from 0 to 360 degrees
d) They are available in two sets of 13 and 16 gauges
Answer: a
Explanation: Angle gauges are more accurate than sine bar as it involves trigonometric functions.
2. How 34’ can be built by using angle gauges?
a) 27’+9’-3’+1’
b) 26’+10’-2’
c) 27’+10’-3’
d) 27’+8’
Answer: a
Explanation: Combinations can be made by only three series of angle gauges. Minutes series is with 1’, 3’, 9’, 27’ angle gauges.
3. In how many series the gauges can be divided?
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: 16 or 13 Gauges can be divided into 3 series i.e. degree, minutes and seconds .
4. What is the approximate size of angle gauges?
a) 76mm long and 16 wide
b) 85mm long and 26 wide
c) 16mm long and 75 wide
d) 70mm long and 18 wide
Answer: a
Explanation: Angle gauges are about 3 inch long and 5/8 inch wide. And their faces are lapped within 0.0002 mm.
5. What is the accuracy of master angle gauges?
a) 0.1 sec
b) 1 sec
c) 0.25 sec
d) 3 sec
Answer: c
Explanation: Master Angle gauges are laboratory standard and most expensive of all. They measure the angle with an accuracy of 0.25 sec.
6. Which gauges are present in the first series of angle gauges?
a) 5°, 10°, 15°, 25° and 40°
b) 1°, 3°, 9°, 27° and 41°
c) 1°, 5°, 9°, 25° and 45°
d) 5°, 10°, 15°, 30° and 45°
Answer: b
Explanation: The standard angles gauges have 5 gauges present in the first series. They consist of 1°, 3°, 9°, 27° and 41° gauges.
7. How many sets of angle gauges are available?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: Two sets of angle gauges are available. One set with 16 gauges with an accuracy of 1’’ and one set with 13 gauges with 3’’.
8. Which of the following option is true for the given statements?
Statement 1: Any angle up to 120 o 4’2’’ be made by a direct combination of angle gauges.
Statement 2: Interferometry can be used to calibrate angle gauges.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: c
Explanation: Direct combination of angle gauges can be made up to angle 81 o 40.9’. For the larger angle, square block is used with angle gauges.
9. What are the two grades of angle gauges?
a) Master and tool room
b) Precise and Normal
c) Standard and Industrial
d) High and low
Answer: a
Explanation: Master grade is laboratory standard and made from steel carbide or tungsten carbide. Tool grade is normal industrial purpose angle gauges made from steel.
10. How angle greater than 90° is measured?
a) By repeating gauges
b) Using square plate
c) Using sine bar
d) Using auto collimator
Answer: b
Explanation: Versatility of angle gauges increases when used with a square plate. Square plates with angle gauge can measure angle greater than 90 o .
11. Which of the following is not a gauge from standard B angle gauges?
a) 0.05’
b) 1’
c) 27’
d) 30
Answer: a
Explanation: Standard A has 13 gauges and standard B has all gauges from standard A except 0.05’ i.e. 12 gauges.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Vernier Height Gauges”.
1. Which of the following is incorrect for vernier height gauge?
a) Both the surfaces of measuring jaw should be at 45 o to the base
b) These gauges can be used for scribing purposes
c) Removable clamps are used
d) Surface plate is used as datum surface for measurements
Answer: a
Explanation: Both surfaces of measuring jaw i.e. upper and lower are parallel to the base. It can be used for measurements under or over a surface. In place of measuring jaw, a scriber can be attached to scribe lines.
2. What is the hardness of measuring jaws of vernier height gauge made up of stainless steel?
a) 350 HV
b) 450 HV
c) 550 HV
d) 650 HV
Answer: d
Explanation: The measuring jaws, scriber and underside of a base are made up of good quality steel and high carbon stainless steel. Hardness of these parts is about 700 and 650 HV for good quality steel and stainless steel respectively.
3. Which of the following option is correct for the given statements about vernier height gauge?
Statement 1: The projection of scriber beyond the jaw should be 10 mm.
Statement 2: Flatness of working surface of scriber can be checked by the knife edge.
a) Only statement 1 is correct
b) Only statement 2 is correct
c) Both the statements are correct
d) Both the statements are incorrect
Answer: b
Explanation: The scriber is projected at least 25 mm beyond the jaws. Height gauges may also have an offset scriber. Flatness of working surfaces of scriber and measuring jaws is checked by knife edge straight edge or optical flats.
4. What is the standard reference temperature for the measurement of the accuracy of vernier height gauges?
a) 20 K
b) 20 o C
c) 40 K
d) 40 o C
Answer: b
Explanation: Temperature of 20 o C should be maintained in the room where the test is conducted. A height gauge should rest on a precision surface plate to increase the testing accuracy.
5. Which of the following option is correct for the given statements about vernier height gauge?
Statement 1: Surface of the vernier and beam should have a dull finish.
Statement 2: Springing of measuring jaws is desirable.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: a
Explanation: Surfaces of vernier and beam have a dull finish for easy readings. A magnifying lens is also provided for this purpose. A proper care of vernier height gauges is very important. Springing of jaws is always avoided.
6. Which of the following is used for checking the perpendicular distance from the graduated face of a beam to the graduated face of vernier?
a) Angle gauge
b) Vernier depth gauge
c) Feeler gauge
d) Slip gauge
Answer: c
Explanation: It is measured with a 0.1 mm feeler gauge. Vernier depth gauges are used to measure the depth of holes and recesses.
7. Vernier is at which position when the scriber is coplanar with the base?
a) Vernier is exactly at the middle position of the scale
b) Vernier reads 1/4 th of the scale
c) Vernier is at 3/4 th position
d) Vernier reads zero
Answer: d
Explanation: Scale on the beam is positioned in the manner that vernier reads zero when scriber and base are coplanar. In case of wear, some adjustments are made to reset zero position.
8. Match the following:
Column 1 is tolerance of guiding edge of the beam in mm and column 2 is for measuring range in mm.
Column 1 Column 2
A) 0.02 - 1) 500
B) 0.04 - 2) 250
C) 0.06 - 3) 1000
D) 0.08 - 4) 750
a) A-2, B-1, C-4, D-3
b) A-1, B-2, C-3, D-4
c) A-3, B-4, C-2, D-1
d) A-4, B-3, C-1, D-2
Answer: a
Explanation: The guiding edge and face of the beam should be perfectly flat. The face of the beam should be square to the base within 0.04 mm per 100 mm.
9. Which of the following is correct about vernier height gauges?
a) The scriber should preferably be of more depth than jaw
b) The perpendicular distance between scale graduations and vernier graduations should be more than 0.01 mm
c) The base is lapped up to an accuracy of 0.05 mm
d) Width of interval between adjacent lines should be 1/2 or 1/3 times of the length of shortest graduations
Answer: d
Explanation: Nominal depth of scriber should be same as measuring jaw so that it can be reversed. The base is ground and lapped up to 0.005 mm of accuracy and for this total span of a surface is considered.
10. What is the range of reading error for measuring a range of height gauges of 250 mm?
a) ±0.02
b) ±0.03
c) ±0.04
d) ±0.05
Answer: a
Explanation: The reading error should not exceed ±0.02 mm for measuring a range of height gauge of 250 mm, ±0.04 for more than 250 mm up to 750 mm and ±0.05 mm for more than 750 mm.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Master Height Gauges”.
1. Which of the following is true for master height gauges?
a) This is a stack of slip gauge blocks
b) Can store readings in memory
c) Less skilled labour
d) Has statistical production control
Answer: a
Explanation: Master height gauge is basically a stack of gauge blocks with a robust housing. They can be used with riser blocks. A simple master height gauge cannot store measurements in memory.
2. How much measuring capacity is increased by using riser blocks with master height gauge?
a) 500 mm
b) 600 mm
c) 700 mm
d) 800 mm
Answer: b
Explanation: Riser blocks are used to adjust the height. With master height gauges it can increase measuring capacity up to 600 mm.
3. Which of the following option is correct for given statements?
Statement 1: Master height gauge is useful in setting other height gauges.
Statement 2: Can provide a BCD output.
a) Only statement 1 is true
b) Both the statements are true
c) Only statement 2 is true
d) Both the statements are not true
Answer: a
Explanation: Master height gauge is used for setting height gauges and provides a high precision standard. BCD output can be provided by electronic digital readout height gauge.
4. Which attachment is needed to check squareness and parallelism with master height gauge?
a) Dial test indicator
b) Gauge block
c) Slip rings
d) Micrometer
Answer: a
Explanation: If dial test indicator or lever is attached to master height gauge then this unit can be used to check parallelism and squareness.
5. Master height Gauge is used to measure ________
a) Hole location
b) Groove widths
c) Pitches
d) Concentricity
Answer: d
Explanation: Master height gauges can be used as a height standard to measure hole location, a width of groove, pitches etc. To check concentricity universal measuring instrument is a more accurate device.
6. Which of the following is incorrect about master height gauges?
a) Can provide a high precision standard
b) It has a digital readout
c) Has a sliding attachment
d) Built-in microprocessor
Answer: d
Explanation: There is no microprocessor and micro switch in master height gauges. A master height gauge has a rectangular column with a sliding attachment.
7. Which of the following option is correct for given statements?
Statement 1: Master height gauge can store measurement in memory.
Statement 2: Functioning of master height gauges is slower than electronic digital readout height gauge.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: Master height gauges are relatively slower than electronic digital read out height gauges. They require more skilled operators.
8. What is the difference between surface gauge and height gauge?
a) Only surface gauge is used on a surface plate
b) Height gauge has a heavy base
c) Height gauge has a measuring head
d) Surface gauge has a smooth and flat base
Answer: b
Explanation: In toolroom applications, the difference between both is, surface gauge has a scriber point and height gauge has a measuring head.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Universal Measuring Instrument”.
1. Which of the following instrument is of the highest accuracy?
a) Digital length gauge
b) Inside micrometer
c) Universal measuring instrument
d) Universal height micrometer
Answer: c
Explanation: Universal measuring instrument is of the highest accuracy due to the presence of sensors, micro switches and microprocessors.
2. Which of the following option is incorrect about the universal measuring instrument?
a) Twin digital display is present
b) Highly skilled operator is required
c) Computation capabilities
d) Automatically sense diameter of bores
Answer: b
Explanation: Twin display is present one in the front and other in the side for easy reading. Low skilled operator is required as it has automatic computation capabilities which eliminate possibilities of operator’s error.
3. Which of the following statement is true for following statements about universal measuring instrument?
Statement 1: Microprocessor and micro switches are present.
Statement 2: Coefficient of thermal expansion of measuring instrument made of steel is the same as a component to be measured.
a) F, T
b) T, T
c) F, F
d) T, F
Answer: b
Explanation: Same coefficient of thermal expansion of measuring instrument and component to be measured hence, there is no effect of temperature variation on measuring accuracy.
4. What is the permissible measuring speed in universal measuring instrument for error free reading?
a) 1 m/sec
b) 1 mm/sec
c) 1 cm/sec
d) 2 cm/sec
Answer: a
Explanation: 1 m/second is the permissible measuring speed for error free reading. These instruments saves inspection time with high accuracy.
5. How many push buttons are needed for convenient and easy operations?
a) 5
b) 6
c) 7
d) 8
Answer: a
Explanation: There are 5 push button keys are present near readout for easy measurement. Functions of these 5 buttons are: selection of measuring program, input of probe constant, changing reference datum, addition and subtraction and zero setting.
6. Which of the following is correct about electronic display unit of universal measuring instrument?
a) Sensitive to electrical interference
b) Non-removable
c) Cast iron protection cover
d) It is plug-in type
Answer: d
Explanation: It is insensitive to electrical interference and oil film. It is easily interchangeable. There is an aluminium protection cover for an electronic display unit.
7. A universal measuring instrument can withstand up to which temperature for correct reading?
a) 100 o C
b) 75 o C
c) 65 o C
d) 50 o C
Answer: d
Explanation: Display unit can withstand temperature up to 50 o C and 95% relative humidity.
8. Which of the following option is correct for given statements about universal measuring instrument?
Statement 1: There is a rack and pinion movement in measuring slide.
Statement 2: An independent power supply unit is screwed to the base.
a) Only statement 1 is true
b) Only statement 2 is true
c) Both the statements are true
d) Both the statements are not true
Answer: b
Explanation: There is no rack and pinion movement or backlash in EDU. It is completely independent and interchangeable. A power supply unit is screwed with 4 screws to the base.
9. What is the range of voltage fluctuations which can be taken care by an electronic unit in universal measuring instrument?
a) 18% to 20%
b) -10% to +50%
c) -18% to +20%
d) 10% to 50%
Answer: c
Explanation: An interrupted power supply is provided to the electronic unit by power supply unit. It takes cares from – 18 to +20% fluctuations of voltage.
10. Match the following:
Column 1: Part of instrument
Column 2: information regarding a instrument
A) Accessories - 1) Tungsten carbide coating
B) Supporting pads - 2) Balance counter weight
C) Handwheel - 3) Cast iron
D) Base - 4) Built-in microswitch
a) A-2, B-1, C-4, D-3
b) A-1, B-2, C-3, D-4
c) A-3, B-4, C-1, C-2
d) A-4, B-3, C-2, D-1
Answer: a
Explanation: Accessories are designed to balance with the counter weight. 3 supporting pads are present with tungsten carbide coating except at the top which can be lapped. Built-in microswitches are present in hand wheel which compensate automatically for probe constant.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Micrometers”.
1. What is the least count of a micrometer?
a) 0.01 mm
b) 0.02 mm
c) 0.1 mm
d) 0.2 mm
Answer: a
Explanation: Least count can be calculated by “Pitch divided by no. of divisions on a circular scale”.
2. What is the use of ratchet stop in micrometer?
a) Prevent motion of spindle
b) Maintain uniform measuring pressure
c) Provide measuring surface
d) Forms measuring tip
Answer: b
Explanation: Ratchet stop is present at the end of thimble cap to maintain a uniform measuring pressure. By ratchet stop standard conditions of measurement are attained.
3. Which of the following is incorrect about micrometer?
a) Thimble and barrel should have a dull finish
b) Total travel of the measuring spindle is called measuring range
c) Graduated surface diameter of barrel should be 5 mm
d) Screw has 10 or 20 threads per cm
Answer: c
Explanation: Thimble and barrel should have a dull finish for ease of reading. Graduated surface diameter of the barrel should not be less than 10 mm.
4. What is the hardness of measuring faces of anvil and spindle?
a) 800 HV
b) 600 HV
c) 1000 HV
d) 100 HV
Answer: a
Explanation: Measuring faces of anvil and spindle has a hardness of about 800 HV or 62 HRC. Faces may be tipped with tungsten carbide.
5. What is the total error in micrometer?
a) Positive and negative deviation from the zero point
b) Error in parallelism
c) Deviation from measurement of a nominal dimension
d) Maximum difference between ordinates of cumulative error
Answer: d
Explanation: Cumulative error is the deviation of measurement from a nominal dimension. It includes errors like thread errors, errors of measuring faces etc. Maximum difference between ordinates of cumulative error is the total error.
6. How many divisions are graduated on thimble?
a) 20
b) 25
c) 45
d) 50
Answer: d
Explanation: Graduation lines should be clearly engraved. 50 divisions are graduated on thimble each representing 0.01mm.
7. Which of the following option is correct about given statements about micrometer?
Statement 1: The anvil should not protrude from the frame.
Statement 2: An adjusting nut is present in micrometer to compensate wear
a) Only statement 1 is true
b) Only statement 2 is true
c) Both the statements are true
d) Both the statements are false
Answer: b
Explanation: The anvil is fixed and should protrude at least 3 mm. It is to permit the attachment of measuring wire support. Adjusting nut is present between spindle and nut’s screw portion. It is provided for adjusting the zero setting and to compensate wear on the measuring faces.
8. What is the value of total error for grade 1 micrometer when micrometer is tested at 20oC?
a) 4+µm
b) 5+µm
c) 6+µm
d) 7+µm
Answer: a
Explanation: Total error should not exceed 4+µ m for ‘grade 1’ micrometer and 10+µm for ‘grade 2’ micrometer when tested at 20 o C.
9. Which of the following is correct about micrometer?
a) Plastic insulating grips are used on the frame
b) Satin chrome finish increase the reading errors
c) A uniform and maximum measuring force is applied
d) Barrel is the removable part of the frame
Answer: a
Explanation: Plastic insulated grips are employed on the frame to reduce heat transfer. Satin chrome finish minimize the reading errors and eliminate glare. A uniform and minimum measuring force should be applied to reduce error.
10. To check the bending in micrometer, what is the difference between the measurement of loaded and unloaded conditions for micrometer range 0 to 25 mm?
a) 1.5 µm per kg
b) 2.0 µm per kg
c) 2.5 µm per kg
d) 3.0 µm per kg
Answer: a
Explanation: In loaded and unloaded conditions, Difference between measurements should not exceed 1.5µm, 2µm, 2.5µm and 3µm per kg for the range 0 to 25, 25 to 50, 50 to 75 and 100 mm respectively.
11. Which of the following option is true for the given statements about micrometer?
Statement 1: There is a fixed spindle and a rotated anvil.
Statement 2: For taking the reading, micrometer dimension is set slightly larger than part size.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: c
Explanation: Spindle is not fixed infact for good results spindle should move freely. Anvil is fixed generally but sometimes anvil is accommodated in reamed hole and a thread extension is provided.
12. Which of the following is incorrect about precautions in using a micrometer?
a) Final movement is given by ratchet
b) Thimble is turned till the Measuring tip just touches the part to be measured
c) Part to be measured is held in right hand and micrometer in left hand for good results
d) Error is reading is may be due to lack of flatness of anvil
Answer: c
Explanation: The part to be measured must be in left hand and micrometer in the right hand for better results. Place small finger and adjoining finger in the U frame. Middle finger supports micrometer and forefinger and thumb are placed near the thimble. This is the correct way of using a micrometer.
13. What is the accuracy range of stick micrometers?
a) ±0.005 mm
b) ±0.05 mm
c) ±0.5
d) ±0.0005 mm
Answer: a
Explanation: Accuracy of stick micrometers is of the order of ±0.005 mm. They are used to measure longer internal lengths. They have a series of extension rods to measure up to maximum length.
14. Which of the following is incorrect?
a) V-Anvil micrometer caliper is used to check out of roundness
b) Blade type micrometer has a non-rotating spindle
c) Tube wall thickness can be measured by an ordinary micrometer
d) Self-centering inside micrometer has an interchangeable measuring head
Answer: c
Explanation: An ordinary micrometer can’t be used for measuring tube wall thickness because of the concavity of internal surfaces. For this, anvil is made of cylindrical form and spindle axis and anvil axis is made perpendicular.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Bench Micrometer”.
1. Which of the following is incorrect about bench micrometer?
a) Anvil retractor device
b) High precision micrometer head
c) Non-adjustable work table
d) Interchangeable dial indicator
Answer: c
Explanation: Work table is adjustable and an accurate alignment of work is provided by adjusting the table. For repeated measurements, anvil retractor device is present.
2. Up to which comparator measurements, dial indicator of bench micrometer can be used?
a) 1 micron
b) 2 micron
c) 3 micron
d) 4 micron
Answer: a
Explanation: A super precision dial indicator is used for comparator measurement. Micrometer head is also highly précised with direct readings in 25 mm units.
3. What is the range of comparator in bench micrometer with dial comparator?
a) ±50 µm
b) ±100 µm
c) ±150 µm
d) ±200 µm
Answer: a
Explanation: Range of bench micrometer and comparator in bench micrometer with dial comparator is 0-25 mm and ±50 µm respectively.
4. What is the accuracy deviation of dial comparator bench micrometer when setting with gauge block?
a) ≤2 µm
b) ≥2 µm
c) ≤1 µm
d) ≥1 µm
Answer: c
Explanation: Use of gauge block increase accuracy of bench micrometer and its accuracy deviation is less than or equal to 1 µm.
5. Which of the following option is correct for given statements about dial comparator bench micrometer?
Statement 1: Moving parts are of satin chrome finish.
Statement 2: Extra large thimble is present.
a) T, F
b) F, T
c) T, T
d) F, F
Answer: c
Explanation: For easy and fast measurement, moving parts and scale are satin chromed finished. Thimble is large so that graduations are widely spaced.
6. What is the thimble diameter in dial comparator bench micrometer?
a) 5 mm
b) 10 mm
c) 20 mm
d) 30 mm
Answer: d
Explanation: Thimble diameter is large so that graduations can be read easily. Its diameter is about 30 mm.
7. Which of the following is correct about dial comparator bench micrometer?
a) Not ideal for small precision parts
b) Immovable anvil
c) Small thimble
d) Non rotating spindle
Answer: d
Explanation: Anvil can be movable. It is mounted on a long guide way. Micrometer screw contains a non- rotating spindle which is precisely grounded.
8. What is the value of measuring pressure in dial comparator bench micrometer?
a) 7.5 N
b) 8.5 N
c) 9.5 N
d) 10 N
Answer: a
Explanation: Measuring pressure in dial comparator bench micrometer is about 7.5 N. Spindle thread pitch is 1 mm. Throat depth is about 32 mm.
9. Which of the following option is correct about bench micrometer?
Statement 1: Friction free motion transfer between anvil and indicator.
Statement 2: Anvil is retractable by trigger control.
a) Statement 1 is correct
b) Statement 2 is correct
c) Both the statements are correct
d) Both the statements are incorrect
Answer: c
Explanation: There is a mechanism for linear friction free motion transfer between anvil and indicator. This is to achieve high accuracy. Retracting of the anvil is done by trigger control. Work is placed between spindle and anvil after retracting and then released.
10. What is the workrest diameter in bench micrometer with dial comparator?
a) 12 mm
b) 14 mm
c) 16 mm
d) 18 mm
Answer: b
Explanation: Workrest diameter is 14 mm with 12 mm height adjustment. Work rests between spindle and anvil. It can be raised to a selected height by using an adjustable work table.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Graduated Scales”.
1. At which interval, the graduated scales are graduated?
a) 1 mm
b) 10 mm
c) 100 mm
d) 10 cm
Answer: a
Explanation: At the intervals of 1 mm, graduated scales are accurately graduated.
2. Which of the following option is correct about given statement?
Statement 1: In conjunction with other instruments, graduated scales can be used for machine setting.
Statement 2: Graduated scales has fixed anvil.
a) T, T
b) F, T
c) T, F
d) F, F
Answer: c
Explanation: With micrometer microscope, graduated scales can be used for instrument and machine set to a high order of accuracy.
3. When glass block is tilted by ‘i’ in optical arrangement with a graduated scale, then find out the displacement of the ray. Given, width=5 mm, refractive index of glass block=1.5 and rotation is 10 mins.
a) 0.05 mm
b) 0.005 mm
c) 0.0005 mm
d) 0.00005 mm
Answer: b
Explanation: For very small angles, h=wi.
4. What is the accuracy range when Graduated scales are used with micrometer microscope?
a) ±1 micron
b) ±1/2 of a micron
c) ±1/4 th of a micron
d) ±3/4 th of a micron
Answer: c
Explanation: Use of microscope micrometer increases the accuracy of graduated scales. ±1/4 th of a micron is the accuracy range when Graduated scales are used with micrometer microscope.
5. Which of the following is incorrect about graduation scales?
a) Scribed or etched marks are less preferable than paints
b) Telescope internal gauge has two spherical contact rods
c) Ball type plug gauge can detect ovality and taper effect
d) Pneumatic hole gauges are used for precision hole gauging
Answer: a
Explanation: Scribed and etched graduations are more preferable than inks. It is for the durability and accuracy of graduations.
6. Which of the option is correct for given statements about graduated scales?
Statement 1: A microscope is fitted over the scale markings for machine setting.
Statement 2: This arrangement has a provision of the micrometer.
a) Only statement 1 is true
b) Only statement 2 is true
c) Both the statements are true
d) Both the statements are not true
Answer: c
Explanation: A microscope is fitted and setting lines are engraved on the microscope eyepiece. This arrangement has a micrometer provision to move the setting lines.
7. In optical arrangement with graduated scale, when glass block is tilted by ‘i’ then incident ray from scale deviates from straight line path. What is the displacement ‘h’?
a) sin/wcosr
b) w cos/sinr
c) w sin/cosr
d) cos/wsinr
Answer:c
Explanation: Scale division is sensed in the same position when optical axis and glass block are perpendicular to each other. Then it travels a straight line. But when glass block is tilted then incident ray is refracted by ‘r’.
8. Match the following:
A) Cylindrical gauges - 1) Small bores
B) Telescope internal gauges - 2) Deep bores
C) Hemispherical gauge - 3) Instrument setting
D) Graduated scale - 4) Hole internal diameter
a) A-2, B-4, C-1, D- 3
b) A-1, B-2, C-3, D-4
c) A-4, B-3, C-2, D-1
d) A-3, B-1, C-4, D-2
Answer: a
Explanation: Telescope internal gauge, Hemispherical and Cylindrical gauges are used for internal measurements.
9. Which of the following statement is true about graduated scales?
Statement 1: For the purpose of machine setting, an optical arrangement can be used with graduated scales.
Statement 2: Glass block is placed between the graduated scale and table.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: a
Explanation: In this arrangement image of scale is optically moved. For this, a glass block is placed between scale and eyepiece.
10. Which of the option is correct for given statements about an optical arrangement with graduated scales?
Statement 1: There are more chances of cumulative error in optical arrangement with scales while using glass blocks.
Statement 2: High resolution over long length can be obtained by this method.
a) Only statement 1 is true
b) Only statement 2 is true
c) Both the statements are true
d) Both the statements are not true
Answer: b
Explanation: In this arrangement, rotation of glass block is easily calibrated due to high resolution. There will be more chances of cumulative errors with other methods.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Slip Gauges”.
1. Which of the following is not a name of slip gauges?
a) Gauge Blocks
b) Johannsen Gauges
c) Gage Blocks
d) Linear Gauges
Answer: d
Explanation: Slip Gauges are also known by Gauge Blocks, Gage Blocks, Jo Blocks and Johannsen Gauges. These are the rectangular or square blocks of steel.
2. Which of the following is not a common basic form of slip gauge?
a) Rectangular
b) Square with centre hole
c) Square without centre hole
d) Parallelogram
Answer: d
Explanation: There are three basic forms of slip gauges. These are rectangular, square with center hole, and square without centre hole. Rectangular blocks are less expensive hence are more widely used.
3. How many grades or classes of slip gauges are present?
a) 3
b) 5
c) 6
d) 4
Answer: b
Explanation: Slip gauges can be designed in 5 grades i.e. Grade 2, Grade 1, Grade 0, Grade 00 & calibration grade.
4. What is the approximate size of slip gauges?
a) 30mm long and 10mm wide
b) 45mm long and 15mm wide
c) 20mm long and 5mm wide
d) 25mm long and 10mm wide
Answer: a
Explanation: Angle gauges are about 30 mm long and 10 mm wide. Slip gauges are like a system to produce precision length.
5. Match the following gauge type with their respective tolerance:
A) A - 1) ±0.05 μm
B) AA - 2) +0.15 μm to −0.05 μm
C) AAA - 3) +0.25 μm to −0.15 μm
D) B - 4) +0.10 μm to −0.05 μm
a) A-2, B-4, C-1, D- 3
b) A-1, B-2, C-3, D-4
c) A-4, B-3, C-2, D-1
d) A-3, B-1, C-4, D-2
Answer: a
Explanation: AAA has very small tolerance and are used to establish standards. AA has low tolerance and is used in calibration of inspection blocks. A has normal tolerance and are used as tool room standards. B has large tolerance used in workshops.
6. Which of the following is not correct about protector blocks?
a) Protector blocks have letter B on its measuring face
b) They are provided with high grade sets of gauge blocks
c) These are made from Tungsten carbide
d) These are 2 mm blocks
Answer: a
Explanation: Protector blocks are 2 mm block with letter P on it.
7. What is the permissible gauge error for Grade 0?
a) ± μm
b) ± μm
c) ± μm
d) ± μm
Answer: a
Explanation: Grade 0 slip gauges have maximum permissible gauge error of ± μm. For grade I and grade II, the permissible gauge error is ± μm and ± μm.
8. Which of the following is used for manufacturing of length bars?
a) Hardened steel
b) High carbon high chromium steel
c) Tungsten carbide
d) Ceramic
Answer: b
Explanation: Length bars are made from high carbon high chromium steel ensuring the hardness to 64RC.
9. Why ceramic slip gauges is better than steel slip gauges?
a) Due to its wringing capability
b) Due to its Resistance to impact
c) Due to its Resistance to wear
d) Due to its thermal Expansion
Answer: c
Explanation: Ceramic slip gauges are about 10 times more resistant to wear as compared to steel slip gauges. Natural stability and durability due to its low friction co-efficient make it more resistant.
10. Which of the option is correct for given statements about slip gauges error?
Statement 1: Squareness Error is the amount by which side face deviates from a right angled position with respect to each measuring face.
Statement 2: Wringing occurs due to molecular adhesion.
a) Only statement 1 is true
b) Only statement 2 is true
c) Both the statements are true
d) Both the statements are not true
Answer: c
Explanation: Wringing is the complete contact between measuring faces. It occurs due to molecular adhesion.
11. Which one of the following is not a recommended set gauge of a metric unit?
a) M112
b) M105
c) M95
d) M33
Answer: c
Explanation: The recommended sets of slip gauges of metric units are M112, M105, M87, M50, M33 and M27.
12. If properly wrung how much pull can two gauge blocks can withstand?
a) 400N
b) 330N
c) 250N
d) 1000N
Answer: b
Explanation: Due to their ultraflat surface, gauge block adhere tightly when wrung. They can withstand 330N pull when wrung properly.
13. Which of the option is correct for given statements about slip gauge form?
Statement 1: Grade 2 is the workshop grade.
Statement 2: Square slip gauge is more expensive and adhere better to each other when wrung
a) Only statement 1 is true
b) Only statement 2 is true
c) Both the statements are true
d) Both the statements are not true
Answer: c
Explanation: Grade 2 is the workshop grade. They are used in setting up machine tools, checking mechanical widths etc. Square slip gauge is expensive but they wear longer and adhere better.
14. Which of the following is not the most important feature of slip gauge?
a) Length between measuring surface
b) Flatness
c) Surface conditions of measuring surface
d) Adhereness efficiency
Answer: d
Explanation: The most important features of slip gauge are flatness, the length between measuring surface and surface conditions of measuring surface. Slip gauges are used to provide end standards of specific length.
15. In absence of parallelism, what is the size of slip gauge?
a) Distance between two measuring faces
b) Distance between the centre of the exposed face to the surface of a body
c) Distance between the top edge of the exposed surface and same edge of a body
d) Distance between contacting part of gauge and body
Answer: b
Explanation: Size of slip gauge in absence of parallelism is the vertical distance between centre of exposed face and surface of a body.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Slip Gauges Accessories”.
1. Which of the following is not a slip gauge accessory?
a) Measuring jaws
b) Holder
c) Rod clamp
d) Base
Answer: c
Explanation: Slip gauge accessories are measuring jaws, holder, base and scribing & centre point. Field of application of slip gauges is extended by using these accessories.
2. How many types of measuring jaws are present?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: There are two types of measuring jaws i.e. Type A and Type B. Type A is for both internal and external measurement and type B is for external measurement only.
3. What is the error in overall dimension when a pair of jaws wrung together?
a) Should not exceed ± 0.0007 mm
b) Less than ± 0.0001 mm
c) Should not exceed ± 0.0001 mm
d) Should not exceed ± 0.001 mm
Answer: c
Explanation: When a pair of jaws wrung, overall dimension error should not exceed ± 0.0001 mm.
4. Which of the option is correct for given statements about measuring jaws types?
Statement 1: Nominal sizes of measuring jaws are engraved on front end face.
Statement 2: In Type B measuring jaws, no dimension is important.
a) Only statement 1 is true
b) Only statement 2 is true
c) Both the statements are true
d) Both the statements are not true
Answer: c
Explanation: The most important dimension is the measuring jaw size. In Type B, the most important part is the wringing face not the dimensions.
5. Which of the following is the range in which holder is available?
a) 0 to 60mm
b) 200 to 250mm
c) 250 to 350mm
d) 350 to 400mm
Answer: a
Explanation: Holders are available in three ranges i.e. 0-60mm, 50-110mm and 100-210mm.
6. How much deviation in height of base is acceptable from marked dimension?
a) ± 0.001 mm
b) ± 0.007 mm
c) ± 0.0007 mm
d) ± 0.0015 mm
Answer: c
Explanation: Height of base is accepted within ± 0.0007 mm deviation from the marked dimension. The base should remain stable when used with the longest size holder.
7. What is the value of hardness for slip gauge accessories?
a) 600 HV
b) 700 HV
c) 750 HV
d) 800 HV
Answer: d
Explanation: Steel is used to make slip gauges and should be defect free. It should be hardened uniformly up to the minimum hardness of 800 HV.
8. Which of the following option is correct for given statements?
Statement 1: Slip gauge and its accessories can be used as a limit gauge.
Statement 2: Slip gauge and accessories can be used for the measurement of plug gauge but not for ring gauges.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: a
Explanation: They can be used as a temporary limit gauge. They are used for the measurement of a ring and plug gauges, inspection of precision equipment and for marking out tools etc.
9. What is the value of flatness for the surface upon which slip gauges are wrung?
a) 0.0001 mm
b) 0.001 mm
c) 0.01 mm
d) 0.1 mm
Answer: a
Explanation: Surface should be flat within 0.0001 mm and parallel to the base within 0.0002 mm.
10. Which of the following is incorrect about slip gauge accessories?
a) Sides of the base are relieved
b) Holder holds rigidly the combination of slip gauges
c) Slip gauge accessories are made from suitable hardened steel
d) There is no sliding movement of slip gauges in wringing
Answer: d
Explanation: The sides of base are relieved to provide a convenient finger grip. In wringing operation, first the two surfaces should be slided transversely then twisted together.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Line Standard”.
1. Which of the following is not a line standard?
a) Yard
b) Meter
c) Precision scale
d) Length bar
Answer: d
Explanation: Length bar is an end standard. Yard, meter and precision scale are line standards.
2. What is the length of the Imperial standard yard?
a) 38 m
b) 38 mm
c) 38 inches
d) 38 cm
Answer: c
Explanation: The imperial standard yard is a bar made of bronze of 1 inch square cross section. It is 38 inches long.
3. Which of the following is incorrect about line standard?
a) These are legal standards
b) A round recess, half inch away from the ends is cut at both ends
c) Slope at the ends is zero
d) Points of supports are called ‘Airy’ points
Answer: b
Explanation: A round recess is cut at both ends up to the central plane of the bar. These are one inch away from two ends.
4. Gold plugs are inserted into Yard. How many lines are engraved on a plug?
a) 2 transversely and 2 longitudinally
b) 3 transversely and 2 longitudinally
c) 2 transversely and 3 longitudinally
d) 3 transversely and 3 longitudinally
Answer: b
Explanation: It has two holes at the ends in which gold plugs are inserted. Plugs have 2 lines longitudinally and 3 transversally and lines are in a neutral plane.
5. Which of the following option is correct about straight edges?
a) Deflection be minimum at the centre
b) Deflection be maximum at the centre
c) Deflection be minimum at right most part
d) Deflection be minimum at left most part
Answer: a
Explanation: For straight edges, minimum deflection at centre is desirable. For this, the support should be 0.554 L apart, where L is length of the bar.
6. What is the distance between supports for a simply supported beam?
a) 0.557 L
b) 0.554 L
c) 0.575 L
d) 0.577 L
Answer: d
Explanation: Distance between supports is obtained by expression, (1/√(n 2 -1))*L . Here, n is no. of supports. For simply supported beam, it is equal to *L.
7. Which of the following is incorrect about the metre ?
a) It is inoxidisable
b) Kept at 10 o C
c) Supported by two rollers
d) Have a web type section
Answer: b
Explanation: The bar is kept under atmospheric pressure and at 0 o C. It has a shape of winged section. This section has a web whose surface lines are on a neutral axis.
8. By which material metre bar is made of?
a) Bronze
b) Platinum
c) Platinum-bronze alloy
d) Platinum-iridium alloy
Answer: d
Explanation: Yard is made up of bronze bar. This bar is made of platinum-iridium alloy in which 90% is platinum and 10% iridium. Meter is the distance between two lines which are engraved on a bar surface.
9. Which of the following option is true for given statements about meter ?
Statement 1: Diameter of rollers is 0.5 cm.
Statement 2: Rollers are placed at a distance of 751 mm.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: Metre bar is supported by 2 rollers of diameter not less than 1 cm diameter. They are symmetrically placed in a same horizontal plane at a distance of 751 mm.
10. Which of the following is incorrect about the precision scale?
a) Precision scale of reference standard is of a H section
b) Fine lines are engraved parallel to the longitudinal axis of the bar
c) Lines are engraved by using ruling engine
d) Lines are scribed with a sharp diamond cutter
Answer: b
Explanation: Fine lines are engraved at 90 o to the longitudinal axis of the bar. Lines should be as fine as possible. Taking care of lines in terms of parallelism, uniform thickness and spacing is really important.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “End Standards”.
1. Which of the following is not end standard?
a) Precision scale
b) Length bars
c) Slip gauges
d) Gap gauges
Answer: a
Explanation: Precision scale is based on line standard. We employ end standards in workshops for all practical measurements.
2. What is the diameter of end bars?
a) 10 mm
b) 20 mm
c) 30 mm
d) 40 mm
Answer: b
Explanation: Length bar is the alternate name of end bars. These are round bar made of carbon steel of about 20 mm diameter.
3. What is the hardness of end bar at the ends?
a) 600 HV
b) 700 HV
c) 800 HV
d) 900 HV
Answer: c
Explanation: These are hardened up to 800 HV only at the ends. These are supported by ‘Airy points’.
4. Which of the following option is correct about given statements related to end standards?
Statement 1: It is possible to transfer line standard to end standard.
Statement 2: Size of end bars varies from 5 mm to 100 mm only.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: a
Explanation: Size of end bars or length bars varies from 10 mm to 1200 mm. To transfer line standard correctly to the ends of the bar, Line standard comparator is used.
5. Which of the following is incorrect about end bars?
a) There are 4 grades of accuracy are available
b) Bars above 150 mm generally not found in a majority of engineering work
c) Workshop grades have internal threaded ends
d) Inspection grades have external threaded ends only
Answer: d
Explanation: 4 grades of accuracy are reference, calibration, inspection and workshop. Inspection and workshop both grades have internal threaded ends.
6. What is the range of measurement of slip gauges when they are used with length bars?
a) 1200 mm
b) 1300 mm
c) 1400 mm
d) 1500 mm
Answer: a
Explanation: Slip gauges are used as end standards. When slip gauges are used in combination with end bars, there range of measurement is up to 1200 mm.
7. Which of the following is incorrect about end standards?
a) End of micrometer anvil is the end standard
b) It is difficult to form 2 parallel surfaces at the end of a bar
c) Slip gauges were made of more length than legal line standard
d) It is difficult to heat treat the ends
Answer: c
Explanation: End bars and slip gauges both were made of an equal length to the legal standard. End standards which are used in general measurement applications are very important.
8. Which of the following option is correct for given statements?
Statement 1: Displacement method can be used for comparison of an end gauge with a line standard.
Statement 2: In displacement method, there is no need for a microscope but a spirit level is required.
a) Only statement 1 is correct
b) Only statement 2 is correct
c) Both the statements are correct
d) Both the statements are not correct
Answer: a
Explanation: Displacement method utilizes a microscope. In this method, line standard is placed on a carrier and micrometer readings are taken by moving the carrier. After this, same is done for end standard.
9. Which of the following is correct about brookes level comparator?
a) It is used for sub-division of length standard
b) Must be kept at temperature 10 o C for correct readings
c) A very accurate spirit level is used
d) Spirit level makes line contact on gauges
Answer: c
Explanation: It is used for sub-division of end standards. It is important to keep the room temp constant. This is important because some metals suffer a change in length when the temp is varied. Room must be kept at 20 o C.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Wavelength Standard”.
1. Which of the following is not correct about wavelength standard?
a) Wavelength of monochromatic light is an invariable unit of length
b) Wavelength standard is a physical standard
c) It is a reproducible standard
d) It is a natural unit of length
Answer: b
Explanation: Wavelength standard need not be preserved as it is not a physical one. This is an advantage of wavelength standard over others.
2. What is the error in a reproduction of wavelength standard?
a) 1 part in 100 million
b) 2 parts in 50 million
c) 2 parts in 50 million
d) 1 part in 50 million
Answer: a
Explanation: Wavelength standard is reproducible and error of reproduction is very less i.e. only 1 part in 100 million.
3. Which of the following is the most suitable for wavelength standard?
a) Cadmium 114
b) Krypton 86
c) Mercury 198
d) Any monochromatic light
Answer: b
Explanation: If used in a hot cathode discharge lamp then It is the most suitable element. Temperature should be maintained at 64 o K.
4. Which colour radiation of krypton 86 is selected for measurement?
a) Yellow
b) Green
c) Orange
d) Blue
Answer: c
Explanation: Orange radiation of Kr 86 is selected for measurement. Orange-red line of Kr 86 is produced under some specific conditions like at the temp of 64 o K.
5. Which of the following option is correct for given statements about wavelength standard?
Statement 1: Gas lasers produce 1000 times more intense light than others.
Statement 2: Lasers cannot be used for some interferometers like Pitter-NPL gauge interferometer.
a) T, F
b) F, T
c) F, F
d) T, T
Answer: d
Explanation: Working of Pitter-NPL gauge interferometer is based on 3 or 4 different wavelengths. Laser contains only a single wavelength.
6. Which of the following is not an advantage of gas laser?
a) Bigger size
b) Highly monochromatic light
c) Produce intense light
d) Enormous path difference between interference fringes
Answer: a
Explanation: Bigger size, high cost and effect of temperature and vibration on wavelength, these are the disadvantages of laser.
7. Which of the following option is correct for the given statements?
Statement 1: End and wavelength standards can be compared without any mechanical movement.
Statement 2: Indirect comparison of line standard and wavelength standard involves movement.
a) Only statement 1 is true
b) Only statement 2 is true
c) Both the statements are true
d) Both the statements are not true
Answer: c
Explanation: Comparison of end and wavelength standard does not involve any mechanical movement. Terminal surfaces of end standard can be used as optical reflectors. But in comparison of line and wavelength standard, movement like movement of carriage are involved.
8. What is the path difference between interference fringes, when krypton 86 is used?
a) 500 mm
b) 800 mm
c) 1000 mm
d) 1200 mm
Answer: b
Explanation: Next to laser, Krypton 86 enables maximum path difference i.e. 800 mm between fringes.
9. Which of the following option is correct about wavelength standard?
a) Wavelength does not depend upon the amount of isotope impurity
b) Solid state lasers having high intrinsic noise can be used to study new lines
c) Krypton 86 is produced by neutron bombardment of gold
d) Cadmium 114 is the secondary international length standard
Answer: d
Explanation: Wavelength depends upon the impurity of isotopes. Mercury 198 is produced by neutron bombardment of gold. Cadmium is the only natural material which can produce an almost symmetrical spectral line.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Conditions of Comparison”.
1. What is TEI?
a) UNDE+NDE+TVE
b) UNDE-NDE-TVE
c) UNDE+NDE-TVE
d) UNDE-NDE+TVE
Answer: a
Explanation: NDE is a nominal differential expansion, UNDE is an uncertainty of nominal differential expansion, TVE is temperature variation error. NDE is the difference between the nominal expansion of master and part.
2. What is the maximum limit of TEI after which attention is required?
a) 5% of the tolerance part
b) 10% of the tolerance part
c) 15% of the tolerance part
d) 20% of the tolerance part
Answer: b
Explanation: If the TEI is > 10% of the part of tolerance, then attention is required. In close tolerance works, thermal effect is a single largest source of error. Efforts like applying correction and air conditioning doesn’t always solve the problem.
3. Which of the option is correct about given statements factors affecting standards?
Statement 1: A uniform temperature is important in metrology labs.
Statement 2: Ambient temperature may change by convection, conduction and radiation.
a) Only statement 1 is correct
b) Only statement 2 is correct
c) Both the statements are correct
d) Both the statements are false
Answer: c
Explanation: A uniform temperature is necessary because rate of thermal expansion is different for different materials. Ambient temp may change by convection, conduction and radiation but the effect of radiations is more troublesome.
4. Up to which length of gauges, there is no appreciable change in length with a method of support?
a) 75 mm
b) 100 mm
c) 150 mm
d) 200 mm
Answer: a
Explanation: For small gauges upto 75 mm length, there is no appreciable change in length for a method of supports. But dimensions of long gauges may change even by their own weight.
5. What is the full form of TEI?
a) Total error index
b) Total expansion index
c) Thermal expansion instrument
d) Thermal error index
Answer: d
Explanation: Thermal error index can be reduced by establishing a more accurate coefficient of expansion, making corrections for NDE, minimizing temperature variation from 20 degree C.
6. What is the value of humidity in test laboratories for performing a measurement or any other operation?
a) 35±10%
b) 45±10%
c) 55±10%
d) 65±10%
Answer: b
Explanation: Lower RH value can invalidate measurement by building static charge. High value of RH can cause leakage. It should be maintained at 45±10%.
7. Which of the following statement is correct for given statements?
Statement 1: Nitra-alloy is an ultrastable material.
Statement 2: In steel coefficient of expansion can be increased by adding nickel.
a) F, F
b) F, T
c) T, T
d) T, F
Answer: d
Explanation: Metallurgic compositions also affect the stability of the material. Coefficient of expansion of steel can be reduced by adding nickel. It is desirable to have materials with the same coefficient of expansion.
8. Which of the following statement is not suitable to reduce error produced by temperature variation?
a) Increase rate of air flow
b) Increase the frequency of variation of temperature
c) Increase the amplitude of temperature variation
d) Redesign masters and comparators
Answer: c
Explanation: Decrease in an amplitude of temperature variation is a factor to reduce error produced by temp variations. Redesigning of masters and comparators may reduce this error by balancing time cons. and coefficient of expansion with part to be measured.
9. Which of the following option is correct for given statements about factors affecting accuracy in metrology?
Statement 1: Acoustic noise should be restricted below 45-60 dB.
Statement 2: Humidity corrodes non-ferrous materials only.
a) Only statement 1 is true
b) Both the statements are true
c) Only statement 2 is true
d) Both the statements are not true
Answer: a
Explanation: There is an effect of acoustic noise on sensitive measurement, it value should be less than 45-60 db. Humidity should be maintained at a constant value, it can corrode ferrous materials.
10. Which of the following option is not suitable for environmental conditions in labs?
a) Wet dust particles decrease insulation resistance
b) Dry dust increase surface resistivity
c) A negative air pressure should be maintained in labs
d) Electrostatic precipitators used to collect dust particles
Answer: c
Explanation: A positive air pressure of about 10 to 20 N/m 2 relative to outside area is recommended in labs. Electrostatic precipitators are used to collect and attract dust particles, for this purpose they can be placed in corners.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Metrology in Quality Assurance”.
1. What does QA and QC stand for?
a) Quality Assurance and Queuing Control
b) Quality Adjustment and Quality completion
c) Quality Assurance and Quality control
d) Quality Adjustment and Queuing control
Answer: c
Explanation: QA stands for Quality Adjustment. QA is concerned with the functions related to the attainment of the required quality. QC stands for Quality control. QC is sustaining the product quality practically and ensuring that it meets the requirements given.
2. What is QA?
a) It is the measurement of degree to which a product satisfies the need
b) Any systematic process used to ensure quality in the process
c) Process of identifying defects
d) It is a corrective tool
Answer: b
Explanation: QA is a systematic process which ensures the quality of the product and guarantees to the user that product will be safer and more reliable.
3. Which of the following option is correct regarding QA and QC?
a) QC is an integral part of QA
b) QA is an integral part of QC
c) QA and QC are independent to each other
d) QC may or may not depend on QA
Answer: a
Explanation: QC is based on the measurements as it concerned with practical means. Metrology is an important tool of quality assurance.
4. Which of the following option involves material and component control?
a) Development of standards
b) Development of specification
c) Quality control
d) Feedback
Answer: c
Explanation: Quality and measurement control involves component control. Specification and design involve the development of specifications, designs and standards. Marketing and servicing involves feedback.
5. Arrange the steps of QA in ascending order?
a) Customer needs, material control, design development, process control, marketing
b) Material control, process control, customer need, design development, finished product
c) Customer needs, design development, material control, process control, finished product
d) Material control, servicing, process control, material control, design development
Answer: c
Explanation: Scheme of QA starts with customer need. They have to be converted into the development of a specification, followed by quality and measurement control, material control and convert into the finished product.
6. What is the first step of QA?
a) Development of standards
b) Identification of customer need
c) Servicing
d) Material control
Answer: b
Explanation: Identification of customer need is the first step of QA after which further basic elements of QA are identified. QA depends not only on QC but also on the activities of the entire company.
7. Match the following:
A) Quality assurance - 1) Process oriented
B) Quality control - 2) National physical laboratory
C) Quality management - 3) Product oriented
D) National measurement system - 4) Overall programmer of QA
a) A-3, B-4, C-2, D-1
b) A-2, B-3, C-1, D-4
c) A-1, B-3, C-4, D-2
d) A-4, B-1, C-3, D-2
Answer: c
Explanation: A quantitative management is a management representative, responsible for resolving all matters pertaining to quality and independent of other functions.
8. Which of the following is an example of QA?
a) Verification
b) Software testing
c) Validation
d) Documentation
Answer: a
Explanation: Software testing and validation are the examples of QC. Validation is an example of QA. QC is a system for coordinating the efforts of groups in an organization to improve quality.
9. Which of the following option is not correct regarding QA and QC?
a) Process capabilities should be monitored on intermittent basis
b) Measuring equipment’s must have a calibration certificate
c) Normally many inspections are done during the process of manufacturing
d) QA depends on the activities of the entire company
Answer: a
Explanation: Process capabilities are controlled on a continuous basis. These are used to eliminate and detect potential causes of non-conformance.
10. Where the nodal point for National Measurement System is located?
a) Bangalore
b) Patna
c) Bombay
d) New Delhi
Answer: d
Explanation: Nodal point for national measurement system is NPL and located in New Delhi. It has responsibilities like the development and management of national standards, evaluation of measuring techniques etc.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Tolerances”.
1. What are the functional dimensions?
a) Have to be machined and fit with other mating components
b) Which have no effect on the performance of quality
c) Need not to be machined to an accuracy of the high degree
d) Function is more important than accuracy
Answer: a
Explanation: Non-functional dimensions have no effect on the performance of quality of the assembly or component. Non-functional dimensions need not to be machined to higher accuracy.
2. Why tolerances are given to the parts?
a) Because it’s impossible to make perfect settings
b) To reduce weight of the component
c) To reduce cost of the assembly
d) To reduce amount of material used
Answer: a
Explanation: Tolerances are provided to the parts because variations in the material properties introduce errors and production machines themselves have inherent inaccuracies. Another reason to introduce tolerance is that it is not possible to make perfect settings by operator so some tolerances are provided.
3. What is bilateral tolerance?
a) Total tolerance is in 1 direction only
b) Total tolerance is in both the directions
c) May or may not be in one direction
d) Tolerance provided all over the component body
Answer: b
Explanation: Total tolerance is specified on both the sides of the basic dimension. This usually have + and – tolerance of equal amount.
4. Which type of tolerance provided in drilling mostly?
a) Bilateral
b) Unilateral
c) Trilateral
d) Compound
Answer: b
Explanation: Mostly unilateral tolerance is provided in drilling as dimension is allowed to vary in one direction only. Hole is always oversize, not undersize.
5. What is mean clearance?
a) Maximum size of hole minus maximum size of shaft
b) Minimum size of hole minus minimum size of shaft
c) Mean size of hole minus mean size of shaft
d) Average of both size of shaft and hole
Answer: c
Explanation: Statistical approach allows wider tolerances compared to complete interchangeability approach. Methods used by statistical approach are usually permits cheaper production. Mean clearance is equal to .
6. Which of the following is incorrect about tolerances?
a) Too loose tolerance results in less cost
b) Tolerance is a compromise between accuracy and ability
c) Too tight tolerance may result in excessive cost
d) Fit between mating components is decided by functional requirements
Answer: a
Explanation: Loose tolerance results in increase in cost, assembly problems and poor performance of the product. Tight tolerance results in unnecessary machining and inspection time.
7. Quality control charts doesn’t depend on which factor?
a) Normal distribution
b) Random sampling
c) Independence between samples
d) Binomial distribution
Answer: d
Explanation: In establishing of realistic specifications, control charts are considered as a good guide for the design office. Quality control charts are based on the assumptions of random sampling and normal distribution.
8. Which of the following option is true for given statements?
Statement 1: Bilateral tolerances are used in mass production techniques.
Statement 2: The basic size should be equal to upper and lower limits.
a) T, T
b) F, F
c) T, F
d) F, T
Answer: c
Explanation: Bilateral tolerances are preferred in mass production techniques where setting of a machine is done for the basic size. If unilateral tolerances are specified in place of bilateral, then basic size should be changed to make it bilateral. Basic size is in half way between lower and upper limits.
9. If a clearance fit is present between shaft and hole, what is the tolerance on shaft or hole for a complete interchangeable approach?
a) ½ of maximum clearance – ½ of minimum clearance
b) ¼ of maximum clearance – ¼ of minimum clearance
c) Maximum clearance – minimum clearance
d) ¾ of maximum clearance – ¾ of minimum clearance
Answer: a
Explanation: There are two approaches for deciding of tolerances and shafts i.e. statistical and complete interchangeable approach. There is no risk is taken about a single non-conforming assembly in complete interchangeable approach.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Interchangeability”.
1. Which of the following option is incorrect about interchangeability?
a) Increase output
b) Increase cost of production
c) Useful in mass production
d) Assembly time increases
Answer: d
Explanation: An interchangeable part is one that can be replaced with a similar part manufactured to the same drawing. It can be used in mass production with an economic oriented approach. Assembly time decreases as mating parts are interchangeable.
2. What are the main considerations for deciding the limits of a particular part?
a) Functional requirement
b) Economics and interchangeability
c) Interchangeability and functional requirement
d) Interchangeability, functional requirement and economics
Answer: d
Explanation: Functional requirements are related to the function of a component that is what is required to do. Interchangeability is for ease of replacement of part. Economics is related to the minimum cost and time.
3. For full interchangeability, what is the relation between the process capability of a machine and manufacturing tolerance of the part?
a) Process capability = Manufacturing tolerance
b) Process capability ≥ Manufacturing tolerance
c) Process capability > Manufacturing tolerance
d) Process capability ≤ Manufacturing tolerance
Answer: d
Explanation: For full interchangeability, only such machines are selected for manufacturing whose process capability ≤ manufacturing tolerance. If this condition is satisfied, then the component will meet the desired tolerance and capable of mating with other.
4. Which of the following option is correct in given statements about interchangeability?
Statement 1: Standardisation is not so much of importance for interchangeability.
Statement 2: Interchangeability follows ‘normal distribution’.
a) F, T
b) T, T
c) F, F
d) T, F
Answer: a
Explanation: Standardisation is important in interchangeability. It is essential to follow a common standard by all, only then interchangeability is possible. All standards used by the manufacturing unit are traceable to international standards.
5. Which of the following option is not correct for ‘full interchangeability’?
a) This type of interchangeability is not feasible sometimes
b) Requires machine which can maintain low process capability
c) Machines with very high accuracy are necessary
d) For interchangeable production, this type of interchangeability is not must
Answer: b
Explanation: Full interchangeability is also known as universal interchangeability. Many times, universal interchangeability is not feasible because it requires machine capable of maintaining very high accuracy and high process capability.
6. What is the main use of automatic gauge in selective assembly?
a) Check accuracy of parts
b) Check parallelism of parts
c) Divide group of parts with some tolerance in smaller groups
d) Use to check errors in parts
Answer: c
Explanation: If parts to be assembled have normal tolerance of 0.01 mm then a gauge can be divided them into 10 different groups of 0.001 mm, this gauge is known as automatic gauge. It is for selective assembly of different parts.
7. What is the correct formula to find no. of groups in selective assembly?
a) Process capability / Tolerance desired
b) Tolerance desired / Process capability
c) Tolerance desired * Process capability
d) Tolerance desired + Process capability
Answer: a
Explanation: No. of groups segregated in selective assembly depends upon desired tolerance and process capability of machine. Conditions like high quality and low cost can be achieved by selective assembly technique.
8. What is a limit system?
a) Series of tolerances
b) Series of fits
c) Series of clearances
d) Series of limits
Answer: a
Explanation: Limit system is a series of tolerances arranged to suit a specific range of size. By this, limits of size are selected and given to mating parts to ensure specific classes of fit.
9. Which of the following is correct for selective assembly?
a) Not suitable for industrial purposes
b) Cost increases due to automatic gauging
c) Wastage is high due to selective selection
d) This method is followed in ball and roller bearing units
Answer: d
Explanation: Selective assembly technique is widely used in industries. It is followed in automobile, air craft industries and in ball and roller bearing units. Tolerances desired in these industries are very narrow.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Terminology”.
1. What does ‘50’ represents in 50H8/g7?
a) Basic size
b) Actual size
c) Maximum limit of size
d) Minimum limit of size
Answer: a
Explanation: 50 represent the basic size of the hole and shaft. H and g are the positions of tolerance zone with respect to zero line for hole and shaft respectively. 8 and 7 are the tolerance size.
2. What is ‘Go limit’?
a) Lower limit of shaft and upper limit of hole
b) Lower limit of shaft and hole
c) Upper limit of shaft and lower limit of a hole
d) Upper limit of shaft and hole
Answer: c
Explanation: ‘Go limit’ deals with upper limit of shaft and lower limit of hole and refers to the maximum material condition. ‘No-go’ limits deals with lower limit of shaft and upper limit of hole and refers to the minimum material condition.
3. Which of the following is incorrect regarding terminology?
a) Grades of tolerances decides manufacture’s accuracy
b) For any basic size there are 20 different shafts
c) Line of zero deviation is known as zero line
d) Tolerance has no sign
Answer: b
Explanation: For any basic size, there are 25 different shafts. These are designated by small letters from a to zc. Each shaft has 20 tolerance grades. Tolerance is the algebraic difference between lower and upper deviation.
4. What is the actual deviation?
a) Algebraic sum between actual size and corresponding basic size
b) Algebraic difference between actual and corresponding basic size
c) Average of actual and basic size
d) Algebraic difference between upper and lower deviation
Answer: b
Explanation: Algebraic difference between a size and a corresponding basic size is called deviation. Limit deviations are upper and lower deviations. Algebraic difference of actual size with basic size is called actual deviation.
5. What is the condition for a positive upper deviation?
a) Maximum limit of size > basic size
b) Maximum limit of size is < basic size
c) Minimum limit of size > basic size
d) Maximum limit of size < basic size
Answer: a
Explanation: Upper deviation is positive when maximum limit of size > its basic size and negative when maximum limits size < basic size. For lowers deviations, it is a positive quantity when minimum limit size is more than its corresponding basic size.
6. How many holes are there for any basic size?
a) 22
b) 24
c) 26
d) 28
Answer: d
Explanation: There are 28 different holes for any basic size. These are designated by capital letters. A, B, CD, C, D, E, EF, F, FG, G, H, JS, J, K, M, N, P, R, S, T, U, V, X, Y, Z, ZA, ZB, ZC these are the 28 holes.
7. What does ES represent in terminology as per IS: 919?
a) Lower deviation of hole
b) Upper deviation of shaft
c) Lower deviation of shaft
d) Upper deviation of hole
Answer: d
Explanation: ‘ES’ and ‘es’ represents upper deviation for hole and shaft respectively. ‘EI’ and ‘ei’ represents lower deviation for hole and shaft respectively.
8. What is ‘IT01’?
a) Basic size of hole
b) Basic size of shaft
c) Tolerance grade
d) Standard tolerance factor
Answer: c
Explanation: ‘IT’ refers to the standard tolerance which belongs to any standard grade of tolerance. Tolerance grades are designated by ‘IT’ letters followed by a number. For example, IT01 is a tolerance grade.
9. For tolerance grades 5 to 16, what is the formula for standard tolerance factor?
a) 0.45 1/3 + 0.001D
b) 10*D
c) 0.45 3 + 0.001 D
d) 20*D
Answer: a
Explanation: For tolerance grades 5 to 16 the value of tolerance magnitude is in terms of standard tolerance factor, i = 0.45 1/3 + 0.001 D. For grade IT6, tolerance is 10i. Above it, at each 5 th step the tolerance magnitude is multiplied by 10.
10. What is the hole size which is covered by IT05?
a) 500 mm
b) 600 mm
c) 700 mm
d) 800 mm
Answer: a
Explanation: There are 7 finest tolerance grades from 1T01 to IT05. It covers sizes up to 500 mm. There are 11 coarsest grades which cover sizes up to 3150 mm. Tolerance grades depend upon shaft or hole size.
This set of Engineering Metrology Questions and Answers for Freshers focuses on “Guide for Selection of Fits”.
1. Which of the following is not true for hole and shaft basis systems?
a) Hole basis system is generally preferred over shaft basis system
b) Shaft basis system can be used when products are made from bright drawn bars
c) Choice of the system depends upon nature of the product
d) In hole basis system, allowances are applied to the hole
Answer: d
Explanation: Hole basis system is preferred because it is easy to produce a shaft with specified tolerances than hole. In hole basis system, all tolerances are applied to shaft and hole size is taken as basic size.
2. Which of the following grade of a hole is mostly used for non-circular fits?
a) H5
b) H6
c) H7
d) H9
Answer: d
Explanation: H9, H5, H6, H7 these all are the grades of a hole. H9 can be obtained by reaming and boring. It is used for non-circular fits. H5 can be obtained by honing or internal grinding. H7 can be produced by broaching and grinding.
3. Which of the following option is incorrect for clearance fits?
a) Shaft ‘a’ gives a large clearance
b) Shaft ‘n’ is used for clearance fits
c) Shaft ‘d’ can be used for loose pulleys
d) Shaft ‘g’ is expensive to manufacture
Answer: b
Explanation: Shaft ‘n’ gives transition fit. It gives clearance to only extreme sizes. It is recommended for tight fits. Grades 5, 6 and 7 are available. Shafts a, b and c gives clearance fit. They all gives large clearance so they are not widely used.
4. What is the range of shafts which produce transition fits?
a) Shaft ‘a’ to ‘h’
b) Shaft ‘e’ to ‘n’
c) Shaft ‘d’ to ‘h’
d) Shaft ‘j’ to ‘n’
Answer: d
Explanation: ‘a’ to ‘h’ shafts produces clearance fits with H7 basic hole. ‘j’ to ‘n’ produce transition fit with H7 basic size. Transition fits may result in either interference or clearance fit. It will depend upon the actual size of tolerance of mating component.
5. Which grades are available in shaft ’j’ assembly?
a) 1 to 5
b) 2 to 6
c) 3 to 7
d) 5 to 11
Answer: d
Explanation: Shaft ‘j’ is a transition fit and available in grades 5 to 11. It is good for location fits which require less clearance than ‘h’ and also where a slight interference is permitted. It can be used in gear rings clamped to steel hubs.
6. Which of the following grade is never used for fits?
a) H10
b) H11
c) H8
d) H9
Answer: b
Explanation: H5, H6, H7, H8, H9, H10, H11 these are the hole grades. H10 is not used for diameter fits. It can be used for milled widths. H11 is never used for fits because this grade is very coarse. H11 is useful only for coarse punched holes or drilled holes.
7. Which of the option is correct about the preference of shaft and holes in machine tool industries?
a) ‘A11’ is of first preference in shafts
b) ‘B9’ is of first preference in holes
c) ‘c2’ is of first preference in shafts
d) ‘b11’ is of second preference in holes
Answer: c
Explanation: a11, c2, d9, d11, e8 etc. are the first preference for shafts and b9, b11, c8, c11, d8 etc. are the second preferences for shafts. First preference of holes are A11, D11, E11, F7, F8 etc. and B9, B11, C9, C11, D9 etc. are the second preferences for holes.
8. Which of the following option is correct for given statements regarding the selection of fits?
Statement 1: Shaft ‘h’ is an interference fit and used only for running parts.
Statement 2: Shaft ‘k’ is the true transition fit.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: Shaft ‘h’ gives clearance fit and available in grades 5 to 11. It is useful for spigot fits. Shaft ‘k’ is a transition fit and it is best suited for location fits. Grades available for this category are also 5 to 11.
9. Which shaft is used in valve shaftings?
a) Shaft ‘s’
b) Shaft ‘f’
c) Shaft ‘b’
d) Shaft ‘t’
Answer: a
Explanation: Shaft ‘s’ gives interference fit. It is used for semi-permanent or permanent assemblies of cast iron and steel members. It can be used for valve shafting’s and collar pressed on the shaft.
10. Which of the following gives interference fit?
a) Shaft ‘n’
b) Shaft ‘p’
c) Shaft ‘m’
d) Shaft ‘g’
Answer: b
Explanation: Shaft ‘p’ gives a true interference fit and available in grades 6 or 7. With hole of grade 8 it behaves as transition fit. It is a standard fit for cast iron and steel. It can be used for fixing of a bush on a gear. Shaft ‘g’ gives clearance fit. Shaft ‘m’ and ‘n’ gives transition fit.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Plain Gauges”.
1. Which of the following is not correct about plain gauges?
a) Used to check threaded portions
b) There is no scale in plain gauges
c) Indicates actual value of the inspected dimension
d) Can be used to check dimension of manufactured part
Answer: c
Explanation: These gauges do not have any scale. These gauges are used only for determining that the inspected part is within a specified limit or not. They do not use to indicate actual value. Plain gauges are mostly used to check unthreaded shafts and holes.
2. What of the following option correctly define a solid gauge?
a) Gauging portion and handle separately manufactured
b) Gauge integral with the handle
c) Gauges with suitable locking devices
d) Gauges that are not used for cylindrical holes
Answer: b
Explanation: When the whole gauge is made from one single piece of metal or gauging portion is integral with the handle, such type of gauges are called solid gauges. Gauging portion and handle of ‘renewable type of gauge’ is separately manufactured.
3. What is the hardness of gauging portion in plain plug gauges?
a) 450 HV
b) 550 HV
c) 650 HV
d) 750 HV
Answer: d
Explanation: Gauging surfaces of plain plug gauges are suitably stabilized, lapped and ground. These surfaces are normally hardened to not less than 750 HV. For sizes up to 63 mm, double ended type of plug gauges are used, and for above 63 mm single ended are used.
4. Which of the following is not true for fixed gauges?
a) Independent of availability of power supply
b) These are not expensive
c) Chances of human errors are more
d) Provide uniform reference standard
Answer: c
Explanation: Fixed gauges are generally error free due to drift of the original adjustment, effect of variation of power, non-linear response etc. Human errors are almost nil except for careful handling. Auxiliary equipment and setups are not required.
5. Up to which diameter, bar type plug gauges are used?
a) 20 mm
b) 40 mm
c) 75 mm
d) More than 75 mm
Answer: d
Explanation: Plain plug gauges which are heavy or diameter more than 75 mm, it is common to use bar type or segmental gauges in this case. Gauge efficiency decrease if sensitiveness of user is impaired by weight.
6. What is the suitable material for small plain plug gauges?
a) Any type of steel
b) Light metal alloys
c) Non-metallic handles may be used
d) Aluminum
Answer: c
Explanation: Suitable wear resisting steel is used to make gauging members of plain plug gauges. For heavy plain plug gauges, handle made of light metal alloys are used. For small plain plug gauges, suitable non-metallic handles may be used.
7. What is the colour of the band at ‘no go’ side of plain gauges?
a) Red
b) Blue
c) Green
d) Yellow
Answer: a
Explanation: To identify which end of the gauge is ‘No Go’ or ‘Go’ end, sometimes ‘No Go’ side is painted with red colour. Otherwise, the work ‘Go’ and ‘No Go’ are written on the handle of ‘Go’ and ‘No Go’ side respectively.
8. What is the range of size that can be checked by double-ended Rib type snap gauges?
a) 1 mm to 10 mm
b) 10 mm to 20 mm
c) 20 mm to 50 mm
d) 3 mm to 100 mm
Answer: d
Explanation: It is convenient to use double ended type rib snap gauges to check sizes of 3 mm to 100 mm. For size, 100 to 250 mm single ended progressive type snap gauges are used. Gauging surface are hardened up to 720 HV. Other surfaces are of smooth finish.
9. Which of the following option is correct regarding anvils of ‘adjustable type gap gauges’?
a) Gauging anvil has only sliding movement
b) Gauging anvil has only rotating movement
c) Gauging anvil has both sliding and rotating movement
d) Anvils are of non-adjustable type
Answer: a
Explanation: In adjustable type gap gauges, gauging anvils are adjustable endwise in the horse shoe frame. The gauging anvils of adjustable type snap gauges have only sliding movement that is no rotating movement for adjustment. A sufficient distance should be present between ‘Go’ and ‘No Go’ anvil.
10. What is the main use of contour gauges?
a) Check shape of irregular work
b) Check profiles
c) Check distance between surfaces
d) Check position of work
Answer: a
Explanation: Contour gauges are generally used to check dimensional accuracy and shape of irregular work e.g. radius gauges are used to check fillet shape. Simple contour gauges are used for thread pitches, form gear tooth profiles etc.
11. Which of the following option is correct for the given statements about plain plug gauges?
Statement 1: Cylindrical plugs are used for diameter above 100 mm.
Statement 2: For very large holes, spherically ended rods are used.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: Cylindrical plugs are not suitable for above 100 mm diameter, it is suitable to use spherical ended rods for such cases. Go gauges of 100 to 200 mm diameter can take the form of a cylindrical ended bar.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Gauge Design”.
1. Which principle is related to Gauge design?
a) Rankin principle
b) Position principle
c) Taylor’s principle
d) Carnot Principle
Answer: c
Explanation: According to Taylor’s principle, “‘No Go’ and ‘Go’ gauges are designed to check the minimum and maximum material limits”. In gauge design, simplicity is the main aim as simple gauge can take measurements accurately and continuously.
2. ‘Go limit’ applied to which limit condition?
a) Maximum material limit
b) Minimum material limit
c) Lower limit of shaft and upper limit of hole
d) Moderate material limit
Answer: a
Explanation: ‘Go’ limit is applied to the limit corresponds to maximum material limit condition that is lower limit of hole and upper limit of shaft while ‘No Go’ limit is applied to minimum material condition that is upper limit of a hole and lower limit of a shaft.
3. Which of the following is true for plug gauges?
a) Size difference between ‘Go’ and ‘No Go’ plug gauges is greater than the tolerance of tested shaft or hole
b) Size difference between ‘Go’ and ‘No Go’ plug gauges is Equal to the tolerance of tested shaft or hole
c) Size difference between ‘Go’ and ‘No Go’ plug gauges is less than the tolerance of tested shaft or hole
d) Size difference between ‘Go’ and ‘No Go’ plug gauges more or less than the tolerance of tested shaft or hole
Answer: b
Explanation: In case of standard gauges, size difference between ‘Go’ and ‘No Go’ plug and snap gauges is equal to tolerance. To maintain size and adequate functioning of snap gauges, robustness and rigidity are the main features.
4. Which of the following is incorrect for the gauging faces of snap gauges?
a) Parallel to each other
b) Square to each other
c) Gauging point and work are in same plane
d) Work and gauging faces are at 60 degree
Answer: d
Explanation: Gauging faces of a gap and snap gauges are square and parallel to each other. If gauging diameter of component is larger than gap setting then it will produce welding action may lead to distortion in gauge are incorrect interpretation of reading.
5. Which of the following can’t be done by ‘Go’ plug gauges?
a) Ensure bore alignability
b) Controls diameter
c) Check straightness of hole
d) Check degree of ovality
Answer: a
Explanation: ‘Go’ plug gauge is preferably full length of hole hence straightness can be checked. ‘Go’ gauges can’t check degree of ovality. ‘No Go’ plug gauges are short and its function depends on the diameter and circularity of hole.
6. What is the effect of wear on the size of ‘Go’ snap gauges?
a) Decrease
b) Increase
c) May increase or decrease
d) No effect
Answer: b
Explanation: Due to wear, size of ‘Go’ plug gauge decreased while size of ‘Go’ snap gauge is increased. Absolute accurate gauge can’t be made by gauge makers. So, it is important to assign some deviation to gauges.
7. What is the use of ‘No Go’ gauges?
a) Check a single element of a feature
b) Check several dimensions simultaneously
c) Check roundness and size at the same time
d) Check location and size at the same time
Answer: a
Explanation: ‘No Go’ gauge should check only one feature at a time. A separate ‘No Go’ gauge is needed for each different individual dimension. ‘Go gauges’ are complex gauges can check several related dimensions simultaneously.
8. Which deviations are provided to a new ‘Go’ plug gauge from the nominal size?
a) One positive deviation
b) One negative deviation
c) Two positive deviations
d) Two negative deviations
Answer: c
Explanation: A new ‘Go’ snap gauge is made with two negative deviations while a new ‘Go’ plug gauge is made with two positive deviations from the nominal size.
9. Which of the following option is correct for the given statements about Gauge design?
Statement 1: ‘No Go’ gauges should put in the condition of maximum impassability in the inspection.
Statement 2: ‘Go’ plug gauge corresponds to a minimum limit.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: c
Explanation: ‘Go’ plug gauge corresponds to the minimum limit of the hole, while the ‘No Go’ gauge is the size of maximum limit. But ‘Go’ snap gauge is of maximum limit of shaft and ‘No Go’ corresponds to a minimum limit.
10. If work tolerance is less than 0.09 mm then how much wear tolerance is applied to ‘Go’ gauge?
a) 10%
b) 20%
c) 30%
d) 40%
Answer: a
Explanation: There is no need of giving allowance for wear when work tolerance is less than 0.09 mm. But, if work tolerance is more than 0.09 mm then 10% tolerance is only given to the ‘Go’ gauge for wear.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Gauges for Tapers”.
1. What is important in testing a tapered job?
a) Check the diameter at smaller end
b) Change of diameter per unit mass
c) Change in length per unit weight
d) Change of diameter per unit length
Answer: d
Explanation: Taper plug and ring gauges are used to test tapers. A taper has two ends, one of bigger diameter and other of smaller diameter. To test a tapered job it is important to check the bigger diameter and also the change of diameter per unit length.
2. How correctness of taper can be checked?
a) Draw a single line of Persian blue along the length
b) Draw two lines of Persian blue at any distance along the diameter
c) Draw three lines of Persian blue at equidistant along the length
d) No need of Persian blue, it can be checked simply by seeing the rotation of spindle
Answer: c
Explanation: 3 lines are drawn with Persian blue along the length on the plug gauge or spindle to test the taper. It is fitted in the gauge and rotated once or twice. If these marks of Persian blue are not rubbed evenly then the taper is not correct.
3. What is the tolerance for a bigger diameter of taper in limit gauges?
a) ± IT4
b) ± IT5
c) ± IT6
d) ± IT7
Answer: c
Explanation: Bigger diameter is situated in the gauge plane. Tolerance on both bigger and smaller diameter will be ± IT6 on the basic size. It can be calculated from taper ratio.
4. What is the distance of bigger diameter from face if the value of diameter is 200mm?
a) 5 mm
b) 7 mm
c) 10 mm
d) 12 mm
Answer: d
Explanation: Distance of diameter at the bigger end from face depends upon the value of diameter itself. For example, if the value of diameter is 200 mm then this distance will be 2 mm or varies between 0.5 to 2 mm.
5. What is the value of hardness for plug and ring gauges used for self-holding tapers?
a) 750 to 860 HV
b) 120 to 540 HV
c) 550 to 740 HV
d) 900 to 1200 HV
Answer: a
Explanation: Good quality steel is used for making these gauges and these are suitably heat treated to give hardness of 750 to 860 HV and for stabilization. Gauges surfaces should be free from rust, crack and burrs.
6. Which of the following option is true for given statements regarding gauges for tapers?
Statement 1: Use of double ended gauges is very important in limit gauges for tapers.
Statement 2: Gauges should be packed in non-absorbent paper.
a) T, T
b) F, T
c) T, F
d) F, F
Answer: b
Explanation: Use of double ended gauges is unnecessary in this case because the diameter difference between low and high limit of the tolerances is converted into lengthwise dimension. Thus hole will be within the tolerance. Diameter at the large end of hole falls between gauge plane and other line at distance Z from it.
7. What is the tolerance for plug gauge on basic size?
a) + IT5
b) – IT7
c) + IT8
d) – IT9
Answer: a
Explanation: Distance between gauge plane and a free end in plug gauges is sometimes denoted as ‘a’. Distance ‘a’ varies between 2 mm to 12 mm. IT5 is the tolerance for plug gauges on the basic size.
8. Which of the following is incorrect about gauges?
a) Wear allowance is of main consideration in limit gauges for tapers
b) Cylindrical ring gauges can be used for gauging external diameters
c) Position gauges can be used to check the geometric relationship of features
d) Workshop and inspection gauges with same tolerance limits are more beneficial
Answer: a
Explanation: Wear allowance is not considered on the gauges. It is because of high cost is involved in manufacturing to that level of accuracy. If the tolerance limit of workshop and inspection gauges is same then the same gauges can be used for both the purposes.
This set of Engineering Metrology Interview Questions and Answers for freshers focuses on “Plug and Ring Gauges for Self holding Tapers”.
1. What is the not true for plug and ring gauges for self-holding tapers?
a) These tapers can be used for accurate alignment of tool
b) Can be used for the purpose of transmitting the torques
c) Use of these gauges helps in arriving at absolute deviation
d) Tapers can be external or internal
Answer: c
Explanation: Self holding tapers are mostly used in the tool shanks and machine spindle noses. Purpose of using these is an accurate alignment of tools and torque transmission. Both plug and ring gauges are used to check tapers because tapers can be both external and internal.
2. Which of the following option is correct for plug gauges, Plain?
a) Have only one ring marked on the gauge plane
b) Have only one ring indicates maximum depth
c) Have two rings
d) Have only one ring indicates minimum depth
Answer: c
Explanation: These gauges have two rings. One ring is marked on the gauge plane. Another ring is used to indicate minimum depth of the taper or internal taper. These rings are also present in tanged plug gauges.
3. What is the alternative name of self-holding tapers?
a) Small tapers
b) Fast tapers
c) Self-releasing taper
d) Large tapers
Answer: a
Explanation: Self-holding tapers are used not only to provide perfect alignment in the machine tools but also to provide a firm seat for driving the tools. Self-holding tapers are also known as slow and small tapers. They have very shallow angle.
4. In which of the following a limit step is present?
a) Plain plug gauge
b) Tanged plug gauge
c) Plain ring gauge
d) Tanged ring gauge
Answer: d
Explanation: A limit step is present in the tanged ring gauge at the small end of the taper. It is used to verify shank length from the gauge plane and also to verify the combined effect of thickness of tang and its offsets.
5. How much extra thickness is added to tang thickness in tanged plug gauge?
a) 0.1 mm
b) 0.05 mm
c) 0.01 mm
d) 0.5 mm
Answer: c
Explanation: 0.01 mm is added to the tank thickness to allow for the tang eccentricity of the plug gauge itself. Tanged plug gauges are used to verify internal tapers in machine sockets or tools and also to ensure that tang will be accepted by tang slot.
6. What is the angle of self-holding tapers?
a) 2 to 3 degrees
b) 7 to 8 degrees
c) 10 to 15 degrees
d) 15 to 17 degrees
Answer: a
Explanation: Self holding tapers have a shallow angle of about 2 to 3 degrees. Morse tapers, Brown and sharp tapers, jarno taper are the type of self-holding taper.
7. Which of the following option is correct for given statements about plug gauges for self-holding tapers?
Statement 1: Plug is inserted with high pressure for checking taper.
Statement 2: Morse taper is a type of self-holding taper.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: The plug gauge is inserted with light pressure as far as it goes, for checking internal tapers. At extreme point the large end face of internal taper shall lie within the marks of two rings given on the plug gauge.
8. Which of the following taper is used for ‘shanks of the twist drills’?
a) Morse taper
b) Brown taper
c) Sharpe taper
d) Jarno taper
Answer: a
Explanation: Morse taper is exclusively used on the shanks of the twists drills. For a different type of morse taper, taper is slightly different. In most of the cases, taper is 5/8 inch per foot.
9. Straight edge is generally used in which gauge for testing taper?
a) Plain plug gauge
b) Plain ring gauge
c) Tanged plug gauge
d) Tanged ring gauge
Answer: b
Explanation: In plain ring gauge, to check external taper of a plain or tapped shank, ring gauge is inserted with light pressure. At the extreme position, taper’s small end shank under test should lie short of the ring gauge face on the small end. It is verified by using a straight edge.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Uses of Comparators”.
1. Which of the following is true for uses of comparators?
a) Can’t be used in mass production
b) Not suitable for inspection purposes
c) Can be used as working gauge
d) Slow rate of working
Answer: c
Explanation: Comparators are used in mass production where components are checked at a fast rate. These can be used as inspection purposes, laboratory standards and working standards or gauges.
2. What is the principle of ‘The Johansson Mikrokator’?
a) Button spinning on a loop of string
b) Principle of interference
c) Optical magnification
d) Principle of transformer
Answer: a
Explanation: Johansson Mikrokator is a mechanical comparator used to obtain mechanical magnification. Principle of Johansson Mikrokator is ‘spinning of a button on a loop string’. Magnification of this comparator is of the order of 5000.
3. From which category ‘Sigma comparator’ belongs?
a) Optical comparator
b) Mechanical comparator
c) Mechanical-optical comparator
d) Pneumatic comparator
Answer: b
Explanation: Sigma comparator is a mechanical comparator. Components of sigma comparator are a plunger, knife edge, cross strip hinge, Y-shaped arm, driving drum, slit diaphragm, a scale and a pointer etc.
4. What is the advantage of mechanical comparator over others?
a) Less moving parts
b) No need of external supply
c) No error due to parallax
d) Large range of instrument
Answer: b
Explanation: Mechanical comparator is cheaper as compared to others. Mechanical comparators have more moving parts due to this friction is more and accuracy is less. External supply is not required. Moving pointer moves over a fixed scale hence error due to parallax is possible.
5. Which of the following is true for ’Cross strip’ in sigma comparator?
a) Has two moving members
b) Cross strip is hinged
c) Two members are at 45 o to each other
d) A flexible strip is attached to any one of the members of cross strip
Answer: b
Explanation: A hinged cross strip is present in sigma comparator which has a fixed and a moving member. These are connected to by thin flexible strips and right angle to each other. External force is applied on the moving member.
6. Which colour of light is filtered by filter present in Zeiss Ultra-optimeter?
a) Red
b) Blue
c) Green
d) Yellow
Answer: c
Explanation: Zeiss ultra-optimeter gives a high degree of magnification. This instrument has an optical system involves a double reflection of light. A green filter is present which filters all but the green light which is less fatiguing to the eye.
7. Which of the following is true for Eden-Rolt Millionth Comparator?
a) Utilise both mechanical and optical magnifications
b) Only mechanical magnification
c) Only optical magnification
d) Only electrical magnification
Answer: a
Explanation: Eden-Rolt Millionth is a comparator which utilizes both optical and mechanical magnification that means it can utilize advantages of both optical and mechanical comparators hence it is a highly sensitive comparator. Design of this comparator is economical and simple.
8. Which of the following option is correct regarding the characteristics of comparators?
a) Minimum inertia
b) Minimum compensation for temperature effect
c) High measuring pressure
d) Minimum versatility
Answer: a
Explanation: Design of the instrument must be such that it can be used for wide range of operations which means instrument must have highest versatility. Instrument should be free from wear effects and from backlash and inertia of the system should be minimum.
9. What is the use of bleed valve in flow type pneumatic comparator?
a) Zero adjustment
b) Measurement of size
c) Connect passage of air from plastic tube to gauging head
d) Used with pressure reducing unit
Answer: a
Explanation: Bleed valve in pneumatic comparator is used for zero adjustment. A screw is also present at the inlet of tapered glass tube by which magnification can be changed by passing some air supply from it.
10. What is the order of overall magnification in Eden-Rolt Millionth Comparator?
a) 50
b) 400
c) 20,000
d) 800
Answer: c
Explanation: Mechanical and optical magnification of this instrument is of the order of 400 and 50 respectively. Thus, the overall magnification of Eden-rolt millionth comparator is of the order of about 20,000.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Pneumatic Comparators”.
1. Which of the following is not correct for pneumatic comparator?
a) Independent of operator skill
b) Loss of accuracy due to gauge wear
c) Speedy operation
d) Total life cost is less
Answer: b
Explanation: In pneumatic comparator, there is no physical contact with setting gauge or part being measured. Due to this reason, there is no loss of accuracy due to gauge wear. It is an accurate, universal, reliable and speedy device.
2. What is the order of magnification in flow type pneumatic gauge?
a) 100 to 1000 times
b) 500 to 5000 times
c) 50 to 500 times
d) 100 to 2000 times
Answer: b
Explanation: Velocity type pneumatic gauge have quick response. It can permit a large clearance between object surface and nozzle which results in less wear in gauging members. Less air consumption. So, the magnification of the order to 500-5000 times is possible.
3. Which of the following is true for Pneumatic sensitivity in pneumatic comparators?
a) Directly proportional to operating pressure
b) Inversely proportion to operating pressure
c) Directly proportional to geometrical area of orifice
d) Independent of area of orifice and operating pressure
Answer: a
Explanation: Pneumatic sensitivity in the pneumatic comparator is directly dependent upon the operating pressure and inversely proportional to the geometrical area of the orifice. It can be represented as dp/dM.
4. What is the formula for overall magnification of pneumatic comparator?
a) 0.4*λ/L a
b) 0.7*λ/L a
c) 0.4*λ*L a
d) 0.7*λ*L a
Answer: a
Explanation: Overall magnification depends upon pneumatic sensitivity, sensitivity of pressure measuring device that is rate of change of reading w.r.t. varying pressure and upon rate of change of geometrical area of orifice w.r.t. ‘L’.
5. What is the relation between overall magnification and pneumatic sensitivity in pneumatic comparators?
a) Independent of each other
b) Overall magnification is directly dependent on the square of pneumatic sensitivity
c) Overall magnification is inversely proportional to the pneumatic sensitivity
d) Overall magnification is directly dependent on the pneumatic sensitivity
Answer: d
Explanation: Overall magnification is the rate of change of linear movement of the pointer to the change in the dimension which produces it and represented as dR/dL. It is directly proportional to the pneumatic sensitivity.
6. Which of the following option is correct for velocity type pneumatic gauge?
a) Operate by sensing momentary rate of flow of air
b) Response speed is less than back pressure type
c) Low amplification
d) Filter is placed after pressure reducing unit
Answer: a
Explanation: It is operated by sensing momentary air flow rate. This flow can be sensed by a tapered glass tube which is mounted on a graduated scale. Inside this bore a float is present which is lifted by the air flow.
7. Which of the following statement is true for pneumatic gauges?
Statement 1: Can be used to check multiple dimensions.
Statement 2: A float is present inside the bore.
a) T, T
b) F, T
c) F, F
d) T, F
Answer: a
Explanation: It is best suited to check multiple dimensions in the least possible time. While measuring a bore it can reveal complete story of size, straightness, taper, bell mouth etc. It is independent of operator skill.
8. In Back pressure type pneumatic gauge, there are two orifices. What is the relationship between upstream pressure of first orifice and pressure between two orifices?
a) Depends upon the distance between two orifice
b) Depends upon relative size of orifice
c) Only on geometric area of first orifice
d) Distance between pressure source and first orifice
Answer: b
Explanation: Upstream pressure and pressure between both orifices, they both are measured with reference to atmospheric pressure. The relationship between both the pressures depends upon relative sizes of the two orifices.
9. After which frequency range, pneumatic measuring system is not correctly measured displacements?
a) 5 cycles/second
b) 4 cycles/second
c) 3 cycles/second
d) 2 cycles/second
Answer: d
Explanation: Pneumatic measuring system can’t measure displacements correctly after 2 cycles/second because its response spend is slow. Its response is slower than electrical systems. Response time of back pressure type can be improved by using filled system pressure gauge.
10. For which diameter range of parts pneumatic gauges can be used?
a) 50 to 500 mm
b) 0.5 to 900 mm
c) 50 to 700 mm
d) 100 to 600 mm
Answer: b
Explanation: Pneumatic gauge can be used for parts of diameter 0.5 mm to 900 mm having tolerance 0.05 mm or less. It can be easily used for on line measurement of parts.
11. Which of the following is measuring head sensitivity with the variation of diameter of measuring orifice?
a) πD
b) πDL
c) πDL 2
d) πD 2 L
Answer: a
Explanation: Measuring head sensitivity is represented by ‘dM/dL’. ‘M’ is the diameter of measuring orifice which is equal to πDL. By differentiating ‘M’w.r.t ‘L’ we get πD. Hence ‘dM/dL’ = πD.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Multicheck Comparators”.
1. Which of the following option is incorrect for multicheck comparators?
a) Economical procedure
b) Inspection of all dimensions at the same time
c) Used where all dimensions are independent with each other
d) These are used to save time of inspection
Answer: c
Explanation: Multicheck comparators are desired in those places where various dimensions have some relationship with each other for example concentricity and diameter measurement. It is an economical procedure.
2. How many electrical check heads are incorporated in electric multicheck?
a) 1
b) 2
c) 5
d) 20
Answer: d
Explanation: Electrical multi check comparator is a combination gauge. 20 or more electrical-check heads are incorporated in electrical multi check comparator to measure a number of dimensions simultaneously.
3. Which of the following is not a requirement for automatic gauging?
a) High speed interface
b) High power and low heat
c) Compact size
d) Validate with safety requirements
Answer: b
Explanation: Automatic gauging machines are very accurate machines. They eliminate manual inspection of parts. All dimensions of part are inspected simultaneously and segregated and classified automatically.
4. Which of the following is incorrect for electric multicheck?
a) High production rate
b) Less chances of error
c) Eliminate manual inspection
d) Increase accuracy
Answer: c
Explanation: The instrument is used in high production checking. To check a dimension a master signal light is used to integrate all individual lights. Inspector has to watch only one light. Instrument is used for all sizes of works.
5. How many measuring heads are present in electric check for each dimension?
a) 1
b) 2
c) 3
d) 4
Answer: a
Explanation: For each dimension, signal lights and one measuring head are used for each dimension which indicates whether It is with in the tolerance limit, oversized or undersized.
6. Which of the following statement is true for multi check gauging?
Statement 1: In air multichecks, it is difficult to set air comparators.
Statement 2: Mass inspection is possible in air multichecks.
a) T, F
b) F, T
c) F, F
d) T, T
Answer: b
Explanation: In air multicheck comparators, group of air comparators are used. It is difficult to set these comparators initially to check various dimensions and to arrange them in compact form. But once this set up is done, other things become very easy.
7. Which of the following comparator is most accurate for mass inspection?
a) Electric multicheck comparator
b) Air multicheck comparator
c) Air electric multicheck comparator
d) Automatic gauging machines
Answer: d
Explanation: Automatic gauging machines are most accurate among them. These are similar to multicheck devices and incorporate comparator amplifying methods. Less skilled operator is required as all the inspection is done automatically.
8. If an air electric multicheck comparator is used to check dimensions of shafts then which of the following option is correct?
a) Air comparators are used for checking concentricity only
b) Air comparators are used for checking concentricity and diameter
c) Electric multicheck is used to check diameter only
d) Electric multicheck is more convenient to check concentricity and diameter
Answer: b
Explanation: Both the air multicheck comparator and electric multicheck comparator are used in this type of comparator. It is convenient and easy to use air comparator to check diameter and concentricity and for other measurements, electric-checks are used.
This set of Engineering Metrology Questions and Answers for Experienced people focuses on “Interferometry Applied to Flatness Testing”.
1. Which of the following is the incorrect condition for a perfectly flat surface when tested for interferometry?
a) Monochromatic light is used
b) Viewing angle should be greater than 0 o
c) Optical flats are important in light wave measurement
d) For perfect flat surface alternate light and dark bands are observed
Answer: c
Explanation: Angle at which bands are viewed is called viewing angle. Viewing angle should be 0 o that is line of sight should be at 90 degrees to the reference surface of optical flats. As this angle increases it will cause error.
2. If the angle at which bands are viewed is 30o in flatness testing with interferometry, what is the possible error?
a) 0%
b) 15%
c) 30%
d) 45%
Answer: b
Explanation: If the viewing angle is 30 degrees then three fringes may be seen as 2.5 that is it will cause error of 15 %. If the viewing angle is 45 degrees then three fringes may be seen as 1.75 that is it will cause nearly 40% error.
3. What is the range of the diameter of optical flats?
a) 10 to 50 mm
b) 50 to 100 mm
c) 100 to 200 mm
d) 25 to 300 mm
Answer: d
Explanation: Optical flats are the circular pieces of optical glass with a high degree of finish on the working surfaces. Its two plane faces are flat and parallel to each other. Optical flats varies from the size of 25 to 300 mm.
4. In flatness testing with interferometry, if surfaces are perfectly wrung. Then which option is correct regarding fringe pattern?
a) No fringe pattern
b) Fringes are closer
c) Fringes are at great distance
d) Indistinguishable pattern
Answer: a
Explanation: If the surface between optical flat and work surface are perfectly wrung together then there will be no air gap between the surfaces and fringe pattern will be not observable.
5. Which of the following is true for quartz flats?
a) Have 200 to 400 % more wearing quality than optical flats
b) Have 10 % more wearing quality than optical flats
c) Have 10 % less wearing quality than optical flats
d) Have 200 to 400 % less wearing quality than optical flats
Answer: a
Explanation: Quartz flats have more wearing qualities than optical flats. It is 200 to 400 percent more than optical flats. Working surfaces are finished to a high optical degree of flatness.
6. Which of the following option is incorrect for flatness testing by interferometry?
a) For checking concave or convex surface optical flat is pressed lightly
b) If angle between optical flat and work surface reduces, then fringe spacing decreases
c) For perfectly flat surface condition of complete interference satisfies
d) Only one point contact between optical flat and surface is possible in some cases
Answer: b
Explanation: If ‘θ’ that is the angle between optical flat and work surface whose flatness to be measured reduces then the fringe space increases and if ‘θ’ increases then fringes brought more closer that is fringe spacing decreases.
7. If the angle between optical flat and surface to be tested is very small, then what is the difference of separation between optical flat and surface between two similar adjacent fringes?
a) λ
b) λ/2
c) λ/3
d) 3λ/2
Answer: b
Explanation: Change in separation between surface and optical flat between 2 adjacent and similar fringes is equal to = λ/2.
8. What is the pattern of fringes, if an optical flat is resting on any hill?
a) Central band dark
b) Concentric dark and light band fringes
c) Straight dark fringes
d) Central band may be light or black
Answer: b
Explanation: If surface has a large number of valleys and hills. Generally, optical flat makes contact with hills. Then it will just behave as if it was placed on the convex surface. There will be concentric bright and dark fringes with central bright fringe.
9. Which of the following option is correct for the given statements about interferometry applied to flatness testing?
Statement 1: If the angle between optical flat and surface is too large then there will be largely spaced fringe pattern is observed.
Statement 2: Quartz flats are very sensitive to heat.
a) T, T
b) F, T
c) T, F
d) F, F
Answer: d
Explanation: If ‘θ’ angle between optical flat and surface whose flatness to be measured is too large then fringes will be too closely placed as to be indistinguishable. Quartz have minimum expansion due to heat.
10. Which of the following option is true for optical flats used in flatness testing?
a) Type A optical flats has only one surface flat
b) Optical flats are better than quartz flats
c) White light source is very important in measurement by light wave interference
d) Working surfaces of optical flats are cylindrical
Answer: a
Explanation: Type A optical flats have only one flat surface. Working surface in such type of optical flats is indicated by an arrow head on the cylindrical surface. This arrow head is pointing towards the working surface.
11. To distinguish hill and valley one surface of optical flat is lightly pressed. Which of the following option is for the valley?
a) Number of fringes increases
b) Fringes move apart
c) Fringes brought closer
d) Centre of fringes is displaced
Answer: b
Explanation: In case of hill or convex surface, centre of fringes is displaced and fringe space decreases. But if by light pressure number of fringes decreased and fringes move apart it is a valley or concave surface.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Surface Contour Test”.
1. Which is the wavelength of a spectrum which is used in surface contour test?
a) 0.0005 mm
b) 0.005 mm
c) 0.05 mm
d) 0.5 mm
Answer: a
Explanation: Surface contour test is used to study surface contours and an optical flat is kept at some inclination over the surface. Generally, daylight is used for this test. Wavelength of the spectrum of daylight is 0.0005 mm.
2. How much change is the elevation of surface corresponds to the single fringe interval in surface contour test?
a) 0.0005 mm
b) 0.0025 mm
c) 0.025 mm
d) 0.05 mm
Answer: b
Explanation: In surface contour test, the change in elevation of surface corresponds to each fringe interval shows clearly the precision of this method. Value of this change in elevation is 0.0025 millimeter.
3. If any surface has a scratch on it and surface is tested by surface contour test then, what is the depth of scratch?
a) *
b) *
c) *
d) *
Answer: b
Explanation: Surface contour method is used for many purposes. It is possible to determine depth of the scratch, high and low spots or hills and valleys, and surface worn at the edges. These all can be determined by this method.
4. What is the method to find low and high spots?
a) Pressure by weight test
b) Volume test
c) Pressure test
d) Density test
Answer: c
Explanation: Two low or high spots can be checked by pressure test. If pressure is applied at a point and fringes move closure than the surface is valley. By applying pressure if fringes move apart then the surface is hill.
5. Which of the following option is true for given statements about surface contour test?
Statement 1: In a monochromatic light, bands are lighter near the point of contact.
Statement 2: To study surface contour it is important to know the point of contact with optical flat.
a) T, T
b) F, F
c) F, T
d) T, F
Answer: c
Explanation: For study, it is important to know where surface and optical flat are in contact. Point of contact is usually where a pressure is applied and air film is squeezed at this place.
Bands are sharper near the point of contact in monochromatic light.
6. Curvature of bands is more. What does this statement indicate when surface is tested under surface contour test?
a) More convexity
b) More concavity
c) Flat surface
d) More scratches
Answer: a
Explanation: The magnitude of concavity and convexity can be had by bands curvature. If the band curvature is more it shows more convexity and opposite to this indicates concavity. So we can have an idea of concavity or convexity by this.
7. Which of the following is not true for optical flats used in surface contour test?
a) Colourless
b) Always wrung on the work piece
c) Work piece and optical flat should be free from dust, dust and fingerprints
d) Optical flat should always be lifted from work piece
Answer: b
Explanation: Optical flats should never be wrung on surface to be measured because it scratches too readily. Optical flats should be rested on work piece carefully. It should be clean and free from dust.
8. What is the nature of the surface if curve bands around the line of contact when the surface is tested under surface contour test?
a) Convex surface
b) Concave surface
c) Flat surface
d) May be convex or concave
Answer: a
Explanation: If band curves around the line of contact or point then the given surface is convex but if the band curves opposite to the line of contact or point then the surface is a concave surface.
9. Given figure is a surface to be tested by surface contour test. How much lower or higher is B than Z in this given figure?
engineering-metrology-questions-answers-surface-contour-test-q9
a) λ/4
b) λ/2
c) 3λ/2
d) 3λ/4
Answer: b
Explanation: In the given figure, BYB is the contour. Y and Z are at the centre of two contours. The edge B is either higher or lower than Z by λ/2. The air gap will increase if we move away from X-X. BYB represents points at equal height, it means that B is higher than Z.
10. How much height intervals relative to optical flat is represented by a spacing of fringes?
a) λ/3
b) λ
c) λ/2
d) λ/6
Answer: c
Explanation: Contour of every fringe lies on points of equal height relative to the surface of optical flat. So, the fringe pattern viewed through optical flat will represent the contour map of the surface under test and spacing of fringes will represent height intervals relative to the optical flat of λ/2.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Optical Flats”.
1. How many types of optical flats are present?
a) 2
b) 1
c) 4
d) 3
Answer: a
Explanation: Optical flats are cylindrical in shape and generally have 2 types i.e Type A and Type B. Type A has only one surface flat. Working surface of Type-A is indicated by an arrow. Type B has both surface flat and parallel to each other.
2. Which of the following is used to make optical flats?
a) Toughened glass
b) Glass wool
c) Fused quartz
d) Porous glass
Answer: c
Explanation: Optical flats are generally made from fused quartz or borosilicate glass as they have the least coefficient of linear expansion. This glass is colourless and free from defects like bubbles, internal strains and extraneous matter.
3. What is the coefficient of linear expansion of fused quartz used to make optical flats?
a) 0.6 x 10 -6 / degree
b) 0.6 x 10 -5 / degree
c) 0.6 x 10 -4 / degree
d) 0.6 x 10 -3 / degree
Answer: a
Explanation: Fused quartz has 0.6 x 10⁻⁶/degree at standard temperature of 20 ° C. This low coefficient of linear expansion accounts for its remarkable ability to undergo large, rapid temperature changes without cracking. Borosilicate glass has coefficient of linear expansion not more than 3.6 x 10 -6 /degree.
4. To what degree the edges of optical flats are bevelled?
a) 30 o
b) 45 o
c) 60 o
d) 90 o
Answer: b
Explanation: Edges of optical flats are generally bevelled to 45 o by suitable grinding and polishing to make edges free from any chips. Working surfaces of optical flats are finished by polishing and lapping process and the cylindrical surfaces are finished by grinding.
5. Working surfaces of Type-B optical flats are inclined to each other at which angle?
a) 5 minute
b) 10 minute
c) 15 minute
d) 20 minute
Answer: a
Explanation: The inclination for measuring surfaces of each type of Type-B optical flat is 5 minutes. Optical flats are usually stored in the wooden box to avoid shocks, dust and moisture during storage and transportation.
6. What is the tolerance on flatness for Type-A optical flats of sizes up to 100 mm?
a) 0.05 cm
b) 0.05 µm
c) 0.05 mm
d) 0.05 m
Answer: b
Explanation: Tolerance on flatness for Type-A opticals flats is 0.05 µm for grade optical flats of size upto 100 mm only. But for the size between 101 mm to 200 mm the tolerance should be 0.10 µm. For grade II, it is 0.01 µm for size upto 100 mm and 0.20 for 101-200 mm.
7. Which of the following is not the dimension of optical flat Type A as per IS : 5440—1969 in mm ?
a) 25 x 10
b) 50 x 30
c) 30 x 10
d) 125 x 30
Answer: c
Explanation: As per IS : 5440-1969 , Optical flats of Type-A have dimensions 25 x 10, 30 x 10, 50 x 15, 75 x 20, 100 x 25, 125 x 30, 160 x 35 for both grade I and II.
8. What is the tolerance on thickness for Type-B opticals flats?
a) 0.05 µm
b) 0.15 µm
c) 0.20 µm
d) 0.30 µm
Answer: c
Explanation: Tolerance on flatness, parallelism and thickness for type-B optical flats is 0.05 µm, 0.15 µm and 0.20 µm respectively for grade I and 0.10 µm, 0.20 µm and 0.30 µm for grade II respectively.
9. Which of the following statement is true for optical flats?
Statement 1: Type-A optical flats are tested for parallelism of working surfaces.
Statement 2: Flatness of working surface is tested by comparing with a master flat.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: Type-A optical flats are used are used to test flatness of working faces and Type-B flats are used to test parallelism of working faces, flatness of working faces and also thickness.
10. Which of the following is the method to test parallelism in Type-B optical flats?
a) Hawking interferometer
b) Enrico interferometer
c) Fizeau interferometer
d) Stephan interferometer
Answer: c
Explanation: Fizeau interferometer is used to test parallelism in optical flats. In this test a light from mercury vapour lamp is focused on eye-piece. Beam splitter is used to reflect the beam which strikes the collimating lens. It collimates the beam and throw it on the surface under test.
11. Type-B optical flat is tested for parallelism. What is the formula for the difference of the thickness of the flat at 2 points on the adjacent fringe? µ
a) λ/2*µ microns
b) λ/4*µ microns
c) λ*µ microns
d) λ*µ microns
Answer: a
Explanation: λ/2*µ microns, this is the formula for the difference of the thickness of the flat at two points on the adjacent fringes. This is obtained by Fizeau interferometer test. This gives the optical parallelism. This parallelism is also represented as geometrical parallelism as flat is made of material of uniform refractive index.
12. Which of the following is the dimension for Type-B optical flats?
a) 25.0 x 12.000 mm
b) 25.0 x 23.000 mm
c) 26.0 x 24.000 mm
d) 26.0 x 24.250 mm
Answer: a
Explanation: Type-B optical flats have dimensions 25.0 x 12.000, 25.0 x 12.125, 25.0 x 24.250, 25.0 x 12.375, 25.0 x 24.000,25.0 x 24.125, 25.0 x 24.250 and 25.0 x 24.375 respectively.
13. Which of the following is the use of Type-A optical flats?
a) Testing parallelism of measuring devices
b) Testing parallelism of measuring anvils
c) Testing micrometer measuring surfaces
d) Testing the flatness of measuring table
Answer: d
Explanation: Type-A optical flats are used to test the flatness of slip gauges, measuring tables, precision measuring surfaces of flats. Type-B are used to test flatness and parallelism of measuring surfaces of anvils. Micrometer etc.
14. Which of the following is of more important in case of Type-B optical flat?
a) Thickness
b) Diameter
c) Length
d) Area
Answer: a
Explanation: For optical flats of Type-A, grades and optical flats are important that means it is usually designated by these two and for Type-B, thickness and grades are important, therefore it is designated by these two.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Scales and Gratings”.
1. What is the range of line spacings in gratings?
a) 4 to 200 per mm
b) 200 to 400 per mm
c) 10 to 500 per mm
d) 500 to 600 per mm
Answer: a
Explanation: Gratings plays an important role in rotary as well as linear measurements. Gratings have line spacing from 4 per mm to 200 per mm in lengths up 4 meters or so. These are usually employed with photoelectric readouts.
2. What is the alternate name of amplitude grating?
a) Ronchi ruling
b) Prismatic grating
c) Phase grating
d) Index grating
Answer: a
Explanation: Grating which has plane lines is called amplitude grating or Ronchi grating. It is a constant interval bar with equal line and space pattern. These are generally used for optical testing purposes and metrology applications.
3. Which of the following option is true for scales and gratings?
a) Ruling in scales are closely spaced
b) Ruling in gratings is far apart
c) Vernier device is required with scales
d) Ruling in scale forms a periodic pattern
Answer: c
Explanation: Scales have lines marked on them that is rulings. Scales are usually made of steel. Lines in scales are spaced far apart so that interpolating devices e.g. vernier device are used to make accurate settings.
4. What is the length of Prismatic grating?
a) 500 mm
b) 400 mm
c) 300 mm
d) 200 mm
Answer: d
Explanation: Prismatic grating is also known as phase grating. Prismatic grating contains triangularly shaped and contiguous grooves. Prismatic grating has 100 to 200 grooves and its length is limited to 200 mm.
5. Which of the following option is true for the given statements?
Statement 1: Stainless steel has a high thermal coefficient of expansion than cast iron hence used to make scales.
Statement 2: Most of the scales are produced by duplicating from master scale.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: stainless steel is used for making metal scales. It is stable with time if properly heated, have good finish, resistant to tarnishing but its coefficient of thermal expansion is less than the cast iron and steel.
6. Which type of visual scale line setting against an index is widely used in sophisticated machines?
a) Simple superposition type
b) Alignment of vernier setting
c) Symmetrical forming between two index marks
d) Asymmetrical forming between index marks
Answer: c
Explanation: Index mark is utilized by all scale readouts, with reference to which reading of scale is noted. Symmetrical forming between two index marks is the type which is mostly used in sophisticated machines due to high setting precision.
7. For how much travel length, metal reflecting gratings are used?
a) 600 mm
b) 900 mm
c) 1700 mm
d) Greater than 1800 mm
Answer: d
Explanation: Three types of gratings are commonly used in more fringe system gratings. Phase transmission grating, Metal reflecting grating and line and space transmission grating. Metal reflecting grating is used for travel length more than 1800 mm.
8. What is the condition to obtain fringes of high intensity?
a) Distance between scale and index grating is as far as possible
b) Distance between scale and index grating is minimum
c) Scale and index grating should be overlapped
d) Scale and index grating should be at the right angle
Answer: b
Explanation: Fringes of high intensity means good contrast. It is the essential condition for obtaining good electrical signals. It can be obtained only when the distance between the scale and index grating is minimum.
9. Which of the following is not true for glass scales?
a) Graduations can be produced by depositing material
b) Easily polished
c) Able to work in case of reflected light but not in transmitting light
d) Ordinary glass has 15-30% less thermal coefficient of expansion than steel
Answer: c
Explanation: Glass scales are stable, and are able to work in both transmitting and reflected light. Graduation on these scales can be produced by etching through ruled wax, by depositing material in the form of thin lines and by depositing photographic emulsions.
10. For bi-directional fringe counting, how many detectors are placed for better balance?
a) 3
b) 4
c) 5
d) 6
Answer: b
Explanation: For bi-directional fringe counting, better balance is obtained when four detectors are placed at 0, 90, 180, 270 phase degree of fringe in which counting intervals of one-quarter of the scale interval are provided.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Straightness”.
1. Who gave the fundamental principle of straightness measurement?
a) Bryan
b) Moire
c) Euler
d) Amedeo
Answer: a
Explanation: Fundamental principle of measurement of straightness is given by Bryan. According to this principle, “A straightness measurement system should be in line with the point at which it is to be measured”.
2. Which of the following represents the quality of straightness in precision engineering?
a) Spirit level
b) Straight edge
c) Autocollimator
d) Dial indicator
Answer: b
Explanation: At many places, it is necessary that the surface must be straight e.g. in lathe machine it is required that the tool must move in straight path. Straight line is the basis of most methods of measurements.
3. What is the tolerance of the straightness of a line?
a) Maximum deviation from the straight line joining two extremities
b) Maximum deviation from the middle point of straight line joining two extremities
c) Minimum deviation from the straight line joining two extremities
d) Minimum deviation from the middle point of straight line joining two extremities
Answer: a
Explanation: The tolerance on the straightness of a line can be defined as the maximum deviation in
relation to the reference straight line joining the two extremities of the line to be checked. Tolerance is used to confirm that a part is uniform over a surface. More straightness is present with less tolerance.
4. For checking straightness, straight edge is placed over a surface and these two are viewed against the light. Which of the following option true if colour of light is red?
a) Gap between 0.12 to 0.17 mm
b) Gap between 0.2 to 0.7 mm
c) Gap between 1.7 to 2 mm
d) Gap between 0.0012 to 0.0017 mm
Answer: d
Explanation: Straight edge and surface are viewed against the light. The gap between surface and straight edge should be negligible small for perfect straight surfaces and the measurement of straightness is observed by seeing the colour of light produced due to interference caused by diffraction of light.
5. What is the name of a pair of straight edges?
a) Drum sticks
b) Lower pair
c) Winding sticks
d) Self closed pair
Answer: c
Explanation: Straight edge is a measuring tool consist of a steel and is used to check the straightness. Straight edges are used in machining industry and automotive service. Winding stick is a pair of straight edges which are used in woodwork.
6. What is the position of straightness interferometer in straightness measurement optics?
a) Before laser head
b) After straightness reflector
c) Between laser head and straightness reflector
d) No need of interferometer
Answer: c
Explanation: Straightness interferometer is placed between laser head and reflector. Beam from the laser passes through the interferometer which splits it into two beams which diverge at an angle and are directed to the reflector. The beams are then reflected from the reflector and return to the interferometer along a new path.
7. What is the range of straightness measurement in straightness measurement optics?
a) ±2.5 mm
b) ±5 mm
c) ±10 mm
d) ±20 mm
Answer: a
Explanation: To measure straightness errors in a linear axis, straightness measurement optics are used. For both short range and long range measurement, length of straightness measurement is ±2.5 mm.
8. Which of the following is not the factor affecting the accuracy of straightness measurement by optics?
a) Air turbulence
b) Optics fixed rigidly
c) Slope error
d) Localised heat sources
Answer: b
Explanation: Factors affecting the accuracy of straightness measurement by optics are Air turbulence, Mechanical vibrations, Optic errors, Slope errors, Optics not fixed in the correct position, Optics not fixed rigidly, Localised heat sources etc.
9. At which part of the precision straight edge is generally lapped?
a) Edges only
b) Base only
c) Base and edges both
d) All over the surface
Answer: a
Explanation: Straight edges are extremely useful for setting up machines such as planers. Precision straight edges are hardened and lapped on the edges by a small radius, which makes a blunt knife edge straight to a few thousands of an mm.
This set of Engineering Metrology Interview Questions and Answers for Experienced people focuses on “Test for Straightness by using Spirit Level and Autocollimator”.
1. How the straightness of any surface can be determined with the help of spirit level?
a) By finding relative angular positions at extreme sections of the surface
b) By finding relative linear distance at middle of the surface
c) By finding relative angular positions at adjacent section
d) By finding relative angular positions at any point
Answer: c
Explanation: In case of the spirit level, the angular variations are measured by the sensitive level on it which gives the difference of height between two points by knowing the spirit level’s least count.
2. At what distance instrument is placed when straightness is determined with the help of autocollimator?
a) 0.5 to 0.75 mm
b) 0.5 to 0.75 cm
c) 0.5 to 0.75 m
d) 0.5 to 0.75 µm
Answer: c
Explanation: In determining the straightness with the help of autocollimator instrument is placed at a distance of 0.5-0.75 m on any rigid support and it is completely independent of the surface to be tested.
3. For testing straightness with the help of spirit level, what is the length of each surface section?
a) Equal to spirit level base length
b) Greater than spirit level base length
c) Less than spirit level base length
d) Doesn’t depend upon spirit base length
Answer: a
Explanation: For determining straightness, a straight line is drawn on the surface. It is divided into sections, the length of individual section is equal to the length of the base of spirit level or the base of a reflector in case of autocollimator.
4. For which surfaces, spirit level is used for testing straightness?
a) Both horizontal and vertical surfaces
b) Vertical surfaces
c) In any plane
d) Horizontal surfaces
Answer: d
Explanation: In testing straightness, spirit level is used only for the horizontal surfaces while autocollimator can be used in any plane. In the case of spirit level, angular variations are measured by placing level on it.
5. Which of the following option is true for autocollimators?
Statement 1: Electronic autocollimator has more resolution than visual autocollimator.
Statement 2: Observations are taken using precision level.
a) F, F
b) F, T
c) T, T
d) T, F
Answer: c
Explanation: Electronic autocollimator has 100 times more resolution than visual autocollimator. Visual autocollimator can measure small angles like 0.5 arc minute. Electronic autocollimator can be used for stable platform applications.
6. 1 sec of arc will correspond to how much rise or fall in surface, when surface straightness is tested by autocollimator?
a) 0.000006λ
b) 0.00006λ
c) 0.00006λ
d) 0.0006λ
Answer: a
Explanation: In this method, reading of tilt of the reflector is taken in seconds from the eyepiece. 1 second of arc is 0.000006 mm/mm. It also depends upon the distance between feel centres in millimeter.
7. Which of the following is not true for autocollimator?
a) Contact measurement
b) Use for small tilts
c) High sensitivity
d) Used to determine parallelism
Answer: a
Explanation: Autocollimator is used in many applications like in shop floors and metrology labs. Used for precision measurement of parallelism, straightness, flatness, perpendicularity etc. It is a not-contact optical instrument.
8. Which of the following method is used for the mathematical treatment of determination of straightness with the help of autocollimator?
a) Taylor’s principle
b) Least square method
c) Bryan method
d) Average method
Answer: b
Explanation: According to the least square method, ‘sum of the deviations of the points from the best line is zero and the sum of square of deviations from the best line is minimum’. First the best line is determined and then applies to this method.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Flatness Testing”.
1. For checking the flatness, which of the following is used to mark the surface?
a) Scriber
b) Prussian blue
c) Alcohol
d) Ruler
Answer: b
Explanation: Prussian Blue is used to mark the surface. When rubbed against another flat surface, the distribution of color on the other surface gives a rough idea of flatness of the surface.
2. Determination of flatness using Prussian blue is used for which kind of surfaces?
a) Small surfaces
b) Large surfaces
c) Both large and small surfaces
d) For surfaces with fine smoothness
Answer: a
Explanation: This method is suitable for small surfaces rather than large surface. This method is assumptious and may give more errors in determination of flatness in large surfaces.
3. As per IS: 2063-1962, which surface is considered as a flat surface?
a) When variation of perpendicular distance from geometrical reference plane remains above a given point
b) When variation of diagonal distance from geometrical reference plane remains below a given point
c) When variation of perpendicular distance from geometrical reference plane remains below a given point
d) When variation of sides distance from geometrical reference plane remains above a given point
Answer: c
Explanation: As per IS: 2063-1962, a surface is considered flat when the variation of perpendicular distance from geometrical reference plane parallel to the general trajectory same as the surface to be tested remains below a given point. The reference plane can be represented by means of surface plane or family of straight lines.
4. When the flatness is measured with the use of optical flats, at what distance bands should be viewed?
a) Distance 10 times the diameter of optical flats
b) Distance 5 times the diameter of optical flats
c) Distance 8 times the diameter of optical flats
d) Distance 2 times the diameter of optical flats
Answer: a
Explanation: The bands are viewed from a distance at least 10 times the optical flat diameter and with the line of vision are perpendicular to the flat. If the bands observed are parallel, straight and evenly spaced, the surface is flat otherwise not.
5. Which of the following method is used for the determination of flatness when the surface is irregular?
a) Half grid method
b) Grid method
c) Contact method
d) Non contact method
Answer: c
Explanation: When the surface is irregular, contact method of testing for flatness is used. In the contact method there is a most intimate possible contact between flat and work piece and there will be attempt to maintain a wedge.
6. Which of the following option is true for given statements for flatness testing?
Statement 1: Straight edges can be used to check flatness.
Statement 2: Single ended straight edge can be used to determine flatness of the surface.
a) T, T
b) F, F
c) T, F
d) F, T
Answer: a
Explanation: Straight edges can be used to test flatness and straightness of the surfaces. Single-edged straight edge can be used to determine flatness by applying it at different places in different directions on the tested surface.
7. Which of the following option is not true for flatness testing?
a) Geometrical plane can be represented by a family of straight lines
b) Flatness can be tested by grid and half grid method
c) Three and four edge type straight edge cannot be used for this purpose
d) Geometrical plane can be represented by a surface plane
Answer: c
Explanation: Three and four edges straight edges can be used to test flatness by applying prussian blue on the working edges and then drawing the straight edge across the surface.
8. What are the requirements for the measurement of flatness using light?
a) Monochromatic light and a pair of optical flats
b) Dichromatic light and sets of optical flats
c) White light and a pair of optical flats
d) Monochromatic light and sets of optical flats
Answer: d
Explanation: Monochromatic light and sets of optical flats are required for measurement of flatness using light. Monochromatic light is used to get none overlapping, clear interference pattern.
9. What is flatness error?
a) Maximum separation of a pair of parallel planes which will contain all points on the surface
b) Minimum separation of a pair of parallel planes which will contain all points on the surface
c) Minimum separation of a pair of perpendicular planes which will contain all points on the surface
d) Maximum separation of a pair of perpendicular planes which will contain all points on the surface
Answer: b
Explanation: Flatness error can be defined as the minimum separation of a pair of parallel planes which will contain all points on the surface. Deviations of large surfaces from true plane are determined by using autocollimator and spirit level.
10. Which of the following is true for testing flatness with optical flats?
a) Too large angle of work with flat is desirable
b) Number of bands appears is an indication of flatness
c) Bands are viewed as perpendicularly as possible
d) Quartz flats are very sensitive to temperature changes
Answer: c
Explanation: Due to very great angle between work and flats, bands will be close together and are nearly invisible. Number of bands appear is not an indication of the surface flatness but relates only to the wedge steepness.
11. What is the range of the diameter of optical flats used in testing the flatness?
a) 25mm to 300mm
b) 1mm to 100mm
c) 50mm to 500mm
d) 1mm to 10mm
Answer: a
Explanation: Size of optical flats used varies from 25mm to 300mm diameter. The range is selected to get a proper interference pattern using light.
This set of Advanced Engineering Metrology Questions and Answers focuses on “Parallelism, Equidistance and Coincidence”.
1. Which of the following is true for testing parallelism between two trajectories?
a) Dial indicator is attached on a fixed machine component
b) Moving parts are moving in different directions in testing the parallelism
c) The two parts are moved by the same amount
d) Parts are moving together
Answer: c
Explanation: The dial indicator is attached to one of the moving machine components and its feeler rests against a specified point on the other moving part. The two parts are moved together by the same amount in the same direction and the variations in the reading are noted.
2. Which of the following is true for coincidence between two axes?
a) Light weight dial indicator is used
b) Direction of measurement doesn’t varies
c) There is no effect of gravity force
d) Mandrel is used to represent the plane
Answer: a
Explanation: Light weight dial indicator is used in this test. The direction of the measurement varies during rotation in relation to the gravity direction. The sensitivity of the apparatus to the gravity force is taken into account.
3. Which of the following is true to check parallelism between two straight lines formed by the intersection of two planes?
a) V-blocks are used for large distance between two lines
b) No need of V-blocks
c) If there is a small distance between straight lines then use of V-blocks is the most necessary
d) It can be checked only by a straight edge
Answer: a
Explanation: If the distance between two lines is not small or large then the V-blocks are used. V- blocks are covered by a straight edge is used. Check for this is made by spirit level. For small distance there is no need of these.
4. What is the tolerance of parallelism of straight lines?
a) 0.015 on 300 mm
b) 0.15 on 300 mm
c) 0.015 on 600 mm
d) 0.15 on 600 mm
Answer: a
Explanation: Permissible deviations or tolerance of parallelism of two plane surfaces or straight lines is 0.015 mm on 300 mm. Free end of the spindle relative to the table surface is in upward direction only.
5. Which of the following is not true for coincidence?
a) Two axes merged in each other
b) Coincidence and perpendicularity are same
c) One axis extends beyond the other
d) Sometimes coincidence is used with is used with more general meaning of parallelism
Answer: b
Explanation: Two lines or axes are said in alignment or coincident when their distance apart at several points is measured over a specified length and this distance doesn’t exceed a specified value. The measured distance may be located either on the actual lines or on their prolongation.
6. Which of the following is true for measurement of equidistance?
a) Related to distance between two axes
b) Related to distance between two planes
c) Related to distance between reference plane and the axes
d) There is no relation with axes and planes
Answer: c
Explanation: When plane passing through the axes is parallel to the reference plane then there is an equidistance. It is related to the distance between reference plane and the axes. It may be different axes, or the same axis.
7. Test for parallelism of 2 planes is carried out in two different directions. What is correct for these directions?
a) Parallel to each other
b) Perpendicular to each other
c) At 45 degree to each other
d) At 60 degree to each other
Answer: b
Explanation: Two planes are parallel when the difference between the maximum and minimum dimension obtained that is maximum error over a given length does not exceed a specified value. The test is carried out in two directions which are perpendicular to each other.
8. Which of the following is not true for mandrel?
a) It represent the axis of rotation of spindle
b) Mandrel is always centred
c) Axis of rotation of mandrel may be hyperboloid
d) Axis of rotation of mandrel may be conical
Answer: b
Explanation: When a mandrel has represented the axis of rotation of spindle etc. It is not necessary that mandrel have been exactly centred and under such conditions the axis of the rotation of mandrel may describe a conical or hyperboloid.
9. Which of the following option is correct for given statements about parallelism?
Statement 1: A dial indicator is used to test parallelism of two planes.
Statement 2: Parallelism defines the distance between two surfaces that are parallel to each other and the datum surface.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: d
Explanation: To test the parallelism, dial indicator can be used. The dial indicator is held on a support with base or flat base and is moved in one plane over a specified length, and the feeler is made to rest against the 2nd plane and the deviations are noted down.
10. How many minimum sides to be measured of a cylinder to test parallelism?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: Parallelism can be defined as the tolerance which controls the parallelism between two features. It is possible to find the parallelism of the cylinder by measuring the two sides of a cylinder.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Vernier and Optical Bevel Protractor”.
1. What is the range of bevel protractor?
a) 0-90°
b) 0-180°
c) 0-360°
d) 90-270°
Answer: c
Explanation: Bevel protractor is the simplest instrument for measuring angles. It measures an angle between two faces of a component. It is used to test angle for very close tolerances. The range of bevel protractor is 0-360°.
2. Where will be the vernier scale is present?
a) Base plate
b) Circular plate
c) Adjustable plate
d) Main body
Answer: b
Explanation: It has a base plate which is attached to the main body. Circular plate contains vernier scale. It contains 24 divisions coinciding with 23 main scale divisions. One full rotation of adjustable blade increase one division in main scale.
3. What is the least count of vernier bevel protractor?
a) 10’
b) 5’’
c) 5’
d) 10’’
Answer: c
Explanation: The least count of bevel protractor is 5’. It is commonly used for angular measurements where more precision is required like for angular measurement in workshops. Optical bevel protractors are the recent development of vernier bevel protractors.
4. Which of the following is correct about the adjustable blade?
a) Adjustable blade is attached to main body
b) Adjustable blade is capable of rotating freely about the centre
c) Adjustable blade is capable of rotating freely about the free edge
d) Adjustable blade is attached to base plate
Answer: b
Explanation: Adjustable blade is attached to the circular plate. It is capable of rotating freely about the centre of the main scale. Main scale is engraved on the main body of the instrument. It can be locked in any position.
5. Upto which value optical bevel protractor can take the readings?
a) 10’
b) 5’
c) 2’
d) 15’
Answer: c
Explanation: Circular graduations can be viewed by a small microscope which is fitted on it. It is possible to read by estimation to about 2 minutes of arc with the help of microscope in optical bevel protractor.
6. Which of the following are the types of mechanical bevel protractor?
a) A, B only
b) A, B, C and D only
c) A, B, C, D and E only
d) A, B and C only
Answer: b
Explanation: There are four types of mechanical bevel protractors i.e. A, B, C, and D. The vernier can read to 5 minutes of arc in A and B type of mechanical bevel protractor whereas in case of type C, the scale can be read in degrees.
7. What is the difference between type A and type B?
a) Least count is 5’ in type A and 10’ in type B
b) Type A is provided with fine adjustment device whereas type B is not
c) Type B is provided with fine adjustment device whereas type A is not
d) The vernier scale is different in both types
Answer: b
Explanation: The difference between type A and Type B is that type A has a fine adjustment device or acute angle attachment whereas type B is not. The scales of all the types of mechanical bevel protractor are graduated either as semicircle marked 0—90—0 with two verniers 180° apart or as a full circle.
8. What are the dimensions of working edge of stock ?
a) 90mm*7mm
b) 100mm*10mm
c) 7mm*90mm
d) 90mm*10mm
Answer: a
Explanation: The working edge of the stock is about 90 mm long and 7 mm in thickness. It is essential that it’s working edge should be perfectly straight and in case departure is there, it should be in the form of concavity.
9. Which of the following is a general dimension of blade?
a) 250mm*3mm
b) 100mm*2mm
c) 150mm*3mm
d) 150mm*2mm
Answer: c
Explanation: It is about 150 or 300 mm in length, 3 mm wide. It is 2 mm in thickness. Its ends are bevelled at angles of 45 degrees and 60 degrees within the accuracy of 5 minutes of arc.
10. What is the parallel limit of blade of optical bevel protractor?
a) 0.003mm
b) 0.02mm
c) 0.002mm
d) 0.03mm
Answer: d
Explanation: Blade is moved along the turret. Working edge of blade should be parallel upto 0.03 mm and straight up to 0.02 mm and over the entire length of 300 mm. Blade can be clamped in any position.
11. What is the flatness tolerance of acute angle attachment?
a) 0.005mm
b) 0.0005mm
c) 0.5mm
d) 0.00005mm
Answer: a
Explanation: Acute angle attachment can be fitted into the body. It can be clamped in any position. Working edge of acute angle attachment should be parallel to the working edge of the stock within 0.015 mm and flat to within 0.005 mm over the entire length of attachment.
12. Which of the following is not true for type D mechanical bevel protractor?
a) It is not provided with vernier
b) Graduated in degrees
c) Have a fine adjustment device
d) Doesn’t have acute angle attachment
Answer: c
Explanation: Type D mechanical bevel protractor is read in degrees. It is not provided with acute angle attachment. It doesn’t contain a vernier or fine adjustment device.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Sine Principle and Sine Bars”.
1. Up to which angle sine bars can measure the angles?
a) 45 degree
b) 60 degree
c) 90 degree
d) 120 degree
Answer: a
Explanation: The sine bars become impractical and inaccurate as the angle exceeds 45° because the bar is physically clumsy to hold in that position and even a slight error of the sine bar can cause large angular errors after this angle.
2. What is the permissible tolerance on flatness of side faces of sine bars of 100 mm as per IS 5359-1969?
a) 0.001 mm
b) 0.005 mm
c) 0.01 mm
d) 0.05 mm
Answer: b
Explanation: As per IS 5359-1969, the flatness of side faces of sine bars of size 100 mm is 0.005 mm and the tolerances of squareness for side faces to upper face and parallelism of side faces to the roller axes are 0.003/25 mm and 0.01/25 mm respectively.
3. Which of the following is not used in making of sine bars?
a) High carbon
b) High chromium
c) Corrosion resistant steel
d) Aluminium
Answer: d
Explanation: Sine bars are used to measure angles accurately or locating any work to a specified angle within a close limit. Sine bars are made from high chromium, high carbon, corrosion resistant steel, ground, hardened and stabilised.
4. Which of the distance of the axes of two cylinders of sine bar?
a) 20 inches
b) 50 inches
c) 5 inches
d) 25 inches
Answer: c
Explanation: In British system, the distance between the axes of the two cylinders is 10 or 5 inches, and in metric system the distance between axes of cylinders is 100, 200 and 300 millimeter.
5. Which of the following is incorrect regarding sine bars?
a) Sine bar is itself a complete measuring instrument
b) Some holes are drilled in the body
c) It can be used to locate any work to a given angle
d) It is capable of self generation
Answer: a
Explanation: The sine bar is itself not a complete instrument or complete measuring instrument. Another datum like surface plates are needed. Some holes are drilled in the bar body. It is to facilitate handling and reduce weight.
6. What are the characteristics permissible tolerance flatness of upper and lower surface of 100mm sine bar I.S. 5359—1969?
a) 0.001mm
b) 0.01mm
c) 0.005mm
d) 0.05mm
Answer: a
Explanation: The permissible tolerance of flatness of upper and lower surfaces of sine bars is 0.001 mm and the tolerance for parallelism of upper and lower surfaces with respect to datum surface is also 0.001 mm.
7. Which of the following is true for the given statements about sine bars?
Statement 1: Grade A sine bars are less accurate than grade B.
Statement 2: Grade B sine bars are accurate up to 0.01 mm/m of length.
a) T, F
b) T, T
c) F, T
d) F, F
Answer: d
Explanation: Sine bars are graded as of A or B grade depending upon the accuracy of the centre distance. B grade of sine bars are accurate up to 0.02 mm per m of length but B grade is less accurate than A grade. A grade sine bars are accurate up to 0.01 mm per m of length.
8. What is the parallelism tolerance of end faces of axes of rollers in sine bar according to British Standards?
a) 0.013mm per 50mm
b) 0.01mm per 25mm
c) 0.013mm per 25mm
d) 0.13mm per 25mm
Answer: c
Explanation: According to British standard, parallelism tolerance of end faces to the axis of the hinge roller is within 0.013 mm/ 25 mm and the accuracy of distance between rollers axes is 0.0025, 0.005 and 0.008 mm for 100 mm, 200 mm and 300 mm bars.
9. What is sine centre?
a) Centre of sine bar
b) Sine bar with block holding centres
c) Sine bar with hole in centre
d) Sine bar with hollow rod in centre
Answer: b
Explanation: A sine bar with block holding centres is known as sine centre. It can be rigidly clamped and adjusted in any position. Sine centres can be used for inspection of the conical objects between centres.
10. As per IS 5359-1969, what is the permissible tolerance on mean diameter of the rollers in 100mm sine bars?
a) 0.005 mm
b) 0.001 mm
c) 0.002 mm
d) 0.01 mm
Answer: c
Explanation: As per IS 5359-1969, the permissible tolerances for mean diameters of rollers and distance between roller axes are 0.002 mm and ±0.03 mm respectively for sine bars of size 100 mm.
11. Which of the following is true for sine table?
a) Sine table is most convenient for the light workpieces
b) Procedure of setting angle is not same as sine bars
c) Table may be safely swung from 0 to 90 degrees
d) Error caused by clamping mechanism is very large
Answer: c
Explanation: Sine table is the development of the sine bar. It is the most accurate and convenient design for heavy workpieces. The principle of setting sine table at any angle is same as for sine bars.
12. Upto which inclination sine centres can be used?
a) 45 degree
b) 90 degree
c) 120 degree
d) 60 degree
Answer: d
Explanation: These are used up to 60 degree angle. Rollers are clamped firmly to the body. Sine centre is a very useful device for testing the conical work centered. The principle of setting sine centre is same as of sine table.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Rotary Tables”.
1. Which of the following is used in mechanical type rotary tables?
a) Bevel gear
b) Spur gear
c) Worm and gear
d) Pinion gear
Answer: c
Explanation: Mechanical rotary table which is cam compensated employs worm and gear as the angle measuring element but cam-compensation of gear error established the final accuracy of this type of rotary table.
2. What is the principle on which precision index table works?
a) Circle divider
b) Taylor’s principle
c) Principle of least square
d) Interference principle
Answer: a
Explanation: Rotary tables are the best-known and widely used circle dividing instrument. Precision index table is a type of rotary table. It is a serrated tooth table which is based on the principle of circular divider.
3. How many teeths are present in the serrated divider in precision index table?
a) 360
b) 720
c) 1000
d) 500
Answer: a
Explanation: The indexing in precision index table corresponds to the number of teeth through which the table is indexed. The serrated divider is limited to 360 teeth. Serrated teeth indexer has been developed in 0.25° increment with accuracy of ± 0.1 second of arc.
4. By which curve, the small increments of angles are achieved in averaging type optical rotary machines?
a) Tan curve
b) Cos curve
c) Sine curve
d) Cot curve
Answer: c
Explanation: Smaller increments of angle are achieved by the sine curve which is generated by electronic or optical pulsing in the averaging type optical rotary table. The circular scale could be read by electrical or by Moire fringe method.
5. How the final unresolved error can be overcome in a mechanical cam compensated rotary table?
a) By the perfection of gear
b) By compensation
c) There is no unresolved final error
d) Perfection of gear is the better in this case than compensation
Answer: b
Explanation: In mechanical cam-compensated type rotary table, accuracy depends upon the accuracy of the worm and gear. Compensation is used to overcome the final unresolved error, rather than perfection of the gear.
6. How many face gears are used by precision index table?
a) 5
b) 4
c) 3
d) 2
Answer: d
Explanation: Precision index table uses two face gears. Both the gears have serrated teeth. Both gears are same in diameter, shape and number of teeth. When both face gears are brought into contact root to crest, then lock together and prevent rotation.
7. Which of the following is not true for the periodic error in worm and gear rotary table?
a) It can be affected by tooth spacing of the gear
b) This error is not taken into consideration
c) It can be affected by the thread form
d) It is the error within two turn of the hand wheel
Answer: d
Explanation: The periodic error is the error within one turn of the hand wheel. It is not taken into consideration. This error is affected by factors like the thread form and tooth form, drunkenness, line up, runout of worm, errors of eccentricity, and spacing of tooth of the gear.
8. What is the effect of lack of true spindle rotation in accurate worm and gear rotary table?
a) Angular error
b) Centre distance error
c) Both angular and centre distance error
d) Decrease repeatability
Answer: c
Explanation: Lack of true spindle rotation in accurate worm and gear rotary table results in both angular error and centre distance error. Rotary table has the advantage of trouble free operation and good repeatability.
9. Which of the following option is true about rotary tables?
Statement 1: Index is not used with optical rotary table.
Statement 2: Accurate worm and gear rotary table can be used with an index plate.
a) T, T
b) T, F
c) F, T
d) F, F
Answer: a
Explanation: It can be used with an index plate to divide the circle, without the loss of accuracy and necessity of reading angle. Optical rotary table cannot use index, because it’s worm and gear is not accurate.
10. Which of the following is true for accurate worm and gear rotary tables?
a) Bidirectional approach is used for setting
b) Can be used for inspection of angles
c) Can’t be used for generation of angles
d) Worm and gear are highly accurate
Answer: b
Explanation: A unidirectional approach is used in accurate worm and gear type table for setting to take care of unavoidable presence of backlash. The accurate worm and gear has an advantage for the inspection and generation of angles.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Clinometers”.
1. At which part spirit level is present in the clinometers?
a) On a rotary member
b) On the fixed member
c) On the base
d) On the circular scale
Answer: a
Explanation: A special case of the application of spirit level is a clinometer. The spirit level is mounted on a rotary member present in the clinometer carried in housing. One face of the housing forms the base of the clinometer.
2. At which interval, circular glass is divided in Hilger and Watts type clinometers?
a) 3’
b) 5’
c) 10’
d) 2’
Answer: c
Explanation: Hilger and Watts type is the most commonly used clinometer. The circular glass scale is enclosed. It is divided from 0 degree to 360 degree at 10′ intervals. An optical micrometer can be used for the subdivision of 10′.
3. Which of the following is not a common function of clinometers?
a) Determine included angle of two adjacent faces
b) Checking angular faces
c) Checking relief angles on small cutting tools
d) Setting inclination table
Answer: c
Explanation: Clinometers can be used for checking relief angles on large cutting tools, for checking angular faces and milling cutter inserts. These can also be used on jig boring machines for setting inclination table and on grinding machines for angular work.
4. What is the range of readings which can be read directly in precision microptic clinometer?
a) 0 o to 180 o
b) 0 o to 270 o
c) 0 o to 90 o
d) 0 o to 360 o
Answer: d
Explanation: Precision microptic clinometer can be used for direct reading over the range 0° – 360°. Special feature of precision microptic clinometer are optical reading system, totally enclosed glass circles, slow motion screw for fine adjustments, eyepiece rotatable to most convenient viewing position.
5. Which of the following is used to illuminate scale in precision microptic clinometer?
a) An integral low voltage lamp
b) An integral high voltage lamp
c) An ordinary lamp
d) A high voltage bulb
Answer: a
Explanation: The scales of precision microptic clinometer are illuminated by an integral low voltage lamp. Daylight illuminated bubble unit is present, but is also provided with a lamp. It is for alternative illumination.
6. What is the purpose of slow motion screw in precision microptic clinometer?
a) To set tool head initially
b) Same function as of locating face
c) Final adjustment to centre the bubble
d) Measure angle between the surfaces
Answer: c
Explanation: The clinometer can be used as a precision setting tool. It can be used to set a tool head or table at a given angle. Micrometer scale is set firstly. Then the glass scale is rotated. It is to bring the relevant graduation to the index, for final adjustment the slow motion screw is used.
7. Which of the following is not a part of index head of centers used in clinometer?
a) Indexing plate
b) Camshaft
c) Crank
d) Worm and worm wheel
Answer: b
Explanation: The index head of the centers mainly consists of indexing plate, a crank and worm and worm wheel. The crank is attached to a worm. Worm is in mesh with the worm wheel.
8. Index centres are actually meant to use on which machine?
a) Milling machines
b) Planer machines
c) Lathe machines
d) Shaper machines
Answer: a
Explanation: Index centres were meant for the use on milling machines. But now their application is extended to inspection work. In such cases, where the measurement of a large number of angular dimensions about a common centre is required, index centres are best suited.
9. What is the purpose of locating face present on the back of the precision microptic clinometer?
a) Allows instrument to be used vertically
b) Allows instrument to be used at an angle
c) Allows instrument to be used horizontally
d) Allows the setting of inclination table
Answer: c
Explanation: With the suitable accessories these clinometers can be used for measuring angular displacements of small part. A locating face is present on the back of the precision microptic clinometer which allows the instrument to be used horizontally with the reflector unit or accessory worktable.
10. What is the use of worm and quadrant arrangement in clinometers?
a) Reading up to 5’ is possible
b) Reading up to 1’ is possible
c) Reading up to 10’ is possible
d) Reading up to 0.1’ is possible
Answer: b
Explanation: Worm and quadrant arrangement is provided in some instruments so that reading up to 1′ is possible. There is no bubble present in some clinometers but a graduated circle is present and it is supported on accurate ball bearings.
11. Which of the option is true for the given statements about clinometers?
Statement 1: Bubble vial is the reference for inclination.
Statement 2: It can’t be used for angular work on grinding machines.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: a
Explanation: Bubble vial is the reference for inclination. To measure the inclination of a surface, the vial is turned until it is approximately level. After this, the slow motion screw is used to centre the bubble.
This set of Engineering Metrology test focuses on “Optical Instruments for Angular Measurement”.
1. Which of the following is not true for autocollimators?
a) Has an infinity telescope
b) Has an autocollimator
c) For smaller angle it is not accurate
d) Very high sensitivity
Answer: c
Explanation: Autocollimator is an optical instrument which is used for the measurement of small angular differences. Autocollimator provides a very sensitive and accurate approach for small angular measurements. Autocollimator is an infinity telescope and a collimator combined into one instrument.
2. What is the relationship between the linear displacement of the graticule image in the eyepiece plane and reflector tilt?
a) Both are independent of each other
b) Linear displacement is directly proportional to the reflector tilt
c) Linear displacement is inversely proportional to the reflector tilt
d) Linear displacement is directly proportional to the square of the reflector tilt
Answer: b
Explanation: Linear displacement of the graticule image is directly proportional to tilt of the reflector. It can be measured by an eyepiece graticule, electronic detector system or optical micrometer, scaled directly in angular units.
3. Up to which accuracy length can be measured by laser interferometer?
a) 1 part in 10 8
b) 2 part in 10 8
c) 1 part in 10 6
d) 2 part in 10 6
Answer: c
Explanation: It is possible to measure length to accuracy of 1 part in 10 6 with laser interferometer. With two retro-reflectors that are placed at a fixed distance, and a length measuring laser interferometer the angle change can be measured to an accuracy of 0.1 second.
4. Which of the following option is correct for the given statements about optical instruments for angular measurements?
Statement 1: Laser interferometer with two-retro reflector uses sine principle.
Statement 2: Photoelectric microptic autocollimator can be used as a visual collimator.
a) F, F
b) T, F
c) F, T
d) T, T
Answer: d
Explanation: Laser interferometer uses the Sine principle. The line which joins the poles of the reflectors makes the hypotenuse of the right triangle. Photoelectric collimator can be used as a visual autocollimator and is available with a dark field graticule.
5. Which of the following is true for automatic position sensing autocollimator?
a) Accuracy is affected by normal mains fluctuations
b) There is no effect of lamp ageing on the accuracy of this instrument
c) Instrument measure in all planes simultaneously
d) It is not ideal for the repetitive checking
Answer: b
Explanation: Accuracy of automatic position sensing autocollimator is not affected by lamp ageing or normal mains fluctuations. Automatic autocollimators are ideal for the repetitive checking of the components.
6. How many pads are included for use under the foot screws in leveling base of autocollimator?
a) 2
b) 3
c) 4
d) 5
Answer: b
Explanation: Three pads are present in the leveling base of autocollimator for use under the foot screws. There is no requirement to remove the autocollimator after use as the autocollimator case is constructed to take both items.
7. What is the main use of steel cube reflector in autocollimator?
a) To provide a 90 degree standard in 3 planes
b) For general bench use
c) Calibrate surface plate
d) For setting but not checking perpendiculars
Answer: a
Explanation: Steel cube reflector can be used as a general purpose reflector. It can be used for providing a 90 degree angle standard in three planes. It can be used for setting or checking perpendiculars.
8. What is the range of readings up to distance of 9 metres in microptic autocollimator?
a) 15 minutes of arc
b) 20 minutes of arc
c) 5 minutes of arc
d) 10 minutes of arc
Answer: d
Explanation: A pair of target wires is used in this instrument. These wires are placed in the focal plane of a collimating lens. It is possible to read the tilt of reflector to normal upto 1/2 sec. of arc with the help of micrometer. The instrument has a range of readings of 10 minutes of arc up to 9 meter distance.
9. Which of the following used moire gratings for angular measurements?
a) Laser interferometer
b) Microptic autocollimator
c) Precision polygons
d) Goniometer
Answer: d
Explanation: Goniometer constitutes the continuously rotating Moire gratings for angular measurements with high accuracy. Two radial gratings are employed in goniometers which are rotating in unison.
10. Which of the following is true for Reading heads present in goniometer?
a) There is only one reading head which is stationary
b) Two readings heads and both are stationary
c) There is only one reading head which is moving with a rotatable work table
d) Two reading heads, one is stationary and other is rotating with work table
Answer: d
Explanation: Two reading heads are present in the goniometer. One head remains stationary while other moving with a rotatable work table. The phase difference between the outputs of heads varies continuously as the second head attached to the rotary table is moved.
11. How much angle accuracy is possible with a goniometer fitted with two 32400 lines radial grating?
a) 0.1 second of arc
b) 1 second of arc
c) 2 second of arc
d) 0.5 second of arc
Answer: a
Explanation: Advantage of goniometer is that grating errors are entirely averaged to zero during the time of measurement thus giving the inherent accuracy. With a goniometer which is fitted with two 32400 lines radial gratings, it is possible to obtain angle measurements to an accuracy of 0.1 second of arc.
12. Which of the following is not true for angle dekkor?
a) It is a type of autocollimator
b) It can be used as a comparator
c) It is a more precise instrument than autocollimator
d) It has a wide field of application without the operation of a micrometer
Answer: c
Explanation: It is a type of collimator and contains a small illuminated scale. The instrument measures by comparing the readings obtained from a standard. This is less precise instrument than autocollimator but it has wide field of application for general angular measurement.
13. What is the alternate name of constant deviation prism?
a) Optical square
b) Dowell prism
c) Circular prism
d) Reflector prism
Answer: a
Explanation: Constant deviation prism is also known as optical square. The special property of optical square is that it always reflects the ray through the same angle, which means doesn’t depend on the angle of incident.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Precision Polygons”.
1. What is the maximum overall diameter for precision polygons?
a) 100 mm
b) 200 mm
c) 300 mm
d) 400 mm
Answer: c
Explanation: Precision polygons are also known as multifaced polygons. These can be used for calibration of rotary tables, dividing head. The overall diameter of polygons should not exceed 300 mm for convenient handling.
2. What are the maximum numbers of faces a precision polygon can have?
a) 30
b) 60
c) 90
d) 72
Answer: d
Explanation: The minimum size of the reflecting face of the precision polygons should be approximately 13 mm x 13 mm. Thus a maximum number of faces of polygons can be seventy two, corresponding to an included angle of 5 degree.
3. How many holes are provided in precision polygons for clamping purpose?
a) 1
b) 2
c) 3
d) 4
Answer: d
Explanation: About four holes are provided in the polygons for the clamping purposes. These holes are plain in the type-1 polygon and threaded in type-2 and type-3 precision polygon respectively.
4. What is the dimension of polygon between top and supporting surfaces for a type 2 precision polygon as per IS: 6987-1973?
a) 75 mm
b) 150 mm
c) 300 mm
d) 600 mm
Answer: b
Explanation: As per IS : 6987-1973, there are three types of precision polygons that is ‘type-1’, ‘type-2’ and ‘type-3’. The dimension of polygon between the top surface and the supporting surface is 75 mm for type -1,150 mm for type-2 and 300 mm for type-3.
5. What is the accuracy of top and supporting surface of type 3 precision polygon as per IS: 6987-1973?
a) 0.005 and 0.04 mm
b) 0.0025 and 0.005
c) 0.007 and 0.0035
d) 0.001 and 0.002 mm
Answer: a
Explanation: The top surface and supporting surface are made flat and parallel to accuracies of 0.0025 and 0.005 mm for type-1 and 0.007 mm and 0.0035 for type-2, 0.005 and 0.04 mm for type-3 and departure from flatness is permissible in concave direction only.
6. What is the primary consideration in the accuracy of precision polygons?
a) How closely the mirror agrees with nominal angle
b) How closely the reflecting surface agrees with nominal angle
c) Primary consideration for precision polygons is how square and flat it is or its surface
d) How many sides polygon has having
Answer: c
Explanation: The primary consideration in accuracy for the certainty of calibration is not how closely reflecting faces or mirror agrees with the nominal angle, but how flat and square it is.
7. Which of the following option is true for the given statements about precision polygons?
Statement 1: It may have unequal angles.
Statement 2: Polygon with 12 sides is used for most of the works.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: c
Explanation: The polygons mostly have equiangular faces but unequal angles can also be provided for some special purposes. These are generally about 15 mm in thickness and 75 mm across flats and have a central hole for mounting purposes.
8. To what accuracy all face of a precision polygon made square to the bottom supporting surface?
a) 2.5 µm
b) 3.5 mm
c) 2.5 mm
d) 3.5 µm
Answer: a
Explanation: All faces of polygon are made square to the bottom surface to an accuracy of 2.5µm. The error in angle between any two adjacent working faces should not be more than 10 seconds of arc.
9. What is the flatness of reflecting faces of precision polygons?
a) Within 0.0002 mm
b) Within 0.0001 mm
c) Within 0.0003 mm
d) Within 0.0004 mm
Answer: b
Explanation: The reflecting faces of precision polygons should be flat with in 0.0001 mm. If individual mirrors are used then they should be mounted in such a way that there is no distortion. The mirror position should be fixed or there should be no possibility of alterations of mirror position from bumping or poor mounting.
10. Which of the following is true for precision polygons?
a) It is not possible to make a full calibration of the rotary table with one polygon
b) Correction factor is applicable for reference to the exact centering
c) Reflecting surfaces should be within 6 to 7 seconds of nominal angle
d) Correction factor is not applicable when the centre of the mirror is used in calibration
Answer: a
Explanation: It is not possible to make a full calibration of the rotary table with only one polygon because of the limited sides. Thus all the lines of the circular scale of an optical rotary table are not inspected for error.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Caliper Principle”.
1. Why is the caliper principle used?
a) For circular divisions
b) For checking flatness
c) For measuring dimensions with vernier caliper
d) For measuring dimensions with micrometer
Answer: a
Explanation: Caliper principle is used for the circular division or to divide a circular disc in number of divisions. Circular division deals with the continuous division of a Circle and measurement. The level of accuracy of circular division depends only on the precision of the equipment and the techniques used.
2. According to caliper principle, complete circular division of a circle must be equal to which angle?
a) 120
b) 180
c) 90
d) 360
Answer: d
Explanation: There are some angles which are not an exact fractional circle division, but is considered as a combination of angles which are uniform divisions. By caliper principle complete circular division of a circle must be equal to 360°.
3. How many microscopes are required to marking a circular disc into 90 o divisions?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: If the caliper principle is applied for marking a circular disc into 90 degree divisions. Then, in this method, we require the use of two microscopes for taking readings at two different positions simultaneously.
4. How many trial lines are marked firstly when caliper principle is used to mark a circular disc into 90 o divisions?
a) 5
b) 4
c) 3
d) 2
Answer: d
Explanation: Firstly two trial lines namely ‘1’ and ‘2’ are marked approximately at 180 degree and the two microscopes A and B are set against these marks. This practice is to divide a circle into two equal halves.
5. How many marks are needed to mark a circular table into 180 o divisions using caliper principle?
a) 1
b) 2
c) 3
d) 4
Answer: d
Explanation: 2 lines are marked at approx. 180° and individual microscopes set against these marks, let microscope A for mark 1 & B for 2. The position below B is noted & marked as 3. If the line division of 1 & 2 was exactly 180°, then the difference between 1 and 3 is the twice the error from 180° which can be measured. The space between 1 and 3 is divided by 4. Then 2 and 4 divide the circle into 180° divisions.
6. Which of the following statement is true for the circular division by caliper principle?
Statement 1: An arbitrary standard of angle is required.
Statement 2: All angles are obtained by the uniform division of the dividing circle.
a) F, T
b) T, T
c) T, F
d) F, F
Answer: a
Explanation: The main advantage of circular division and angular measurements is that, there is no need of arbitrary standard of angle but all angles can be obtained by uniform division of the circle.
7. How many marks are needed to mark a circular table into 90o divisions?
a) 2
b) 4
c) 6
d) 8
Answer: d
Explanation: Eight marks are required to divide a circular table into 90 degree division. Four marks are required to divide it correctly 180 degree say 0 to 180 and then another four marks are needed to divide it in 90 to 270 degree. By this table is divided into 90 degree divisions.
8. Which of the following option is true for caliper principle?
Statement 1: This principle can be used to calibrate precision polygons.
Statement 2: Fully calibrated lines can be correctly engraved after marking the circular table and also after calibration of lines.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: c
Explanation: Caliper principle can also be used to calibrate the polygons. After dividing the circles, lines can be correctly engraved on the disc at given intervals. By using the calibration of lines and it’s known for errors of setting.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Calibration of Polygons”.
1. How many auto-collimators are required when the polygons are calibrated by using only auto-collimators?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: Any precision polygon is usually calibrated by two autocollimators before using, in order to know the errors. For this method, precision polygon is mounted on a table and this table is a rotating table.
2. What is the accuracy of comparison method used for calibration of polygons?
a) ±0.1 seconds
b) ±0.2 seconds
c) ±0.3 seconds
d) ±0.4 seconds
Answer: c
Explanation: If all the exterior angles of the upper polygon are compared with the angle between any two faces of the lower polygon then by comparison method of calibration of polygons, the accuracy of ± 3 seconds can be obtained.
3. What is the relation between angle of two autocollimators and angle between polygon faces when polygon is calibrated? (R 1 , R 2 are the readings.)
a) P = R + (R 1 +R 2 )
b) P = R + (R 2 -R 1 )
c) P = R – (R 1 +R 2 )
d) P = R – (R 1 -R 2 )
Answer: b
Explanation: The angle between two polygon face is P and between two autocollimators is R. Readings are taken by using autocollimators let readings are R 1 and R 2 . Then the angle between polygon face is equal to autocollimator angle plus difference in readings.
4. How many auto-collimators are required for comparison method of calibration of polygons?
a) 1
b) 2
c) 3
d) 4
Answer: a
Explanation: In comparison method of calibration of polygons, two polygons which are identical to each other and one table which can rotate is used. For viewing purpose a single autocollimator is used.
5. Which of the following is the correct option for given statements about calibration of polygons?
Statement 1: Autocollimators angle is constant during calibration.
Statement 2: Wild rotary table can be used as the base of precision polygons.
a) F, F
b) T, T
c) F, T
d) T, F
Answer: b
Explanation: Angle between two autocollimators is constant that is ∑R/n is equal to R where n is the number of polygon faces. Precision polygons are placed on a rotary table for calibration and wild type is used in many places.
6. What is formula for the angle between autocollimator when polygon is calibrated by using two autocollimators?
a) (360 0 /n)-∑(R 2 -R 1 )/n
b) (180 0 /n)-∑(R 2 -R 1 )/n
c) (360 0 /n)-∑(R 2 -R 1 )*n
d) (180 0 /n)-∑(R 2 -R 1 )*n
Answer: a
Explanation: Summation of angle between polygon faces is equal to 360 degree. If there be n number of sides in a polygon then dividing the equation throughout by n that is (360 0 /n)-∑(R 2 -R 1 )/n.
7. Which of the following option is true for calibration of polygons by using auto-collimators?
Statement 1: Imperfect centering has a great effect on calibration.
Statement 2: This method gives a high degree of accuracy without reference to any angular standard.
a) T, T
b) T, F
c) F, T
d) F, F
Answer: c
Explanation: It is not necessary for calibration of polygons that the autocollimators be aimed at the centre of polygons as there is no effect of imperfect centering in this method of calibration or autocollimators.
8. By computed least square method, what is the accuracy obtained for polygons up to 12 faces?
a) ±1.0 second
b) ±2.0 second
c) ±3.0 second
d) ±4.0 second
Answer: a
Explanation: If each faces pair of the upper polygon is compared with all the faces of the lower polygon and the angles are computed by the least square method then the better accuracy will achieve. By this, the accuracy of ± 1.0 second may be obtained for up to 12 faces polygons.
9. Which of the following is not true for comparison method used for calibration of polygons?
a) Identical polygons are used
b) Polygons are mounted one above the other
c) Polygons are mounted on the fixed table
d) Reflecting faces of both the polygons are viewed simultaneously
Answer: c
Explanation: Two identical polygons are mounted one above the other on a table which can rotate. The autocollimator is placed in a position that it views simultaneously the reflecting faces of both the polygon.
10. What is correct for the angle of autocollimators used for calibration of polygons?
a) Angle between autocollimators is equal to the nominal angle between adjacent faces
b) Angle between autocollimators is more than the nominal angle between adjacent faces
c) Angle between autocollimators is less than the nominal angle between adjacent faces
d) Angle between autocollimators is more or less to the nominal angle between adjacent faces
Answer: a
Explanation: The angle between autocollimators are set such that the angle is equal to the nominal angle between adjacent faces of the polygon, it is to give reflections from adjacent faces of the polygon.
This set of Engineering Metrology Problems focuses on “Check the Angle of a Tapered Hole”.
1. How many balls are needed in the method to check the angle of a tapered hole?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: In the method of checking the angle of a tapered hole, there is a need for two balls. Depth gauge and height gauge are also required. This method is suitable for checking the angle of a tapered ring gauge.
2. At what position a smaller ball is placed in the hole to check the angle of a tapered hole?
a) Lower position
b) Upper position
c) Middle position
d) At any position
Answer: a
Explanation: In the method to check the angle of tapered hole, Firstly the small ball of radius let R is inserted in lower position in the hole and depth H from the upper surface of tapered hole to the top of the ball is measured.
3. Which of the following gauge is generally used to measure distance between top of ball and tapered hole in the method of checking angle of a tapered hole?
a) Depth gauge
b) Slip gauge
c) Height gauge
d) Angle gauge
Answer: c
Explanation: In this method of checking the angle of tapered hole the bigger ball of radius let R is placed in the hole and distance H. The distance between tapered hole and the top of the ball is measured with height gauge.
4. Which of the following is correct about smaller ball using in the method of checking angle of tapered hole by using balls?
a) Small ball should be of the size so that it will be seated somewhere in between hole
b) Small ball should be of the size so that it will be seated at the bottom most position in the hole
c) Small ball should be of the size so that it will be seated at the top most position in the hole
d) There is no effect of ball position on the method
Answer: a
Explanation: In this method to check the angle of tapered hole, balls are used. Smaller ball is of such size that it will be seated somewhere between the hole that is not at the bottom and not at the top. Above it bigger ball will be placed.
5. Which of the following is true about the method of checking the angle of a tapered hole?
Statement 1: Balls of different sizes are used.
Statement 2: This method can be used to check relief clearance of dies.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: c
Explanation: To check the angle of tapered hole, balls of different size are used. This method is suitable for checking the angle of a tapered ring gauge and very suitable for measuring the relief clearance of dies.
6. What is the formula to find angle of tapered hole?
a) CosA/2 = (R 1 -R 2 )/(H 1 +H 2 +R 1 -R 2 )
b) SinA/2 = (R 1 -R 2 )/(H 1 +H 2 +R 1 -R 2 )
c) TanA/2 = (R 1 -R 2 )/(H 1 +H 2 +R 1 -R 2 )
d) CotA/2 = (R 1 -R 2 )/(H 1 +H 2 +R 1 -R 2 )
Answer: b
Explanation: SinA/2 = (R 1 -R 2 )/(H 1 +H 2 +R 1 -R 2 ) this is the formula to find angle of tapered hole where A is the angle of tapered hole. R 1 and R 2 is the radius of smaller and bigger ball respectively. H 1 and H 2 are the heights.
7. Which of the following is true for the measurement of small tapers by balls?
a) Weight of the ball cause no effect on the accuracy of reading
b) Measuring pressure exerted can cause axial movement
c) Measuring pressure exerted cause no effect on the accuracy of reading
d) Accuracy of small taper measurement is same as large taper
Answer: b
Explanation: A precaution is needed when the small taper is measured with the help of balls. If the ball is allowed to drop in the hole, it will wedge the taper of the hole. Ball weight and measuring pressure that is exerted over it can cause appreciable axial movement and can give inaccurate readings.
8. What is the modified formula of checking angle of tapered hole when both the balls lie inside the groove?
a) SinA/2 = (R 2 -R 1 )/(H 1 +R 2 -(H 2 +R 2 ))
b) SinA = (R 2 -R 1 )/(H 1 +R 2 -(H 2 +R 2 ))
c) SinA/2 = (R 2 -R 1 )/(H 1 -R 2 -(H 2 +R 2 ))
d) SinA = (R 2 +R 1 )/(H 1 +R 2 -(H 2 +R 2 ))
Answer: a
Explanation: When both smaller and bigger ball are inside the groove then the formula to find angle of tapered hole will modify. The modified formula is SinA/2 = (R 2 -R 1 )/(H 1 +R 2 -(H 2 +R 2 )), where A is the angle of tapered hole.
This set of Engineering Metrology Quiz focuses on “Determine the Included Angle of an Internal Dovetail”.
1. Which of the following is not correct for dovetail joints?
a) Sloping sides act as a guide
b) The slope is 1:5 for softwoods
c) Used in box constructions
d) Difficult to make manually
Answer: b
Explanation: In dovetail joint, the sloping sides acts as guide and during the mating operation prevent the lifting of the female mating part. The slope is 1:6 for softwoods and 1:8 for hardwoods.
2. Which of the following statement is correct regarding the dovetail joint?
Statement 1: Angle between sloping face and imaginary centre plane is important.
Statement 2: It is difficult to pull apart the joint when glue is added.
a) F, F
b) F, T
c) T, F
d) T, T
Answer: d
Explanation: In case of dovetail the angle between sloping face and an imaginary vertical centre plane is important. The dovetail joints are very strong due to the shape of ‘tails’ and ‘pins’. This makes it difficult to pull the joint apart and it is nearly impossible when glue is added to the joint.
3. How many pins are used in the method of determination of an angle of a dovetail?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: To measure the angle of an internal dovetail, there is a need for two pins. These pins are of equal size. Along with the pins, slip gauges and micrometer is also used in this method.
4. What is the shape of tails and pins in an internal dovetail joint?
a) Circle
b) Square
c) Rectangle
d) Trapezoidal
Answer: d
Explanation: The shape of tails and pins in dovetail joint is trapezoidal. A dovetail joint or simply is a joinery technique which is most commonly used in woodworking e.g. furniture, timber framing etc.
5. Which of the following is true about pins the method which is used to determine the included angle of an internal dovetail?
a) Pins touch both the sides of dovetail
b) Pins touches only one side of dovetail
c) Pins are of different size is used
d) Balls of different size is used
Answer: a
Explanation: In this method of checking the included angle of an internal dovetail, firstly the two pins are placed in the position such that touches both the sides of dovetail and then distance across the pins is measured.
6. Which of the following is not a name of dovetail joint?
a) Swallowtail joint
b) Fantail joint
c) Profile joint
d) Culvertail joint
Answer: c
Explanation: In Europe, dovetail joint is also known as swallowtail joint and a fantail joint. In pre dates history, dovetail joint is also called Culvertail joint. Profile joint is not the name of dovetail.
7. Which of the following formula is true for the angle of internal dovetail?
a) Tan A = (l 2 -l 1 /2) / h
b) Sin A/2 = (l 2 -l 1 /2) / h
c) Cos A = (l 2 -l 1 /2) / h
d) Sin A = (l 2 -l 1 /2) / h
Answer: a
Explanation: Formula for finding the angle of an internal dovetail is Tan A = (l 2 -l 1 /2) / h where l 1 and l 2 are the distance across the pins and h is the height of slip gauges. Thus by knowing these three parameters, angle A can be calculated.
8. Which of the following is used to measure the distance across the pins when included angle of the dovetail is determining by using pins?
a) Vernier
b) Micrometer
c) Screw gauge
d) Slip gauge
Answer: b
Explanation: Micrometer is used to determine the distance across the pins. For setting pins at required height slip gauges are used.
Dovetail joints can be used in jet engines for attaching turbine blades to the shaft in jet engines and also for clockmaking, joining adjacent sections etc.
9. The method used for determining the angle of internal dovetail for some measurements. Which of the following is suitable for this method?
a) Angle of taper plug gauge
b) Any round taper work which can be placed on a surface
c) Any flat tapered work which can be placed on a surface
d) Angle of taper ring gauge
Answer: d
Explanation: This method is suitable to check angle of a plug gauge which is tapered and any round and flat tapered work which can be placed on a surface. Angle of taper ring gauge can be determined by the method of finding the angle of tapered hole by using balls.
10. Which of the following option is not true for the given statement about the method of determination of angle of internal dovetail by using pins?
Statement 1: Pins should extend above the top surface of a dovetail.
Statement 2: Pins are raised on slip gauges.
a) T, T
b) F, F
c) F, T
d) T, F
Answer: c
Explanation: The pins used in this method are raised on two sets of slip gauge blocks which are of equal heights. In this method one care should be taken that the pins do not extend above the dovetail’s top surface.
This set of Engineering Metrology MCQs focuses on “Measure an Internal Taper in Blind Hole”.
1. Which of the following is used to measure an internal taper in a blind hole?
a) One pin
b) Two balls
c) Single ball
d) Two pins
Answer: b
Explanation: For this method of measurement of internal taper of blind holes, generally two steel balls are used. These balls are generally made up of steel.
2. Which of the following is the first step in the method of measuring an internal taper in a blind hole?
a) Balls are placed in bottom of the taper
b) All the balls are placed over the support
c) Pins are placed in bottom of the tape
d) All the pins are placed over the support
Answer: a
Explanation: In the method of measurement of internal taper of blind hole the first step is that the two balls which are of equal diameter are placed in the bottom. Each ball is placed in bottom corner of the internal taper of blind hole.
3. Which of the following is used to fill the gap between the balls?
a) Combination of pins
b) Combination of balls
c) Slip gauges
d) Plug gauges
Answer: c
Explanation: In this method, after placing the balls the gap between the balls is filled with the combination of the slip gauges. The length of slip gauges between the balls should be noted very carefully.
4. Which of the following is the blind hole?
a) All ordinary holes are called blind holes
b) Those hole which has specified depth without breaking through the other side
c) Those holes which goes all the way through metal
d) Clearance holes are the blind holes
Answer: b
Explanation: Blind holes are those which are drilled or reamed etc. at a specified depth. It is drilled without breaking through the other side. Those holes which go all the way through the work piece are known as through holes.
5. How the error in angle measurement can be decreased when the internal taper of the blind hole is measured?
a) Increase the height of slip gauge combination
b) Decrease the height of slip gauge combination
c) In place of balls, pins are used
d) Balls of different diameter are used
Answer: a
Explanation: When the internal taper of blind hole is measured by using balls then the error in the angle measurement of taper can be decreased by choosing the height of slip gauge combination as large as possible.
6. Which of the following is true for the measurement of internal taper in the blind hole?
a) Roller of large radius should be used
b) No effect of roller size
c) Roller of small radius should be used
d) Both the rollers are of different size
Answer: c
Explanation: In this method of measurement of internal taper, the radius of rollers should be small so that the contact between the flanks of sloping sides and rollers is made in a plane which is near to the base.
7. What is the formula for the internal tapered angle of blind hole?
a) Sin A/2 = (l 1 -l 2 )/2h
b) Cot A/2 = (l 1 -l 2 )/2h
c) Cos A/2 = (l 1 -l 2 )/2h
d) Tan A/2 = (l 1 -l 2 )/2h
Answer: d
Explanation: Tan A/2 = (l 1 -l 2 )/2h or A = 2 tan -1(l 1 -l 2 )/2h is the formula to measure the internal tapered angle of the blind hole where (l 1 -l 2 ) is the different in length of slip gauges and h is the height of slip gauges upon which balls are placed.
8. Which of the following is used as a support in the blind hole when the internal taper is measured by using balls?
a) Wooden block
b) Slip gauges
c) Balls of larger diameter
d) Internal taper itself acts as a support
Answer: b
Explanation: A combination of slip gauges of height let ‘h’ is prepared and placed in the hole as support. Now, place the two balls in the upper position. Each ball touched the tapered side of the hole and space is filled with another combination of slip gauges.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Measure the Angle of a V-Groove”.
1. Which of the following is used for measuring the angle of V-groove?
a) Two discs of same size
b) Two pins of different size
c) One disc only
d) One pin only
Answer: b
Explanation: For measuring the angle of V-groove, two discs or two pins are used. These pins or discs are of different size. There is also a need of height gauge in this angle measurement method.
2. What is the first step in the measurement of angle of the V-groove?
a) Small disc is placed in the groove
b) Flatness of groove is tested
c) Bigger disc is placed in the groove
d) Both discs are placed simultaneously
Answer: a
Explanation: In the method of measuring the angle of V-groove, First step is that the small disc is placed in the groove. After that height of the smaller disc above the surface plate is measured with the help of height gauge.
3. Which of the following is true about the method of measuring the angle of V-groove?
a) Larger disc is placed over the smaller disc in groove
b) Larger disc is placed in the groove after removing the smaller disc
c) Smaller disc is placed below the smaller disc
d) Larger disc is placed in the groove without removing the smaller disc
Answer: b
Explanation: After removing the smaller disc from the groove, bigger disc is placed in the groove. The height of disc let ‘h2’ is again measured with the help of height gauge.
4. Which of the following is not true for the high accuracy in the method of finding the angle of V-groove?
a) Height of smaller should be measured by sensitive indicator
b) Height of larger discs should be measured by using slip gauges
c) Use of height gauge give more accuracy than slip gauges
d) Use of both slip gauge and sensitive indicator increase accuracy
Answer: c
Explanation: To increase the accuracy of the method or for higher accuracy, height of the smaller and bigger disc let h1 and h2 respectively can be measured by using sensitive indicator. Use of slip gauges for this purpose will also improve accuracy.
5. Which of the following statement is true for the measurement of angle of V-groove using discs?
Statement 1: This method is good for the measurement of the angle of machine tool sides.
Statement 2: Discs should always touch the sloping sides of the groove.
a) T, T
b) F, T
c) T, F
d) F, F
Answer: a
Explanation: This method which is used to measure angle of V-grooves is also very suitable for measuring the angle of profile and angle of machine-tool slides.
The discs used in this method should be of such diameter that they always touch the sloping sides of the groove only.
6. Which of the following can be used in the case of threads to measure the difference in heights of discs when the angle of V-groove?
a) Slip gauges
b) Height gauges
c) Screw gauges
d) Dial indicator
Answer: d
Explanation: This method is also very suitable for measuring the angle of shallow grooves and threads.
To measure the difference of disc height say, in case of threads, can be measured by dial indicator.
7. What is the formula of the angle of a V-groove?
a) Sin A/2 = (d 2 -d 1 )/2 ÷ (h 2 -h 1 )-((d 2 -d 1 )/2)
b) Tan A/2 = (d 2 -d 1 )/2 ÷ (h 2 -h 1 )-((d 2 -d 1 )/2)
c) Cot A/2 = (d 2 -d 1 )/2 ÷ (h 2 -h 1 )-((d 2 -d 1 )/2)
d) Cos A/2 = (d 2 -d 1 )/2 ÷ (h 2 -h 1 )-((d 2 -d 1 )/2)
Answer: a
Explanation: Sin A/2 = (d 2 -d 1 )/2 ÷ (h 2 -h 1 )-((d 2 -d 1 )/2) is the formula of angle of groove where A is the angle of V-groove, d 2 and d 1 are the diameters of discs and h 2 and h 1 are the height of discs from surface plate.
8. What is the formula of distance between centre of discs in the method of measurement of the angle of V-grooves using discs?
a) (h 2 +h 1 )-((d 2 -d 1 )/2)
b) (h 2 -h 1 )-((d 2 -d 1 )/2)
c) (h 2 -h 1 )+((d 2 -d 1 )/2)
d) (h 2 -h 1 )-((d 2 +d 1 )/2)
Answer: b
Explanation: If O 1 and O 2 are the centres of the two balls used in this method and O 1 B is drawn parallel to one of the inclined surfaces & O 2 B is perpendicular to O 1 B. Then, O 2 O 1 B equals half the angle of V-groove and the distance between centres i.e. O 1 O 2 is given by (h 2 -h 1 )-((d 2 -d 1 )/2).
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Calibration of Linear and Angular Measuring Instruments”.
1. What is the relation between variation due to observation, manufacturing process and measuring process of a product?
a) σ observation = σ process + σ measurement
b) σ observation = σ process – σ measurement
c) σ observation = σ process * σ measurement
d) σ observation = σ process / σ measurement
Answer: a
Explanation: The variation in the observation depends upon the variation in the product due to manufacturing process and variation due to measuring process. In order to keep σobservation minimum measurement should be kept minimum so that product as a whole is reliable.
2. What is the maximum permissible error for class I micrometers?
a) 0.002 mm
b) 0.004 mm
c) 0.008 mm
d) 0.016 mm
Answer: b
Explanation: In micrometers, to cover the entire range the error in readings is checked by slip gauges. The maximum permissible error for class I micrometers is 0.004 mm and 0.008 mm for class II micrometers.
3. What is the permissible error in the perpendicular motion of ocular microscope column w.r.t. The work stage over 100 mm movements?
a) 0.04 mm
b) 0.05 mm
c) 0.07 mm
d) 0.06 mm
Answer: d
Explanation:The permissible error in the perpendicular motion of ocular microscope column w.r.t. The work stage over 100 mm movements is 0.06mm.
4. Which of the following is used to check change in ocular lines position due to column rotation in universal micrometer?
a) Dial indicator
b) Slip gauges
c) Control shaft
d) Universal microscope
Answer: c
Explanation: A special control shaft is used to check this where a right angled blade is provided at right angle to shaft diameter line. The ocular line is made to coincide with the blade and the column is titled, the shift in position of the ocular line is noted, this shift is the required error.
5. What is the least count of clinometer which is used to check reading of column rotation used for setting of helix angles in universal micrometer?
a) 1’
b) 2’
c) 3’
d) 4’
Answer: a
Explanation: The permissible error which is allowed in the entire range of column rotation is ± 5′. A clinometer is used to check this which is of 1′ least count. The clinometer is put over column top. Given Inclination is further checked with clinometer.
6. Which of the following is true for the calibration of instruments?
a) In casting and fabrication shops the measurements made are of more precise nature as compared to those made in machine shop and tool room
b) Periodical calibration is made for optical measuring instruments
c) There is no need of periodic calibration in universal microscope
d) Preventive maintenance is not necessary for optical measuring instruments
Answer: b
Explanation: In machine shop and tool room the measurements made are of more precise than those made in casting and fabrication shops, so instruments used in these shops require more frequent calibration. Annual programme can be made for periodical calibration and for general preventive maintenance in optical measuring instruments like universal microscope.
7. What is the permissible error in straight movement of longitudinal and transverse table in horizontal plane?
a) 0.002 mm
b) 0.003 mm
c) 0.004 mm
d) 0.005 mm
Answer: a
Explanation: The permissible error in straight movement of longitudinal and transverse table is 0.002 mm in horizontal plane and 0.005 mm in vertical plane. This can be checked by using a rectangular straight edge and a dial indicator of least count 0.001 mm with an attachment for fixing dial indicator.
8. Which of the following is true for checking the Relative perpendicular motion of the longitudinal and transverse carriage?
a) The permissible error allowed is 0.005 mm in 2500 mm length.
b) This is checked using a slip gauges
c) Precision square of class I or 0 is used
d) Maximum error in precision error is of ± 10″ in squareness
Answer: c
Explanation: The permissible error allowed in this case is 0.005 mm in 1100 mm length. This can be done by using a precision square of class I or class 0 accuracy having a maximum error of ± 10″ in squareness.
9. What is the maximum permissible error in wear of centres?
a) 0.04 mm
b) 0.03 mm
c) 0.02 mm
d) 0.01 mm
Answer: d
Explanation: The centres are set and checked for straightness. It can be observed while rotating the centres. The maximum error permissible for wear of centres is 0.01 mm.
10. What is the least count of dial indicators which can be calibrated using passmeter?
a) 0.01 mm
b) 0.03 mm
c) 0.05 mm
d) 0.07 mm
Answer: a
Explanation: The dial indicators of least count 0.01 mm can be calibrated by using passmeter or by micrometer dial comparator of least count 0.002 mm. The dial indicators can also be calibrated using slip gauges.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Measurements of Limit Gauges”.
1. Which of the following is generally used to check the hardness of the gauging surface of screw ring gauges?
a) Rockwell hardness testing machine
b) Charpy hardness testing machine
c) Diamond pyramid machine
d) Scratch test
Answer: d
Explanation: The hardness of the gauging surface of limit gauges may be generally measured on a hardness testing machine, preferably on the diamond pyramid machine. In certain types of gauges like screw and plane ring gauges, hardness is checked by means of a scratch test.
2. Up to which accuracy small gap gauges can be measured by using slip gauges?
a) ± 0.001 mm
b) ± 0.002 mm
c) ± 0.003 mm
d) ± 0.004 mm
Answer: a
Explanation: Small gap gauges can be measured to an accuracy of ± 0.001 mm by using slip gauges and length bars but the accuracy of measurement of larger gap gauges is not so high, due to probable springing open of jaws when inserting the slip gauge combination.
3. What is the advantage of the use of slip gauge standards for dial comparators?
a) Size of the standard is equal to one of the limits of the plug gauge size
b) Size of the standard is greater than one of the limits of the plug gauge size
c) Size of the standard is less than one of the limits of the plug gauge size
d) Slip gauges are more accurate
Answer: a
Explanation: The advantage of the slip gauge standards for dial comparators is that size of the standard is equal to one of the limits of the plug gauge size and hence the effect of errors of the comparator scale graduations is minimised.
4. Which of the following is not used to measure the plain plug gauges if the tolerance less than 0.025 mm?
a) Bench micrometer
b) Diameter measuring machine
c) Hand micrometer
d) High magnification dial comparator
Answer: c
Explanation: If the tolerance on the plug gauge is less than 0.025 mm then, it is important to use more accurate measurement method. In such cases, bench micrometer or high magnification dial comparator or diameter measuring machine should be employed. In this case, hand micrometer can only measure over a limited range of size.
5. Which of the following is most convenient to measure the cylindrical ring gauges?
a) Slip gauges
b) Micrometer
c) Measurement by using rollers
d) Pneumatic comparators
Answer: d
Explanation: Cylindrical ring gauges are most conveniently measured on pneumatic comparators; the taper and ovality of the gauges is quickly investigated and accuracy of the order of ± 0.001 mm is obtained by using pneumatic comparators.
6. What is the standard magnification used by an optical projector to inspect form of profile gauges?
a) 50
b) 100
c) 150
d) 200
Answer: a
Explanation: Profile gauges are most conveniently inspected by optical projection at a standard magnification. The standard magnification mostly used is 50. Another standard magnification which can be used is 100 but it is generally not used due to reduced intensity of illumination at the projector screen, it is generally not greater than 50.
7. Which of the following statement is true for measurement of height and depth gauges?
Statement 1: These can be measured by comparators.
Statement 2: Gap of light method is not good for depth gauges.
a) T, T
b) T, F
c) F, F
d) F, T
Answer: b
Explanation: Height and depth gauges can be measured by depth micrometers, bench micrometers or comparators. The recommended method for depth and height gauges is ‘gap of light’ method.
8. Which of the following is true for parallel screw plug gauges?
a) The minor diameter is measured by making a measurement on a diameter measuring machine between the flat ends of Vees
b) The flank angle is measured by making a measurement on a diameter measuring machine between the flat ends of Vees
c) The effective diameter is measured by making a measurement on a diameter measuring machine between the flat ends of Vees
d) Pitch is measured by making a measurement on a diameter measuring machine between the flat ends of Vees
Answer: a
Explanation: The major diameter is obtained on the diameter measuring machine which is standardised in a similar way as bench micrometer. The minor diameter is measured on a diameter measuring machine between the flat ends of Vees which are placed in the thread groove on the gauge’s opposite sides.
9. Which of the following is best gauge/machine to inspect the parallel screw ring gauges?
a) Hand micrometer
b) Plug check gauges
c) Comparators
d) Bench micrometer
Answer: c
Explanation: Screw ring gauges inspection by plug check gauges verifies that the ring gauges lie between their size limits. The major diameters are measured by inspection of the thread form which provides an indirect verification.
10. Which of the following is true for the measurement of taper ring gauges?
a) Taper ring gauges of sizes above the diameter of 20 mm are best measured by inserting precision balls of different sizes in the gauge
b) Taper ring gauges of sizes below the diameter of 20 mm are best measured by inserting precision balls of different sizes in the gauge
c) Taper ring gauges of size equal to the diameter of 20 mm are best measured by inserting precision balls of different sizes in the gauge
d) Taper ring gauges of all sizes are best measured by inserting precision balls of different sizes in the gauge
Answer: b
Explanation: Taper ring gauges of diameter below than 20 mm are best measured by inserting precision balls of different sizes in the gauge and the distance between the top of each ball and one of the end faces of the gauge is measured.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Checking of Slip Gauges”.
1. Which of the following is generally used to calibrate slip gauges?
a) Micrometer
b) Collimator
c) Interferometer
d) Gap gauge
Answer: c
Explanation: As a result of handling in the labs or inspection workshops, slip gauge is responsible for displaying the signs of wearing after the appreciable period of use and therefore, should be checked or re-checked at regular intervals. It can be easily done with the help of millionth measuring machine such as Newall Interferometer.
2. Which of the following is true for checking of slip gauges with interferometer?
a) Both ends of gauges examined simultaneously
b) Right end is examined first
c) Left end is examined first
d) Any end can be examined after one another
Answer: a
Explanation: The absolute measurement and gauge comparison are done by an interferometer. It consists of a higher interferometer arranged in such a way that both ends of this type of gauge are checked simultaneously in the same area of view.
3. Up to which accuracy differences in length can be measured when slip gauges are calibrated by interferometer?
a) 0.02 mm
b) 0.002 mm
c) 0.0002 mm
d) 0.00002 mm
Answer: d
Explanation: The gauges show interference fringes across the faces at both ends after simple adjustment, and from the relative positions of these differences in length accuracy achieved is 0.00002 mm.
4. Which of the following is used to compute absolute length when slip gauges are calibrated by interferometer?
a) Scale
b) Slide rule
c) Scriber
d) Caliper
Answer: b
Explanation: The absolute length is computed with the special slide rule provided for this purpose and in Zeiss interferometer the corresponding linear measurement in microns is determined by special slide rule.
5. Which of the following is not a part of the instrument used for checking slip gauges?
a) Collimator
b) Monochromatic light source
c) White light source
d) Lens
Answer: d
Explanation: Arrangement contains a dual collimator, white light source and slit which provides white light. A monochromatic light source, condenser and a slit which provide monochromatic light.
6. How are mirrors arranged when lengths of two slip gauges are compared?
a) Mirrors are arranged in such a manner that both the end faces of slip gauges appear to overlap
b) Mirrors are arranged in such a manner that both the end faces of slip gauges appear separately
c) Lenses are arranged in such a manner that both the end faces of slip gauges appear to overlap
d) Lenses are arranged in such a manner that both the end faces of slip gauges appear separately
Answer: a
Explanation: Mirrors are arranged in such a manner that both the end faces of slip gauges appear to overlap, when lengths of two slip gauges are compared.
7. What is the main purpose of micrometer eyepiece in the instrument used to compare the lengths of two slip gauges?
a) Measure the fraction of bands
b) To read the fringe
c) Measure the length
d) To measure the width of fringe
Answer: a
Explanation: In the instrument used to compare lengths of two slip gauges a micrometer eyepiece is present which accurately measure the fractions of bands, but it is better to estimate the fraction.
8. Under what condition white light bands appear when a comparison of lengths of two slip gauges takes place?
a) Optical paths from dividing mirror are less
b) Optical paths from dividing mirror are more
c) Optical paths from dividing mirror are equal
d) Optical paths from dividing mirror can be more or less
Answer: c
Explanation: The standard gauge is adjusted so that the end faces of slip gauges are at an optical path distance from the dividing mirror when illuminated by the source of white light. Under these conditions the interference fringes appear are known as ‘white light band’. These are produced when the optical paths from the dividing mirror are same or equal.
9. Which of the following indicate the exact point of equality when the comparison of lengths of two slip gauges takes place?
a) A prominent white band
b) A prominent black band
c) A prominent black & white band
d) A prominent grey band
Answer: b
Explanation: A prominent black band indicates the exact point of equality which has other bands, fringed with colour on either side, successive bands being of minimised intensity until invisible.
10. Which of the following statement is true regarding Zeiss interferometer used for the measurement of slip gauges?
Statement 1: Zeiss interferometer is used for relative comparative measurement of slip gauges.
Statement 2: It uses three wavelengths of cadmium light.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: Zeiss interferometer is a compact instrument which is used for absolute comparative measurement of slip gauges. The absolute length of a slip gauge by this method can be determined by three methods First is by comparison with a standard block. second is by a combined measurement of 3 gauge blocks. and the third is by measurement with a wrung-on gauges block.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Automatic Inspection Machines”.
1. Which of the following is not true about automatic inspection machine?
a) Human intervention is required to judge the quality
b) Consists a logic system
c) Self diagnostic system is present
d) Microprocessors are present
Answer: a
Explanation: Automatic inspection machines are very economical in high production manufacturing facilities for final inspection. Human intervention is not required to judge the quality. One or more measuring stations are required for the inspection of parts.
2. What is not a use of rocker-arm components in automatic gauging system?
a) Amplify motion
b) Enable probe to reach very difficult areas
c) Enable positioning of part
d) Transfer movement from datum through not more than one pivot points
Answer: d
Explanation: Rocker-arm components could be used for more accuracy to transfer movement from the datum through one or more pivot points to the probe. Advantage of such a system amplifies the motion, enables probe to areas which are difficult to reach, and enables positioning of part.
3. Which of the following is true about the self-diagnostic system present in automatic inspection machines?
a) Increase downtime
b) Easy but slow identification
c) Improved efficiency of maintenance
d) Increase settling time
Answer: c
Explanation: Self-diagnostic systems are used in automatic inspection machines and these systems allow easy and fast identification of circuits which are faulty, reducing downtime and improving maintenance efficiency.
4. What is done to avoid out-of-sequence mishaps in automatic inspection machine?
a) Clamping between centres and sequence of part lifting are linked on different controls
b) Clamping between centres and gauge fixtures are linked on different controls
c) Sequence of part lifting and gauge fixtures are linked on different controls
d) Sequence of part lifting, clamping between centres and gauge fixtures are linked on same controls
Answer: d
Explanation: To avoid out-of-sequence mishaps, clamping between centres, the sequence of part lifting and the gauge fixtures moving down and up, etc. are linked by a single control mechanism. All movements of the gauge structures are cam operated in each gauging station and powered by a electric motor reducer.
5. Which of the following is true about probes used in automatic inspection machines?
a) Retractable type
b) Non-retractable type
c) Auxiliary probe is not used
d) Heads of probes are not held back till the part is in gauging position
Answer: a
Explanation: The probes should be made retractable type as far as possible, to prevent possible damage and wear to the probes. The probe heads are held back till the part is in a position of gauging.
6. Which of the following statement is true for automatic inspection machines?
Statement 1: Measurement information is displayed on the screen.
Statement 2: Bad parts are not segregated automatically.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: a
Explanation: Bad parts or faulty parts are segregated and discharged into the reject chute. This is done to avoid any possibility of using them in a final assembly. Automatic or semi-automatic mastering of the system is present in automatic gauging machine and is easily performed.
7. Why retooling is fast and less expensive in automatic inspection machines?
a) Only hardware changes are needed
b) Both hardware and software changes are needed
c) No hardware changes are needed
d) Software program doesn’t need any change
Answer: c
Explanation: Retooling is fast and not much expensive because no hardware changes are required and the software program is able to achieve these. Electronic gauging machines provide information that can be interfaced with computers or CRT or analysers.
8. Which of the following is true about the design of structure of automatic inspection machine?
a) Separate structure is designed for transportation and gauging system
b) Same structure is designed for transportation and gauging system
c) Anti vibration mounts are placed only one leg of gauging structure
d) Anti vibration mounts are placed only on two front legs of gauging structure
Answer: a
Explanation: The design of structure of the machine is to be completely separate for the transportation system and also separate for the gauging system. Anti-vibration mounts are used on each of the supporting leg of the structure of gauging. These are used to insulate the gauging fixture from any possible vibrations.
9. Which of the following option is true for given statements about automatic inspection machines?
Statement 1: Safety devices are incorporated to avoid damage to the gauging fixture.
Statement 2: Gauging devices entering the part is positively pushed.
a) T, T
b) T, F
c) F, T
d) F, F
Answer: b
Explanation: The gauging devices entering the part should be spring loaded into their proper position and not positively pushed. If excessive force is needed anywhere then the further operation is stopped to avoid damage.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Electronic Gauging”.
1. What is the relation between e.m.f. and displacement in electronic gauging systems?
a) E.m.f is directly proportional to displacement
b) E.m.f is inversely proportional to displacement
c) E.m.f is independent to displacement
d) E.m.f is directly proportional to cube of displacement
Answer: a
Explanation: Mostly the electric gauging systems are based on the principle of displacement transducer e.g. LVDT which produces an e.m.f. This is linearly proportional to the displacement.
2. For which purpose indicating instrument is used in electronic gauging?
a) To display calculations
b) To display dimensions
c) To display electrical pulse
d) To display part number
Answer: c
Explanation: By using electronic techniques or electronic gauging systems the speed of gauging increased. The electrical impulse produced in electronic gauging system is generally displayed by an indicating instrument.
3. What is the operating speed of tolerance boundary circuits in electronic gauging?
a) 5 millisec or faster
b) 5 millisec
c) Below 5 millisec
d) Below 2 millisec
Answer: a
Explanation: Response time in electronic gauging systems is very fast. Tolerance boundary circuits are available in these gauging systems. These circuits operate in about 5 milliseconds or faster.
4. Which of the following is true about sensing devices used in electronic gauging systems?
a) Large size
b) Large size and expensive measuring fixture
c) Large size and inexpensive measuring fixture
d) Small size and inexpensive measuring fixture
Answer: d
Explanation: Sensing devices used in electronic gauging systems are of smaller size permitting use of a measuring fixture which is simple and less expensive. Accuracy of measurement in these systems is very high.
5. What is the range of high resolution transducers used in electronic gauging systems?
a) 1.5 mm
b) 2.5 mm
c) 3.5 mm
d) 4.5 mm
Answer: b
Explanation: High resolution transducers are used in electronic gauging systems. These transducers have a linear measuring range of 2.5 mm which may have a resolution of the order 0.00003 millimeter.
6. Which of the following option is correct for given statements about electronic gauging systems?
Statement 1: Size control systems are based on the principle of electronic gauging.
Statement 2: Gauging reliability is high.
a) T, T
b) F, F
c) T, F
d) F, T
Answer: a
Explanation: The size control system and automatic inspection have been developed based on the principles of electronic gauging systems. In these systems, it can be possible to set the desired dimension very precisely.
7. Which of the following is not true when electronic gauging is used for the adjustments when grinding operation is carried out?
a) Corrective actions can’t be carried out during grinding operation
b) Machine can stop automatically when necessary
c) Machine can recognise that components are falling in reject limits
d) Accuracy is very high
Answer: a
Explanation: It is possible to take the corrective actions on the grinding machine during operation of grinding and also possible to stop the machine automatically if the dimension of the component falls in the incorrect limits.
8. Which of the following option is true for the given statements about electronic gauging systems?
Statement 1: Capacitive pick-ups used in electronic gauging systems which make contact with the measuring tip.
Statement 2: Arithmetic operation can be carried out on electrical signals.
a) F, F
b) F, T
c) T, T
d) T, F
Answer: b
Explanation: Capacitive pick-ups do not make any contact so there is no wear problem on the tip or measuring tip. It is also possible to carry out simple arithmetic operations on the electrical signals which are generated by transducers.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Meaning of Surface Texture”.
1. What is the importance of the valley in any irregular surface?
a) Reduce metal to metal contact
b) Retain film of lubricating oil
c) Reduce stress concentration
d) Improve surface texture
Answer: b
Explanation: The hills in any irregular surface helps in reducing metal to metal contact and valleys are useful to retain the film of lubricating oil on the surface otherwise it will be difficult to maintain lubricating oil film on the surface.
2. What is the relation between rate of wear and contact surface area?
a) Rate of wear is inversely proportional to the contact surface area
b) Rate of wear is directly proportional to the contact surface area
c) Rate of wear is inversely proportional to the square of contact surface area
d) Rate of wear is directly proportional to the square of contact surface area
Answer: b
Explanation: If any surface has large number of irregularities i.e. hills and valley then the surface will obtain good bearing properties. Rate of wear is proportional to the load per unit area and surface area in contact.
3. Which of the following option is true for given statements about surface texture?
Statement 1: Concept of surface roughness is sensory.
Statement 2: Failure due to fatigue starts always at sharp corners.
a) T, F
b) F, T
c) F, F
d) T, T
Answer: d
Explanation: Concept of a roughness of surface is sensory. Surface roughness has been understood by a sense of touch and light. Failure due to Fatigue starts at sharp corner because at sharp corners stress concentration is more and that part fails earlier.
4. Which of the following is not true about first order irregularities?
a) Arising due to irregularities in machine tool itself
b) Arising due to weight of material itself
c) Arise due to vibrations
d) May arises due to deformation of work under action
Answer: c
Explanation: First order irregularities includes the irregularities arising out of inaccuracies in the machine tool itself. This includes the irregularities on surface arising due to work deformation under the action of cutting forces and the material weight itself.
5. Under which group, does waviness in surface falls?
a) Primary texture
b) Secondary texture
c) Tertiary texture
d) Quaternary texture
Answer: b
Explanation: If the hills and valleys are not close to each other or they both are far apart, it is due to the machine tool imperfections and this is referred to as waviness or secondary texture.
6. In how many categories, geometrical irregularities can be classified?
a) 3
b) 2
c) 4
d) 5
Answer: c
Explanation: Geometrical irregularities can be classified into four categories i.e. First Order, Second Order, Third Order, Fourth Order and these four categories are further grouped under two groups.
7. Match the following order with their irregularities.
A. First Order - 1. Feed marks of cutting tool
B. Second Order - 2. Lack of straightness of guideways
C. Third Order - 3. Rupture of material during chip removal
D. Fourth Order - 4. Vibrations
a) A-3, B-2, C-4, D-1
b) A-2, B-4, C-1, D-3
c) A-2, B-4, C-3, D-1
d) A-1, B-2, C-4, D-3
Answer: b
Explanation: Second order Irregularities caused by vibrations due to any reason such as chatter marks. If the machine is perfect and free of vibrations, some irregularities can be caused by machining itself due to the characteristic of the process, such type of irregularities include third order. Fourth order includes the irregularities due to rupture of the material during the chip removal.
8. Under which group, does third order irregularities fall?
a) Primary group
b) Secondary group
c) First group
d) Second group
Answer: d
Explanation: Irregularities of small wavelength falls under second group and caused by the direct action of the cutting element or by some disturbance such as friction. It includes irregularities of third and fourth order.
9. Which type of irregularities comes under the first group?
a) First and second order
b) Second and third order
c) Third and fourth order
d) First and fourth order
Answer: a
Explanation: First group includes irregularities of considerable wave-length. These errors include irregularities of first and second order. These are mainly due to misalignment of centres. These errors are also referred to as Waviness.
10. Which of the following is true about texture in case of finishing process?
a) Directional and irregular
b) Regular and directional
c) Irregular and non-directional
d) Regular and non-directional
Answer: c
Explanation: In case of finishing process, the texture is non-directional and non regular while if the surface is machined by a single point cutting tool then the surface will have roughness which is directional and uniformly spaced.
11. Under which category, does the error arises due to non-linear feed motion falls?
a) Second group
b) Primary texture
c) Waviness
d) Roughness
Answer: c
Explanation: The error caused by lack of straightness of guide-ways and non-linear feed motion are also referred to as Waviness or Secondary Texture. These errors or irregularities are of considerable wavelength.
12. Which of the following option is true if hills and valleys on any surface are very close?
a) Wavelength is more
b) Wavelength is small
c) Surface appears more wavy
d) Surface appears rough but wavelength is more
Answer: b
Explanation: If the hills and valleys are close to each other on any surface then the wavelength is very small and the surface appears rough and if they are far apart then the wavelength is more and appears more wavy.
13. Which term is used for errors of first and second order?
a) Micro geometrical error
b) Macro geometrical error
c) Mini geometrical error
d) Mili geometrical error
Answer: b
Explanation: The error or irregularity falls under first and second order are also termed as macro-geometrical errors and the irregularities or error of third and fourth order are termed as micro-geometrical errors.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Surface Roughness”.
1. What is meant by roughness?
a) Minute succession of hills of different height
b) Minute succession of valleys and hills of different height and varied spacing
c) Minute succession of valleys and hills of same height and same gap
d) Minute succession of valleys of different depth
Answer: b
Explanation: Imperfections are bound to be on surface and they take the form of succession of hills and valleys which vary in height and spacing which result in irregularity of the surface. Roughness is the form of these minute imperfections.
2. Surfaces produced by straight and cylindrical grinding tools tend to create which type of roughness?
a) Regularly spaced but directional roughness
b) Regularly spaced but non directional roughness
c) Irregularly spaced but directional roughness
d) Irregularly spaced but non directional roughness
Answer: c
Explanation: The roughness on the surface tends to be both irregularly spaced and directional in straight and cylindrical grinding and in the case of boring or lapping process the surface roughness tends to be irregular and non-directional in nature.
3. Which of the following is necessary for the complete study of surface roughness?
a) Measurement of all the components of elements
b) Analysis of all the component element
c) Assessment of the effects of combined texture
d) Measurement and analysis of all the components and assessment of combined texture
Answer: d
Explanation: For the complete study of the surface roughness, it is important that the analysis and measurement of all the component elements be made and an assessment of the effects of the combined texture be made.
4. Which of the following is true for measurement of surface roughness?
a) 3 dimensional geometry can be easily measured
b) Direction of measurement is perpendicular to the lay
c) Direction of measurement is parallel to the lay
d) Direction of measurement is parallel to the direction of the predominant surface marking
Answer: b
Explanation: There are difficulties in the measurement of surface roughness in three dimensional geometry, but for simplification purposes, it is reduced into two dimensional geometry. To measure, the direction is generally perpendicular to the direction of the predominant surface markings or “lay”.
5. How much a stylus instrument can be magnified to plot or find minute irregularities?
a) 50 times
b) 500 times
c) 5000 times
d) 50,000 times
Answer: d
Explanation: The shape of the hills and valleys is best studied in a cross-section normal to the surface using a stylus instrument which plots a graph in which even the minute irregularities are magnified upto 50,000 times whereas the length over which observations are made is magnified only by 50-300 times.
6. Which of the following is true about Tomlinson surface meter?
a) It is a mechanical instrument
b) It is an electrical instrument
c) It is a mechanical cum optical instrument
d) It is an optical instrument
Answer: c
Explanation: The Tomlinson surface meter uses mechanical cum optical means for magnification. It has a diamond stylus on the surface finish recorder. This instrument is given reliable results.
7. What do you mean by dominant spacing?
a) Distance between successive peaks when irregularities are comparatively uniform in shape and size
b) Distance between middle point of successive hills when irregularities are comparatively uniform in shape and size
c) Distance between middle point of successive valleys when irregularities are comparatively uniform in shape and size
d) Distance between successive peaks when irregularities are regardless of shape and size
Answer: a
Explanation: When the irregularities are uniform in shape and size, then the distance between the peaks or successive peaks is described as pitch or dominant spacing. These spacings are measured by using an instrument.
8. Which of the following is used for the direct measurement of surface quality and commonly used in U.S.A.?
a) Profilometer
b) Tomlinson surface meter
c) Talysurf
d) Replica method
Answer: a
Explanation: Profilometer is most commonly used in U.S.A. It is used for direct measurement of surface quality. It is a dynamic instrument and principle is similar to the gramophone pick-up.
9. Which of the following parameter is important for specifying surface roughness?
a) Size of irregularity
b) Spacing of irregularity
c) Height of irregularities
d) Height, spacing and form of irregularities
Answer: d
Explanation: The surface roughness is concerned with both the size and the shape of the irregularities. Both size and shape i.e. height of irregularities, their spacing and form are important for specifying surface roughness.
This set of Engineering Metrology online test focuses on “Terminology as per Indian Standards”.
1. What do you mean by Geometrical Surface?
a) Surface prescribed by design without any errors of form or surface roughness
b) Surface limiting the body and separating it from surrounding
c) Close representation of real surface
d) Outer surface of the body
Answer: a
Explanation: Geometrical surface is the surface prescribed by design or by process of a manufacturer, neglecting errors of form or surface roughness. Real surface is the surface limiting the body and separating it from surrounding surface.
2. Under which category, does the scratches falls?
a) Lay
b) Effective surface
c) Flaws
d) Geometrical surface
Answer: c
Explanation: Flaws are the type of irregularities which occur at one place or at relatively infrequent or at very widely varying intervals in surface. Scratches, cracks, random blemishes etc. are the type of flaws.
3. Which of the following statement is wrong about sampling length?
a) It is the length of profile necessary for evaluation of irregularities to be taken account
b) It is known as cut off length in regard to measuring instruments
c) It is measured in a direction parallel to general direction of profile
d) It is the length of profile necessary for evaluation of surface roughness parameters
Answer: d
Explanation: Sampling length is the profile length which is necessary for the evaluation of the irregularities. This is also called as the ‘cut-off length’ in regard to the measuring instruments. It is measured in parallel direction to the direction of the profile.
4. What is the general instrument cut off for majority engineering work?
a) 0.08 mm
b) 0.8 mm
c) 0.1 cm
d) 0.5 mm
Answer: b
Explanation: For majority of the engineering work, 0.8 mm is considered to be quite satisfactory for instrument cut-off and for most waviness measurements upper limit of about 25 mm is suitably accepted.
5. What is the upper limit that is commonly accepted for waviness measurement?
a) 10mm
b) 20mm
c) 25mm
d) 15mm
Answer: c
Explanation: There is no theoretical value that could be assigned to maximum spacing for waviness as higher value of waviness tends to merge with other general errors in geometric forms. 25mm is the upper limit commonly accepted as suitable for waviness measurement.
6. What is the correct formula for average wavelength to describe surface roughness? (Where, R a is the arithmetic mean deviation from the mean line of profile)
a) 2π x R a / Mean slope
b) 2π x R a x Mean slope
c) 2π / R a x Mean slope
d) 2π / R a / Mean slope
Answer: a
Explanation: R t is the maximum height of peak to valley within the assessment length. R t measurement is valuable for providing guidance for planning metal-cutting operations and analysing finish. Average wavelength = 2π x R a / Mean slope.
7. Which of the following is an effective surface as per Indian standard?
a) A real surface is an effective surface
b) It is the direction of predominant surface pattern
c) Close representation of real surface
d) Real surface which doesn’t represent instrumental means
Answer: c
Explanation: A real surface is the surface which limiting the body and separating it from the surface of surrounding and effective surface is the close representation of real surface which is obtained by instrumental means.
8. Which of the following is true for a mean and center line of profile?
a) When the waveform is repetitive then there is some difference between mean and centre line
b) Mean line of profile is the mean distance between more prominent irregularities
c) Mean line profile is the average value of ordinates from mean line
d) Centre line of profile is the line which is parallel to the direction of profile and area embraced above and below the line is equal
Answer: d
Explanation: Mean line of the profile is the line which have the form of the geometrical profile. Mean line of profile divides the effective profile so that the sum of the squares of distances between effective points and the mean line is a least. When the waveform is repetitive, the centre and mean line are equivalent.
9. What is ten point height of irregularities?
a) Average difference between 10 highest peaks
b) Average difference between 10 deepest valleys
c) Average difference between 5 highest peaks and 5 deepest valleys
d) Average difference between 10 highest peaks and 10 deepest valleys
Answer: c
Explanation: Ten point height of irregularities is represented by R z and defined as the average difference between the 5 highest peaks and the 5 deepest valleys within the sampling length measured from a line, not crossing the profile and parallel to the mean line.
10. Which of the following is a criterion of a good bearing surface?
a) Positive skew
b) Negative skew
c) Negative peak roughness
d) Positive start up length
Answer: b
Explanation: Skew will show whether porous, sintered and cast iron surfaces will yield a meaningful Ra measurement. Negative value of skew is the criterion for a good bearing surface.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Methods of Measuring Surface Finish”.
1. Which of the following is the best for the examination of surface finish?
a) Touch inspection
b) Visual inspection
c) Scratch inspection
d) Microscopic inspection
Answer: d
Explanation: Microscopic inspection is the best method for examining the surface finish. Visual, touch and scratch inspection methods are not as accurate as microscopic. In these methods, minute flaws can’t be detected.
2. Upto which limits irregularities can be detected with touch inspection of a surface?
a) 0.0001 mm
b) 0.001 mm
c) 0.01 mm
d) 0.1 mm
Answer: c
Explanation: Touch inspection method can tell which surface is rougher. In this method, the finger-tip is moved along the surface at a speed of about 25/sec and the irregularities of about 0.01 mm can be easily detected.
3. Which of the following material is not used for rubbing on the surface to be inspected in scratch inspection?
a) Softer material
b) Hard material
c) Plastic
d) Lead babbitt
Answer: b
Explanation: In scratch inspection method, a softer material like plastic or lead babbitt is rubbed over the surface to be inspected. It carries the impression of the scratches on it which can be easily visualised.
4. Which of the following option is true for given statements about method of measurement of surface finish?
Statement 1: Minute flaws can be easily detected by touch inspection.
Statement 2: Direct instrument measurement is enabled to determine a numerical value of surface finish.
a) F, T
b) T, F
c) F, F
d) T, T
Answer: a
Explanation: The main limitation of the method of inspection by touch is that the degree of surface roughness can not be assessed by this and also the minute flaws can’t be detected by the only touch.
5. What is the limitation of microscopic inspection to check surface finish?
a) An average value is needed
b) Small portion of surface can be detected at a time
c) A master finish surface is also needed
d) It is necessary to inspect whole surface together
Answer: b
Explanation: Microscopic inspection method have some limitation that at a time only a small portion of the surface can be inspected. So for inspection, several readings are required in this method to get an average value.
6. In the method of microscopic inspection what is the angle of beam light with the work?
a) 20 0
b) 30 0
c) 60 0
d) 90 0
Answer: c
Explanation: In one method of microscopic inspection, a straight edge is placed on the surface to be inspected and a beam of light is projected at about 60 degree to the work. The shadows cast into the surface scratches are magnified and studied.
7. Which of the following is true for a method of measurement of surface finish with surface photographs?
a) Different type of illumination is needed
b) No effect of type of illumination
c) Same type of illumination is needed
d) Monochromatic light is needed
Answer: a
Explanation: In the method of surface inspection with magnified photographs of the surface are taken with different types of illumination. After this photographs with different illumination are studied and compared.
8. In case of vertical illumination in measuring surface finish with surface photographs, which will appear as bright area?
a) Flat portion
b) Scratch
c) Irregularity
d) Hills
Answer: a
Explanation: In the inspection of surface with photographs if we use vertical illumination, then irregularities and scratches appear as dark spots and flat portion of the surface as bright area. But in case of oblique illumination, the case is reverse.
9. Which of the following method use pendulum in measuring the surface finish?
a) Micro interferometer
b) Wallace surface dynamometer
c) Reflected light intensity method
d) Microscopic inspection
Answer: b
Explanation: Wallace surface dynamo meter is like a friction meter which consists a pendulum in which the testing shoes are present which are clamped to a bearing surface and a spring pressure which is predetermined can be applied.
10. Which of the following is not true for the method of measurement of surface finish by micro interferometer?
a) Optical flat is used
b) Monochromatic source of light is used
c) Depth of defect can’t be measured
d) Interference lines plays an important role in identification of the defect
Answer: c
Explanation: In the method of inspection of surface by using micro interferometer, an optical flat is used which is placed on the surface to be examined and illuminated by using monochromatic light. Interference bands are studied by using a microscope. Defects or scratches appear as interference lines extending from the dark bands into the bright bands.
11. Which of the following is the direct measure of surface finish in Wallace surface dynamometer?
a) Time of swing
b) Angle of swing
c) Length of swing
d) Height of swing
Answer: a
Explanation: In the case of Wallace surface dynamometer, if the surface to be tested is smooth, there will be less friction and pendulum swings for a longer time period. So, time of swing of pendulum is a direct measure of surface finish.
12. Which of the following is a destructive method in measuring surface finish?
a) Gloss measurement
b) Taper sectioning
c) Diffraction technique
d) Micro interferometer
Answer: b
Explanation: In taper sectioning method, a section is cut through the surface to be inspected at a shallow angle, thus magnifying height variations by a factor of cot theta, and the section is studied by optical microscope. It is an accurate but destructive method.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Advantages of Dial Indicators”.
1. Which of the following is true for the use of dial indicators?
a) Skilled labour is necessary
b) Useful for quantity control in inspection room
c) Useful for quality control in inspection room
d) Considerable practice is required before use
Answer: c
Explanation: Ease of reading in a dial indicator is the best advantage over other conventional type gauges of linear measuring instruments, for which before the proficiency of use requires a degree of skill and considerable practice.
2. Which of the following is provided in dial gauge to raise the plunger?
a) A finger lever
b) Probe
c) Spring
d) A pointer
Answer: a
Explanation: The dial gauge instrument is used in such a way that plunger move sharply in either direction. So the instrument should be made so that by such movement, it will not be damaged and its accuracy and setting will not be spoiled. A knob or finger lever is provided for raising the plunger.
3. What is the relation between accuracy attained and range of travel in measurement with dial gauges?
a) Accuracy attained is directly proportional to the range of travel
b) Accuracy attained is inversely proportional to the range of travel
c) Accuracy attained is directly proportional to the square of a range of travel
d) Accuracy attained is independent to the range of travel
Answer: b
Explanation: When a measurement is done by using dial indicators then the accuracy achieved in measurement is inversely proportional to the range of travel in measurement. There is no need of very large range to attain high accuracy.
4. What is the range of dial indicators?
a) 1 mm
b) 5 mm
c) 7 mm
d) 10 mm
Answer: d
Explanation: Range of travel of dial indicator is of the order of 10 mm. On finished work, dial gauges are mostly used as comparators and a narrow range is needed to have high accuracy.
5. Which of the following is not an advantage of dial indicator?
a) Use in mass production
b) Suited for precision dimensional control
c) Specialised skilled labour helps in attain greater accuracy
d) Versatile
Answer: c
Explanation: Dial gauges are best suited for precision dimension control where tolerance is very little. Over a long period dial gauge instrument is capable of giving trouble-free and dependable measurements.
6. How much operating pressure is required on a measuring head to obtain the zero reading in dial indicators?
a) 20 oz
b) 40 oz
c) 60 oz
d) 80 oz
Answer: d
Explanation: On a measuring head, the required operating pressure in dial gauges to obtain the zero reading is of the order of 80 oz and should remain constant over the whole range.
7. Which of the following is a problem in using dial gauges?
a) Gauge wear
b) Effect of temperature variation
c) Economy
d) Oscillation in the pointer
Answer: d
Explanation: Other advantages of dial gauges over conventional gauges are that it is not subjected to the gauge wear and there is no effect of temperature variation on the instrument. It is a versatile and economic instrument.
8. Which of the following option is true for the given statements about dial indicators?
Statement 1: Dial indicators can inspect dimensional variation.
Statement 2: It is not suitable to use to check out of roundness.
a) T, F
b) F, T
c) F, F
d) T, T
Answer: a
Explanation: Dial indicator is able to inspect dimensional variations which are very difficult to detect by conventional gauges. Type of roundness and taper can be detected with the help of roundness.
9. Which of the following is true for the advantages of dial indicators?
a) Slow speed but good adaptability
b) Adaptability and positive visibility
c) Positive visibility and expensive set ups
d) Use of different inspectors but inexpensive set-ups
Answer: b
Explanation: In addition to the speed of the dial indicator gauge, positive visibility and adaptability, economy and accuracy, place them in the category of a precision measurement instrument.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Working Mechanism of Dial Indicators”.
1. Which of the following is necessary for the working mechanism of dial indicators?
a) High magnification ratio
b) Low magnification ratio
c) Moderate magnification ratio
d) Good magnification ratio is achieved by using gear and pinions in a large area
Answer: a
Explanation: High magnification ratio is important in this instrument which is achieved by the use of an arrangement of gears and pinions in a small area. Gear train is arranged in a manner similar to a clock movement.
2. What is the purpose of a pin which is located in a slot in rack guide in dial indicator?
a) Prevent movement of plunger perpendicular to its own axis
b) Prevent rotation of plunger about its own axis
c) Prevent plunger displacement
d) Prevent movement of plunger in case of misalignment
Answer: b
Explanation: The plunger rotation about its own axis is prevented by a pin which is located in a slot in a rack guide carries a rack accurately meshing with the pinion. The plunger is a perfect sliding fit in its bearings.
3. What is the pressure exerted by spring in dial gauge?
a) 2 oz
b) 3 oz
c) 4 oz
d) 6 oz
Answer: d
Explanation: In order to keep the plunger in a normal position or extended position a spring is used. This spring is a light coil spring and the pressure exerted by this spring is of about 6 oz.
4. Why rotatable bevels are used in dial indicators?
a) Facilitate the work of machine setting
b) Acts as an offset attachment
c) Prevent shocks
d) For making final zero setting
Answer: d
Explanation: Most of the dial indicators include a rotatable bezel. Rotatable bezel is used to make the final zero setting at any position in the full circle. A clamp is also provided for locking it in any position.
5. Which of the following is attached to dial face for rapid checking of parts?
a) Tolerance pointers
b) Contact points
c) Special stems
d) Lever attachments
Answer: a
Explanation: Tolerance pointers can be attached to the dial face for rapid checking of the parts. These pointers can be used to clearly indicate any tolerance, whether bilateral or unilateral, on the dial gauge.
6. What is the purpose of lever attachment used in dial indicators?
a) Checking of parts
b) Transfer motion at the right angle to the spindle
c) Transfer motion at the 180 degree to the spindle
d) Transfer motion at the 60 degree to the spindle
Answer: b
Explanation: Lever attachments are very useful part in a dial indicator. The attachment transfers motion 90 degree directly to the indicator spindle. There is provision to avoid any type of errors caused due to play in bearings and wear.
7. Which of the following is used to inspect deep recesses by dial indicators?
a) Rotatable bezels
b) Cushioned pointers
c) Stem indicators
d) Contact points
Answer: c
Explanation: Dial indicators can also be used inspect deep recesses but in this case, an additional part attachment is required i.e. a stem indicator. Long stem indicators are used where deep recesses are to be inspected.
8. Which of the following option is true for given statements about dial indicators?
Statement 1: Gears are precision cut to prevent backlash.
Statement 2: Change of contact points make dial indicators more versatile.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: d
Explanation: To take up the backlash, a hair spring is fitted to the dial gauge gear trains by a gear and pinion meshing. The gears are precision cut and the movement assembly resembles that of high-grade watch to prevent the gear from backlash.
9. Why a revolution counter is used in dial gauge?
a) To withstand sudden shock
b) To indicate correctly the number of revolution
c) To count and display the number of revolutions
d) To transfer motion at right angle
Answer: b
Explanation: A revolution counter is present in dial gauge, if the pointer makes more than one revolution, it will correctly indicate the number of revolutions and enable a complete reading to be made when the indicator is used for direct measurement.
This set of Tough Engineering Metrology Questions and Answers focuses on “General Care of Dial Gauges”.
1. Which of the following statement is true for dial indicators?
a) It can be used as a direct measuring instrument
b) It can only be used as a comparator
c) There is no effect on accuracy if the surface of contact point worn out
d) Test for repeatability is done only once at the starting
Answer: b
Explanation: Dial gauges are only used as comparators and should not be used as direct measuring instruments. It provides only relative measurement. These are used to check consistency and accuracy in manufacturing processes.
2. What will happen if plunger lifting lever released suddenly?
a) Break the plunger
b) Lever will break
c) No effect
d) Distort rack teeth
Answer: d
Explanation: When the plunger lifting lever raised to allow work to be inserted under the contact point, then after completing this it must be released slowly. Sudden release will distort the rack teeth.
3. Which of the following is true for plunger used in dial indicator?
a) It should never be greased or oil
b) It should be greased monthly
c) It should be oil or greased after every use
d) It should be oiled weekly
Answer: a
Explanation: Oiling and greasing are not desirable in plunger of dial indicator. Oiling of plunger will only result in picking up of dust and sticking. The plunger should never be greased or oiled.
4. When does the back mounting used in dial indicators?
a) When space is limited and positive clamping is not required
b) When space is more and positive clamping is required
c) Space is limited and positive clamping is required
d) Space is more and positive clamping is not required
Answer: c
Explanation: A dial indicator could be mounted either by the back or by the stem. Back mounting of dial indicator provides more positive clamping. It is preferred where fixture design mount permits adjustment and space is limited.
5. Which of the following is not true about the clamping force and clamping of dial indicators?
a) Too great clamping force may jam the plunger
b) Clamp should be loose in case of back lug
c) Tight clamp will always cause slip
d) Steel stem are best for clamping
Answer: a
Explanation: If the dial gauge is clamped by the steel stem, then a great a clamping force will cause the jamming of plunger in the stem. The fixture hole must be smooth and true to avoid distortion, locking and binding of stem in it.
6. Which of the following is not true for contact points used in dial indicators?
a) These are generally blackened
b) Made of hardened steel
c) General purpose contact point is of square form
d) Contact end is polished
Answer: c
Explanation: The contact points are made of hardened steel and blackened to avoid rusting. To prevent scratching of workpiece, the contact end is polished. The general purpose contact point is of spherical shape.
7. What is the accuracy of dial indication for 2.3 turns?
a) Within ±1 graduation
b) Within ±0.1 graduation
c) Within ±2 graduations
d) Within ±0.2 graduations
Answer: a
Explanation: The dial indicator should be accurate to within ±1 graduation with 2.3 turns, that is the variation of the actual object size with the setting master is displayed by the pointer position with a maximum error of ± 1 graduation, at any position within 2.3 turns.
8. Which of the following is true for flat surface of flat contacts in dial gauges?
a) Should be parallel to the plunger
b) Should be truly square to the measuring surface of fixture
c) Should be square to the plunger
d) Should be perpendicular to the measuring surface of plunger
Answer: c
Explanation: If contact points of dial gauge are worn, then it should be replaced as early as possible. The surface of flat contacts should be square truly to the plunger and for accurate reading should be parallel to the measuring surface of the fixture.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Test Indicators”.
1. Which of the following has a maximum sensitivity?
a) Vernier caliper
b) Test indicator
c) Dial indicator
d) Passmeter
Answer: b
Explanation: Accuracy, dependability, performance of test Indicators are outstanding and also long life. Maximum sensitivity and accuracy ensured by jewel mounting of the movement in conjunction with gears and pinions which are precision ground.
2. Which type of housing is used in the test indicator?
a) Box type
b) Spherical
c) Split type
d) Detachable
Answer: a
Explanation: Test indicator is a self-contained instrument, a separate unit which can be easily replaced and removed when in a case or need of repair or for maintenance. The housing of test indicator is of box type.
3. Which of the following is the difference between test indicator and dial indicator?
a) Test indicator has lever type contacts
b) Dial indicator is lighter than test indicator
c) Dial indicator is smaller than test indicator
d) Stylus is present in dial indicator but not in test indicator
Answer: a
Explanation: Test indicators are different from the dial indicators. The obvious difference between these two is that dial indicators have plunger-type contacts and test indicators have lever-type contacts. Test indicators are also lighter and smaller than dial indicators.
4. Which of the following is true about housing of test indicator?
a) Opens at the bottom only
b) Opens at the top only
c) Opens at bottom and top both
d) Opens at front only
Answer: d
Explanation: The housing of test indicator opens at the front only. Single piece construction of side panels and also of bottom surface. The housing encloses totally the movement. It provides maximum protection against shock and damages.
5. Which of the following option is true for the given statement about test indicators?
Statement 1: It can’t measure depth of holes.
Statement 2: Spring force is low.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: The test indicators cannot measure the depth of the holes as dial indicators can. On the test indicator the spring force is very lower, which is desirable while measuring deformable materials.
6. Which of the following is true about the material used for making parts in test indicators?
a) No part is made of plastic
b) All parts are made of hardened steel
c) Cover over the dial face is made of hardened metal
d) Cover over the dial face is made of plastic
Answer: d
Explanation: Plastic parts are not used on this instrument but there is an exception of the cover over the dial face which is made up of plastic. Easy to read by sharply defined dial face is present with contrasting numerals.
7. What is the shape of the front end of the housing of a test indicator?
a) Rectangle
b) Shape of a fork
c) Square
d) Shape of a round ball
Answer: b
Explanation: The design of front end of the housing is of the shape of a fork and between this fork the axis of the stylus is mounted, thus providing added shock resistance and stability. The precision alignment of the 2 mounts also insures maximum accuracy.
8. Which of the following option is true about the guideways present is test indicator?
a) Dovetail guideways are present only at the top of the housing
b) Dovetail guideways are present only at the bottom of the housing
c) Dovetail guideways are present at the top and bottom of the housing
d) Square guideways are present only at the top of the housing
Answer: c
Explanation: Dovetail guideways are present at top and bottom of the housing which permits easy movement of the mounting shanks. By simply tightening a clamp nut which is knurled they can be clamped at any desired point. No need of separate tool.
9. Which of the following is not an advantage of automatic reversing in test indicators?
a) Error free reading
b) Less effort
c) Eliminate reversing lever
d) Indicator hand always move anti-clockwise
Answer: d
Explanation: Automatic reversing is present in test indicator which eliminates the need of reversing lever. The indicator hand present in it always moves in clockwise direction which ensures error-free readings.
10. Which of the following option is true for the given statements about test indicators?
Statement 1: Housing has a satin chrome finish.
Statement 2: Stylus is made of stainless hardened steel.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: c
Explanation: It has a Corrosion-proof housing with satin chrome finish and stainless hardened steel for the stylus. Test indicators are of unique quality and durability. Even after millions of measurement test indicators are still accurate and meet specifications.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Indicators Gauges”.
1. What is the alternative name of passmeter?
a) Dial-type adjustable ring gauge
b) Dial-type adjustable snap gauge
c) Dial-type adjustable plain gauge
d) Dial-type adjustable plug gauge
Answer: b
Explanation: Passmeter is also called as a dial-type adjustable snap gauge. Passmeter instrument is quite similar to the micrometer screw gauge. A passmeter has very big scale present in its frame on which a pointer moves.
2. Which of the following is used for magnification purpose in passmeter?
a) Lever and gear movement
b) Anvil and lever
c) Anvil and gear
d) Clamping screw and anvil
Answer: a
Explanation: The lever and gear movement are used for magnification purposes in a passmeter. It is an indicator gauge and even much more accurate than the dial indicator instrument.
3. Which of the following is a part of internal dial gauge?
a) Solid body and clamping screw
b) Solid tube body and lever
c) Solid tube body with finger probe
d) Hollow tube body and lever
Answer: d
Explanation: Internal dial gauges is a comparison gauge and used to check bore diameters by the comparative method. The instrument consists of a hollow tube body which contained a lever pivoted.
4. What is the range of measurement in a single setting of internal dial gauge with scale division value of 0.002 mm?
a) ±0.06 mm
b) ±0.02 mm
c) ±0.01 mm
d) ±0.1 mm
Answer: a
Explanation: The range of measurement in a single setting of internal dial gauge is approximately ± 0.06 with scale division value of 0.002 mm and ± 0.22 millimeter for scale division value of 0.01 millimeter.
5. What is the smallest size that can be measured by internal dial gauge?
a) 5 to 10 mm in diameter
b) 7 to 10 mm in diameter
c) 11 to 18 mm in diameter
d) 5 to 18 mm in diameter
Answer: c
Explanation: The contacts present in internal dial gauge are interchangeable having extension rods to broaden the measurement range. This instrument can check the smallest size of the order or 11 to 18 mm in diameter.
6. How many tolerance pointers are provided on the scale of passmeter?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: There are two tolerance pointers are present on the scale of passmeter which can be set in any position just by unscrewing the cap which is present on the cover and by using a special setting wrench.
7. What is the value of pressure applied by the spring on the back of the movable anvil in passmeter?
a) 500±50 grammes
b) 100±5 grammes
c) 500±100 grammes
d) 700±200 grammes
Answer: d
Explanation: A detent is present in the passmeter which is used for retracting the movable anvil while taking the measurement. The spring which is present at the back of the movable anvil exerts a contact pressure of about 700 ± 200 grammes.
8. What is the diameter of the contact point of a spindle in dial pipe gauge?
a) 2.5 mm
b) 3.5 mm
c) 4.5 mm
d) 5.5 mm
Answer: a
Explanation: Dial pipe gauge is specially used for easy measurement of pipe’s wall thickness. It is a dial thickness gauge. Diameter of a contact point of the spindle is 2.5 mm. Minimum measurable inside diameter of pipe is about 3.5 mm.
9. What is the largest size range that can be checked by internal dial gauges?
a) 156 to 200 mm
b) 106 to 200 mm
c) 86 to 120 mm
d) 56 to 120 mm
Answer: c
Explanation: The largest size range that can be checked by internal dial gauge is from 86 to 120 mm. It has lever whose one end of the lever is attached to the movable contact of this instrument and other end actuates the pointer.
10. How many contacts are present in internal dial gauges?
a) 1 which is fixed
b) 2, one fixed and other movable
c) 3, two fixed and one movable
d) 4, two fixed and two movable
Answer: c
Explanation: The internal dial gauge instrument has three contacts which are spaced equally along the circumference of the head. Out of three contacts, one is movable and the other two are fixed or non-movable type.
11. Which of the following is not true about passmeter?
a) Fixed spindle
b) Adjustable anvil
c) Used for external measurement
d) Movable pointer
Answer: a
Explanation: An adjustable anvil is present in passmeter. The adjustment of this anvil is done by first removing the protecting cover from the frame and then releasing the clamping screw. A movable spindle is present in passmeter.
12. Upto which depth dial caliper gauge can reach?
a) 60 mm
b) 80 mm
c) 20 mm
d) 10 mm
Answer: b
Explanation: Internal caliper gauge is used for comparison of inside diameter quickly. It can reach 80 mm of depth. It is a comparison gauge and can be used with micrometer or master ring for zero setting.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Screw Threads Terminology”.
1. What is the name of screw thread which is formed on a cone?
a) Parallel screw thread
b) Straight screw thread
c) Tapered screw thread
d) Cylindrical screw thread
Answer: c
Explanation: A screw thread is formed by forming a continuous helical groove on the external or internal surface of cylinder. The screw thread formed on frustum of a cone or a cone is called as tapered screw thread.
2. What type of thread is formed on female screw gauge?
a) External thread
b) Internal thread
c) Both internal and external
d) Major screw thread
Answer: b
Explanation: An internal thread is that which formed on the inside of a workpiece e.g. on female screw gauge or a nut. An external thread is that which formed on the outside of a workpiece e.g on bolts or studs.
3. Which of the following option is true for truncation?
a) Thread can be tranculated at crest only
b) Thread can be tranculatd at root only
c) Thread can be tranculated at crest and root both
d) Thread can’t be tranculated at crest and root both
Answer: c
Explanation: A thread is truncated sometimes at the crest or at the root or at both root and crest and root. The radial distance from the crest to the nearest apex of the fundamental triangle is truncation at the crest is and at the root it is the radial distance from the root to the nearest apex.
4. What is dedendum for external threads?
a) Radial distance between pitch and minor cylinder
b) Radial distance between major and pitch cylinder
c) Radial distance between major and minor cylinder
d) Axial distance between major and pitch cylinder
Answer: a
Explanation: Addendum for an external thread is defined as the radial distance between the major cylinder and pitch cylinder and for internal addendum is the radial distance between the minor cylinder and pitch cylinder. Dedendum for external thread is the radial distance between the pitch cylinder and minor cylinder and this is the radial distance between the major and pitch cylinders for internal thread.
5. Which of the following is not a name of the major diameter of an external thread?
a) Outside diameter
b) Crest diameter
c) Full diameter
d) Cone diameter
Answer: d
Explanation: For a straight thread, Major diameter is the diameter of the major cylinder. It is also known to as the outside diameter or full diameter for external threads. Sometimes it is also called crest diameter.
6. Which of the following is not true about the axial thickness of screw thread?
a) Measured in direction perpendicular to the axis of thread
b) Measured on pitch cylinder
c) Distance between opposite faces of same thread
d) Measured at the same thread
Answer: a
Explanation: In a screw thread axial thickness is the distance between the opposite faces of the same thread. It is measured on the pitch cylinder and in a direction parallel to the thread axis.
7. What is the alternative name of functional diameter?
a) Cone diameter
b) Virtual diameter
c) Root diameter
d) Inside diameter
Answer: b
Explanation: Functional diameter is also known as virtual diameter. For an internal or external thread, this is the pitch diameter of the enveloping thread, lead and flank angles having the full depth of engagement but not at roots and crests.
8. What is a thread per inch in screw thread?
a) Pitch in inches
b) Axial distance moved by threaded part
c) Reciprocal of pitch in inches
d) Radial distance moved by threaded part
Answer: c
Explanation: Thread per inch is the reciprocal of the pitch. The angle made by the thread helix at the pitch line with plane perpendicular to the axis is known as lead angle. Lead angle is measured in an axial plane.
9. Which of the following is not true about effective diameter?
a) Also known as pitch diameter
b) It decides quality of fit between nut and screw
c) This is the diameter of minor cylinder
d) It is a very important dimension for screw threads
Answer: c
Explanation: In case of straight thread, effective diameter is the diameter of the pitch cylinder and is also called as pitch diameter. Effective diameter is the most important dimension at it decides the quality of the fit between the nut and the screw.
10. Which of the following is true for the multiple start screw threads?
a) It is produced by a single helical groove
b) Grooves should be different in spacing
c) It gives a quick transverse
d) It is formed in a transverse section on a cylinder
Answer: c
Explanation: Multiple start screw threads is produced by forming two or more than two helical grooves, equally spaced and similarly formed in an axial section on a cylinder. This gives a ‘quick traverse’ without sacrificing core strength.
11. Which of the following statement is true for screw threads?
Statement 1: Flank angle of symmetrical thread is known as thread’s half-angle.
Statement 2: It is measured parallel to the axis of a thread.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: a
Explanation: In a screw thread the angles between individual flanks and perpendicular to the thread axis which passes through the vertex of the fundamental triangle are called flank angles. The flank angle of a symmetrical thread is called as the half-angle of a thread.
12. Flanks of the threads connect the crest with the roots.
a) True
b) False
Answer: a
Explanation: Flanks of thread are straight edges which connect the crest and the root. Angle of thread is the angle between the flanks or slope of the thread measured in an axial plane and also known as the included angle.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Effect of Pitch Errors”.
1. What is the effect of pitch error?
a) Increase effective diameter of bolt
b) Decrease effective diameter of screw
c) Increase effective diameter of nut
d) Increase effective diameter of both nut and screw
Answer: a
Explanation: An error in pitch increases the effective diameter of a screw or bolts virtually and virtually decreases the effective diameter of a nut. The meaning of the virtual change is that if any screw is perfect except for pitch error, if its effective diameter is not reduced, it will not easily screwed into a perfect ring gauge of same nominal size.
2. What is the virtual change in effective diameter caused by pitch error in whitworth thread?
a) 1.821 X pitch error
b) 1.921 X pitch error
c) 1.111 X pitch error
d) 1.211 X pitch error
Answer: b
Explanation: If p is the error in a pitch for a whitworth thread, then the virtual increase or decrease in the thread effective diameter in case of bolt or nut is given by the formula: Virtual change in effective diameter = 1.921 x p.
3. What is the virtual change of effective diameter of bolt or nut in case of whitworth thread in terms of error in flank angle?
a) 0.1921 X p(θ 1 + θ 2 )
b) 0.182 X p(θ 1 + θ 2 )
c) 0.0195 X p(θ 1 + θ 2 )
d) 0.0105 X p(θ 1 + θ 2 )
Answer: d
Explanation: A Corresponding reduction in the effective diameter is also needed for the errors in flank angles, if the screw or nut is to fit a perfect ring gauge of the same nominal size. Formula for virtual change in effective diameter is : 0.0105 X p(θ 1 + θ 2 ). Where p is the normal pitch and θ 1 and θ 2 are the error in flank angles.
4. Which of the following is periodic pitch error?
a) Successive portion of thread is longer than the mean
b) Successive portion of thread is shorter than the mean
c) Successive portion of thread is longer or shorter than the mean
d) Successive portion of thread is neither longer nor shorter than the mean
Answer: c
Explanation: Periodic pitch error repeats itself along the thread at regular intervals of time. In this type of error, successive thread portions are either shorter or longer than the mean. It occurs when the tool velocity work ratio s not constant.
5. What is the formula of virtual effective diameter in case of unified threads?
a) Simple effective diameter + [ + 0.0098 p (θ 1 + θ 2 )].
b) Simple effective diameter – [ + 0.0098 p (θ 1 + θ 2 )].
c) Simple effective diameter + [ + 0.0098 p (θ 1 + θ 2 )].
d) Simple effective diameter – [ + 0.0098 p (θ 1 + θ 2 )].
Answer: a
Explanation: For unified thread total virtual effective diameter is Simple effective diameter + [ + 0.0098 p (θ 1 + θ 2 )] while in case of metric thread it is Simple effective diameter + [ + 0.0131 p (θ 1 + θ 2 )].
6. Which of the following is not correct when minor and major diameter have errors?
a) Will cause interference between mating parts
b) Flank contact increases
c) Less root section
d) Less wall thickness
Answer: b
Explanation: Errors on the minor and major diameters will cause interference in the mating thread. Due to errors in minor and major diameter, the wall thickness and root section will be less, also the flank contact will be decreases and the component will be weak in strength.
7. Which of the following are main elements, error in any of these can cause rejection of thread?
a) Major diameter and minor diameter
b) Major diameter, minor diameter and effective diameter
c) Major diameter, minor diameter, effective diameter and pitch
d) Major diameter, minor diameter, effective diameter, angle of thread and pitch
Answer: d
Explanation: In case of plain holes and shafts, there is one dimension only which has to be considered i.e. diameter. Errors in diameter if exceed the permissible tolerance, will result in rejection of part. But in case of screw threads there are minimum 5 important elements which are Major diameter, minor diameter, effective diameter, angle of thread and pitch and error in any one of these will result rejection of the thread.
8. What is the nature of the graph between cumulative pitch error and length of thread in case of progressive pitch error?
a) Straight line
b) Parabolic
c) Hyperbolic
d) Exponential
Answer: a
Explanation: Progressive pitch error can be caused due to pitch error in any generating machine or in the lead screw of a lathe. The graph between cumulative pitch error and thread length in progressive pitch error is a straight line.
9. Which of the following is the correct option for given statements about the effect of pitch error?
Statement 1: Pitch error can cause progressive tightening on assembly.
Statement 2: Tool work velocity ratio will play an important role to prevent pitch errors.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: d
Explanation: The threads are commonly generated by a point cutting tool. For pitch to be correct, the ratio of the tool linear velocity and work’s angular velocity must be correct and constant, otherwise pitch errors will occur.
10. Which of the following is not related to the drunken thread?
a) Periodic pitch error
b) Erratic pitch error
c) Progressive pitch error
d) Irregular pitch error
Answer: c
Explanation: Drunken thread has erratic pitch, in which the advance of the helix is irregular in thread’s 1 complete revolution. Thread drunkenness is a case of a periodic pitch error recurring at regular intervals of 1 pitch.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Gauge Wear”.
1. In which gauges wear takes place more rapidly?
a) Screw thread gauges
b) Plain gauges
c) Profile gauge
d) Go/nogo gauge
Answer: b
Explanation: Screw thread gauges wear more rapidly than plain gauges. When effective diameter NOT GO and full form GO ring gauges are used, manufacturing tolerance of work is reduced by the amount that must be allowed for wear in the full form ring gauges.
2. What is the common range of wear in ring thread gauge?
a) 0.0025mm – 0.005mm
b) 0.025mm – 0.05mm
c) 0.0025mm – 0.0075mm
d) 0.025mm – 0.075mm
Answer: d
Explanation: It is common for a hardened ring thread gauge to wear from 0.025 mm to 0.075 mm during a few days of operation. Gauge tolerance is adjusted in such a way that takes wear allowance into account.
3. What is the wear allowance recommended by BSI for solid ring and plug gauges?
a) 0.01mm
b) 0.5mm
c) 0.05mm
d) 0.001mm
Answer: c
Explanation: The allowance recommended by B.S.I, for wear on generally used solid ring and plug gauges is 0.002 inch . Frequent checking of solid pattern gauges is necessary in order to obviate this effect.
4. What is the relation between the effective diameter of a thread hole and an effective diameter of the screw in screw thread gauge?
a) minimum effective diameter of a thread hole must necessarily be greater than the maximum effective diameter of the screw
b) maximum effective diameter of a thread hole must necessarily be greater than the minimum effective diameter of the screw
c) minimum effective diameter of a thread hole must necessarily be lesser than the maximum effective diameter of the screw
d) maximum effective diameter of a thread hole must necessarily be greater than the minimum effective diameter of the screw
Answer: a
Explanation: The minimum effective diameter of a thread hole must necessarily be greater than the maximum effective diameter of the screw. The pitch diameter of a parallel thread is the diameter of the imaginary co-axial cylinder which intersects the surface of the thread in such a manner that the intercept on a generator of the cylinder.
5. Which of the following statement is incorrect about adjustable thread gauges?
a) It is used for precision gauging purposes
b) It shows more gauge wear than solid gauge wear
c) It overcome the disadvantages by solid gauge wear
d) Its wear allowance is 0.0125mm
Answer: b
Explanation: In order to overcome the disadvantages of solid gauge wear, the adjustable pattern screw thread gauge was evolved which is widely employed for precision gauging purposes. Although wear can be compensated for but the B.S. allowance of 0.002″ for solid gauges is reduced by about 0.0005″.
6. What is the provision for wear of Go gauges is made by?
a) A margin greater than maximum metal limit of work
b) A margin greater than tolerance zone of gauge
c) A margin lesser than maximum metal limit of work
d) A margin between tolerance zone of gauge and maximum metal limit of work
Answer: d
Explanation: ‘Go’ gauges provision for wear is made by the introduction of a margin between the maximum metal limit of the work and tolerance zone for the gauge. Wear should not be permitted beyond the maximum metal limit of the work, when the limit is of critical importance.
7. What is the magnitude of wear allowance in Go gauges in present British System?
a) One-fifth of gauge tolerance
b) One-third of gauge tolerance
c) One-tenth of gauge tolerance
d) One-fifteenth of gauge tolerance
Answer: c
Explanation: Wear allowance magnitude is one-tenth of the gauge tolerance. In British system dispenses with workshop and inspection gauges and we give the same tolerance limits on workshop and inspection gauges and the same gauges can be used for both purposes.
8. If work tolerance is less than 0.09mm, then how much wear allowance is given to Go gauge?
a) 5% gauge tolerance
b) No allowance
c) 1% gauge tolerance
d) 2.5% gauge tolerance
Answer: b
Explanation: When work tolerance is less than 0.09 mm there is no need of giving allowance for wear. 10% gauge tolerance is given only on ‘Go’ gauge for wear if work tolerance is more than 0.09 mm.
9. Where should tolerance zone is placed for Go Gauges in present British System?
a) Inside work limits
b) Outside work limits
c) Equal to work limits
d) Regardless to work limits
Answer: a
Explanation: The tolerance zone for the ‘Go’ gauges should be placed inside the work-limits. In First System, tolerances on the workshop gauge are arranged to fall inside the work tolerance, further ‘Go’ gauge should eat away 10% of work tolerance.
10. Where should tolerance zone is placed for No-Go Gauges in present British System?
a) Inside work limits
b) Outside work limits
c) Equal to work limits
d) Regardless to work limits
Answer: b
Explanation: The tolerance zone for the ‘No Go’ gauges should be placed outside the work-limits. In First System, inspection gauge tolerances fall outside the work tolerance and tolerance on No Go’ gauge should be one-tenth of work tolerance.
This set of Engineering Metrology online quiz focuses on “Tolerance for Screw Thread Gauges and Screw Threads”.
1. How many variables are taken into consideration for the calculation of effective diameter tolerance?
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: The screw threads combination is very much complex. There is a complicated interplay between pitch, thread angle and effective diameter. The effective diameter tolerance must take into consideration the three variables i.e. the major diameter, the length of thread engagement, the pitch.
2. What is the formula for tolerance on effective diameter ?
a) a∛D +b√L +c√p
b) a∜D +b√L +2c√p
c) a∛D +b√2L +c√p
d) 2a∛D +2b√L +3c√p
Answer: a
Explanation: Effective diameter tolerance depends on the Diameter, length of thread, pitch. It depends on them non linearly. Equation of tolerance is a∛D +b√L +c√p where D = major diameter, L = length of engagement, p = pitch, a, b, c are constants.
3. How the values of constants affect the accuracy of tools?
a) Decrease in accuracy will increase the value of constants
b) Increase in accuracy will increase the value of constants
c) Decrease in accuracy will reduce the value of constants
d) Increase in accuracy will reduce the value of constants
Answer: d
Explanation: The value of these constants will depend upon the prevailing accuracy of tools and machines used to produce the screw threads. Increase in accuracy will reduce the value of constants. The specifications provide for three grades of fits, close, medium, free.
4. What are the values of constants for whit worth threads?
a) a=0.003 b=0.005, c=0.002
b) a=0.002, b=0.003, c=0.005
c) a=0.004, b=0.005, c=0.006
d) a=0.001, b=0.002, c=0.003
Answer: b
Explanation: The value of these constants according to British Standard Specifications for Whitworth threads for medium fit are a=0.002, b=0.003, c=0.005 i.e. the equation of tolerance on effective diameter is 0.002∛D +0.003√L +0.005√p
5. What is the relation between close fit and free fit?
a) Close fit tolerance is one third of free fit
b) Close fit tolerance is one half of free fit
c) Close fit tolerance is two thirds of free fit
d) Close fit tolerance is three fourths of free fit
Answer: c
Explanation: The basic formula gives effective diameter tolerance for medium fit. Close fit tolerances are two-thirds of free fit, and free fit tolerance is one and a half times that of medium fit. This results in tolerance increasing by 50% each time from close-medium-free fit.
6. Match the following fit with their use?
A B
1) Close a) Suitable for bulk of screw threads
2) Medium b) Suitable for screw requiring fine snug fit
3) Free c) Suitable for interchangeable screw threads
a) 1-a, 2-b, 3-c
b) 1-c, 2-b, 3-a
c) 1-b, 2-a, 3-c
d) 1-b, 2-c, 3-a
Answer: d
Explanation: Close fit applies to screw requiring a fine snug fit. Medium fit is suitable for better class of ordinary interchangeable screw threads and free fit is suitable for bulk of screw threads of ordinary commercial quality.
7. What is the major diameter tolerance of effective diameter for external threads?
a) +0.01√p
b) -0.05√p
c) +0.05√p
d) -0.01√p
Answer: a
Explanation: In major diameter, the tolerance is given by expression Effective Diameter tolerance = +0.01√p. It is applicable for all grades of fits for external threads. In major diameter, no such tolerance is laid down for internal threads.
8. What is the minor diameter tolerance of effective diameter for external threads?
a) Effective diameter tolerance+0.03√p & Effective diameter tolerance+0.01√p
b) Effective diameter tolerance+0.02√p & Effective diameter tolerance+0.01√p
c) Effective diameter tolerance+0.013√p & Effective diameter tolerance+0.02√p
d) Effective diameter tolerance+0.01√p & Effective diameter tolerance+0.02√p
Answer: c
Explanation: Minor diameter tolerance for external threads is for close fit and is for external threads in case of medium and free fit.
9. Which of the following is incorrect for the minor diameter tolerance of effective diameter for internal threads?
a) For 26 tpi : Tolerance = 0.2p+0.004”
b) For 26 tpi : Tolerance = 0.2p+0.005”
c) For 22 tpi : Tolerance = 0.2p+0.005”
d) For 26 tpi : Tolerance = 0.2p+0.007”
Answer: b
Explanation: For minor diameter tolerance of internal threads, tolerance for 26 tpi and finer is equal to 0.2p + 0.004”, tolerance for 24 tpi and 22 tpi is equal to 0.2p+0.004”, tolerance for 20 tpi and coarser is equal to 0.2p+0.004”.
10. Why Wide tolerance on core diameter of internal threads is given?
a) To prevent binding at the root of the tap
b) To prevent binding at the crest of the tap
c) To prevent binding at the flank of the tap
d) To prevent binding at the face of the tap
Answer: a
Explanation: To prevent binding at the root of the tap wide tolerance on the core diameter of internal threads is given. It permits a tapping drill being used of ample size. This follows a general practice and results in a flat crest to the root of the thread.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Screw Thread Gauge Tolerance”.
1. How many types of tolerances are there in screw thread gauge tolerance?
a) 2
b) 3
c) 5
d) 4
Answer: b
Explanation: Tolerance for plug and ring screw gauges are covered in three classes, i.e. Reference, Inspection and workshop. Workshop gauges being within the work tolerance, and inspection and reference being outside.
2. What is the reference gauge tolerance for 6” diameter gauge?
a) 0.001”
b) 0.002”
c) 0.003”
d) 0.004”
Answer: a
Explanation: Tolerances were graded in terms of diameter. The workshop and inspection tolerance on gauges for 6” inches is 0.002” on effective diameter. Reference gauge tolerance was half of these tolerances i.e. 0.001” for 6”. This tolerance included the virtual effect of pitch and angle errors.
3. What is the tolerance on effective diameter for gauges upto 1.5” diameter as per B.S.S. No. 919?
a) 0.0002”
b) 0.0003”
c) 0.0004”
d) 0.0005”
Answer: c
Explanation: B.S.S. No. 919 was issued on screw gauge tolerance as an emergency. Specifications widened tolerance more on smaller size than larger. The tolerance was divided into two separate elements. For gauges upto 1.5″ diameter, Tolerance on effective diameter = 0.0004″.
4. What is the equivalent of pitch and angle tolerance on effective diameter for gauges upto 1.5” diameter as per B.S.S. No. 919?
a) 0.0004”
b) 0.0005”
c) 0.0006”
d) 0.0007”
Answer: b
Explanation: For gauges upto 1.5″ diameter, Equivalent of pitch and angle tolerance on effective diameter = 0.0005″. The simple effective diameter tolerance on NO GO gauge was same but virtual tolerance was halved. It is due to the fact that short length of thread is not liable to much pitch error.
5. What is the effect of pitch error upon the effective diameter of a screw thread?
a) D1 = E x K
b) D1 = 2E x K
c) D1 = E x K/2
d) D1 = E x K x 4
Answer: a
Explanation: The compensations for pitch and angle errors are also provided for by the application of corrections for each of these quantities. Effect of pitch error upon effective diameter of a screw thread is
D1 = E x K where D1=Effective dia. equivalent of pitch error, E = max. cumulative pitch error along the thread, K = constant for the shape of thread.
6. A constant ‘K’ is used for defining the shape of thread. What is the value of ‘K’ for Whitworth?
a) 1.5
b) 1.62
c) 1.73
d) 1.92
Answer: d
Explanation: Effect of pitch error upon the effective diameter of a screw thread is D1 = E x K,
K = constant for the shape of thread = 1.92 for Whitworth, = 1.73 for International metric threads and = 2.27 for B.A.
7. What is the compensation for angle error?
a) ΔE=3p*ΔΘ/100
b) ΔE=p*ΔΘ/100
c) ΔE=p*ΔΘ/50
d) ΔE=p*ΔΘ/200
Answer: a
Explanation:The compensation for angle error, ΔE is related to the pitch p as follows: ΔE=p*Θ/100 where ΔΘ is the angle error in degrees. It is necessary that ΔE and p should be expressed in the same measure, i.e. English or metric. The angle error is the arithmetical sum of the errors of the two flank angles irrespective of their signs.
8. Which of the following item must fall within the prescribed limit for plug gauges?
a) Measured effective diameter along the pitch line
b) Measured effective diameter perpendicular to the pitch line
c) Measured minor diameter along the pitch line
d) Measured minor diameter perpendicular to the pitch line
Answer: a
Explanation: There are some requirements on effective dia which must be met before the gauge can be accepted i.e. the measured effective diameter along the pitch line and the measured effective diameter is +ΔE1+ΔE2 for plug gauges.
9. Which of the following item must fall within the prescribed limit for ring gauges?
a) Measured effective diameter +ΔE1+ΔE2
b) Measured effective diameter +ΔE1-ΔE2
c) Measured effective diameter -ΔE1-ΔE2
d) Measured effective diameter -ΔE1+ΔE2
Answer: c
Explanation: For ring gauges, requirements that must met are the measured effective diameter along the pitch line and the measured effective diameter -ΔE1-ΔE2. It should be noted that the max. allowable pitch error or the max. allowable angle error can readily be found from the formulae given, by evaluating ΔE1or ΔE2 to the full effective diameter tolerance allowed on any given size of gauge.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Diameter and Pitch Combinations”.
1. What is the range of diameters that have been specified in IS: 4218 -1976?
a) 1-50mm
b) 1-500mm
c) 1-250mm
d) 1-100mm
Answer: b
Explanation: The diameter and pitch combinations for ISO Metric screw threads in the diameter range of 1 to 500 mm have been specified in the IS: 4218 —1976. This standard specifies several pitches for various diameters.
2. According to IS: 4218 -1976, How many types of pitches are present?
a) 2
b) 1
c) 4
d) 3
Answer: a
Explanation: According to this IS: 4218 -1976, there are two types of pitches i.e. coarse series and fine series. For any diameter in study, coarse pitch is the largest of the pitches associated with that diameter , the rest of the pitches being always finer than the coarse pitch are called fine pitches.
3. How many choices for diameters are present in IS: 4218 -1976?
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: IS: 4218 -1976 gives three choices for diameters i.e. first choice, second choice and third choice, and recommends the use of diameters given in the first choice as far as possible for various applications.
4. How many tolerance grades are there for ISO metric screw threads?
a) 4
b) 5
c) 6
d) 7
Answer: d
Explanation: On ISO metric threads, tolerances are defined by tolerance position and tolerance grades. There are 7 tolerance grades and these are 3, 4, 5, 6, 7, 8, and 9. 3, 4 and 5 are for precision threads and 6 for medium quality and for less precision methods are 7, 8 and 9.
5. For a diameter of 20mm, several pitches given are 1, 1.5, 2 and 2.5mm. Which of the following is coarse pitch?
a) 1mm
b) 2 and 2.5mm
c) 1.5, 2 and 2.5mm
d) 2.5mm
Answer: d
Explanation: For the diameter of 20 mm various pitches allowed are 1, 1.5, 2 and 2.5 mm. Of these 2.5 is coarse pitch, and the 1, 1.5 and 2 are fine pitches. Only largest of the pitches falls under coarse pitch and other remaining comes under fine pitches.
6. What is the symbol designated for the pitch diameter combination of an ISO Metric screw thread by IS: 4218 -1976?
a) M
b) PD
c) DP
d) P
Answer: a
Explanation: According to this IS: 4218 -1976, the pitch diameter combination of an ISO Metric screw thread is designated by the letter M followed by the values of the nominal thread diameter and the pitch.
7. What is the correct way to write pitch diameter combination of thread size 20mm and pitch 2.5mm?
a) M 20:2.5
b) M {20,2.5}
c) M 20×2.5
d) M 20-2.5
Answer: c
Explanation: While the designation of pitch diameter combination of screw thread, letter M is followed by the values of the nominal thread diameter and the pitch, the two being separated by the sign ‘x’. Hence, combination of thread size 20mm and pitch 2.5mm is shown by M 20×2.5.
8. What should M 22 designate in pitch diameter combination?
a) 22mm diameter with lowest fine pitch
b) 22mm diameter with standard coarse pitch
c) 22mm diameter with highest fine pitch
d) 22mm diameter with all pitch
Answer: b
Explanation: When no pitch is mentioned in the designation of pitch diameter combination, it means standard coarse pitch is implied e.g., M 22 shall designate a pitch diameter combination of threads size 22 mm and coarse pitch of 2.5 mm.
9. Which of the following is the first choice of diameter which is indicated by IS?
a) 20
b) 18
c) 17
d) 22
Answer: a
Explanation: The first choice of diameters which are indicated by IS are 1,1.2,1.6,2,2.5,3,4,5,6,8,10,12,16, 20,24, 30, 36, 42, 48, 56, 64, 72, 80, 90, 100, 110, 125, 140, 160,180, 200, 220, 250 and 280.
10. Which of the following tolerance grades can be used for minor diameter and pitch diameter of internal threads?
a) 4, 6, 8
b) 3, 4, 5, 6, 7
c) 3, 4, 5
d) 4, 5, 6, 7, 8
Answer: d
Explanation: The tolerance grades recommended for minor diameter and pitch of internal threads are 4, 5, 6, 7, and 8 and for major diameter of external threads and for pitch diameter of external threads are 4, 6, 8 and 3, 4, 5, 6, 7, 8, 9 respectively.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Involute Curve”.
1. What is the alternative name of involute gears?
a) Straight tooth gear
b) Helical gear
c) Cycloid gear
d) Spiral gear
Answer: a
Explanation: Commonly used forms of gear teeth are:
involute
cycloidal
Involute gears are also called spur gears and straight tooth.
2. Where does involute gear is used?
a) For crude purposes
b) General purpose in precision engineering
c) Where heavy loads comes on machine
d) Where impact loads comes on machine
Answer: b
Explanation: Involute gears are used for general purpose in precision engineering. The cycloidal gears are not used in modern engineering generally, but can be used for some crude purposes where impact and heavy loads come on the machine.
3. What type of teeths is present in involute rack?
a) Spiral
b) Helical
c) Straight
d) Double helical
Answer: c
Explanation: The straight teeth are present in involute rack. Only a simple cutter is needed to form the complex involute form on gear. It is an advantage which is associated with involute curve or profile.
4. Upon which factor, shape of involute curve depends?
a) Base circle diameter
b) Pitch circle diameter
c) Addendum circle diameter
d) Face width
Answer: a
Explanation: The shape of involute curve entirely depends upon the diameter of base circle as involute is generated from a base circle. Pressure angle and pitch also important for the profile of involute.
5. Which of the following is correct about involute curve?
a) Involute curvature increases with increase in base circle diameter
b) Involute is straight line when diameter of base circle is zero
c) Involute curvature increases with increase in pitch circle diameter
d) Involute curvature decreases with increase in base circle diameter
Answer: d
Explanation: The curvature of the involute decreases as the diameter of base circle goes on increasing and when diameter of base circle is infinity then finally involute becomes straight line.
6. What is the standard pressure angle for an involute system?
a) 20 or 14.5 degree
b) 20 or 30 degree
c) 30 or 14.5 degree
d) 40 or 30 degree
Answer: a
Explanation: The involute system has a standard value of pressure angle which is 20° or 14.5° whereas on the cycloidal system does not have a standard pressure angle, it varies from zero at pitch line to a maximum at the teeth tips.
7. Which of the following is true for an involute curve?
a) Tangent to any point on involute is parallel to the generator at that point
b) Tangent to any point on involute is perpendicular to the generator at that point
c) Tangent to any point on involute is at 45 degree to the generator at that point
d) Tangent to any point on involute is at 30 degree to the generator at that point
Answer: b
Explanation: It is important to fulfill the requirements of law of gearing for an involute curve. The tangent at any point on involute will be perpendicular to the generator at that point. This condition fulfils the requirements needed for laws of gearing.
8. What is the effect of centre distance between two gears on velocity ratio of involute gear pair?
a) Less for less velocity ratio
b) Less for more in velocity ratio
c) More or less for more velocity ratio
d) No effect
Answer: d
Explanation: Variations in the centre distance between 2 gears have no effect on the velocity ratio between an involute gears pair. It is an advantage associated with the involute for the flank curve of gear.
9. What is the involute curve?
a) Point Locus on a straight line which rolls around a circle without slipping
b) Point Locus on a straight line which rolls around a line without slipping
c) Point Locus on a circle which rolls around a pitch circle without slipping
d) Point Locus on a circle which rolls around a line without slipping
Answer: a
Explanation: An involute curve is a point locus on straight line which rolls, around a circle without slipping. It could also be defined as the point locus on a piece of string which in unwound from a cylinder or stationary cylinder.
10. Which of the following factor is least important for an involute profile?
a) Number of teeth
b) Pressure angle
c) Pitch
d) Gear it mates with
Answer: d
Explanation: The involute gear profile is important in machine design, since unlike with other gear systems, involute gear tooth profile depends on only the number of teeth on the gear, pitch and pressure angle but does not depend on the gear it mates with.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Terminology of Gear Tooth”.
1. Which of the following is the correct mathematical formula for module?
a) D/N
b) D/2N
c) 2D/N
d) 4D/N
Answer: a
Explanation: Module is defined as the length of the pitch circle diameter / tooth. Thus, if Pitch Circle Diameter of gear is D and number of teeth is N, then module is equal to D/N. It is generally expressed in millimeter.
2. What is the standard value of clearance?
a) 0.572 x m
b) 0.182 x m
c) 0.157 x m
d) 0.821 x m
Answer: c
Explanation: Term clearance used in terminology of gear tooth is the radial distance from the tooth top to the bottom of a mating tooth space when the teeth are engaged symmetrically. Standard value of clearance is 0.157 m where m is module.
3. What is the value of addendum?
a) 1 module
b) 2 modules
c) 3 modules
d) 4 modules
Answer: d
Explanation: This is the radial distance from the pitch circle to the tooth tip. Its value is equal to 1 module. Another term diametral pitch is defined as a number of teeth per inch of pitch circle diameter.
4. What is dedendum?
a) Addendum + 2 x clearance
b) Addendum + clearance / 2
c) 2 x Addendum + clearance
d) Addendum + clearance
Answer: d
Explanation: Dedendum is the radial distance from the pitch circle to the bottom of the tooth space. Dedendum is equal to Addendum plus Clearance = m + 0.157 m = 1.153 m as one addendum is a module and standard value of clearance is 0.157 m.
5. What is the flank of tooth?
a) Part of the surface of tooth which is above the pitch surface
b) Part of the surface of tooth which is below the pitch surface
c) Part of the surface of tooth which is in the middle of top and bottom of the pitch surface
d) Part of the surface of tooth which is at the top of the pitch surface
Answer: b
Explanation: Face of the tooth is that part of the tooth surface which is lying above the pitch surface. Flank of Tooth is that part of the tooth surface which is below the pitch surface.
6. What is tooth thickness?
a) Circular pitch / 2
b) Circular pitch / 4
c) 2x Circular pitch
d) 4 x Circular pitch
Answer: a
Explanation: Thickness of tooth is the distance of arc measured along the pitch circle from its intercept with one flank to its intercept with the other flank of the same tooth.
Tooth thickness = C.P./2 or πm/2.
7. What is the name of angle which is present between line of action and common tangent to the pitch circles?
a) Helix angle
b) Lead angle
c) Pitch angle
d) Pressure angle
Answer: d
Explanation: The angle between the line of action and the common tangent to the pitch circles is called as pressure angle. The standard values of pressure angle are 14.5 degree and 20 degree. Pressure angle is generally represented by φ.
8. Which of the following is not the correct formula for base pitch?
a) Base circumference / Number of teeth
b) π x Base circle diameter / N
c) π x D sinφ / N
d) π x m x cosφ
Answer: c
Explanation: Base pitch is the distance which is measured around the base circle from the origin of the involute on the tooth to the origin of a involute on the next tooth.
Base pitch = Base circumference / Number of teeth
= π x Base circle diameter / N = π x D cosφ / N = π x m x cosφ.
9. What is blank diameter?
a) Pitch circle diameter plus addenda
b) Pitch circle diameter plus twice the addenda
c) Base circle diameter plus addenda
d) Base circle diameter plus twice the addenda
Answer: b
Explanation: Blank diameter is that diameter of blank from which gear is out. Blank diameter is equal to the pitch circle diameter plus addenda.
Blank diameter = mN + 2m = m x .
10. Which of the following is not necessary to find normal module of helical gear?
a) Number of teeth
b) Pitch diameter
c) Helix angle
d) Tooth thickness
Answer: d
Explanation: The formula for normal module of helical gear is m n = cosα where N is number of teeth, D is pitch diameter and α is helix angle. Also, m n = p n /π where p n is normal circular pitch.
11. What is worm lead in worm and worm gear?
a) N w x 2p x
b) N w x 4p x
c) N w x p x
d) N w / p x
Answer: c
Explanation: Worm lead is represented by L and L = N w x p x where, N w is number of threads in worm and is p x axial pitch. Lead angle in worm and worm gear is represented by ψ and tanψ = L/πd where d is pitch diameter.
This set of Engineering Metrology Question Bank focuses on “Sources of Errors in Manufacturing Gears”.
1. Which of the following is true for generating method of gear formation?
a) No use of cutter
b) Profiles of several teeth are formed simultaneously
c) Linear motion of the tool and the blank is not constant
d) Each tool space is cut independently
Answer: b
Explanation: Gear teeth are generally made by two methods, reproducing method and generating method. Method in which the cutting tool forms the several teeth profiles simultaneously during constant relative motion of the blank and tool is known as Generating method.
2. Which of the following is true for high power gears?
a) Operated at low speed
b) Operated at high speed
c) Operated at moderate speed
d) Operated at high or moderate speed
Answer: a
Explanation: High power gears are operated at low speeds generally but it has to transmit large force. Therefore for this purpose the gear teeth should specify fullest possible contact along the tooth length.
3. Which of the following gear is used for counting and timing purposes?
a) High speed gears
b) High power gears
c) Low speed gears
d) Precision gears
Answer: d
Explanation: Constant gearing ratio is the main requirement of the precision gears. Precision gears are generally used for indexing devices and measuring instruments, or in counting and timing purposes, and usually have small face width and small module.
4. What is the kinematic error in gears?
a) Minimum error in gear rotation per gear revolution
b) Accumulated permissible error in gear rotation per gear revolution
c) Maximum error in gear rotation per gear revolution
d) Accumulated permissible error in gear rotation in two gear revolutions
Answer: b
Explanation: Kinematic error is defined as the permissible accumulated error in gear rotation per gear revolution. The kinematic accuracy index is the maximum kinematic error. It can be defined as the maximum angular error in gear rotation, when it meshes in single-profile engagement with a precise gear.
5. What is profile error?
a) The minimum distance of any point on the profile of tooth form and normal to the design profile when the two coincide at the reference circle
b) The minimum distance of any point on the profile of tooth form and parallel to the design profile when the two coincide at the reference circle
c) The maximum distance of any point on the profile of tooth form and parallel to the design profile when the two coincide at the reference circle
d) The maximum distance of any point on the profile of tooth form and normal to the design profile when the two coincide at the reference circle
Answer: d
Explanation: Profile error is a possible error on spur, helical or bevel gear etc. It is the max distance of any point on the profile of tooth and normal to the design profile when two coincide at the reference circle.
6. What is a cyclic error?
a) Mean value of the discrete values of variation in the kinematic error of the gear taken for all cycles during one revolution
b) Mean value of the range of variation in the kinematic error of the gear taken for all cycles during one revolution
c) Mean value of the range of variation in permissible deviations in basic pitch of the gear taken for all cycles during one revolution
d) Mean value of the range of variation in the angular error of the gear taken for all cycles during one revolution
Answer: b
Explanation: The cyclic error is defined as the mean value of the range of variation in the kinematic error of the gear which is taken for all cycles during 1 revolution. It can also be explained as an error which occurs during each revolution of the element under consideration.
7. How bearing contact of mating gears is represented?
a) By the relative size of the bearing contact pattern in mm
b) By the relative size of the bearing contact pattern in cm
c) By the relative size of the bearing contact pattern in meter
d) By the relative size of the bearing contact pattern in percent
Answer: d
Explanation: Bearing contact for mating gears is represented by the relative size of the bearing contact pattern in % and along the length of tool it is represented by the ratio of the traces of contact, subtracting gaps larger than the size of the module, to the full tooth length.
8. Another name for Wobble ______________
a) Radial run-out
b) Eccentricity
c) Composite error
d) Axial run-out
Answer: d
Explanation: Run out is the total range of reading of an indicator with the contact point applied to a rotated surface, without axial movement about an axis which is fixed. Axial runout is the runout measured parallel to the rotation axis, at a specified distance.
9. What is undulation?
a) Departure of the actual tooth surface from design surface
b) Departure of the virtual tooth surface from design surface
c) Departure of the design surface from actual tooth surface
d) Departure of the design surface from virtual tooth surface
Answer: a
Explanation: Undulation is a departure of the actual tooth surface from the design surface and undulation height is the normal distance between 2 surfaces that contain the crests and the troughs of the tooth undulation.
10. Which of the following is true for eccentricity?
a) Half the radial run-out
b) Half the axial run-out
c) Equal to the radial run-out
d) Equal to the axial run-out
Answer: a
Explanation: Radial runout is the runout measured along a perpendicular to the rotation axis. Eccentricity is half the radial run-out.
11. Which of the following can be used to ensure smoothness of gear operation?
a) By limiting the minimum permissible deviation in base circle
b) By limiting the maximum permissible deviation in base circle
c) By limiting the maximum permissible deviation in basic pitch
d) By limiting the minimum permissible deviation in basic pitch
Answer: c
Explanation: Smoothness of gear operation is important to provide for noiseless engagement and longer service life of gearing. The smoothness of gear operation can be ensured by limiting the maximum permissible deviations in basic pitch.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Gear Measurement”.
1. What is the effect of improper alignment of each tooth?
a) Tooth thickness increases
b) Face width decreases
c) Load will not distributed evenly
d) Pitch of teeth reduced
Answer: c
Explanation: Good alignment of each tooth on a gear is essential, as otherwise the load will not be distributed evenly over its face. It is quite probable that the load may be carried by one edge only introducing high bearing stresses, if teeth of a gear are machined poorly.
2. Which of the following is not true about concentricity of teeth?
a) Fluctuating velocity will be noticed when not concentric
b) Can be checked by using projector
c) Inaccuracy of parts when not concentric
d) Should be tested to ensure the proper heat treatment
Answer: d
Explanation: Concentricity of teeth is an important item and should be checked to ensure that the set up and equipment is in good order. When teeth are not concentric then fluctuating velocity will be noticed on the pitch line while transmitting motion.
3. Which of the following option is true about an analytical method of inspection of gears?
a) Analytical method is widely used for industries
b) This method is fast
c) All individual elements of gear teeth are checked
d) More accurate
Answer: c
Explanation: Analytical method is slow and tedious and not of much use for industry. By analytical inspection of gears we mean that all the individual elements of the gear teeth are checked. The discrete error values of pitch, tooth profile etc can’t give a true overall assessment of the accuracy of a gear.
4. Which of the following element is not determined by analytical inspection?
a) Profile
b) Composite vibrations
c) Spacing
d) Pitch
Answer: b
Explanation: The analytical inspection of the gears consists in determination of these Profile, Spacing, Pitch, Backlash, Runout or eccentricity or concentricity, thickness of tooth and Lead. These teeth elements in which the errors are caused due to manufacturing errors are determined by analytical inspection.
5. Which of the following option is correct for given statements about gear measurement?
Statement 1: Improper alignment of each teeth will cause high bearing stresses.
Statement 2: Gear blank should be tested for dimensional accuracy.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: d
Explanation: The gear blank should be tested for dimensional accuracy and eccentricity as outside diameter forms the datum from where the tooth thickness is measured, it forms an important item to be controlled. It is quite probable that the load may be carried by one edge only introducing high bearing stresses, if teeth of a gear be machined poorly.
6. Which of the following is not determined by the functional type of inspection?
a) Lead
b) Noise level
c) Variation in action
d) Vibration
Answer: a
Explanation: The functional inspection consists of carrying out the running test of gear with another gear which is more accurate and is known as master gear or control gear, to determine composite vibration, noise level, or variation in action.
7. Which of the following statement is true about inspection of gear?
a) Profile is determined by functional inspection
b) Backlash is determined by analytic inspection
c) Analytic test require running test of gear
d) Thickness of tooth is measured by functional inspection
Answer: b
Explanation: Functional type of inspection is done by running test of gear with another gear. It is used to determine noise level and composite variation. Analytical method is used to determine backlash, lead and runout.
8. Which of the following machine is used for rolling tests?
a) Parkson gear tester
b) Tooth caliper
c) Base pitch measuring instrument
d) Involute profile testing machine
Answer: a
Explanation: Rolling test is generally performed on Parkson Gear Tester. This test reveals any errors in pitch, tooth form and concentricity of pitch line. Any of the above errors will cause the variation of centre distance, when two gears are in mesh with each other.
9. If reference circle of gear is eccentric then which error is reflected by this eccentricity?
a) Cyclic error
b) Periodic error
c) Pitch error
d) Undulation
Answer: c
Explanation: It must be emphasised that there are some in-built limitations in the gear itself while the accuracy of measurement of gear depends upon the measuring equipment available, such as the inability of a gear to define its own axis of rotation. Thus if the reference circle of gear is eccentric, it would be reflected in pitch error.
10. Which of the following option is true for given statements about gear measurement?
Statement 1: There is no effect of cutter accuracy on the accuracy of gear.
Statement 2: Accuracy of individual elements is necessary for precision gears.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: The accuracy of any gear mainly depends upon the cutter accuracy and the setting of the machine. Optical projection and rolling tests will suffice for most of the gears. It is necessary to determine the accuracy of individual elements in the manufacture of high precision gears.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Coordinate Measuring Machines”.
1. What precise movement does CMM have?
a) Precise movement in x coordinate
b) Precise movement in x and y coordinates
c) Precise movement in y and z coordinates
d) Precise movement in x, y and z coordinates
Answer: d
Explanation: Co-ordinate measuring machines are useful for three dimensional measurements. These machines have precise movements in x,y and z coordinates which can be easily measured and controlled.
2. Which type of CMM is most suited for large heavy workpieces?
a) Cantilever type
b) Bridge type
c) Horizontal boring mill type
d) Floating bridge type
Answer: c
Explanation: Bridge type CMM is more difficult to load. It less sensitive to mechanical errors. Horizontal boring mill type is best suited for heavy and large workpieces. Highly accurate type is vertical bore mill type but is usually slower to operate.
3. Which direction is sensed by a linear measurement transducer used in CMM?
a) Positive direction only
b) Negative direction only
c) Both positive and negative direction
d) Not used to sense directions
Answer: c
Explanation: Each slide in CMM is equipped with the help of a precision linear measurement transducer in 3 directions. It gives digital display and also senses a positive or negative direction. These are manufactured in both computer-controlled models and manual.
4. What is the accuracy of present day co-ordinate measuring machine?
a) 10 microns
b) 5 microns
c) 2 microns
d) 1 micron
Answer: a
Explanation: Co-ordinate measuring machines of present day are three-axis digital read-out type and these machines work up with an accuracy of 10 microns. Resolution of present day co-ordinate machine is 5 microns.
5. What is the name of an element which uses inductive coupling?
a) Inducto conduct
b) Inductosyn
c) Conductosyn
d) Conducto induct
Answer: b
Explanation: CMM utilize a measuring element known as Inductosyn data element. It uses inductive coupling between conductors and the conductors are separated by a small air gap. As Inductosyn is not subjected to wear, it does not develop inaccuracy.
6. Which principle is used in the three master guideways and probe location?
a) Principle of dynamic design
b) Principle of static design
c) Principle of kinematic design
d) Principle of effective design
Answer: c
Explanation: In the probe location and three master guideways, the principles of kinematic design are used. Whole machine is supported on a 3-point suspension with its massive granite work table.
7. What is the cause of translational errors in CMM?
a) Error in scale division
b) Error in straightness
c) Twisting error
d) Roll error
Answer: b
Explanation: Translational errors result from errors in the division of scale and straightness error perpendicular to the corresponding axis direction. Errors in scale division are known as positional errors. Error in straightness is the cause of translational errors.
8. Which of the following is not related to the geometrical accuracy of CMM?
a) Straightness of axes
b) Squareness of axes
c) Position accuracy
d) Axial length measuring accuracy
Answer: d
Explanation: Geometrical accuracy concerned with the straightness of axes, position accuracy and squareness of axes while total measuring accuracy concerns volumetric length measuring accuracy and axial length measuring accuracy.
9. How many measurement parameters are considered in checking axes accuracy of straightness in CMM?
a) 2
b) 4
c) 6
d) 8
Answer: c
Explanation: Six measurement parameters need to be considered in the straightness of axes. Straightness of x-axis measured in y and z directions. Straightness of z-axis in x and y directions and of y-axis in x and z directions.
10. How many reference gauges are measured for volumetric length measuring accuracy in CMM?
a) 2
b) 3
c) 4
d) 5
Answer: b
Explanation: It is defined as the difference between the reference length of gauges, oriented freely and the corresponding results from the machine. 3 reference gauges are measured. Their lengths corresponding to approx. 1/3, 1/2 and 3/4 of the full travel of the longest axes.
11. Which of the following is true for trigger type probe system used in computer controlled CMM?
a) Bucking mechanism is a 2 point bearing
b) Current coordinate position stored when circuit is close
c) Contacts of point bearing arranged at 90 degree
d) Contacts of point bearing act as electrical micro switches
Answer: d
Explanation: The “buckling mechanism” in trigger type probe system is a 3 point bearing, the contacts of which are arranged around the circumference at 120 degrees. These contacts act as micro switches.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Alignment Tests on Lathe”.
1. What is the purpose of locating cylinder in the test of the true running of the main spindle?
a) To locate the chuck
b) To locate the main spindle
c) To locate the feeler
d) To level the machine
Answer: a
Explanation: Locating cylinder is provided to locate the face plate or chuck. Threads get worn out soon thus, locating surface can not be threaded one. Locating surface should be cylindrical and must run truly.
2. In what direction the parallelism of the main spindle to saddle movement is checked?
a) Vertical direction
b) Horizontal direction
c) Both vertical and horizontal direction
d) At an angle
Answer: c
Explanation: Parallelism of the main spindle to saddle movement is checked in both vertical and horizontal direction. In this method, mandrel is used and this mandrel should be so proportioned that its overhang does not produce sag.
3. What is axial play?
a) Freedom of spindle movement in axial direction
b) Freedom of spindle movement perpendicular to axial direction
c) Freedom of spindle movement in direction of cutting forces
d)Freedom of spindle movement in horizontal direction
Answer: a
Explanation: Meaning of axial play is the indispensable freedom of movement of spindle in the axial direction to prevent it from seizing by heating. It is different from axial slip. Axial slip is the axial movement of spindle which follows the same pattern.
4. What will happen if an axial play is not provided to the spindle?
a) It will try to expand
b) It will try to bend
c) It will shrink in some time
d) It will show fracture
Answer: b
Explanation: If axial play is not allowed, it would try to bend. Thus there will be no adverse effect of axial play if the direction of cutting forces remains constant or same. If this direction of cutting force changes, there would be some error introduced due to axial movement of spindle.
5. In leveling of machine, which direction is more important in horizontal plane?
a) Longitudinal
b) Transverse
c) Both longitudinal and transverse
d) Both longitudinal and transverse direction is not important
Answer: c
Explanation: Both longitudinal and transverse directions are equally important in horizontal plane. It will produce a simple bend and undesirable stresses; if any long lathe bed is not installed truly horizontal then there will be a deflection in bed.
6. What is the effect of axial slip in screw cutting?
a) Pitch will not be uniform
b) Pitch will be uniform
c) Pitch will be short
d) Pitch will be high
Answer: a
Explanation: Due to the axial slip, the pitch will not be uniform in the case of screw cutting. It is due to periodic movement of the spindle. However this is not of so much importance while turning.
7. Which of the following is done for testing the true running of headstock centre?
a) Feeler of dial indicator is pressed perpendicular to the taper surface
b) Feeler of dial indicator is pressed parallel to the taper surface of cent
c) Feeler of dial indicator is pressed at acute angle to the taper surface of cent
d) Feeler of dial indicator is pressed at obtuse angle to the taper surface of cent
Answer: a
Explanation: For testing this error of true running of headstock centre, the feeler of the dial indicator is pressed perpendicular to the centre taper surface, and the spindle is then rotated. The deviation which is indicated by the dial gauge gives the trueness of the centre.
8. Which type of surface is produced in case of deviation from parallelism of spindle axis from bed in vertical axis?
a) Tapered
b) Straight
c) Threaded
d) Hyperboloid
Answer: d
Explanation: A hyperboloid surface is produced due to any type of deviation from parallelism of axis of spindle from bed in the vertical axis. For this test, a mandrel is fitted in the taper socket of the spindle.
9. Which of the following is not used in testing the pitch accuracy of lead screw?
a) A negative stop
b) Slip gauge
c) Length bars
d) Dial gauge
Answer: a
Explanation: Test for pitch accuracy of the lead screw is performed by fixing a positive stop on the lathe bed. Against the stop, the length bars and slip gauges can be located. On the carriage, indicator is mounted and first it makes contact against the length of slip gauges.
10. What is the permissible error in working accuracy of cylindrical turning when a job is held between centers when a practical test is performed?
a) 0.02mm/100 mm
b) 0.01mm/100mm
c) 0.02mm/300 mm
d) 0.01mm/300 mm
Answer: c
Explanation: Working accuracy of machine facing is a permissible error of 0.02 mm over the diameter of test work piece, which is taken as 300 mm for swing over bed of upto 500 mm, and 400 mm for swing over 500 mm. Hence the permissible error is 0.02 mm/300 mm.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Alignment Tests on Milling Machine”.
1. What is the load condition when a relative alignment of machine parts and accuracy of control devices measured?
a) No load condition
b) Half load condition
c) Full load condition
d) One-fourth load condition
Answer: a
Explanation: The relative alignment of all machine parts and the accuracy of the driving mechanisms and control devices are measured under the condition of no load. The result of these measurements must lie within the prescribed limits.
2. What is another name of the axial play?
a) Full play
b) Front play
c) Back play
d) End play
Answer: d
Explanation: Another name of the axial play is end play. End play is important especially on machines of high speed and it should be within the prescribed limits. It is the freedom of spindle moving in axial direction.
3. What is the length of mandrel which is used to test true running of internal taper on milling machine?
a) 50 mm
b) 100 mm
c) 300 mm
d) 1000 mm
Answer: c
Explanation: To test true running of internal taper, a mandrel of 300 mm length is fixed in the taper of spindle. A dial gauge is set on the table of machine and feeler is adjusted to touch the lower surface of this mandrel.
4. What is the error caused when transverse movement is not parallel with spindle axis on milling machine?
a) Milled surface will not be square to base
b) Depth of cut will vary
c) Eccentricity of tapered hole
d) Axial slip
Answer: b
Explanation: To test transverse movement parallel with spindle axis. The table is set in its mean position and dial gauge is fixed. The table is crosswise moved and any deviation on reading of dial gauge is noted. Due to this error when cross slide is moved, the depth of cut will vary.
5. Which of the following is not true about the testing of eccentricity of external diameter?
a) Locating shoulder is fixed
b) Feeler is placed on the surface of shoulder
c) Vibrations are produced due to eccentricity
d) Cutter will float sideways due to eccentricity
Answer: a
Explanation: The feeler is placed on the shoulder surface. The locating shoulder is rotated and a deviation is noted. It is due to eccentricity of the spindle in the hole in which it fits. Vibrations are produced due to eccentricity and the cutter will float sideways and cut oversize, or undersize.
6. What is the length of the bracket which is used for checking the parallelism of centre slot with the longitudinal movement of the table?
a) 50 mm
b) 500 mm
c) 150 mm
d) 750 mm
Answer: c
Explanation: The parallelism of the central slot with the longitudinal movement of the table is checked with the help of a bracket. Length of the bracket is 150 millimeter with a tennon which enters the T-slot.
7. At how many points the axial slip is tested on the collar of the spindle?
a) 2, 180 degree apart
b) 2, 90 degree apart
c) 4, 90 degree apart
d) 3, 60 degree apart
Answer: a
Explanation: In testing cutter spindle axial slip, if the feeler touches at the same spot where the turning tool on the emery wheel has machined the spindle collar in the assembled machine, then the feeler will not show deviation. Therefore, axial slip must be tested at two points 180 degree apart on the collar of the spindle.
8. Which of the following option is true for given statements about alignment test on a milling machine?
Statement 1: Heavy cast iron standards are always rigid sand solid enough to withstand stresses.
Statement 2: Each trial measurement of machines is based on its correct erection.
a) T, T
b) T, F
c) F, F
d) F, T
Answer: d
Explanation: Machine tools are sensitive to shocks and impacts, even heavy cast iron standards are not always rigid and solid enough to withstand all the stresses which can be caused due to falling during transportation and also due to various type of deformations.
9. What is the permissible error for internal taper for true running nearest to spindle nose?
a) 0.02mm – 0.045mm 0.04 mm
b) 0.01mm – 0.025mm 0.03 mm
c) 0.1mm – 0.25mm 0.02 mm
d) 0.0mm – 0.025mm 0.01 mm
Answer: b
Explanation: Permissible error for testing internal taper for true running is 0.01 mm nearest to the spindle nose and this permissible error is 0.025 millimeter at a distance of 300 millimeter.
This set of Engineering Metrology Questions and Answers for Entrance exams focuses on “Alignment Tests on Pillar Type Drilling Machine”.
1. How Flatness of clamping surface of the base test is performed?
a) By placing a straight edge on one gauge block
b) By placing a straight edge on four gauge blocks
c) By placing a straight edge on two gauge blocks
d) By placing a straight edge on three gauge blocks
Answer: c
Explanation: The Flatness of clamping surface test is performed by placing a straight edge on two gauge blocks on the base plate in various positions and the error is noted down by inserting the feeler gauges.
2. What is the maximum error for Flatness of clamping surface?
a) 0.1/1000 mm
b) 0.1/100 mm
c) 0.5/100 mm
d) 0.01/1000 mm
Answer: a
Explanation: The maximum error allowed for Flatness of clamping surface is 0.1/1000 mm clamping surface. The surface should be concave only for correct results.
3. How perpendicularity of drill head guide to the base plate is performed?
a) By placing the frame level with graduations from 0.03 to 0.05 mm/m on spindle table
b) By placing the frame level with graduations from 0.05 to 0.1 mm/m on guide column
c) By placing the frame level with graduations from 0.05 to 0.1 mm/m on spindle table
d) By placing the frame level with graduations from 0.03 to 0.05 mm/m on guide column
Answer: d
Explanation: The perpendicularity of drill head guide to base plate test is performed by placing the frame level on guide column and base plate and the error is noted by noting the difference between the readings of the two levels.
4. In the perpendicularity of drill head guide to base plate test, what is the position of guide column?
a) Inclined at the upper end towards the front only
b) Declined at the upper end towards the front only
c) Inclined at the upper end towards the back only
d) Declined at the upper end towards the front only
Answer: a
Explanation: The error should not exceed 0.25/1000 mm guide column for a vertical plane passing through the axes of both spindle and column and the guide column should be inclined at the upper end towards the front only, and 0.15/1000 mm for a horizontal plane passing through the axes of both spindle and column.
5. What is the maximum error for perpendicularity of spindle sleeve with a base plate?
a) 0.15/1000 mm for plane vertical to plane passing through the axes of both spindle and column
b) 0.15/1000 mm for plane horizontal to plane passing through the axes of both spindle and column
c) 0.5/1000 mm for plane vertical to plane passing through the axes of both spindle and column
d) 0.5/1000 mm for plane horizontal to plane passing through the axes of both spindle and column
Answer: b
Explanation: The error should not exceed 0.25/1000 mm for plane vertical to plane passing through the axes of both spindle and column and the sleeve should be inclined toward column only ; and 0.15/1000 mm for plane horizontal to plane passing through the axes of both spindle and column.
6. In testing of the true running of spindle taper, what is the position of dial indicator?
a) Dial indicator is fixed on the base
b) Dial indicator is placed on the table
c) Dial indicator is fixed on the sleeve
d) Dial indicator is fixed on the table
Answer: d
Explanation: For true running of spindle taper test, the test mandrel is placed in the tapered hole of spindle and a dial indicator is fixed on the table and its feeler made to scan the mandrel.
7. What is the error for the true running of spindle taper for machines with taper larger than Morse No. 2?
a) 0.03/100
b) 0.01/100
c) 0.04/300
d) 0.04/100
Answer: c
Explanation: The error for the true running of spindle taper should not exceed 0.04/300 mm for machines with taper larger than Morse No. 2 and 0.03/100 mm for machines with taper upto Morse No. 2.
8. In how many planes, they test for parallelism of the spindle axis with its vertical movement is performed?
a) In two planes 60° to each other
b) In two planes 30° to each other
c) In two planes 45° to each other
d) In two planes 90° to each other
Answer: d
Explanation: The test for parallelism of the spindle axis with its vertical movement is performed in two planes right angle to each other. The dial indicator is fixed on the table with its feeler touching the mandrel and test mandrel is fitted in the tapered hole of the spindle.
9. For testing squareness of spindle axis with table, when was reading taken down?
a) At every 90° rotation of spindle
b) At every 180° rotation of spindle
c) At every 60° rotation of spindle
d) At every 120° rotation of spindle
Answer: b
Explanation: The dial indicator is fixed in the spindle tapered hole and its feeler touch the straight edge At A and then, reading is noted down. The spindle is rotated by 180° so that the feeler touches at point A’ and again reading is noted down.
10. What is the permissible error for squareness of spindle axis with table test?
a) 0.05/300 mm
b) 0.08/300 mm
c) 0.1/300 mm
d) 0.01/300 mm
Answer: c
Explanation: The difference of two readings gives the error in squareness of spindle axis with table. The permissible errors are 0.08/300 mm with lower end of spindle inclining towards column only to first plane and 0.05/300 mm for plane perpendicular to the previous plane.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Coordinate Measuring Machines”.
1. What precise movement does CMM have?
a) Precise movement in x coordinate
b) Precise movement in x and y coordinates
c) Precise movement in y and z coordinates
d) Precise movement in x, y and z coordinates
Answer: d
Explanation: Co-ordinate measuring machines are useful for three dimensional measurements. These machines have precise movements in x,y and z coordinates which can be easily measured and controlled.
2. Which type of CMM is most suited for large heavy workpieces?
a) Cantilever type
b) Bridge type
c) Horizontal boring mill type
d) Floating bridge type
Answer: c
Explanation: Bridge type CMM is more difficult to load. It less sensitive to mechanical errors. Horizontal boring mill type is best suited for heavy and large workpieces. Highly accurate type is vertical bore mill type but is usually slower to operate.
3. Which direction is sensed by a linear measurement transducer used in CMM?
a) Positive direction only
b) Negative direction only
c) Both positive and negative direction
d) Not used to sense directions
Answer: c
Explanation: Each slide in CMM is equipped with the help of a precision linear measurement transducer in 3 directions. It gives digital display and also senses a positive or negative direction. These are manufactured in both computer-controlled models and manual.
4. What is the accuracy of present day co-ordinate measuring machine?
a) 10 microns
b) 5 microns
c) 2 microns
d) 1 micron
Answer: a
Explanation: Co-ordinate measuring machines of present day are three-axis digital read-out type and these machines work up with an accuracy of 10 microns. Resolution of present day co-ordinate machine is 5 microns.
5. What is the name of an element which uses inductive coupling?
a) Inducto conduct
b) Inductosyn
c) Conductosyn
d) Conducto induct
Answer: b
Explanation: CMM utilize a measuring element known as Inductosyn data element. It uses inductive coupling between conductors and the conductors are separated by a small air gap. As Inductosyn is not subjected to wear, it does not develop inaccuracy.
6. Which principle is used in the three master guideways and probe location?
a) Principle of dynamic design
b) Principle of static design
c) Principle of kinematic design
d) Principle of effective design
Answer: c
Explanation: In the probe location and three master guideways, the principles of kinematic design are used. Whole machine is supported on a 3-point suspension with its massive granite work table.
7. What is the cause of translational errors in CMM?
a) Error in scale division
b) Error in straightness
c) Twisting error
d) Roll error
Answer: b
Explanation: Translational errors result from errors in the division of scale and straightness error perpendicular to the corresponding axis direction. Errors in scale division are known as positional errors. Error in straightness is the cause of translational errors.
8. Which of the following is not related to the geometrical accuracy of CMM?
a) Straightness of axes
b) Squareness of axes
c) Position accuracy
d) Axial length measuring accuracy
Answer: d
Explanation: Geometrical accuracy concerned with the straightness of axes, position accuracy and squareness of axes while total measuring accuracy concerns volumetric length measuring accuracy and axial length measuring accuracy.
9. How many measurement parameters are considered in checking axes accuracy of straightness in CMM?
a) 2
b) 4
c) 6
d) 8
Answer: c
Explanation: Six measurement parameters need to be considered in the straightness of axes. Straightness of x-axis measured in y and z directions. Straightness of z-axis in x and y directions and of y-axis in x and z directions.
10. How many reference gauges are measured for volumetric length measuring accuracy in CMM?
a) 2
b) 3
c) 4
d) 5
Answer: b
Explanation: It is defined as the difference between the reference length of gauges, oriented freely and the corresponding results from the machine. 3 reference gauges are measured. Their lengths corresponding to approx. 1/3, 1/2 and 3/4 of the full travel of the longest axes.
11. Which of the following is true for trigger type probe system used in computer controlled CMM?
a) Bucking mechanism is a 2 point bearing
b) Current coordinate position stored when circuit is close
c) Contacts of point bearing arranged at 90 degree
d) Contacts of point bearing act as electrical micro switches
Answer: d
Explanation: The “buckling mechanism” in trigger type probe system is a 3 point bearing, the contacts of which are arranged around the circumference at 120 degrees. These contacts act as micro switches.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Three Dimensional Measuring Machine”.
1. Which of the following is provided as scales in three dimensional measuring machines?
a) Laser interferometer
b) Straight edge
c) Vernier caliper
d) Screw gauge
Answer: a
Explanation: Laser interferometers are provided as scales in three dimensional measuring machines. A cooling system is also provided in this machine. This cooling system is to reduce the temperature rise when it is in operation.
2. Which motor is used to control axes movement in three dimensional measuring machines?
a) Tachometer
b) Torque motor
c) Induction motor
d) Stepping motor
Answer: d
Explanation: Axes movement in three dimensional measuring machines is controlled by stepping motors. Stepping motors are attached to lead-screws. 3 carriages are provided and mounted upon double V-ways.
3. Which material is used for the base in three dimensional measuring machines?
a) Steel
b) Aluminium
c) Granite
d) Lead
Answer: c
Explanation: The machine base and metrology system should be made independent of each other. The external forces upon the metrology system should be constant. Granite is chosen for building the machine base because of low coefficient of expansion.
4. How many pneumatic isolators are used to support the base of three dimensional measuring machines?
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: Three dimensional measuring machine has pneumatic isolators. The base of the machine is supported on 3 pneumatic isolators. The frame of a machine is built of steel because temperature-controlled oil shower is included.
5. Which of the following is true about electronic gauge stylus used in three dimensional measuring machines?
a) It is ball tipped
b) Tip is trapezoidal
c) Polygonal tip
d) Pointed tip
Answer: a
Explanation: The electronic gauge stylus is ball-tipped. It is a single axis, linear variable displacement transducer carried and positioned by the vertical or we can say ‘z’ slide. The axis of the linear variable displacement transducer is mounted at a 45 degree angle w.r.t the y and z axes.
6. How many laser interferometers are provided on y-axis slide?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: Two laser interferometers are provided on the y-axis slide. These are suitably separated. The difference in readings taken by these 2 lasers is used as a servo input to drive a piezoelectric crystal.
7. Which mounts are used to support frame?
a) Effective mounts
b) Dynamic mounts
c) Static mounts
d) Kinematic mounts
Answer: d
Explanation: Kinematic mounts are used to support the frame inside the machine base. The plane of the supports is coincident with the bending neutral axis of the machine base. Its influence is thereby minimized on the metrology frame.
8. Which drive is used in slide drive system present in three dimensional measuring machines?
a) Rack and pinion drive without gear teeth
b) Rack and pinion drive with gear teeth
c) Worm and worm gear drive without teeth
d) Worm and worm gear drive with teeth
Answer: a
Explanation: A portion of each bearing is evacuated and acts like a vacuum chuck to hold the bearing. The bearing surface balance provides lift. The slide drive system used in three dimensional measuring machines can be considered as a rack and pinion drive without gear teeth.
9. Which of the following option is true for given statements about 3-dimensional measuring machines?
Statement 1: A cooling system is present in 3-dimensional measuring machine.
Statement 2: It is designed for 3-dimensional calibration but not adaptable for computer control.
a) T, T
b) F, F
c) F, T
d) T, F
Answer: d
Explanation: Three dimensional measuring machines are useful in modern sophisticated industry. 3-D measuring machines are designed for 3-dimensional calibration. This machine is also adaptable for computer control.
10. Which type of error is introduced when the travel direction of LVDT is not normal to the part surface?
a) Sine error
b) Cosine error
c) Tangent error
d) Cotangent error
Answer: b
Explanation: When the direction of travel of Linear variable displacement transducer is not normal to the part surface, the cosine error is introduced. A correction is provided in this machine for this cosine error.
11. Which type of pathways is used for laser interferometer present in three dimensional measuring machines?
a) Helium unshielded pathways
b) Neon unshielded pathways
c) Helium shielded pathways
d) Neon shielded pathways
Answer: c
Explanation: Displacement accuracy is achieved by laser interferometers. Laser interferometers are operated in helium-shielded pathways. The interferometers are located in strict accordance with the Abbe principle.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Universal Measuring Machine”.
1. What is the difference between CMM and UMM?
a) UMM can’t inspect geometrical features while CMM does it
b) CMM is more accurate than UMM but can’t inspect geometrical features
c) UMM is more accurate than CMM and can inspect geometrical features
d) CMM is more accurate than UMM but can’t inspect geometrical features
Answer: c
Explanation: Co-ordinate measuring machine doesn’t inspect the geometric features of the part but universal measuring machine does it. Co-ordinate measuring machine is less accurate than a universal measuring machine.
2. Which type of standard is UMM for calibration of hole location gauges?
a) Primary standard
b) Secondary standard
c) Basic standard
d) Reference standard
Answer: a
Explanation: Universal measuring machine is a primary standard for calibration of hole location gauges. A hole-location gauge is calibrated on universal measuring machine and used to inspect a Co-ordinate measuring machine.
3. Which of the following is used to locate awkward shaped workpieces in UMM?
a) Swinging table
b) Tilt table
c) Rotary table
d) Angular table
Answer: c
Explanation: The workpieces of awkward shape can be located by using a rotary table to align reference holes with the measuring axes. When the dimensions are specified with respect to centre hole in the part, then initial line-up is facilitated by using the reference hole in the rotary table centre.
4. Which of the following is used to measure macro-circuit components in UMM?
a) Telescope
b) Microscope
c) Probe tip
d) Capstan
Answer: b
Explanation: For measuring the location of small holes, a microscope is used and also for parts which are damaged by physical contact. Parts like components of macro-circuit, which doesn’t have reference surfaces against which an indicator probe-tip may register, can be measured by a microscope.
5. Which of the following are the foundations of mechanical accuracy in UMM?
a) Geometry and length
b) Roundness, geometry and length
c) Geometry, division of circle and length
d) Roundness, geometry, division of circle and length
Answer: d
Explanation: “Cubic concept” of accuracy in the UMM requires the individual mastery of 4 mechanical arts-Roundness, geometry, division of circle and length. These are the “Foundations of Mechanical Accuracy” truly.
6. Which of the following option is true for given statements about UMM?
Statement 1: Measurement on CMM is faster than UMM.
Statement 2: UMM can resolve the exact nature of error of features of all parts.
a) T, T
b) F, T
c) T, F
d) F, F
Answer: a
Explanation: Universal measuring machine is capable of resolving the exact nature of the error of features of all parts. This machine discloses information about measurement which in turn permits the machine or methods improvement.
7. Which of the following principle is used to derive authority for angles of angle gauges or angular relationships in mechanical parts and assemblies?
a) Self-assessment principle of dividing the circle
b) Self proving principle of dividing the circle
c) Self verification principle of dividing the circle
d) Self explaining principle of dividing the circle
Answer: b
Explanation: Accurate circle division is a requirement of all machine shops and laboratories. The self-proving principle of dividing the circle is used to derive the authority for “angles” of angle gauges, rotary tables, or the angular relationships in mechanical parts and assemblies.
8. Which of the following is the authority for roundness?
a) Precision spindle
b) Probes
c) Dividing circle
d) Rotary tables
Answer: a
Explanation: It is important to achieve roundness for precision machine tools of many mechanical parts and with their spindles especially. A precision spindle is an authority for roundness.
9. Which of the following is not true for UMM?
a) Less skilled operator is needed
b) It is a slow machine
c) Used as a special purpose machine in metrology laboratories
d) A valuable machine for comparing master gauges and length standards
Answer: a
Explanation: UMM is a slow machine. It requires a highly skilled operator to use. The accuracy created in these machines has overcome the needs of most industries. As a result, today UMM is only found as a special-purpose machine in metrology labs.
10. Which of the following is a foundation of all geometrical accuracy?
a) Vertical plane
b) Flat plane
c) Rough plane
d) Oblique plane
Answer: b
Explanation: The foundation of all geometric accuracy is the flat plane. Meehanite cast iron is a prime material component for the elements of geometry because it is available readily, easily cast to shape and relatively uninfluenced by relative-humidity.
This set of Engineering Metrology Questions and Answers for Campus interviews focuses on “Numerical Controlled Coordinate Measuring Machines”.
1. In which of the following numerical controlled CMM used?
a) Workshops
b) Production floors
c) Workshop and production floors both
d) Can be used anywhere
Answer: c
Explanation: CMMs are designed originally for the measurement of high-precision on relatively few workpieces in the metrology labs but are now used both in the workshop and on the production floor.
2. Which of the following technique is used to measure the profile of cams on numerical controlled CMM?
a) Scanning technique
b) Searching technique
c) Standing technique
d) Sorting technique
Answer: a
Explanation: The profile or form of cams and cutting dies, etc., can be measured on numerical controlled CMM by a scanning technique. This technique takes about 50 measurements and processes them every second.
3. Which of the following is responsible to control the processes in numerical controlled machines?
a) Symbols and letters
b) Letters and numbers
c) Numbers and symbols
d) Numbers, symbols and letters
Answer: d
Explanation: Numerical control is a programmable automation of machines and processes in which process is controlled by symbols, letters and numbers. In numerical control program, instruction changes when job changes.
4. Which type of probe system is used in CMM?
a) One dimensional probe system
b) Two dimensional probe system
c) Three dimensional probe system
d) Both one and two dimensional probe system
Answer: c
Explanation: Coordinate measuring machines both portable and bridge-type have a probe system. These probe systems have three dimensional probes which are suitable for dynamic measurements.
5. In CMMs adequate numbers of soft keys are present. What are soft keys?
a) Keys with variable functions
b) Keys not hard to press
c) Soft running keys so that less fatigue to operator
d) Keys made of soft material
Answer: a
Explanation: In CMMs which are installed with microprocessor based controls, suitable number of soft keys are provided. These keys are the keys with variable functions, which handle commands required for man-machine dialogue.
6. Which of the following option is true for given statements about numerical controlled CMM?
Statement 1: Idle time of the production equipment is more.
Statement 2: Software for automatic evaluation is incorporated.
a) T, T
b) F, F
c) T, F
d) F, T
Answer: d
Explanation: In a numerical controlled coordinating measuring machine, software suitable for automatic calibration of the probe, calculation of geometric elements and automatic evaluation and recording is incorporated.
7. What is the use of SPC software in CMMs?
a) Dynamic analysis of measurement
b) Statistical analysis of measurement
c) System analysis of measurement
d) Quality analysis of measurement
Answer: b
Explanation: SPC software is a feature present in CMMs. It is for statistical analysis of measurements. Temperature compensation is also present for a change in the temperature due to various reasons like environmental change.
8. Which of the following is used to inspect nonlinear surfaces in very fast way in CMMs?
a) Laser triangulation probe
b) Impact protection
c) Wave lasers
d) Line laser
Answer: d
Explanation: Laser triangulation probes are used to scan the surface and after scanning it transmits a continuous flow of data. Line lasers are the fastest way to inspect non-linear surfaces. It is widely used in reverse engineering.
9. Which of the following is true for the given statements about numerical controlled CMM?
Statement 1: Command like full 3D alignment is provided.
Statement 2: Repeat function is used to simplify the inspection of features which are similar.
a) T, T
b) F, F
c) F, T
d) T, F
Answer: a
Explanation: Various commands are provided in CMMs. These commands are full 3-D alignment, multipoint measurement of circle centers, choice of 3 working planes, probe diameter compensation etc.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Computers in Metrology”.
1. How a system is used to check the surface finish of a surface by CAI?
a) As a mirror
b) As a lens
c) As a black body
d) As a grey body
Answer: a
Explanation: For checking surface finish of a surface by machine vision or CAI, the surface is treated as a mirror. The vision system looks at an image of a light source reflected in the surface. Changes in that image signify the defective area.
2. How many degrees of freedom is in the robotic arm?
a) 1
b) 2
c) 3
d) 4
Answer: d
Explanation: A robot arm has four degrees of freedom, the motions are three rectangular linear motions and wrist motion. It is brought for the inspection near the equipment while being machined.
3. Which of the following is used to control the robot arm?
a) Microprocessor
b) Keyboard
c) Mouse
d) Computer
Answer: a
Explanation: The motion of the robot arm is controlled by a microprocessor. It performs simultaneous multi-axis control of position, acceleration and speed and provides high dynamic arm performance.
4. How many levels are organized in an inspection data handling?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: The inspection data handling is organized at 2 levels; first is to perform the dimensional analysis of the part to discriminate good parts, bad parts and reworkable parts and second is the inspection data is reduced on real-time statistical basis to derive trends.
5. What is the use of stroboscope technology?
a) Optically freezing the motion of rotating part
b) Mechanically freezing the motion of reciprocating part
c) Optically freezing the motion of reciprocating and rotating part
d) Mechanically freezing the motion of reciprocating and rotating part
Answer: c
Explanation: Stroboscope technology is used for optically freezing the motion of reciprocating or rotating parts. Fibre optics is the main reason for the remote inspection. It is possible by fibre optics.
6. Which of the following is used for automatic inspection?
a) Universal probes
b) Hydrolysis probes
c) Electronic probes
d) Mechanical probes
Answer: a
Explanation: Hundreds of readings may be taken in an automatic process and then processed, analysed and results are produced. Automatic inspection is carried out by universal probes. Operator intervention is not required in a fully automatic inspection.
7. How many points are needed on the circumference to define a circle by computer?
a) One
b) Two
c) Three
d) Four
Answer: c
Explanation: If 3 points on the circumference of a circle are completely defined then a computer can easily define the circle. Manually this work is very painstaking and very time consuming too. Also in gear measuring machine, the use of computer give final results in no time and very accurately.
8. What is another name of computer aided inspection?
a) Computer aided machining
b) Visionary machining
c) Machine vision
d) Visionary inspection
Answer: c
Explanation: Machine vision is a technique which allows a sensor to view a scene and derive a decision logically without further human intervention. Advantages of machine vision systems are consistency, high speed and reliability.
9. Which of the following is mounted on a robot arm for inspecting complicated surfaces?
a) Vision sensor
b) Proximity sensor
c) Heat sensor
d) Touch sensor
Answer: a
Explanation: It’s possible to look directly for defects if the defects are relied upon to have a distinct contrast with the correct surface. The vision sensor can be mounted on a robot arm for inspecting large or complicated surfaces.
10. Which of the following is used to detect the modulated reflected light from any irregularity on the surface?
a) Television camera
b) Light intensity sensor
c) Modulator
d) Video processor
Answer: d
Explanation: When the light beam hits the material then any surface irregularity modulates the reflected light. This is detected by a video processor and also microcomputer in an evaluation unit.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Principles of TQM”.
1. What is the full form of TQM?
a) True quality machining
b) Total quality management
c) True quantitative machining
d) Total queue management
Answer: b
Explanation: Total quality management is a process that promotes unending improvement in the efficiency and effectiveness of all elements of a business. Quality finds the 1st place in the entire business action.
2. Which of the following is correct for TQM?
a) Quality strategy in TQM emanates from top
b) TQM is a static process
c) It is a management approach to short-term success through customer
d) It is used to improve processes not products
Answer: a
Explanation: Quality strategies and values in TQM emanates from top. Strategy of defect prevention leads to plans of action and strategic goals. Customer orientation is also a principle of TQM. Regular feedback is needed to meet the needs of customers.
3. Which part in quality management is the critical part?
a) Process thinking
b) Performance measurement
c) Customer’s view
d) Systematic approach
Answer: d
Explanation: A critical part of quality management is the systematic and strategic approach to achieving an organization’s vision and goals. This process includes the formulation of a strategic plan that integrates quality as a core component.
4. Which of the following is not true for communication in TQM?
a) Three way communication
b) It should be clear
c) Forceful
d) Open involvement
Answer: a
Explanation: Communication is two way in total quality management. It should be forceful, effective, consistent and clear. It is very essential for active and open involvement in all company’s visions.
5. Which of the following is correct option for given statements about TQM?
Statement 1: Design of the formal system is a one time effort.
Statement 2: TQM is a management philosophy.
a) F, F
b) F, T
c) T, T
d) T, F
Answer: b
Explanation: Design of a system is not a onetime effort but it wills changes continuously according to the customer need and organization.
TQM is a management philosophy to a journey of excellence of organization and also to satisfy needs of customer.
6. What are the core principles of the TQM in a company-wide effort?
a) Customer and process orientation only
b) Continuous improvement only
c) Process orientation and continuous improvement only
d) Continuous improvement, process and customer orientation
Answer: d
Explanation: TQM as a company-wide effort emphasizes 3 core principles. These principles are process orientation, customer orientation and continuous improvement. Some core areas are essential to implement these principles that organization need to follow.
7. Which drivers are used in TQM system?
a) Competition, Survival and export drive
b) Teamwork participation and customer satisfaction
c) Quality tools and technique
d) Management commitment and vision
Answer: a
Explanation: Management commitment and vision, teamwork participation, Quality tools and techniques are the system models and competition. Survival, profitability, Customer expectations are the drivers. System models, drivers and TQM all together forms a TQM system.
8. What is included in the quality assessment in TQM?
a) Strategic quality planning
b) Management of process quality
c) Quality and operational results
d) Information and analysis
Answer: b
Explanation: Any TQM company needed a good process management. These include design, R & D, process management quality for all work units and suppliers and also quality improvement and assessment.
9. How many stages are needed for inspection and testing in TQM as per ISO 9001?
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: There are three stages of inspection and testing as per ISO 9001. These stages are receiving inspection and testing, in process inspection and third is testing and final inspection and testing.
10. Which factor is the basis of Decision making in TQM?
a) Facts only
b) Opinions only
c) Facts and opinions both
d) Neither facts nor opinions
Answer: a
Explanation: Decision-making within the organization should be only based on facts. It is not based on opinions like personal interests and emotions. Data should support this type of decision-making process.
This set of Tricky Engineering Metrology Questions and Answers focuses on “Quality Management and Quality System Requirements”.
1. What is the primary focus of the quality management system?
a) Customer focus
b) Engagement of people
c) Process approach
d) Improvement
Answer: a
Explanation: The primary focus of quality management system is to meet the requirements of a customer. The main aspect to sustain success in an organisation is to retain the confidence of customers and other parties on whom it depends.
2. What are the responsibilities of management in quality system management?
a) Frequently change responsibilities of employees for flexibility
b) Frequently change authorities for flexibility
c) Authority changes but fixed responsibility
d) Fix authority and responsibility
Answer: d
Explanation: The management should fix responsibility and authority of every employee to control and detect nonconformity affecting quality. It must provide all the resources like methods, machinery and money of the desired standard to result in quality work.
3. What is not true for the quality system requirements?
a) Generic
b) Depends upon size of organisation
c) Independent of type of organisation
d) Applicable to any organisation
Answer: b
Explanation: All the quality system requirements for organisations as per ISO 9001:2015 are generic. These are intended to be applicable to any organization. It does not depend on organisation type or size, or the products and services it provides.
4. What does quality plans specify in a quality system?
a) Work instructions
b) Checklists
c) Clause to clause interpretation of work
d) All resources and their schedule
Answer: d
Explanation: Quality plans in quality system specified all the resources and their schedule of acquisition to match with desired schedule of activities. Quality manual provides clause to clause interpretation of work in supplier’s context.
5. In how many groups, the quality system and management requirements are divided as per ISO-9001:2000?
a) 2
b) 3
c) 4
d) 5
Answer: d
Explanation: According to ISO-9001:2000, all the quality system and management requirements are considered in 5 heads. These are i) quality management system, ii) resource management, iii) management responsibility, iv) product realisation and v) measurement, analysis and improvement.
6. What is quality control?
a) Process of recognition of entire manufacturing process
b) Concerned with the integration of all the efforts in organisation
c) Detection of defects in a product
d) Minimization of material level
Answer: c
Explanation: Quality control deals with the detection of defects in a product. It also deals with the sorting out rejects. Most of the techniques used in quality control are based on statistical methods.
7. Which option is correct for given statements about quality assurance?
Statement 1: It assures that quality requirements will fulfilled.
Statement 2: Quality assurance is product oriented.
a) F, F
b) T, F
c) T, T
d) F, T
Answer: b
Explanation: Quality assurance is process oriented while quality control is product oriented. Quality assurance is a way of preventing defects and is focused on providing confidence that quality requirements needed will be fulfilled.
8. What is the purpose of ISO standards created for quality management systems?
a) To certify the process
b) To certify the quality of a product
c) To certify the quality of service
d) To certify the quantity used for product
Answer: a
Explanation: The Quality Management System standards created by ISO are meant to certify the processes of an organization but not the product or service itself. Standards of ISO 9000 do not certify the quality of the service or product.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Tools and Techniques of TQM”.
1. Which statistical technique integrates product design and manufacturing process?
a) Tree analysis
b) Problem solving techniques
c) Quality function deployment
d) Taguchi approach
Answer: d
Explanation: Taguchi’s approach for quality combines statistical methods and engineering to achieve rapid movement in quality and cost by optimising the design of a product. It integrates manufacturing process and product design.
2. What is the key step in Taguchi’s approach?
a) Tolerance design
b) System design
c) Parameter design
d) Process design
Answer: c
Explanation: Taguchi’s approach is based on integrating system design , parameter design and tolerance design . Parameter design is the key step as it offers the concept of uncontrollable factor.
3. What is called the stratification of information?
a) Breaking down a whole group into smaller sub groups
b) Isolating the vital few from the trivial many
c) Grouping of scattered information
d) Sequencing of processes in a quality system
Answer: a
Explanation: Stratification of information is one of the statistical tools which means breaking down of the whole group into smaller sub-groups. Run charts, effect diagram, pareto diagram and scatter diagrams are also the statistical tools.
4. Which technique is used to relate complex cause and effect relationships?
a) Affinity diagram
b) Pareto diagram
c) Scatter diagram
d) Interrelationship diagram
Answer: d
Explanation: Interrelationship diagram is a quality improvement technique which shows the relationship between inter-related factors. This diagram displays the factors which are involved in complex problems.
5. What is PDPC?
a) A statistical tool
b) Quality improvement technique
c) Quality assurance technique
d) Statistical process control technique
Answer: b
Explanation: PDPC is process decision program chart which helps in the selection of the best process to obtain desired result. It is a quality improvement technique. It evaluates existing process and also look at alternatives.
6. What is the first step in problem solving process?
a) Plan
b) Do
c) Check
d) Action
Answer: a
Explanation: Problems are best solved by the cycle: Plan-Do-Check-Action. In planning, a course of action is planned according to customer requirement and conditions of service then the process must be executed according to this plan.
7. How many control charts are normally used for statistical control of variables?
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: Three control charts are normally used for statistical control of variables. These are i) Mean chart, ii) Range chart, and iii) standard deviation charts. Control charts help in the understanding of inherent capability of process and bring the process under control.
8. Which tool is used to analyse the effects of a failure of individual components on the system?
a) FTA
b) FMEA
c) Quality circles
d) Fool proofing
Answer: b
Explanation: Failure mode and effect analysis is a statistical tool used to review the new product design with respect to the requirements of customers before it is sent to production. It is used basically to analyse the failure effect of individual components on the system as a whole.
9. What is the formula for process capability index?
a) C p
b) C p
c) (1-C p )K
d) (1+C p )K
Answer: a
Explanation: Process capability index is also known as measure of process capability and denoted by C pk . C pk = *C p . K is the correction factor and always has a positive value. C p is the process capability potential also known as process capability variation and is equal to the .
10. What is arrow diagram in TQM?
a) A diagram used to plan the most appropriate schedule
b) Diagram shows the relationship strength between the variables
c) Used large amount of data and organise it on the basis of natural relationship between items
d) Diagram showing the sequencing and inter relationships between factors
Answer: a
Explanation: Arrow diagram is a statistical tool used to plan the most appropriate schedule for any task and to effectively control it during the progress of the process. Arrow diagram helps in establishing the most suitable plan for a project.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Principle of Working”.
1. What is the use of a laser beam in image formation?
a) Triangulation system for measuring system
b) Reduce glare of image
c) Controls contrast of image
d) Controls brightness of image
Answer: a
Explanation: Laser beam is used for triangulation system for measuring distance. Polarised or ultraviolet light is used to reduce glare or increase contrast. It is important that light source is placed correctly since it influences the contrast of the image.
2. Where is backlighting is best suited?
a) Simple silhouette image is required to obtain minimum image contrast
b) Certain key features on the surface of the object are to be inspected
c) Simple silhouette image is required to obtain maximum image contrast
d) Three-dimensional feature is being inspected
Answer: c
Explanation: Backlighting is suited when a simple silhouette image is required to obtain maximum image contrast. When certain key features on the surface of the object are to be inspected, front lighting is used.
3. Which light is preferred if three dimensional features are being inspected?
a) Front lighting
b) Side lighting
c) Backlighting
d) Any lighting is suited
Answer: b
Explanation: Side lighting or structured lighting may be required when a three-dimensional feature is being inspected. The proper orientation and fixturing of part also deserve full attention. Selection of proper illumination technique is important for any feature.
4. Why do CCD or CID cameras are used?
a) To generate the electronic signal representing the image
b) To generate image’s hard copy
c) To determine lighting of the image
d) To capture heat signature
Answer: a
Explanation: CCD or CID cameras are used to generate the electronic signal that represents the image. The camera collects light from the image scene via lens and uses a photosensitive target to converts it into electronic signal.
5. Where is the Vidicon Camera used?
a) Open-circuit television systems
b) In Image processing
c) In image analysis
d) Closed-circuit television systems
Answer: d
Explanation: Vidicon Camera used in closed-circuit television systems can be used for machine vision systems. An image is formed in camera by focussing the incoming light through a series of lenses onto the photoconductive faceplate of the vidicon tube.
6. What is used in solid state cameras?
a) Image sensor IC
b) CMOS image sensors
c) Charge coupled device image sensors
d) Digital camera image sensor
Answer: c
Explanation: Solid state cameras are generally used in machine vision systems. These uses charge injected device or charge coupled device image sensors. They contain linear or matrix array of small, accurately spaced photo-sensitive elements fabricated on silicon chips using integrated circuit technology.
7. How many detector elements are present in a matrix array solid state camera?
a) 156 x 156 per array
b) 216 x 216 per array
c) 116 x 116 per array
d) 256 x 256 per array
Answer: d
Explanation: A typical matrix array solid state cameras have 256 x 256 detector elements per array. Solid state cameras are small and rugged. Sensors of solid state cameras are do not wear out with use. There is very less image distortion in solid state cameras because of placement of photo detectors accurately.
8. What is the common rate of an image forming in a camera?
a) 20 images per second
b) 30 images per second
c) 25 images per second
d) 50 images per second
Answer: b
Explanation: A camera may typically form an image 30 times per sec i.e. at 33 m sec intervals. At each time interval the entire image has to be captured and frozen for processing by an image processor. An analog to digital converter is used to convert analog voltage of each detector into digital value.
9. What is windowing?
a) Technique used to concentrate the processing in a desired area of an image
b) Technique used for image restoration
c) Technique for image analysis
d) Technique to describe and measure the properties of image features
Answer: a
Explanation: Windowing is a technique used to concentrate the processing in a desired part of image and also ignoring the non-desired part or non-interested part of the image. In this, an electronic mask is created around a small area of an image.
10. Which of the following method is used to reduce processing of image?
a) Triangulation technique
b) Digital imaging technique
c) Run length encoding
d) Stereo vision
Answer: c
Explanation: General techniques to reduce processing are edge detection and run length encoding. In run-length encoding, each line of the image is scanned, and transition points from black to white or vice versa are noted, along with the number of pixels between transitions.
11. What is stadimetry?
a) Direct imaging technique in which distance is judged by apparent object distance
b) Indirect imaging technique in which distance is judged by apparent object distance
c) Direct imaging technique in which distance is judged by actual distance of the object
d) Indirect imaging technique in which distance is judged by actual distance of the object
Answer: a
Explanation: Stadimetry is a technique used to determine the object distance from a vision system camera. It is a direct imaging technique in which distance of the object is determined by the apparent size of object in the field of view of camera.
12. Which method is not used to determine object orientation?
a) Equivalent ellipse
b) Triangulation technique
c) Structured light method
d) Light intensity distribution
Answer: b
Explanation: Measuring the distance of an object from a vision system camera, determining object orientation, and defining object position are three important tasks performed by machine vision systems. The object orientation can be determined by the methods of an equivalent ellipse, the connecting of three points method, light intensity distribution and structured light method.
13. Which method is used for interpreting images?
a) Light intensity distribution
b) Stereo vision
c) Optical computing
d) Template matching
Answer: d
Explanation: Template matching and feature weighing are the most commonly used methods of interpreting images. In template matching a mask is generated electronically to match a standard image of an object.
14. What do you mean by image interpretation?
a) Identification of type of image
b) Identification of an object based on recognition of its image
c) Identification of color content of image
d) Identification of each pixel of image
Answer: b
Explanation: Image interpretation involves identification of an object based on recognition of its image. These results are then compared with a presorted set of standard criteria and the various conclusions are drawn.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Gray Scale Vs Binary Imaging”.
1. Which type of conversion is involved in machine vision inspection system?
a) Continuous tone image into a binary image
b) Binary image into a continuous tone image
c) Binary image into black and white image
d) Low quality grayscale image to high quality grayscale image
Answer: a
Explanation: The machine vision inspection systems involve the conversion of continuous tone image as seen by a B & W television camera into a binary image. Considerable skill are used for this in optics and lighting.
2. How many different values can be picked by gray scale image?
a) 2
b) 125
c) 126
d) 256
Answer: d
Explanation: For a grayscale image, the intensity of the image varies across the brightness spectrum. This variation is gradual. The intensity is a whole number at any point in a range of 0 to 255, thus it can pick a value from 256 different values.
3. What is the meaning of pixel value ‘1’ in binary imaging?
a) Black
b) White
c) Gray
d) Yellow
Answer: b
Explanation: Any image is made of a number of pixels and value of these pixels may vary between a certain range. For binary image, the pixel value is 0 or 1 which means only two shades. 1 is for white and 0 is for black.
4. Which of the following option is correct for the given statements about gray scale and binary imaging?
Statement 1: All binary images are gray scale images.
Statement 2: In gray scale imaging, every pixel is represented by 8 bits.
a) F, F
b) T, F
c) F, T
d) T, T
Answer: d
Explanation: All binary images are grayscale but all grayscale images are not binary images as binary image can take only 2 values. Grayscale have a transition between pure white or pure black.
5. What is the most important characteristic of a binary image?
a) Segmentation
b) Distance transform
c) Dilation
d) Erosion
Answer: b
Explanation: An important characteristic of a binary image is the distance transform. Distance transform gives the distance of every set pixel from the nearest unset pixel. The distance transform can be calculated efficiently.
6. What is the format of binary images?
a) PBM
b) PGM
c) PPM
d) PMP
Answer: a
Explanation: The format of the binary image is PBM or portable bit map and PGM or portable gray map is the format of grayscale images. PPM is also an image format and is known as portable pix map.
7. Which type of display is used to read fonts of character?
a) 2 segment display
b) 4 segment display
c) 6 segment display
d) 7 segment display
Answer: d
Explanation: Fonts of characters are read by a display of 7 segments. It is a form of an electronic display device which is widely used in electronic meters, basic calculators and electronic meters etc.
8. Which is not a part of the parameters used to define grayscale in gray scale model?
a) Hue
b) Contrast
c) Lightness
d) Saturation
Answer: b
Explanation: In some cases, rather than using the RGB or CMY color models to define grayscale, three other parameters are defined. These are hue, saturation and lightness. In a grayscale image, the saturation is apparent color intensity, hue is apparent color shade and lightness is apparent brightness.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Circular Scanning”.
1. What is mathematical morphology?
a) Method of image rendering
b) Method of image processing and analysis
c) Method of image compression
d) Method of image formation
Answer: b
Explanation: Mathematical morphology is a method of image analysis and processing which is based on set theoretical descriptions of image measurements and transformations. It uses the concept of a structuring element, a predefined shape which is employed as a probe to test out the spatial nature of a pattern.
2. What is not true for circular scanning?
a) They are solid state device
b) They are used for line following
c) They are used for surface inspection
d) They are used for evaluation
Answer: d
Explanation: Circular scanning devices are used for surface inspection of bore and cylinder outside diameter, angular position measurement, line following etc. Circular scanning is a solid state device that is configured as a light sensitive discretely segmented annular ring.
3. Circular scanners are consists of which type of diodes?
a) Monolithic arrays of silicon photodiodes
b) Silicon avalanche photodiodes
c) Multi element silicon photodiodes
d) Two dimensional arrays of silicon photodiodes
Answer: a
Explanation: Circular scanners devices consist of monolithic arrays of silicon photodiodes. These are self-scanned photodiode arrays which have their geometry, defined.
4. On which factor does the output of photodiode in circular scanners depends upon?
a) Frequency of illumination incidented
b) Frequency of illumination reflected
c) Amplitude of illumination incidented
d) Amplitude of illumination reflected
Answer: c
Explanation: In circular scanners, each photodiode site will output a signal that is directly proportional in amplitude to the illumination incident upon it. This output is a serial analog data stream whose rate is determined by the input clock frequency.
5. What are the factors which are responsible for the time required to read out the number of elements in a circular scan?
a) Size of scanner
b) Property of photodiode
c) Average scan time for reading
d) Frequency of input clock and number of elements
Answer: d
Explanation: The requirements of light intensity are a function of the circular scan time and the physical size of each photodiode. The total time required to read out the number of elements is a function of the input clock and the number of elements in the array.
6. What is not a function of circular scanning?
a) Tracking
b) Slicing of 3D object into 2D image
c) Displacement
d) Cylindrical bore inspection
Answer: b
Explanation: The various applications of circular scanning could be for detecting presence/absence of a feature, cylindrical bore or other defect inspection, displacement, tracking, location recognition, etc.
7. What is tracking?
a) Obtaining coordinates of a particular object in an image
b) Obtaining a path followed by a moving object
c) Obtaining the coordinate data necessary to position the sensing system along defined patterns
d) Obtaining the coordinates of a frame that is captured
Answer: c
Explanation: Tracking and cylindrical bore or other defect inspections are the applications of circular scanning. In circular scanning, tracking means obtaining the coordinate data necessary to position the sensing system along defined patterns.
8. What is displacement?
a) Calibration, verification, and alignment of an object moving in an angular motion about a pivotal centre
b) Verification and alignment of an object moving in an angular motion about a pivotal centre
c) Calibration and alignment of an object moving in an angular motion about a pivotal centre
d) Calibration and verification of an object moving in an angular motion about a pivotal centre
Answer: a
Explanation: Displacement and location recognition are the applications of circular scanning. Displacement in circular scanning refers to calibration, verification, and alignment of an object moving in an angular motion about a pivotal centre.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Photogrammetry”.
1. How many location photographs are required for photogrammetry?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: In photogrammetry photograph are taken from at least two different locations so that “lines of sight” can be developed from each camera to points on the object. These lines of sight are intersected mathematically to produce the 3-D coordinates of the points of interest.
2. What does the inner orientation of camera define in photogrammetry imaging process?
a) Geometric parameters of the imaging process
b) Location of object points in space
c) View direction
d) Finding fixed points
Answer: a
Explanation: The coordinates of image define the locations of the object points on the film. The exterior orientation of a camera defines location of points in space and direction of view. The inner orientation of camera defines the geometric parameters of the imaging process.
3. What does close range photogrammetry called in computer vision community?
a) Topographic modeling
b) Image-based modeling
c) Aerial photogrammetry
d) Engineering photogrammetry
Answer: b
Explanation: In Terrestrial photogrammetry also known as close-range Photogrammetry, the camera is located on the ground, pole mounted and handheld. This type of photogrammetry is sometimes called Image-Based Modeling in the computer vision community.
4. What is the fundamental principle of photogrammetry?
a) Interference
b) Resection principle
c) Triangulation
d) Intersection principle
Answer: c
Explanation: Photogrammetry is a 3-D coordinate measuring technique that uses photographs as the fundamental medium for metrology. The fundamental principle used by this technique is triangulation or Aerial Triangulation.
5. What is the type of photograph if the tilt of the axis of the camera from the plumb line is 2 degrees?
a) Oblique photograph
b) Horizontal photograph
c) Tilted photograph
d) Vertical photograph
Answer: d
Explanation: If the tilt of the axis of a camera from the plumb line is less than 3 degree then the photograph is vertical photograph but if the tilt of camera axis is more than 3 degree then it is called as tilted photograph.
6. What is the type of photograph on which the apparent horizon doesn’t appear?
a) Low oblique
b) High oblique
c) Tilted
d) All type of oblique photographs
Answer: a
Explanation: Oblique photographs are of two types : High oblique photograph and low oblique photograph. High oblique photograph is an oblique photograph in which the apparent horizon appears while low oblique photograph: is one on which the apparent horizon doesn’t appear.
7. Which is not correct about interpretative photogrammetry?
a) It form basis for remote sensing
b) Involves study of photographic images
c) Involves recognition and identification of objects and judgement of their significance
d) Also involves the use of collected data after analysis
Answer: d
Explanation: Photo interpretation or interpretative photogrammetry involves the study of photographic images but remote sensing involves not only the photograph analysis but also the use of data collected from remote sensing instruments.
8. Which of the following option is true for given statements about photogrammetry?
Statement 1: Both aerial and terrestrial photogrammetry used in Urban planning.
Statement 2: Terrestrial photogrammetry is more suitable for movement related issues.
a) T, T
b) F, F
c) F, T
d) T, F
Answer: a
Explanation: Urban planning takes advantage of terrestrial and aerial methods. Planners and designers collaborate on the best perspective for a specific project using aerial photogrammetry and terrestrial photogrammetry helps to see the interrelation between urban constructions, security issues etc.
9. Which photogrammetry method has topographical mapping as a common application?
a) Interpretative Photogrammetry
b) Metric photogrammetry
c) Aerial Photogrammetry
d) Space Photogrammetry
Answer: b
Explanation: Metric photogrammetry consists of making precise measurements on photographs to determine relative point locations. Common applications of Metric Photogrammetry are topographical mapping and plan metric mapping.
10. Which instrument lets an operator see two photos at once?
a) Goniometer
b) Collimator
c) Theodolite
d) Stereo plotter
Answer: d
Explanation: Stereoscopic plotting instruments or stereoplotters or plotters are the instruments designed to provide accurate solutions for point positions of objects from their corresponding positions of images on overlapping pairs of a photo.
This set of Engineering Metrology Questions and Answers for Aptitude test focuses on “Grazing Incident Technique to Evaluate Surface Flatness”.
1. How many data points can be analyzed in 20 seconds using grazing incidence interferometry?
a) 35,000
b) 45,000
c) 55,000
d) 65,000
Answer: d
Explanation: A laser-based system is developed to view part surface topography using grazing incidence interferometry. It is a microprocessor based system. It can analyze more than 65,000 data points and computer flatness in less than 20 seconds.
2. Which of the following option is true for the evaluation of the surface by using grazing incident technique with laser beam system?
a) It can two dimensional profiles with submicron accuracy
b) It measure half the part surface at a time
c) It can produce three dimensional profiles with submicron resolution
d) Video screen is used to view test results
Answer: b
Explanation: It measures the whole part surface at one time and produces 2 and 3-D profiles with sub-micron resolution and accuracy. Test results can be viewed with the help of video screen and hard copied on a printer.
3. How much a laser beam can be expanded inside interferometer using grazing incidence interferometry?
a) 200 mm
b) 200 nm
c) 400 mm
d) 400 nm
Answer: a
Explanation: In this instrument, inside the interferometer a laser beam can be expanded into 200 mm column of light. The interference pattern obtained by this process represents the shape of the part of the surface.
4. Which system is used to automatically interpret the interference pattern?
a) Phase measuring interferometric system
b) Multi-color microscopic interferometry system
c) Two point distance measuring interferometric system
d) Michelson interferometric system
Answer: a
Explanation: Phase measuring interferometric system or we can say PMI can automatically interpret the interference pattern. It can capture a large number of data samples from test surface.
5. In how many picture elements the test surface is divided if a high contrast video system captures the image of an interference pattern?
a) 455336
b) 55536
c) 65536
d) 75536
Answer: c
Explanation: If a high contrast video system is used to capture images of the interference pattern then it divides the test surface into 65,536 picture pixels or picture elements. The map or pixel map is superimposed over the interference pattern and its intensity profile is recorded.
6. How many data samples can be captured by the PMI system?
a) 1 million
b) 2 million
c) 1.5 million
d) 4 million
Answer: b
Explanation: PMI system or phase measuring interference system can capture over 2 million data samples. After capturing, it interprets them and then compiles the data into a 3-D image of the test surface.
7. From which part the light column is divided into beams in grazing incident technique?
a) At the hypotenuse of the system’s precision prism
b) At base of the system’s precision prism
c) After reflecting from the test surface
d) At perpendicular of the system’s precision prism
Answer: a
Explanation: At the hypotenuse of the precision prism of the system, the light column is divided into two beams i) the reference and ii) test beam. When these beams recombine, they interfere with one another and create a series of light and dark bands or an interference pattern.
8. How the intensity variation appears at each pixel in the grazing incident technique with laser beam system?
a) As a cosine wave
b) As a sine wave
c) Straight line
d) Hyperbolic
Answer: b
Explanation: The intensity variation at each pixel appears as a sine wave and recorded by the microprocessor. It is used to determine its relative phase. The phase differences are used to define the surface topography.
9. Which of the following statement is true about the grazing incident technique used to evaluate surface flatness?
Statement 1: Grazing incidence design turns rough surface into polished mirror surface to facilitate measurement.
Statement 2: It is important to prevent test beam to strike at grazing angle for measurement performance.
a) F, F
b) T, T
c) F, T
d) T, F
Answer: d
Explanation: The performance of measurement can be improved by striking the test beam at a grazing angle. The grazing incidence design turns non-reflective, rough surfaces into a polished mirror surface to facilitate measurement.
10. How many diffraction gratings are used by interferometer in grazing incident technique with laser beam system?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: The interferometer uses 2 linear diffraction gratings. These gratings are used to split and recombine the light into reference and test beams. The diffracted light of first order from the first grating reflects off at a grazing angle and it is the test beam. The zero order diffracted light is reference beam and passes parallel to the surface.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Visual Inspection”.
1. What is the use of an interference microscope?
a) Measure depth of scratches
b) Measure width of crack
c) Develop a permanent visual record
d) Only illuminate the cracks
Answer: a
Explanation: Interference microscope is used to measure the depth of scratches in the finish of finely lapped or polished surfaces. This is a nondestructive technique and is generally used in visual inspection.
2. What is the tube diameter of rigid borescope?
a) 0.1 to 10 mm
b) 0.5 to 90 mm
c) 0.2 to 100 mm
d) 0.9 to 70 mm
Answer: d
Explanation: The borescope’s applications are limited with a straight line path between the observer and surface to be observed. The diameter of tube of rigid borescope may range from 0.9 to 70 mm and length from 0.15 to 30 metres.
3. What is the use of fluorescent penetrants?
a) Develop permanent visual records of a remote object
b) Illuminates and observes internal, closed or inaccessible areas
c) Enhance the observation of surface cracks
d) Evaluate surface finish, shape and microstructure
Answer: c
Explanation: Fluorescent penetrants are generally used for visual inspection. It is used to enhance the observation of cracks. Image sensors are also used for visual inspection which develops permanent visual records.
4. What is the field of view range of borescope?
a) 30 to 180 degree
b) 10 to 90 degree
c) 60 to 360 degree
d) 10 to 180 degree
Answer: b
Explanation: The field of view of borescope can range from 10 to 90°. It is possible to have orbital scan which involves the rotation of the optical shaft for scanning purpose. The illumination system used in bprescope incorporates features like different viewing head, orbital scan, and adjustable focussing of the objective lens.
5. What type of fibre is present in the optical tube of mini borescope?
a) Quartz fibre
b) Asbestos fibre
c) Plastic fibre
d) Resin fibre
Answer: a
Explanation: Mini borescope uses a single image-relaying rod or quartz fibre in the optical tube in place of conventional relay lenses. Mini borescope is a variant of borescope along with hybrid borescopes, extendable borescopes, or rigid chamberscope.
6. Which of the following option is true about hybrid borescopes?
a) Use rod lenses combined with concave lenses
b) Use rod lenses combined with concave mirror
c) Use rod lenses combined with convex lenses
d) Use rod lenses combined with convex mirror
Answer: c
Explanation: Hybrid borescopes uses rod lenses combined with convex lenses to-relay the image. Extendable borescope enable the use of extension tubes. These both are the variants of the borescope and used for visual inspection.
7. Upto which length the flexible fiberscopes are available?
a) 12 m
b) 14 m
c) 16 m
d) 18 m
Answer: a
Explanation: Flexible fiberscopes are available upto 12 m length and in diameter range of 1.4 to 13 mm. Image guide fibres with fibre size 65 to 17 µm and light guide bundle with 30µm diameter fibre are used in flexible fiberscopes.
8. Which of the following option is true for the given statements about flexible fibrescope?
Statement 1: Fibrescope produce higher resolution than videoscope.
Statement 2: Videoscopes have longer working length than fibrescope.
a) T, T
b) T, F
c) F, F
d) F, T
Answer: d
Explanation: Videoscopes produce higher resolution and have longer working length than fiberscope. The display used in this reduces eye fatigue and enables point-to-point measurement on the viewing screen with the help of reticles.
9. For what distance, videoscopes are used with CCD probes for electronic transmission?
a) Less than 15 m
b) More than 15 m
c) Less than 10 m
d) More than 10 m
Answer: b
Explanation: For more than 15 meter distance, videoscopes with CCD probes or charge coupled device probes are used for electronic transmission of black and white or colour images to a video monitor.
10. Which of the following is not true about rigid chamberscope?
a) Enable use of extension tube
b) Have zoom facility
c) Used for rapid inspection
d) Offer greater magnification
Answer: a
Explanation: Chamberscopes offer more magnification than conventional rigid borescopes. They have zoom facility and used for rapid inspection of large chambers. They include variable direction of view with high intensity lightning.
11. Where does the CCD chip is placed in flexible fiberscope?
a) At proximal end
b) Ar median point
c) At the distal end
d) Anywhere between proximal and distal end
Answer: c
Explanation: A CCD chip consists of a large number of light-sensitive picture elements or pixels arranged in a pattern of rows and columns, is placed at the distal end. The objective lens focuses the object image on the surface of the CCD chip.
12. Which type of special purpose system is used for the examination of hazardous process or for extreme radiations?
a) Fibrescope
b) Chamberscope
c) Periscope
d) Vacuum borescope
Answer: c
Explanation: Periscopes allow examination of dangerous or hazardous areas. Periscopes are designed for high pressure and temperature, extreme radiation or underwater applications. Vacuum borescopes recording and observation of images inside vacuum chambers.
13. Which of the following is not true for rigid borescopes?
a) Operates like telescope in reverse
b) Good for rapid examination
c) Video adaptation is present
d) Semi Rigid sheathing is present
Answer: d
Explanation: Semi rigid borescopes are operated like telescope in reverse. A borescope spreads the field of view. Semi Rigid sheathing is present in flexible illuminated fibrescopes and it allows the inspection at most difficult to reach spots.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Laser Inspection”.
1. Which of the following is not true about metrology lasers used in laser inspection?
a) These are high-power instruments
b) Used for rapid non-contact gauging of delicate parts
c) Have low optical cross-talk
d) Wide dynamic range
Answer: a
Explanation: These are low-power instruments. Laser systems have wide dynamic range, high contrast and low optical cross-talk. Laser systems can be used in inspection of surfaces and in dimensional measurements and are very useful in precision and accuracy measurements.
2. What is the wavelength of light produced by He-Ne laser in laser inspection?
a) 6988 Å
b) 5328 Å
c) 5928 Å
d) 6328 Å
Answer: d
Explanation: He-Ne lasers are used in laser inspection. Light produced by He-Ne lasers is at a wavelength of 6328 Å or 0.6 μm and that is in phase and coherent. This source is a 1000 times more intense than other monochromatic sources.
3. Which technique is not suitable to measure large diameter parts or large gaps?
a) Diffraction pattern technique
b) Scanning laser technique
c) Photodiode array imaging
d) Laser triangulation sensor
Answer: a
Explanation: Diffraction pattern technique is not suitable for diameters larger than few mm and is used to measure small gaps and small diameter parts. In this method, a parallel laser beam which is coherent is diffracted by a small part, and the resultant pattern is focussed on a linear diode array by a lens.
4. What is the accuracy of scanning laser gauge for objects of 10-50 mm diameter?
a) ±0.15 μm
b) ±0.25 μm
c) ±0.35 μm
d) ±0.45 μm
Answer: b
Explanation: Scanning laser gauge can provide an accuracy of ±0.25 μm for objects of 10 to 50 millimeter diameter. It can also be used for objects of diameter from 0.05 to 450 millimeter and offers repeatability of 0.1 μm.
5. Which of the following is true about resolution in two frequency laser interferometer?
a) Straightness resolution – 90 nm
b) Angular resolution – 3 arc seconds
c) Flatness resolution – 2 nm
d) Linear resolution – 1 nm
Answer: d
Explanation: The advantage of two frequency laser interferometer technique is that system does not depend upon the beam intensity and provides high sensitivity, it is also independent of noise due to air turbulence. The linear resolution by two frequency laser interferometer technique is 1 nm, angular resolution is 0.03 arc seconds and straightness resolution is 40 nm.
6. How much accuracy can be achieved by photodiode array imaging?
a) ±0.05 μm
b) ±0.15 μm
c) ±0.5 μm
d) ±0.25 μm
Answer: a
Explanation: In photodiode array imaging method which is a laser inspection technique in which the stationary part’s shadow is projected on a solid-state diode array image sensor. For large parts, 2 arrays are used i.e. one array for each edge. Accuracies as high as ±0.05 μm can be achieved by this method.
7. Which application is ideally suited for two frequency laser interferometer?
a) Pitch and yaw measurement
b) Hole diameters
c) Thickness measurement
d) Measurement of edge locations
Answer: a
Explanation: 2 frequency laser interferometer techniques are ideally suitable for measuring linear positioning, pitch, yaw and straightness in two planes. The two-frequency laser head provides, one frequency with a P polarisation i.e. M beam and another frequency with an S polarisation i.e. R beam.
8. The location of the image spot directly depends on which factor in laser triangulation sensor technique?
a) Wavelength of laser
b) Measuring range
c) Standoff distance
d) Focal length of lense
Answer: c
Explanation: The location of the image spot in laser triangulation sensor technique depends directly upon the standoff distance between the sensor and the surface of object. If standoff distance changes, it will result in a lateral shift of the spot along the sensor array.
9. Which technique from given laser inspection techniques is useful for measuring the diameter of hot steel bars?
a) Laser scanning gauge
b) Frequency laser interferometer
c) Laser triangulation sensors
d) Photodiode array imaging
Answer: a
Explanation: The Laser scanning gauge technique is very useful to measure the diameter and roundness of hot steel bars under the vibration conditions to an accuracy of 0.025 millimeter over diameters of 5 to 25 millimeter.
10. Where does wire is placed in a measurement of diameter using the technique of gauging wide diameter from the diffraction pattern formed in a laser beam?
a) Between collimator and lens
b) Between collimator and source
c) Between collimator and plane of measurement
d) Between collimator and detectors
Answer: c
Explanation: Gauging wide diameter is a method of the measurement of the thin wire diameter with the use of the interference fringes resulting from diffraction by the wire in the laser beam. Output variation from the photodetector is caused by changes in fringes.
11. How many sensors are needed to measure part thickness by using laser triangulation sensors?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: It is possible to measure part thickness or the inside bore diameter with the help of 2 sensors in laser triangulation sensor technique. The measurement accuracy and measurement range are directly related.
This set of Basic Engineering Metrology Questions and Answers focuses on “Evaluating Uncertainty in Measurement”.
1. Which type of distribution approach is not followed by systematic error?
a) U-shaped distribution approach
b) Rectangular distribution approach
c) Triangular distribution approach
d) Normal distribution approach
Answer: d
Explanation: Conventional approach used to evaluate measurement uncertainty is based on random error and systematic error. Systematic error follows Rectangular, Triangular or U-shaped distribution approach.
2. Which approach is accepted as an international procedure in evaluating the uncertainty of measurement?
a) Conventional approach
b) Modern approach
c) Experimental approach
d) Observational approach
Answer: b
Explanation: Modern approach is accepted as an international procedure. It is useful even for those problems where limited observations are possible. It is problem specific and defines the method explicitly.
3. How many methods of evaluation of uncertainty are based upon modern approach?
a) 2 methods namely Type-A and Type-B
b) 2 methods namely Type-1 and Type-2
c) 3 methods namely Type-A, Type-B and Type-C
d) 3 methods namely Type-1, Type-2 and Type-3
Answer: a
Explanation: Modern approach is based on Type A method and Type B method. When observations are taken under same measurement conditions, Type A method is used. In type B method of modern approach, the uncertainty in measurement is evaluated by the judgement of the available information.
4. Which of the following option is correct for given statements about evaluation of uncertainty of measurement?
Statement 1: Principle of evaluation of uncertainty by modern approach is approximately the same as conventional approach.
Statement 2: Conventional approach is problem specific.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: a
Explanation: Modern approach defines the method explicitly and is problem specific. In those problems where only limited observations are possible, modern approach is very useful.
5. Which type of approach is followed by random errors?
a) Poisson distribution approach
b) Binomial distribution approach
c) Gaussian distribution approach
d) Polynomial distribution approach
Answer: c
Explanation: Random errors are those which can be caused by little variation in the standard setting of position, operator errors in reading the display of instrument etc. Random error follows the normal frequency or Gaussian distribution approach.
6. What is the main characteristic of random errors used to determine maximum measuring error?
a) Cumulative error
b) Standard deviation
c) Variance
d) Median
Answer: b
Explanation: Random errors are those which are produced due to large number of fluctuating and unpredictable errors that are non controllable in nature. The main characteristic of random errors is standard deviation, used to determine maximum measuring error.
7. What is the relation between maximum error for a measurement method and standard deviation in the case of random errors?
a) Maximum error equal to standard deviation
b) Maximum error is two times of standard deviation
c) Maximum error is three times of standard deviation
d) Maximum error is four times of standard deviation
Answer: c
Explanation: Spread of possible random error values is determined by the maximum error. The maximum error for a measurement method is three times the standard deviation. The maximum error and standard deviation determine the accuracy of measurement.
8. Which of the following error is not a systematic error?
a) Error induced due to stylus pressure
b) Instrument location errors
c) Error due to parallax
d) Error due to play in the instrument’s linkages
Answer: d
Explanation: Systematic errors can be caused due to calibration errors, Stylus pressure, ambient conditions , Avoidable errors and incorrect theory.
9. What is the advantage of statistical methods?
a) Increase the value of
b) Increase the value of
c) Decrease the value of
d) Increase the value of
Answer: a
Explanation: The value of increases with the help of statistical methods which means offer same quality at low cost or good quality at same cost or both i.e. better quality and less cost. Convention approach which is based upon random errors for evaluating the uncertainty of measurement follow the statistical methods.
10. What is true about random errors?
a) Sign of error can be predicted
b) Probability of occurrence of same absolute value is not equal for negative and positive errors
c) Constant in magnitude
d) Arithmetic mean in a measurement series approaches zero as measurement number increases
Answer: d
Explanation: Random errors can be caused by friction and may be due to play in the linkage of instruments. These errors are variable in sign and magnitude. These are sometimes negative and sometimes positive. Its sign cannot be predicted.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Type A Evaluation of Uncertainty”.
1. What do you mean by Type-A evaluation of uncertainty?
a) Involves a series of independent measurements of a quantity
b) Involves a series of dependent measurements of a quantity
c) Uncertainty which is characterized using an assumed probability distribution based on information available
d) Evaluated by judgment of available information
Answer: a
Explanation: Type-A evaluation of uncertainty is mainly based on repeated observations. Type-A evaluation of uncertainty involves making a series of a large number of independent quantity measurements.
2. What is used as an input estimate in Type-A evaluation of uncertainty?
a) Standard deviation
b) Arithmetic mean
c) Variance
d) Geometric mean
Answer: b
Explanation: The arithmetic mean is used as the input estimate in Type-A evaluation of uncertainty, and the standard deviation of the mean is used as the standard uncertainty. Those evaluation of standard uncertainty that is not a Type-A is a Type-B evaluation.
3. What is ANOVA in statistical analysis?
a) Analysis of variance
b) Analysis of various attributes of statistics
c) Analysis of non-observable variables
d) Assessment of various attributes of statistics
Answer: a
Explanation: Type-A evaluation of uncertainty is evaluated by using statistical analysis of series of observations scattered around some mean value which are associated with the ANOVA or analysis of variance.
4. Which is not used to evaluate Type-A uncertainty?
a) Arithmetic mean
b) Standard deviation
c) Sensitivity coefficient
d) Degree of freedom
Answer: c
Explanation: The best way to evaluate Type-A uncertainty data is by calculating the arithmetic mean, standard deviation or degree of freedom. Arithmetic mean is calculated first, followed by standard deviation and degree of freedom is calculated at last.
5. Which of the following is not treated as Type-A uncertainty?
a) Thermal stability
b) Noise
c) Repeatability
d) Resolution
Answer: d
Explanation: Here, the meaning of noise is the effect on a signal due to surrounding electrical interference and magnetic fields. Noise is treated as a random Type-A uncertainty. Other random Type-A uncertainty with a normal distribution is thermal stability and repeatability.
6. Which of the following statement is true about Type-A uncertainty?
Statement 1: Most of the systematic uncertainty is Type-A uncertainty.
Statement 2: Type-A uncertainties vary each and every time a measurement is made.
a) T, T
b) F, T
c) F, F
d) T, F
Answer: b
Explanation: Most of the systematic uncertainty is Type-B uncertainties while most of the random uncertainties are Type-A uncertainties. Every time when any measurement is made, Type-A uncertainty varies.
7. In which guide the symbols, terms and methods used for evaluating measurement uncertainty are described?
a) AUM
b) SUM
c) RUM
d) GUM
Answer: d
Explanation: The symbols, terms and methods used for evaluating measurement uncertainty are described in the GUM or Guide to the Expression of Uncertainty in Measurement, which was published in 1993 by the ISO .
8. What is the equation for experimental variance used in Type-A evaluation of uncertainty?
a) σ = √[ ∑ n i=1 ].
b) σ = √[ ∑ n i=1 2 ].
c) σ = √[ ∑ n i=1 2 ].
d) σ = √[ ∑ n i=1 ].
Answer: b
Explanation: Standard deviation is basically the measurement of the dispersion of a data set from its average. Formula is given by, σ = √[ ∑ n i=1 2 ], where x’ is arithmetic mean and is equal to [ ∑ n i=1 ].
9. How can Type-A uncertainties can be quantify?
a) Using quality transducer
b) Using stepper motor
c) Using LCR meter
d) Using conductivity meter
Answer: a
Explanation: Better quality transducer can be used to reduce Type-A and Type-B elemental uncertainties. Calibration can quantify Type-A elemental uncertainty, but not reduce it. Calibration can quantify as well as reduce the level of Type-B elemental uncertainty.
10. What is the value of the degree of freedom used in evaluation by Type-A method?
a) N
b) N+1
c) N-1
d) N+2
Answer: c
Explanation: The number of degrees of freedom used for evaluation is one less than the number of independent measurements of quantity i.e. if number of independent measurements are 100 then the degree of freedom is equal to .
This set of Engineering Metrology Assessment Questions and Answers focuses on “Type B Evaluation of Standard Uncertainty”.
1. Which type of uncertainty is evaluated in Type-B Evaluation?
a) When observations are taken under same conditions
b) When information has possible variability of input variables
c) When Information is present non continuous manner
d) When information is available and is used as it is without any judgement
Answer: b
Explanation: The standard uncertainty where the available information is present with a possible variability of input variables is evaluated by Type-B method of evaluation. For making Type-B evaluations critical thinking, intellectual honesty and professional skill are required.
2. Type-B method is a type of which evaluation approach?
a) Gaussian approach
b) Triangular distribution approach
c) U shaped distribution approach
d) Modern approach
Answer: d
Explanation: Type-B method is a part of modern approach, it’s another part is Type-A method. Type-B evaluation of uncertainty use manufacturer’s specifications like previous measurement data for material or measuring instrument.
3. What is the coverage factor in a Type-B method?
a) Any numerical value only
b) A multiple of sigma only
c) A numerical value or multiple of sigma
d) Always equal to one
Answer: c
Explanation: The coverage factor is specified either as one numerical value or may be stated at a multiple of sigma. The uncertainty or we can say standard can be obtained by the dividing the given value by the multiple.
4. What value of uncertainty cannot be taken in a Type-B method?
a) Standard uncertainty without certificate
b) Resultant of previous value
c) Evaluated on the basis of experience
d) Reference value from the literature
Answer: a
Explanation: The value of uncertainty may be taken from a reference value from the literature, a resultant value of a previous measurement, using the standard uncertainty for which calibration certificate is available or could be evaluated on the basis of experience.
5. If calibration certificate state the uncertainty at Xσ and quoted uncertainty is N, then what is the value of standard uncertainty?
a) X*N
b) X/N
c) N/X
d) N X
Answer: c
Explanation: The standard uncertainty will be obtained by dividing the given value by the multiple. For example, if a calibration certificate states the uncertainty at 5a, the standard uncertainty is then simply, quoted uncertainty/5.
6. When is rectangular distribution is used in Type-B evaluation method?
a) When value of measurand is equal to upper limit
b) When value of measurand is equal to lower limit
c) When measurand lies anywhere within the limits
d) When no limits can be determined
Answer: c
Explanation: Rectangular distribution is used when the limits can be determined and the value of the measurand is equally likely to lie anywhere within the limits.
7. When is triangular distribution is used in a Type-B method?
a) When most values are near the origin
b) When most values are near the right most position of distribution
c) When most values are near the left most position of distribution
d) When most values are near the centre of distribution
Answer: d
Explanation: Triangular distribution of Type-B evaluation is used when it is known that most of the values used are more likely to be near the centre of the distribution, rather than at the extreme limits.
8. What is the sensitivity coefficient?
a) It describes how sensitive the input data is
b) It describes to what extent output data is influenced with variation in input data
c) It describes to what extent input can change
d) It describes to what extent input data is influenced with variation in the number of observations
Answer: b
Explanation: The sensitivity coefficient describes to what extent the output estimate is influenced by variation of the input estimate. The sensitivity coefficient can be calculated by varying the quantity over range of uncertainty list and measuring its influence on the measurand.
9. Which of the following is not treated as Type-B uncertainty?
a) Hysteresis
b) Common Mode Voltage
c) Nonlinearity
d) Repeatability
Answer: d
Explanation: Resolution, Scale Size and Quantization, Hysteresis, Common Mode Voltage, Installation, Nonlinearity or Linearity, Spatial Variation, Loading uncertainties, Sensitivity and Zero offset, these all are Type-B uncertainties.
10. Which distribution is related to U-probability distribution of Type-B evaluation of uncertainty?
a) Arcsin distribution
b) Binomial distribution
c) Poisson distribution
d) Bernoulli distribution
Answer: a
Explanation: U-probability distribution of Type-B evaluation method of uncertainty is used when the values are at extreme limits and values are least at mean for example Arcsin distribution. Standard uncertainty = a/√2.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Expanded Uncertainty”.
1. What is the actual definition of expanded uncertainty?
a) Uncertainty of the measurement result expressed as a standard deviation
b) Quantity defining an interval about the measurement result
c) Evaluation method of uncertainty by the statistical analysis of series of observations
d) Uncertainty Evaluation method by other than the statistical analysis
Answer: b
Explanation: The quantity that defines an interval about the measurement outcome which can be expected to include a large portion of the distribution of values that could be attributed to the measurand.
2. What is the relation of expanded uncertainty with coverage factor and combined uncertainty?
a) Expanded uncertainty = Coverage factor * Combined uncertainty
b) Combined uncertainty = Coverage factor * Expanded uncertainty
c) Coverage factor = Combined uncertainty * Expanded uncertainty
d) Coverage factor * Combined uncertainty * Expanded uncertainty = 1
Answer: a
Explanation: The equation which is used to calculate expanded uncertainty is a very basic equation. To calculate expanded uncertainty, one will need to multiply a coverage factor by the combined uncertainty.
3. What is the confidence interval for the value of coverage factor ‘2’?
a) 95 %
b) 94 %
c) 95.45 %
d) 94.45 %
Answer: c
Explanation: Confidence interval for the value of coverage factor 2 is generally taken as 95 % but it is not the actual value. The actual value for this is 95.45 %. For 95 % confidence interval, actual ‘k’ or coverage factor is 1.96.
4. Which table is generally used to find the coverage factor?
a) Student’s T table
b) F distribution table
c) Wishart distribution table
d) Tau distribution table
Answer: a
Explanation: Student’s T table is generally used to find coverage factor. The values are generally found at the bottom of the table especially the last row and it is generally marked with the infinity symbol.
5. What is the value of coverage factor which is generally used in the manufacturing industry?
a) 2
b) 2.89
c) 3
d) 3.89
Answer: d
Explanation: In the manufacturing industry, the main aim is for a failure rate of 1 in ten thousand or a coverage factor ‘k’ of 99.99% confidence, where coverage factor = 3.89. However, Confidence intervals can be greater or smaller for different industries depending on acceptable failure rates.
6. Which of the following option is true for given statements about expanded uncertainty and coverage factor?
Statement 1: Last calculation is the expanded uncertainty when estimating uncertainty in measurement.
Statement 2: In metrology industry, the mostly used value of the coverage factor is 2.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: c
Explanation: In metrology industry, a typically estimate of uncertainty to 95.45% confidence and coverage factor where k=2 is used. It can vary according to requirement. Last calculation is generally the expanded uncertainty while estimating measurement uncertainty.
7. Which option is not correct about coverage factor?
a) It is a number which is generally larger than 1
b) Range – 2 to 7
c) Can be calculated by using MS excel
d) Depends on the selected coverage probability
Answer: b
Explanation: The coverage factor generally depends upon the probability distribution type of the output measurement quantity in the measurement model and on the selected coverage probability. Its range is generally between 2 to 3, can be more for special purposes.
8. What is the formula for relative expanded uncertainty?
a) U r = U/| y |
b) U r = U/y
c) U r = U*| y |
d) U r = U*2y
Answer: a
Explanation: In analogy with relative standard uncertainty U r and relative combined standard uncertainty U c,r the relative expanded uncertainty of a measurement result y is U r = U/ | y |, y is not equal to zero and U is expanded uncertainty.This set of Engineering Metrology Interview Questions and Answers focuses on “Tool Maker’s Flats and High Precision Surface Plates”.
1. What is the shape of the tool maker’s flats?
a) Circular
b) Rectangular
c) Square
d) Triangular
Answer: a
Explanation: Tool maker’s flats are small circular surface plates which are used for the high precision measurement work.
2. Which of the following is not true about tool maker’s flats?
a) Tool maker’s flats should be free from inclusions
b) Tool maker’s flats are of less hardness
c) Working surfaces are produced by lapping
d) Should be located in a stirred atmosphere
nswer: b
Explanation: Tool maker’s flats should be free from inclusions which after proper heat treatment gives a high hardness. Working surfaces are finished by lapping to possess a high degree of accuracy and uniformity.
3. Why are shallow grooves provided in larger flats?
a) To minimize the possibilities of uneven hardening
b) For design purpose
c) To maintain high accuracy for a longer period
d) To make them lighter
Answer: a
Explanation: A shallow groove is provided around the periphery of larger flats to avoid uneven hardening and for easy handling.
4. Which of the following is not true about the requirements of material selection for tool maker’s flats?
a) Suitable surface for the wringing purpose
b) High degree of rigidity
c) Wear resistance
d) Absorb radiant heat
Answer: d
Explanation: Material should have a proper surface so that gauges can be wrung on to it and it should have a high degree of rigidity and freedom from warping. Material should reflect radiant heat.
5. What is the tool maker’s flat size which generally uses both the faces as a working surface?
a) 30 to 45 mm
b) 50 to 75 mm
c) 75 to 100 mm
d) 100 to 200 mm
Answer: b
Explanation: Both the faces are highly finished in the range of 50-75 mm size and both are used as working surface and above this range it has only one face finished as working surface.
6. Which of the following hardness is given by Solid steel tool maker’s flats?
a) 93HRC
b) 83HRC
c) 73HRC
d) 63HRC
Answer: a
Explanation: Solid steel tool maker’s flats after proper heat treatment gives a hardness of 93HRC or 850HV as high hardness is a desirable property for precision flats.
7. What is the minimum thickness of top in a high precision surface plate?
a) 20 mm for 350 mm dia
b) 25 mm for 250 mm dia
c) 30 mm for 250 mm dia
d) 20 mm for 250 mm dia
Answer: d
Explanation: Minimum thickness of top in a high precision surface plate is 20 mm for 250 mm dia, 25 mm for 300 mm dia and 30 mm for 350 mm dia.
8. What is the advantage of granite over cast iron in making surface plates?
a) Reflects radiant heat
b) Won’t rust by moisture
c) Strength for given weight is high
d) No need of inserts and fasteners
Answer: b
Explanation: Granite absorbs radiant heat which is a disadvantage. Granite won’t rust by moisture but may distort. Strength of cast iron is more than granite for a given weight.
9. Which of the following is true regarding high precision surface plates?
a) The top of high precision plate projects about 32 mm beyond the framing
b) The top of high precision plate projects about 32 mm below the framing
c) The top of high precision plate projects about 12 mm beyond the framing
d) The top of high precision plate projects about 12 mm below the framing
Answer: c
Explanation: The top of high precision plates is machined around the sides and generally projects approx 12 mm beyond the framing.
10. What is the minimum total depth in high precision surface plates for 300 mm dia ?
a) 60
b) 70
c) 80
d) 90
Answer: c
Explanation: Minimum total depth for 250, 300, 350 mm dia is 70, 80, 90 mm respectively.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Angle Plates”.
1. What is the angle between the two surfaces of an angle plate?
a) 45 degree
b) 120 degree
c) 90 degree
d) 180 degree
Answer: c
Explanation: Angle plate is an accessory used for measurement purpose along with surface plates and two surfaces of angle plate are at 90 degrees to each other.
2. Which of the following is correct about the hardness of angle plates?
a) Minimum hardness of 100 HB
b) Minimum hardness of 180 HB
c) Maximum hardness of 180 HB
d) Maximum hardness of 100 HB
Answer: b
Explanation: Angle plates are generally made of cast iron and have 180 HB minimum hardness. Angle plates are available in various designs.
3. What is the purpose of baffle plates?
a) Support angle plates
b) Protect casting from direct flame heat
c) Used as an accessory with surface plates
d) Support surface plates
Answer: b
Explanation: Baffle plate creates a barrier between flames and casting, and protects casting from direct heat generated by flames.
4. Which of the following is incorrect about angle plates?
a) Plates are given heat treatment after being finished
b) Angle plates can be used for inspection purposes
c) Box squares can be used instead of angle plates
d) Surfaces of angle plates are scraped
Answer: a
Explanation: Heat treatment is given to the angle plates before being finished to relieve internal stresses. Angle plates are widely used for inspection purposes. Surface of angle plates are scraped to give them a smooth finish and flatness.
5. How many faces are there in multipurpose angle plate?
a) About 50 faces
b) About 40 faces
c) About 30 faces
d) About 10 faces
Answer: d
Explanation: A multipurpose angle plate generally has 10 faces. All faces are at 90 degrees to each other and also perfectly and accurately ground.
6. What is the accuracy of the working surfaces of multipurpose angle plates?
a) 0.002 mm in 25 mm length
b) 0.005 mm in 25 mm length
c) 0.005 mm in 50 mm length
d) 0.002 mm in 50 mm length
Answer: a
Explanation: Working surfaces and end surfaces of plates should be square within the accuracy of 0.002 mm in 25 mm length and 0.005 mm in 25 mm length respectively.
7. Which of the following is true for threaded hole position?
a) Threaded holes are provided only on the sides of angle plates for handling purpose
b) Threaded holes are provided only on the faces of angle plates so that it can be used as fixture
c) Angle plates have threaded holes on the sides and faces so that it can be used as fixture
d) No threaded holes are present in angle plates
Answer: c
Explanation: Sometimes angle plates are used as fixture and for this threaded holes are made on sides and faces of plates. Fixture is a work locating and holding a device.
8. What is the accuracy of surface straightness in angle plates?
a) ±0.001 mm in 25 mm length
b) ±0.01 mm in 25 mm length
c) ±0.04 mm in 25 mm length
d) ±0.004 mm in 25 mm length
Answer: a
Explanation: High accuracy of straightness is needed as straight planes are the basis for measurement works. Angle plates have ±0.001 mm in 25 mm length surface straightness.
9. Which option is correct about these two following statements regarding outer faces of angle plates?
Statement 1: Casting strains are eliminated by natural ageing.
Statement 2: Outer faces of angle plates have recessed grooves.
a) Only statement 1 is true
b) Both statements are false
c) Only statement 2 is true
d) Both statements are true
Answer: d
Explanation: Strain produced in the casting process is eliminated by either natural ageing or artificial seasoning. In natural ageing metal is kept at room temperature to gain its full strength. Outer faces of these plates have grooves for holding and locating purposes.
10. Which of the following option is correct about given statements?
S1: Clamping pallets allows easy fixing of workpieces.
S2: In annealing furnace, angle plates are heating up to 10 degree Celsius.
S3: Straight edges can be used for checking the straightness of the parts.
a) T, T, F
b) F, T, F
c) F, F, T
d) T, F, T
Answer: d
Explanation: In heat treatment operation, angle plates are placed in annealing furnaces where it is heated up to 55 o C . It should be maintained at this temperature for about 3 hours or more which depends upon the mass of casting.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “V-Block”.
1. What is the use of V-Blocks?
a) For checking only squareness of square work pieces
b) For checking roundness
c) Only for the support purposes
d) To support triangular surfaces only
Answer: b
Explanation: V-Blocks are generally used for cylindrical workpieces to check their roundness and for marking centres. V-blocks are like precision metalworking jigs which are used to hold workpieces. These are available in market with wide range of varieties.
2. What is the bearing area of V-Blocks?
a) 5%
b) 10%
c) 15%
d) 20%
Answer: d
Explanation: Vee-Blocks have bearing area of greater than or equal to 20%. V-blocks are used for inspection and workshop purposes. A small groove is present at the bottom of the ‘V’. They are used with screw clamps for holding the work.
3. What is the symmetrization accuracy of vees in V-Blocks?
a) 0.002 mm per 20 mm length
b) 0.001 mm per 20 mm length
c) No effect of symmetry
d) 0.02 mm per 20 mm length
Answer: a
Explanation: V blocks have symmetrization accuracy of 0.002 mm per 20 mm length in Vs and straightness accuracy is ±0.01 mm per 20 mm length.
4. Which of the following is incorrect about V-Blocks?
a) V-Blocks should be checked periodically for accuracy
b) V-Blocks are used to establish centre axis of a cylindrical piece precisely
c) First check the V-Blocks visually before using
d) V-Blocks cannot be used with clamps
Answer: d
Explanation: V-blocks should be checked periodically for accuracy and also checked for scratches and dents. Sometimes clamps are used with V-Blocks to secure the work.
5. Which V block is used for checking triangle effect?
a) V block with 120-degree angle is used
b) V block with 90-degree angle is used
c) V block with 60-degree angle is used
d) V block with 30-degree angle is used
Answer: a
Explanation: V-blocks with 120-degree vee angle are available for some special purposes like checking triangle effect or taps. V-blocks with 90-degree angle are general purpose V-Blocks.
6. Which of the following grades is specified by IS: 2494-1964?
a) Two grades of vee Blocks, viz. Grade A and B
b) Four grades of vee Blocks, viz. Grade A, B, C and D
c) Two grades of vee Blocks, viz. Grade 1 and 2
d) Four grades of vee Blocks, viz. Grade 1, 2, 3 and 4
Answer: c
Explanation: Depending upon the accuracy there are two grades are specified by IS: 2494-1964. Vee blocks should check periodically to correct inaccuracies in blocks if any.
7. Which of the following option is correct for the given statements about working surface of V blocks?
Statement 1: V-Blocks have only one working surface i.e. flanks of vees.
Statement 2: Side faces of V-blocks are not working surfaces.
a) Both statements are true
b) Statement 1 is correct
c) Statement 2 is correct
d) Both statements are false
Answer: d
Explanation: V-blocks generally have four working faces. These working faces are flanks of vees, base end faces, top and sides faces of V-blocks. They are generally supplied as matched pairs in which 2 V-blocks are of almost same size with the same grade of accuracy.
8. Which of the following option is correct for the given statements related to V-blocks?
Statement 1: V-blocks can be used as a magnetic work holding device.
Statement 2: V-blocks with internal magnets help in milling operation.
a) T, T
b) T, F
c) F, T
d) F, F
Answer: a
Explanation: Some V-blocks also has an internal magnet which can be used for holding magnetic work. V-blocks are widely used work holding device which can be used for many operations like drilling, grinding and milling.
9. Which of the following is correct for departure from flatness in Vees?
a) Any departure from flatness in vees should be a concavity
b) Any departure from flatness parallel to the vee axis should be a concavity
c) Any departure from flatness parallel to the vee axis should be a convexity
d) Any departure from flatness in vees can be a concavity or convexity
Answer: b
Explanation: Any departure from flatness on surfaces other than vees should be a concavity and from vees should be convexity. Any departure from flatness parallel to the vee axis should be a concavity.
10. Which of the following is incorrect about V blocks?
a) Cylindrical piece should be placed on the vee sides
b) Cylindrical piece should be placed on the edges of the vees
c) V-Blocks generally sold in pairs
d) V-blocks can support square, round and rectangular pieces
Answer: b
Explanation: Cylindrical pieces should not be placed on the edges; it should be on the vee sides otherwise there is an inaccuracy in marking centres. V-blocks are mostly used to hold cylindrical work pieces but it can also support square and rectangular pieces.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Bench Centres”.
1. What is the material of the bench center’s base?
a) Copper
b) Wood
c) Cast Iron
d) Steel
Answer: c
Explanation: The base of Bench centre is generally made from close-grained cast iron and should be free from any casting defect. Defects may cause error and failure of materials.
2. Why T- slots are provided on the base of bench centres?
a) To reduce its weight
b) For the attachment of centre holders
c) For the attachment of base to table
d) For easy loading and unloading
Answer: b
Explanation: For the attachment of centre holder, T-slots are provided at the base of bench centre. A spring loaded centre is present for easy loading and unloading.
3. What is the range in which distance between the centres varies?
a) 100 to 200 mm
b) 200 to 400 mm
c) 300 to 400 mm
d) 500 to 1500 mm
Answer: d
Explanation: Distance between the centres in centre bench depends upon the centre height and varies between 500 to 1500 mm with centre height accordingly.
4. Which of the following is incorrect about bench centre’s physical characteristics?
a) Centre holders may be located in any position
b) Box type straight edges have a rigid cross section for minimum deflection
c) Minimum hardness of bench centre’s base is 180 HB
d) Male or female centres are non-adjustable on bench centres
Answer: d
Explanation: Along the vees of the centre holders, male or female centres can be adjusted and locked in any desired position.
5. What will happen due to out-of-straightness of a part?
a) Less finished surface of part
b) No error in roundness
c) Failure of a part
d) Doubling run out effect
Answer: d
Explanation: A doubling run out effect and roundness error is caused by out-of-straightness of the part. Run out is also called as out-of true running.
6. What are the centre heights that available for Bench centres?
a) 125 mm
b) 125, 160 mm
c) 125, 250 and 300 mm
d) 125, 160, 200, 250 and 300 mm
Answer: d
Explanation: 125, 160, 200, 250 and 300 mm heights of centres are available in bench centres and according to these heights, centre distance is decided.
7. Match the following apparatus with the function they perform.
A) Straight Edges 1) Checking Eccentricity
B) V-Blocks 2) Checking Flatness
C) Bench Centres 3) Small angle measurement
D) Spirit Level 4) Checking Roundness
a) A-2, B-4, C-1, D-3
b) A-1, B-2, C-3, D-4
c) A-3, B-1, C-4, D-2
d) A-4, B-3, C-2, D-1
Answer: a
Explanation: Straight edges are used with surface plates to check straightness and flatness. V-blocks are used to check roundness of cylindrical pieces. Bench centres are used for rotary components to check eccentricity. Spirit levels are used to measure small inclination.
8. How much deviation is permitted in parallelism of centres axis w.r.t. guideways for 125-160 mm center height?
a) 0.01 mm/200 mm
b) 0.01 mm/300 mm
c) 0.1 mm/300 mm
d) 0.001 mm/300 mm
Answer: b
Explanation: This permissible deviation in parallelism is specified by IS: 1980-1978.
9. Which option is correct for given statements about out of roundness of V blocks?
Statement 1: Shafts can be out-of-roundness due to improper centre alignment.
Statement 2: Adjustable V-Blocks can be used to show out-of-roundness.
a) T, T
b) T, F
c) F, T
d) F, F
Answer: a
Explanation: Many factors affects the roundness of shafts like angle of centres, alignment of centres, centre holes, run-out of piece etc. Adjustable V-Blocks can be used to measure correct roundness.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Spirit Level”.
1. What is the use of Spirit Levels?
a) Angular measurements only
b) Static leveling only
c) Static leveling of equipment and angular measurement
d) Finding roundness of rotating parts
Answer: c
Explanation: Spirit level is the device which is used to measure small inclination or angle of tilt and also used for the static leveling of machineries. It has a sealed glass tube and a scale is engraved on it.
2. How sensitivity of spirit level is expressed?
a) Angle in seconds/1 division of tube
b) Angle in minutes/2 divisions of tube
c) Angle in minutes/1 division of tube
d) Angle in seconds/2 divisions of tube
Answer: a
Explanation: Sensitivity of a spirit level is the angle of tilt in seconds to the 1 division of tube i.e. bubble will move by 1 division of the tube. One division = about 2.5 mm.
3. Where the bubble rests on the scale when spirit level is placed horizontally?
a) Left most
b) Centre
c) Right most
d) Bottom
Answer: b
Explanation: A scale is engraved on the glass of spirit level tube and bubble rests at centre position. When the spirit level is tilted through a small angle then this bubble will always try to remain at the highest position.
4. What is the range of base length of type-1 spirit level?
a) 20-90 mm
b) 100-200 mm
c) 200-300 mm
d) 200-500 mm
Answer: b
Explanation: 3 types of spirit level are specified by BS-1958 in which type-1 spirit level has base length in the range of 100-200 mm and type-2 has base length between 200-500 mm.
5. If angle of tilt is equal to 10 seconds of arc and length of one division is equal to 2.5 mm in a spirit level then what is radius of tube?
a) 51.5 m
b) 51.5 mm
c) 25.5 m
d) 25.5 mm
Answer: a
Explanation: If radius of tube is R then, arc l is equal to Rα where α is taken in seconds. 1 radian is approximately equal to the 206,265 seconds of arc. 10 sec. = 0.0000485 radian. Tilt = 2.5 mm/R. By this, R = 51.5 m approximately.
6. Which of the following is used as a replacement of spirit vial in electrical level?
a) Steel rule
b) Protractor
c) Square block
d) Pendulum
Answer: d
Explanation: In an electrical level, a pendulum is present in place of spirit vial. Displacement of a pendulum is amplified by electrical means or electrically. A separate meter is used to show the readings.
7. What is the length of electronic precision levels?
a) 100 mm
b) 200 mm
c) 300 mm
d) 400 mm
Answer: b
Explanation: Electronic precision level is of about 200 mm length with 0.01 mm/m numerical division. Measuring range of electronic precision level is ±1.99 mm/m. It shows the stability of the indication after 3 seconds.
8. What is the maximum measuring error in electronic precision level?
a) ≤ ± 5% of indicated measuring value
b) ≥ ± 10% of indicated measuring value
c) ≤ ± 20% of indicated measuring value
d) ≥ ± 15% of indicated measuring value
Answer: b
Explanation: Electronic precision level has an LCD digital display with maximum measuring error of less than or equal to ±5% of indicated measuring value. Electronic precision level are used to obtain high accuracy. Measuring range is large.
9. Which of the following given statement is true/false about the sensitivity of spirit level?
Statement 1: Sensitivity of the spirit level increases as the radius of tube increases.
Statement 2: Spirit levels are insensitive to the temperature variation.
a) F, F
b) F, T
c) T, F
d) T, T
Answer: c
Explanation: Sensitiveness of the spirit level is decided by its tube radius. Variation in temperature will cause change in tension of ether vapours in the tube of a spirit level. So, spirit levels are very sensitive to temperature change.
10. Which of the following is true for spirit level?
a) The tube is completely filled with the liquid
b) The Liquid almost fills the tube
c) One-fourth part of the tube is filled with liquid
d) One-tenth part of the tube is filled with liquid
Answer: b
Explanation: The glass tube of spirit level is almost filled by liquid, there is a bubble at the highest position of the tube. The movement of the bubble along the tube radius depends upon the angle of tilt.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Combination Set”.
1. Which type of instrument is a combination set?
a) Used for highly precision works
b) A non-precision instrument
c) Used to check flatness only
d) A simple ruler with graduations on it
Answer: b
Explanation: Combination set is a non-precision instrument which can be used to determine flatness, measuring angles, inspection and layout work etc. It is the most adaptable instrument.
2. Which of the following is not correct about combination set?
a) A squaring head is permanently fixed on the scale
b) Combination set can be used for layout work
c) Interchangeable heads are present in a combination set
d) Can be used in metalworking
Answer: a
Explanation: Combination set has a scale on which heads are attached these heads are interchangeable which can slide along its length. They are not permanently fixed. They can be used for metalworking also.
3. Where the spirit level is present in a combination set?
a) Centre head
b) Squaring head
c) Scale
d) There is no spirit level on combination set
Answer: b
Explanation: A combination set has scale, centre and square head, protractor, spirit level etc. A spirit level is present at the squaring head of the combination set which is used to check the parallelism of surface.
4. What is the angle of one surface of squaring head to the scale in combination set?
a) 105 degree
b) 60 degree
c) 75 degree
d) 90 degree
Answer: d
Explanation: One surface of the squaring head is always at 90 degrees to the scale which is adjustable by a locking bolt and nut arrangement. There is a heavy scale in combination set which is grooved along its length.
5. What is the use of the centre head attachment with the scale?
a) Height measurement
b) Depth measurement
c) Locating centre of bar stock
d) Squaring operations
Answer: c
Explanation: Scale and squaring head are used for measuring depth and height, and squaring operations. Scale and centre head are used for locating the centre. Part to be centred should place beneath the scale and against the sides of centre head for locating the centre.
6. Which of the following option is correct for the given statements about protractor in combination set?
Statement 1: A protractor is permanently fixed on the scale of combination set.
Statement 2: The protractor head of combination set contains a spirit level.
a) F, T
b) T, T
c) F, F
d) T, F
Answer: a
Explanation: The protractor is not permanently fixed but can slide along the scale. And for checking an inclination plane a spirit level is present on protractor head.
7. What is incorrect about the combination set?
a) A non-reversible type protractor head can be used
b) Cast iron heads have a black wrinkle finish
c) Protractor scale is graduated from 0-360 degree
d) Centre of a round block can be located by centre head
Answer: c
Explanation: Protractor scale has 0-90 degree graduation on either side of centre or has 0-180 degree graduations. In some combinations sets, non-reversible types of protractor heads are also present.
8. Which of the following option is correct for given statements about combination set?
1) Combination set can be used as a simple ruler or scale.
2) Square head of combination head with scale can be used as a tri-square.
a) Statement 1 is true
b) Statement 2 is true
c) Both the statements are true
d) Both the statements are false
Answer: c
Explanation: By detaching all the heads from a combination set, it can be used as simple ruler. Square head has 90 and 45 degrees edge so that it can be used as a tri-square.
9. Match the following apparatus with their suitable option:
A) Combination set 1) Digital display
B) Electronic precision level 2) Comparator
C) Johansson mikrokator 3) Extremely flat surface
D) Optical flats 4) Sliding heads
a) A-4, B-1, C-2, D-3
b) A-2, B-3, C-1, D-4
c) A-1, B-2, C-3, D-4
d) A-3, B-4, C-1, D-2
Answer: a
Explanation: Combination set is a multipurpose instrument with a scale and one or more sliding heads on it. Electronic precision level has an LCD display. Optically flats are extremely flat surfaces which are used to check flatness of other surfaces.
10. Which is not a part of the combination set?
a) Scriber point
b) Spirit level
c) Centre head
d) Slip gauge
Answer: d
Explanation: Scriber point is present in combination set for scribing. Spirit level is present on centre head and projector head. Slip gauges are the rectangular blocks and are not a part of combination set.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Radius Gauges”.
1. Which of the following is another name of radius gauge?
a) Ring gauge
b) Planer gauge
c) Fillet gauge
d) Plug gauge
Answer: c
Explanation: Fillet gauge is another name of radius gauge. Fillet gauges are used to check the radius of an object. Radius gauges can also be used for inspection work.
2. Why a radius is provided at the meeting point of two surfaces?
a) To reduce material
b) To avoid collision
c) To increase stability
d) To avoid stress concentration
Answer: d
Explanation: Sharp corners are subjected to more stress. So, to avoid stress concentration, radius is provided.
3. Which of the following option is incorrect with respect to radius gauges?
a) Concave radius is an internal radius
b) Radius gauges are used for final inspection
c) If the curved surface is external then this radius is known as female radius
d) Radius gauges are suitable for both fillet and radius measurement
Answer: c
Explanation: If the curved surface is external then it is called male radius or simply radius. Term Female radius is used for internal curved surface.
4. Match the following:
A) Precision polygons - 1) Indexing
B) Radius gauge - 2) Checking known angles
C) Dividing head - 3) Measure concave surfaces
D) Sine bar - 4) Calibration of rotary table
a) A-1, B-3, C-2, D-4
b) A-4, B-3, C-1, D-2
c) A-3, B-2, C-4, D-1
d) A-2, B-1, C-3, D-4
Answer: b
Explanation: Precision polygons are used to calibrate dividing heads and rotary tables. Radius gauges are used to measure and check concave and convex surfaces. Sine bars are used to locate work at a given angle. Sine bars are also used to measure known and unknown angles.
5. Which of the following option is true for given statement?
Statement 1: For gauging the radius, a light source is used with radius gauge.
Statement 2: Pitch of the threads can be measured by radius gauge.
a) T, F
b) T, T
c) F, T
d) F, F
Answer: a
Explanation: A light source is used with radius gauges. Work is placed between light source and eye. It is the light passage due to which work can be gauged properly. To determine thread pitch, pitch screw gauge are used.
6. What is another name of blades of radius gauge?
a) Leaf
b) Petal
c) Cutter
d) Scale
Answer: a
Explanation: Each radius gauge has a number of blades. These blades are also known as leaves. Leaves can be used in any position to measure radius.
7. Which of the following is not a type of radius gauge?
a) Acrylic
b) Guitar
c) Digital
d) Planer
Answer: d
Explanation: Planer gauge is a measuring instrument which is used to measure slot width and setting tool height. It has two triangular blocks whose sides can be clamped.
8. What is the measuring range for radius gauge?
a) 0.00075-0.025 m
b) 0.0075-0.5m
c) 0.075-5m
d) 0.75-5m
Answer: a
Explanation: Measuring range of radius gauge is generally 0.00075 to 0.025 meter. The blades are specially shaped and can be used to measure fillets and radius against shoulders or corners.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Feeler Gauges”.
1. What is the use of feeler gauge?
a) To find the thickness of work piece
b) To measure the gap width
c) To check straightness
d) To check flatness
Answer: b
Explanation: Feeler gauges are used to measure gap width between two parallel faces e.g. finding clearance between two parallel surfaces.
2. What is the tensile strength of blade of feeler gauge with thickness up to 0.5 mm?
a) 170 kgf/mm 2
b) 270 kgf/mm 2
c) 50 kgf/mm 2
d) 70 kgf/mm 2
Answer: a
Explanation: The blades of feeler gauges are made of heat treated tool steel. For thickness up to 0.5 mm, the tensile strength of blades is 170 kgf/mm 2 and for 0.5 mm or above thickness it is 70 kgf/mm 2 .
3. Which of the following is incorrect about feeler gauge?
a) Feeler gauge can be used to check spark plug gaps
b) A Feeler gauge has number of blades of equal thickness
c) Blades are hinged in a sheath
d) Each thin blade is inter-leaved between two thick blades
Answer: b
Explanation: A feeler gauge is used to check gaps and clearance between two surfaces like spark plugs and tappet clearance. A feeler gauge has a number of blades of different grades and thicknesses. For maximum protection, blades are assembled in a protective sheath.
4. How much overall length is available for feeler gauge blades?
a) 50 mm
b) 30 mm
c) 70 mm
d) 100 mm
Answer: d
Explanation: The overall length available for the blades is 100 mm. and thickness of blades generally varies from 0.03 to 1 mm.
5. Which if the following option is correct for given statements?
Statement 1: Feeler gauge can be used to check clearance between cylinder and piston.
Statement 2: The working of feeler gauges is completely depended on the sense of feel.
a) Statement 1 is true but statement 2 is not true
b) Statement 2 is true but statement 1 is not true
c) Both the statements are not true
d) Both the statements are true
Answer: d
Explanation: The feeler gauge is not forced in the gap and it should not slide freely. For a perfect working, gauge should give a ‘’gauge fit’’ type of feel.
6. Match the set number with number of blades in the set as per BIS.
Set number - No. of blades
A) 2 - 1) 8
B) 6 - 2) 9
C) 3 - 3) 11
D) 1 - 4) 16
a) A-2, B-3, C-4, D-1
b) A-1, B-2, C-3, D-4
c) A-3, B-4, C-1, D-2
d) A-4, B-1, C-2, D-3
Answer: a
Explanation: 7 sets of feeler gauge are recommended by Bureau of Indian Standard. These sets are to furnish maximum utility with minimum number of blades.
7. What is the maximum variation in thickness of a feeler gauge blade of 0.3 mm thick blade?
a) 0.04
b) 0.05
c) 0.06
d) 0.07
Answer: a
Explanation: Maximum variation in thickness for feeler gauge blades up to the thickness of 0.03 mm including 0.03 should not exceed 0.04 mm. For blades over 0.3 mm, this variation is 0.006 mm.
8. According to BIS, What is the thickness of feeler gauge blades for set number 1?
a) 0.3 to 0.1
b) 0.03 to 0.1
c) 0.05 to 0.3
d) 0.5 to 0.3
Answer: b
Explanation: Set number 1 has 8 blades in the set with a thickness of blades from 0.03 to 0.1 in steps of 0.01.
9. Which of the following option is correct for given statements?
Statement 1: The series of feeler gauge blades are of thicknesses from 0.03 to 1 mm.
Statement 2: Feeler gauge blades are non-removable and are assembled in a protective sheath.
a) T, F
b) F, T
c) T, T
d) F, F
Answer: a
Explanation: Feeler gauge blades are hinged on a screw and nut. So, they are removable in nature. They are assembled in a protective sheath which protects the blades when they are not in use.
10. What is the width of feeler gauge blades at heel and tip respectively?
a) 12, 6
b) 5, 11
c) 20, 15
d) 15, 25
Answer: a
Explanation: Blades are 6 mm wide at tip and width at the heel is 12 mm. Width is less at the tip because they are tapered for the outer part of their length.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Angle Gauges”.
1. Which of the following option is incorrect with respect to angle gauges?
a) Sine bar is better than angle gauges
b) Angle gauges are made of high carbon high chromium steel
c) Angle gauges can measure the angle from 0 to 360 degrees
d) They are available in two sets of 13 and 16 gauges
Answer: a
Explanation: Angle gauges are more accurate than sine bar as it involves trigonometric functions.
2. How 34’ can be built by using angle gauges?
a) 27’+9’-3’+1’
b) 26’+10’-2’
c) 27’+10’-3’
d) 27’+8’
Answer: a
Explanation: Combinations can be made by only three series of angle gauges. Minutes series is with 1’, 3’, 9’, 27’ angle gauges.
3. In how many series the gauges can be divided?
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: 16 or 13 Gauges can be divided into 3 series i.e. degree, minutes and seconds .
4. What is the approximate size of angle gauges?
a) 76mm long and 16 wide
b) 85mm long and 26 wide
c) 16mm long and 75 wide
d) 70mm long and 18 wide
Answer: a
Explanation: Angle gauges are about 3 inch long and 5/8 inch wide. And their faces are lapped within 0.0002 mm.
5. What is the accuracy of master angle gauges?
a) 0.1 sec
b) 1 sec
c) 0.25 sec
d) 3 sec
Answer: c
Explanation: Master Angle gauges are laboratory standard and most expensive of all. They measure the angle with an accuracy of 0.25 sec.
6. Which gauges are present in the first series of angle gauges?
a) 5°, 10°, 15°, 25° and 40°
b) 1°, 3°, 9°, 27° and 41°
c) 1°, 5°, 9°, 25° and 45°
d) 5°, 10°, 15°, 30° and 45°
Answer: b
Explanation: The standard angles gauges have 5 gauges present in the first series. They consist of 1°, 3°, 9°, 27° and 41° gauges.
7. How many sets of angle gauges are available?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: Two sets of angle gauges are available. One set with 16 gauges with an accuracy of 1’’ and one set with 13 gauges with 3’’.
8. Which of the following option is true for the given statements?
Statement 1: Any angle up to 120 o 4’2’’ be made by a direct combination of angle gauges.
Statement 2: Interferometry can be used to calibrate angle gauges.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: c
Explanation: Direct combination of angle gauges can be made up to angle 81 o 40.9’. For the larger angle, square block is used with angle gauges.
9. What are the two grades of angle gauges?
a) Master and tool room
b) Precise and Normal
c) Standard and Industrial
d) High and low
Answer: a
Explanation: Master grade is laboratory standard and made from steel carbide or tungsten carbide. Tool grade is normal industrial purpose angle gauges made from steel.
10. How angle greater than 90° is measured?
a) By repeating gauges
b) Using square plate
c) Using sine bar
d) Using auto collimator
Answer: b
Explanation: Versatility of angle gauges increases when used with a square plate. Square plates with angle gauge can measure angle greater than 90 o .
11. Which of the following is not a gauge from standard B angle gauges?
a) 0.05’
b) 1’
c) 27’
d) 30
Answer: a
Explanation: Standard A has 13 gauges and standard B has all gauges from standard A except 0.05’ i.e. 12 gauges.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Vernier Height Gauges”.
1. Which of the following is incorrect for vernier height gauge?
a) Both the surfaces of measuring jaw should be at 45 o to the base
b) These gauges can be used for scribing purposes
c) Removable clamps are used
d) Surface plate is used as datum surface for measurements
Answer: a
Explanation: Both surfaces of measuring jaw i.e. upper and lower are parallel to the base. It can be used for measurements under or over a surface. In place of measuring jaw, a scriber can be attached to scribe lines.
2. What is the hardness of measuring jaws of vernier height gauge made up of stainless steel?
a) 350 HV
b) 450 HV
c) 550 HV
d) 650 HV
Answer: d
Explanation: The measuring jaws, scriber and underside of a base are made up of good quality steel and high carbon stainless steel. Hardness of these parts is about 700 and 650 HV for good quality steel and stainless steel respectively.
3. Which of the following option is correct for the given statements about vernier height gauge?
Statement 1: The projection of scriber beyond the jaw should be 10 mm.
Statement 2: Flatness of working surface of scriber can be checked by the knife edge.
a) Only statement 1 is correct
b) Only statement 2 is correct
c) Both the statements are correct
d) Both the statements are incorrect
Answer: b
Explanation: The scriber is projected at least 25 mm beyond the jaws. Height gauges may also have an offset scriber. Flatness of working surfaces of scriber and measuring jaws is checked by knife edge straight edge or optical flats.
4. What is the standard reference temperature for the measurement of the accuracy of vernier height gauges?
a) 20 K
b) 20 o C
c) 40 K
d) 40 o C
Answer: b
Explanation: Temperature of 20 o C should be maintained in the room where the test is conducted. A height gauge should rest on a precision surface plate to increase the testing accuracy.
5. Which of the following option is correct for the given statements about vernier height gauge?
Statement 1: Surface of the vernier and beam should have a dull finish.
Statement 2: Springing of measuring jaws is desirable.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: a
Explanation: Surfaces of vernier and beam have a dull finish for easy readings. A magnifying lens is also provided for this purpose. A proper care of vernier height gauges is very important. Springing of jaws is always avoided.
6. Which of the following is used for checking the perpendicular distance from the graduated face of a beam to the graduated face of vernier?
a) Angle gauge
b) Vernier depth gauge
c) Feeler gauge
d) Slip gauge
Answer: c
Explanation: It is measured with a 0.1 mm feeler gauge. Vernier depth gauges are used to measure the depth of holes and recesses.
7. Vernier is at which position when the scriber is coplanar with the base?
a) Vernier is exactly at the middle position of the scale
b) Vernier reads 1/4 th of the scale
c) Vernier is at 3/4 th position
d) Vernier reads zero
Answer: d
Explanation: Scale on the beam is positioned in the manner that vernier reads zero when scriber and base are coplanar. In case of wear, some adjustments are made to reset zero position.
8. Match the following:
Column 1 is tolerance of guiding edge of the beam in mm and column 2 is for measuring range in mm.
Column 1 Column 2
A) 0.02 - 1) 500
B) 0.04 - 2) 250
C) 0.06 - 3) 1000
D) 0.08 - 4) 750
a) A-2, B-1, C-4, D-3
b) A-1, B-2, C-3, D-4
c) A-3, B-4, C-2, D-1
d) A-4, B-3, C-1, D-2
Answer: a
Explanation: The guiding edge and face of the beam should be perfectly flat. The face of the beam should be square to the base within 0.04 mm per 100 mm.
9. Which of the following is correct about vernier height gauges?
a) The scriber should preferably be of more depth than jaw
b) The perpendicular distance between scale graduations and vernier graduations should be more than 0.01 mm
c) The base is lapped up to an accuracy of 0.05 mm
d) Width of interval between adjacent lines should be 1/2 or 1/3 times of the length of shortest graduations
Answer: d
Explanation: Nominal depth of scriber should be same as measuring jaw so that it can be reversed. The base is ground and lapped up to 0.005 mm of accuracy and for this total span of a surface is considered.
10. What is the range of reading error for measuring a range of height gauges of 250 mm?
a) ±0.02
b) ±0.03
c) ±0.04
d) ±0.05
Answer: a
Explanation: The reading error should not exceed ±0.02 mm for measuring a range of height gauge of 250 mm, ±0.04 for more than 250 mm up to 750 mm and ±0.05 mm for more than 750 mm.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Master Height Gauges”.
1. Which of the following is true for master height gauges?
a) This is a stack of slip gauge blocks
b) Can store readings in memory
c) Less skilled labour
d) Has statistical production control
Answer: a
Explanation: Master height gauge is basically a stack of gauge blocks with a robust housing. They can be used with riser blocks. A simple master height gauge cannot store measurements in memory.
2. How much measuring capacity is increased by using riser blocks with master height gauge?
a) 500 mm
b) 600 mm
c) 700 mm
d) 800 mm
Answer: b
Explanation: Riser blocks are used to adjust the height. With master height gauges it can increase measuring capacity up to 600 mm.
3. Which of the following option is correct for given statements?
Statement 1: Master height gauge is useful in setting other height gauges.
Statement 2: Can provide a BCD output.
a) Only statement 1 is true
b) Both the statements are true
c) Only statement 2 is true
d) Both the statements are not true
Answer: a
Explanation: Master height gauge is used for setting height gauges and provides a high precision standard. BCD output can be provided by electronic digital readout height gauge.
4. Which attachment is needed to check squareness and parallelism with master height gauge?
a) Dial test indicator
b) Gauge block
c) Slip rings
d) Micrometer
Answer: a
Explanation: If dial test indicator or lever is attached to master height gauge then this unit can be used to check parallelism and squareness.
5. Master height Gauge is used to measure ________
a) Hole location
b) Groove widths
c) Pitches
d) Concentricity
Answer: d
Explanation: Master height gauges can be used as a height standard to measure hole location, a width of groove, pitches etc. To check concentricity universal measuring instrument is a more accurate device.
6. Which of the following is incorrect about master height gauges?
a) Can provide a high precision standard
b) It has a digital readout
c) Has a sliding attachment
d) Built-in microprocessor
Answer: d
Explanation: There is no microprocessor and micro switch in master height gauges. A master height gauge has a rectangular column with a sliding attachment.
7. Which of the following option is correct for given statements?
Statement 1: Master height gauge can store measurement in memory.
Statement 2: Functioning of master height gauges is slower than electronic digital readout height gauge.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: Master height gauges are relatively slower than electronic digital read out height gauges. They require more skilled operators.
8. What is the difference between surface gauge and height gauge?
a) Only surface gauge is used on a surface plate
b) Height gauge has a heavy base
c) Height gauge has a measuring head
d) Surface gauge has a smooth and flat base
Answer: b
Explanation: In toolroom applications, the difference between both is, surface gauge has a scriber point and height gauge has a measuring head.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Universal Measuring Instrument”.
1. Which of the following instrument is of the highest accuracy?
a) Digital length gauge
b) Inside micrometer
c) Universal measuring instrument
d) Universal height micrometer
Answer: c
Explanation: Universal measuring instrument is of the highest accuracy due to the presence of sensors, micro switches and microprocessors.
2. Which of the following option is incorrect about the universal measuring instrument?
a) Twin digital display is present
b) Highly skilled operator is required
c) Computation capabilities
d) Automatically sense diameter of bores
Answer: b
Explanation: Twin display is present one in the front and other in the side for easy reading. Low skilled operator is required as it has automatic computation capabilities which eliminate possibilities of operator’s error.
3. Which of the following statement is true for following statements about universal measuring instrument?
Statement 1: Microprocessor and micro switches are present.
Statement 2: Coefficient of thermal expansion of measuring instrument made of steel is the same as a component to be measured.
a) F, T
b) T, T
c) F, F
d) T, F
Answer: b
Explanation: Same coefficient of thermal expansion of measuring instrument and component to be measured hence, there is no effect of temperature variation on measuring accuracy.
4. What is the permissible measuring speed in universal measuring instrument for error free reading?
a) 1 m/sec
b) 1 mm/sec
c) 1 cm/sec
d) 2 cm/sec
Answer: a
Explanation: 1 m/second is the permissible measuring speed for error free reading. These instruments saves inspection time with high accuracy.
5. How many push buttons are needed for convenient and easy operations?
a) 5
b) 6
c) 7
d) 8
Answer: a
Explanation: There are 5 push button keys are present near readout for easy measurement. Functions of these 5 buttons are: selection of measuring program, input of probe constant, changing reference datum, addition and subtraction and zero setting.
6. Which of the following is correct about electronic display unit of universal measuring instrument?
a) Sensitive to electrical interference
b) Non-removable
c) Cast iron protection cover
d) It is plug-in type
Answer: d
Explanation: It is insensitive to electrical interference and oil film. It is easily interchangeable. There is an aluminium protection cover for an electronic display unit.
7. A universal measuring instrument can withstand up to which temperature for correct reading?
a) 100 o C
b) 75 o C
c) 65 o C
d) 50 o C
Answer: d
Explanation: Display unit can withstand temperature up to 50 o C and 95% relative humidity.
8. Which of the following option is correct for given statements about universal measuring instrument?
Statement 1: There is a rack and pinion movement in measuring slide.
Statement 2: An independent power supply unit is screwed to the base.
a) Only statement 1 is true
b) Only statement 2 is true
c) Both the statements are true
d) Both the statements are not true
Answer: b
Explanation: There is no rack and pinion movement or backlash in EDU. It is completely independent and interchangeable. A power supply unit is screwed with 4 screws to the base.
9. What is the range of voltage fluctuations which can be taken care by an electronic unit in universal measuring instrument?
a) 18% to 20%
b) -10% to +50%
c) -18% to +20%
d) 10% to 50%
Answer: c
Explanation: An interrupted power supply is provided to the electronic unit by power supply unit. It takes cares from – 18 to +20% fluctuations of voltage.
10. Match the following:
Column 1: Part of instrument
Column 2: information regarding a instrument
A) Accessories - 1) Tungsten carbide coating
B) Supporting pads - 2) Balance counter weight
C) Handwheel - 3) Cast iron
D) Base - 4) Built-in microswitch
a) A-2, B-1, C-4, D-3
b) A-1, B-2, C-3, D-4
c) A-3, B-4, C-1, C-2
d) A-4, B-3, C-2, D-1
Answer: a
Explanation: Accessories are designed to balance with the counter weight. 3 supporting pads are present with tungsten carbide coating except at the top which can be lapped. Built-in microswitches are present in hand wheel which compensate automatically for probe constant.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Micrometers”.
1. What is the least count of a micrometer?
a) 0.01 mm
b) 0.02 mm
c) 0.1 mm
d) 0.2 mm
Answer: a
Explanation: Least count can be calculated by “Pitch divided by no. of divisions on a circular scale”.
2. What is the use of ratchet stop in micrometer?
a) Prevent motion of spindle
b) Maintain uniform measuring pressure
c) Provide measuring surface
d) Forms measuring tip
Answer: b
Explanation: Ratchet stop is present at the end of thimble cap to maintain a uniform measuring pressure. By ratchet stop standard conditions of measurement are attained.
3. Which of the following is incorrect about micrometer?
a) Thimble and barrel should have a dull finish
b) Total travel of the measuring spindle is called measuring range
c) Graduated surface diameter of barrel should be 5 mm
d) Screw has 10 or 20 threads per cm
Answer: c
Explanation: Thimble and barrel should have a dull finish for ease of reading. Graduated surface diameter of the barrel should not be less than 10 mm.
4. What is the hardness of measuring faces of anvil and spindle?
a) 800 HV
b) 600 HV
c) 1000 HV
d) 100 HV
Answer: a
Explanation: Measuring faces of anvil and spindle has a hardness of about 800 HV or 62 HRC. Faces may be tipped with tungsten carbide.
5. What is the total error in micrometer?
a) Positive and negative deviation from the zero point
b) Error in parallelism
c) Deviation from measurement of a nominal dimension
d) Maximum difference between ordinates of cumulative error
Answer: d
Explanation: Cumulative error is the deviation of measurement from a nominal dimension. It includes errors like thread errors, errors of measuring faces etc. Maximum difference between ordinates of cumulative error is the total error.
6. How many divisions are graduated on thimble?
a) 20
b) 25
c) 45
d) 50
Answer: d
Explanation: Graduation lines should be clearly engraved. 50 divisions are graduated on thimble each representing 0.01mm.
7. Which of the following option is correct about given statements about micrometer?
Statement 1: The anvil should not protrude from the frame.
Statement 2: An adjusting nut is present in micrometer to compensate wear
a) Only statement 1 is true
b) Only statement 2 is true
c) Both the statements are true
d) Both the statements are false
Answer: b
Explanation: The anvil is fixed and should protrude at least 3 mm. It is to permit the attachment of measuring wire support. Adjusting nut is present between spindle and nut’s screw portion. It is provided for adjusting the zero setting and to compensate wear on the measuring faces.
8. What is the value of total error for grade 1 micrometer when micrometer is tested at 20oC?
a) 4+µm
b) 5+µm
c) 6+µm
d) 7+µm
Answer: a
Explanation: Total error should not exceed 4+µ m for ‘grade 1’ micrometer and 10+µm for ‘grade 2’ micrometer when tested at 20 o C.
9. Which of the following is correct about micrometer?
a) Plastic insulating grips are used on the frame
b) Satin chrome finish increase the reading errors
c) A uniform and maximum measuring force is applied
d) Barrel is the removable part of the frame
Answer: a
Explanation: Plastic insulated grips are employed on the frame to reduce heat transfer. Satin chrome finish minimize the reading errors and eliminate glare. A uniform and minimum measuring force should be applied to reduce error.
10. To check the bending in micrometer, what is the difference between the measurement of loaded and unloaded conditions for micrometer range 0 to 25 mm?
a) 1.5 µm per kg
b) 2.0 µm per kg
c) 2.5 µm per kg
d) 3.0 µm per kg
Answer: a
Explanation: In loaded and unloaded conditions, Difference between measurements should not exceed 1.5µm, 2µm, 2.5µm and 3µm per kg for the range 0 to 25, 25 to 50, 50 to 75 and 100 mm respectively.
11. Which of the following option is true for the given statements about micrometer?
Statement 1: There is a fixed spindle and a rotated anvil.
Statement 2: For taking the reading, micrometer dimension is set slightly larger than part size.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: c
Explanation: Spindle is not fixed infact for good results spindle should move freely. Anvil is fixed generally but sometimes anvil is accommodated in reamed hole and a thread extension is provided.
12. Which of the following is incorrect about precautions in using a micrometer?
a) Final movement is given by ratchet
b) Thimble is turned till the Measuring tip just touches the part to be measured
c) Part to be measured is held in right hand and micrometer in left hand for good results
d) Error is reading is may be due to lack of flatness of anvil
Answer: c
Explanation: The part to be measured must be in left hand and micrometer in the right hand for better results. Place small finger and adjoining finger in the U frame. Middle finger supports micrometer and forefinger and thumb are placed near the thimble. This is the correct way of using a micrometer.
13. What is the accuracy range of stick micrometers?
a) ±0.005 mm
b) ±0.05 mm
c) ±0.5
d) ±0.0005 mm
Answer: a
Explanation: Accuracy of stick micrometers is of the order of ±0.005 mm. They are used to measure longer internal lengths. They have a series of extension rods to measure up to maximum length.
14. Which of the following is incorrect?
a) V-Anvil micrometer caliper is used to check out of roundness
b) Blade type micrometer has a non-rotating spindle
c) Tube wall thickness can be measured by an ordinary micrometer
d) Self-centering inside micrometer has an interchangeable measuring head
Answer: c
Explanation: An ordinary micrometer can’t be used for measuring tube wall thickness because of the concavity of internal surfaces. For this, anvil is made of cylindrical form and spindle axis and anvil axis is made perpendicular.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Bench Micrometer”.
1. Which of the following is incorrect about bench micrometer?
a) Anvil retractor device
b) High precision micrometer head
c) Non-adjustable work table
d) Interchangeable dial indicator
Answer: c
Explanation: Work table is adjustable and an accurate alignment of work is provided by adjusting the table. For repeated measurements, anvil retractor device is present.
2. Up to which comparator measurements, dial indicator of bench micrometer can be used?
a) 1 micron
b) 2 micron
c) 3 micron
d) 4 micron
Answer: a
Explanation: A super precision dial indicator is used for comparator measurement. Micrometer head is also highly précised with direct readings in 25 mm units.
3. What is the range of comparator in bench micrometer with dial comparator?
a) ±50 µm
b) ±100 µm
c) ±150 µm
d) ±200 µm
Answer: a
Explanation: Range of bench micrometer and comparator in bench micrometer with dial comparator is 0-25 mm and ±50 µm respectively.
4. What is the accuracy deviation of dial comparator bench micrometer when setting with gauge block?
a) ≤2 µm
b) ≥2 µm
c) ≤1 µm
d) ≥1 µm
Answer: c
Explanation: Use of gauge block increase accuracy of bench micrometer and its accuracy deviation is less than or equal to 1 µm.
5. Which of the following option is correct for given statements about dial comparator bench micrometer?
Statement 1: Moving parts are of satin chrome finish.
Statement 2: Extra large thimble is present.
a) T, F
b) F, T
c) T, T
d) F, F
Answer: c
Explanation: For easy and fast measurement, moving parts and scale are satin chromed finished. Thimble is large so that graduations are widely spaced.
6. What is the thimble diameter in dial comparator bench micrometer?
a) 5 mm
b) 10 mm
c) 20 mm
d) 30 mm
Answer: d
Explanation: Thimble diameter is large so that graduations can be read easily. Its diameter is about 30 mm.
7. Which of the following is correct about dial comparator bench micrometer?
a) Not ideal for small precision parts
b) Immovable anvil
c) Small thimble
d) Non rotating spindle
Answer: d
Explanation: Anvil can be movable. It is mounted on a long guide way. Micrometer screw contains a non- rotating spindle which is precisely grounded.
8. What is the value of measuring pressure in dial comparator bench micrometer?
a) 7.5 N
b) 8.5 N
c) 9.5 N
d) 10 N
Answer: a
Explanation: Measuring pressure in dial comparator bench micrometer is about 7.5 N. Spindle thread pitch is 1 mm. Throat depth is about 32 mm.
9. Which of the following option is correct about bench micrometer?
Statement 1: Friction free motion transfer between anvil and indicator.
Statement 2: Anvil is retractable by trigger control.
a) Statement 1 is correct
b) Statement 2 is correct
c) Both the statements are correct
d) Both the statements are incorrect
Answer: c
Explanation: There is a mechanism for linear friction free motion transfer between anvil and indicator. This is to achieve high accuracy. Retracting of the anvil is done by trigger control. Work is placed between spindle and anvil after retracting and then released.
10. What is the workrest diameter in bench micrometer with dial comparator?
a) 12 mm
b) 14 mm
c) 16 mm
d) 18 mm
Answer: b
Explanation: Workrest diameter is 14 mm with 12 mm height adjustment. Work rests between spindle and anvil. It can be raised to a selected height by using an adjustable work table.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Graduated Scales”.
1. At which interval, the graduated scales are graduated?
a) 1 mm
b) 10 mm
c) 100 mm
d) 10 cm
Answer: a
Explanation: At the intervals of 1 mm, graduated scales are accurately graduated.
2. Which of the following option is correct about given statement?
Statement 1: In conjunction with other instruments, graduated scales can be used for machine setting.
Statement 2: Graduated scales has fixed anvil.
a) T, T
b) F, T
c) T, F
d) F, F
Answer: c
Explanation: With micrometer microscope, graduated scales can be used for instrument and machine set to a high order of accuracy.
3. When glass block is tilted by ‘i’ in optical arrangement with a graduated scale, then find out the displacement of the ray. Given, width=5 mm, refractive index of glass block=1.5 and rotation is 10 mins.
a) 0.05 mm
b) 0.005 mm
c) 0.0005 mm
d) 0.00005 mm
Answer: b
Explanation: For very small angles, h=wi.
4. What is the accuracy range when Graduated scales are used with micrometer microscope?
a) ±1 micron
b) ±1/2 of a micron
c) ±1/4 th of a micron
d) ±3/4 th of a micron
Answer: c
Explanation: Use of microscope micrometer increases the accuracy of graduated scales. ±1/4 th of a micron is the accuracy range when Graduated scales are used with micrometer microscope.
5. Which of the following is incorrect about graduation scales?
a) Scribed or etched marks are less preferable than paints
b) Telescope internal gauge has two spherical contact rods
c) Ball type plug gauge can detect ovality and taper effect
d) Pneumatic hole gauges are used for precision hole gauging
Answer: a
Explanation: Scribed and etched graduations are more preferable than inks. It is for the durability and accuracy of graduations.
6. Which of the option is correct for given statements about graduated scales?
Statement 1: A microscope is fitted over the scale markings for machine setting.
Statement 2: This arrangement has a provision of the micrometer.
a) Only statement 1 is true
b) Only statement 2 is true
c) Both the statements are true
d) Both the statements are not true
Answer: c
Explanation: A microscope is fitted and setting lines are engraved on the microscope eyepiece. This arrangement has a micrometer provision to move the setting lines.
7. In optical arrangement with graduated scale, when glass block is tilted by ‘i’ then incident ray from scale deviates from straight line path. What is the displacement ‘h’?
a) sin/wcosr
b) w cos/sinr
c) w sin/cosr
d) cos/wsinr
Answer:c
Explanation: Scale division is sensed in the same position when optical axis and glass block are perpendicular to each other. Then it travels a straight line. But when glass block is tilted then incident ray is refracted by ‘r’.
8. Match the following:
A) Cylindrical gauges - 1) Small bores
B) Telescope internal gauges - 2) Deep bores
C) Hemispherical gauge - 3) Instrument setting
D) Graduated scale - 4) Hole internal diameter
a) A-2, B-4, C-1, D- 3
b) A-1, B-2, C-3, D-4
c) A-4, B-3, C-2, D-1
d) A-3, B-1, C-4, D-2
Answer: a
Explanation: Telescope internal gauge, Hemispherical and Cylindrical gauges are used for internal measurements.
9. Which of the following statement is true about graduated scales?
Statement 1: For the purpose of machine setting, an optical arrangement can be used with graduated scales.
Statement 2: Glass block is placed between the graduated scale and table.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: a
Explanation: In this arrangement image of scale is optically moved. For this, a glass block is placed between scale and eyepiece.
10. Which of the option is correct for given statements about an optical arrangement with graduated scales?
Statement 1: There are more chances of cumulative error in optical arrangement with scales while using glass blocks.
Statement 2: High resolution over long length can be obtained by this method.
a) Only statement 1 is true
b) Only statement 2 is true
c) Both the statements are true
d) Both the statements are not true
Answer: b
Explanation: In this arrangement, rotation of glass block is easily calibrated due to high resolution. There will be more chances of cumulative errors with other methods.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Slip Gauges”.
1. Which of the following is not a name of slip gauges?
a) Gauge Blocks
b) Johannsen Gauges
c) Gage Blocks
d) Linear Gauges
Answer: d
Explanation: Slip Gauges are also known by Gauge Blocks, Gage Blocks, Jo Blocks and Johannsen Gauges. These are the rectangular or square blocks of steel.
2. Which of the following is not a common basic form of slip gauge?
a) Rectangular
b) Square with centre hole
c) Square without centre hole
d) Parallelogram
Answer: d
Explanation: There are three basic forms of slip gauges. These are rectangular, square with center hole, and square without centre hole. Rectangular blocks are less expensive hence are more widely used.
3. How many grades or classes of slip gauges are present?
a) 3
b) 5
c) 6
d) 4
Answer: b
Explanation: Slip gauges can be designed in 5 grades i.e. Grade 2, Grade 1, Grade 0, Grade 00 & calibration grade.
4. What is the approximate size of slip gauges?
a) 30mm long and 10mm wide
b) 45mm long and 15mm wide
c) 20mm long and 5mm wide
d) 25mm long and 10mm wide
Answer: a
Explanation: Angle gauges are about 30 mm long and 10 mm wide. Slip gauges are like a system to produce precision length.
5. Match the following gauge type with their respective tolerance:
A) A - 1) ±0.05 μm
B) AA - 2) +0.15 μm to −0.05 μm
C) AAA - 3) +0.25 μm to −0.15 μm
D) B - 4) +0.10 μm to −0.05 μm
a) A-2, B-4, C-1, D- 3
b) A-1, B-2, C-3, D-4
c) A-4, B-3, C-2, D-1
d) A-3, B-1, C-4, D-2
Answer: a
Explanation: AAA has very small tolerance and are used to establish standards. AA has low tolerance and is used in calibration of inspection blocks. A has normal tolerance and are used as tool room standards. B has large tolerance used in workshops.
6. Which of the following is not correct about protector blocks?
a) Protector blocks have letter B on its measuring face
b) They are provided with high grade sets of gauge blocks
c) These are made from Tungsten carbide
d) These are 2 mm blocks
Answer: a
Explanation: Protector blocks are 2 mm block with letter P on it.
7. What is the permissible gauge error for Grade 0?
a) ± μm
b) ± μm
c) ± μm
d) ± μm
Answer: a
Explanation: Grade 0 slip gauges have maximum permissible gauge error of ± μm. For grade I and grade II, the permissible gauge error is ± μm and ± μm.
8. Which of the following is used for manufacturing of length bars?
a) Hardened steel
b) High carbon high chromium steel
c) Tungsten carbide
d) Ceramic
Answer: b
Explanation: Length bars are made from high carbon high chromium steel ensuring the hardness to 64RC.
9. Why ceramic slip gauges is better than steel slip gauges?
a) Due to its wringing capability
b) Due to its Resistance to impact
c) Due to its Resistance to wear
d) Due to its thermal Expansion
Answer: c
Explanation: Ceramic slip gauges are about 10 times more resistant to wear as compared to steel slip gauges. Natural stability and durability due to its low friction co-efficient make it more resistant.
10. Which of the option is correct for given statements about slip gauges error?
Statement 1: Squareness Error is the amount by which side face deviates from a right angled position with respect to each measuring face.
Statement 2: Wringing occurs due to molecular adhesion.
a) Only statement 1 is true
b) Only statement 2 is true
c) Both the statements are true
d) Both the statements are not true
Answer: c
Explanation: Wringing is the complete contact between measuring faces. It occurs due to molecular adhesion.
11. Which one of the following is not a recommended set gauge of a metric unit?
a) M112
b) M105
c) M95
d) M33
Answer: c
Explanation: The recommended sets of slip gauges of metric units are M112, M105, M87, M50, M33 and M27.
12. If properly wrung how much pull can two gauge blocks can withstand?
a) 400N
b) 330N
c) 250N
d) 1000N
Answer: b
Explanation: Due to their ultraflat surface, gauge block adhere tightly when wrung. They can withstand 330N pull when wrung properly.
13. Which of the option is correct for given statements about slip gauge form?
Statement 1: Grade 2 is the workshop grade.
Statement 2: Square slip gauge is more expensive and adhere better to each other when wrung
a) Only statement 1 is true
b) Only statement 2 is true
c) Both the statements are true
d) Both the statements are not true
Answer: c
Explanation: Grade 2 is the workshop grade. They are used in setting up machine tools, checking mechanical widths etc. Square slip gauge is expensive but they wear longer and adhere better.
14. Which of the following is not the most important feature of slip gauge?
a) Length between measuring surface
b) Flatness
c) Surface conditions of measuring surface
d) Adhereness efficiency
Answer: d
Explanation: The most important features of slip gauge are flatness, the length between measuring surface and surface conditions of measuring surface. Slip gauges are used to provide end standards of specific length.
15. In absence of parallelism, what is the size of slip gauge?
a) Distance between two measuring faces
b) Distance between the centre of the exposed face to the surface of a body
c) Distance between the top edge of the exposed surface and same edge of a body
d) Distance between contacting part of gauge and body
Answer: b
Explanation: Size of slip gauge in absence of parallelism is the vertical distance between centre of exposed face and surface of a body.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Slip Gauges Accessories”.
1. Which of the following is not a slip gauge accessory?
a) Measuring jaws
b) Holder
c) Rod clamp
d) Base
Answer: c
Explanation: Slip gauge accessories are measuring jaws, holder, base and scribing & centre point. Field of application of slip gauges is extended by using these accessories.
2. How many types of measuring jaws are present?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: There are two types of measuring jaws i.e. Type A and Type B. Type A is for both internal and external measurement and type B is for external measurement only.
3. What is the error in overall dimension when a pair of jaws wrung together?
a) Should not exceed ± 0.0007 mm
b) Less than ± 0.0001 mm
c) Should not exceed ± 0.0001 mm
d) Should not exceed ± 0.001 mm
Answer: c
Explanation: When a pair of jaws wrung, overall dimension error should not exceed ± 0.0001 mm.
4. Which of the option is correct for given statements about measuring jaws types?
Statement 1: Nominal sizes of measuring jaws are engraved on front end face.
Statement 2: In Type B measuring jaws, no dimension is important.
a) Only statement 1 is true
b) Only statement 2 is true
c) Both the statements are true
d) Both the statements are not true
Answer: c
Explanation: The most important dimension is the measuring jaw size. In Type B, the most important part is the wringing face not the dimensions.
5. Which of the following is the range in which holder is available?
a) 0 to 60mm
b) 200 to 250mm
c) 250 to 350mm
d) 350 to 400mm
Answer: a
Explanation: Holders are available in three ranges i.e. 0-60mm, 50-110mm and 100-210mm.
6. How much deviation in height of base is acceptable from marked dimension?
a) ± 0.001 mm
b) ± 0.007 mm
c) ± 0.0007 mm
d) ± 0.0015 mm
Answer: c
Explanation: Height of base is accepted within ± 0.0007 mm deviation from the marked dimension. The base should remain stable when used with the longest size holder.
7. What is the value of hardness for slip gauge accessories?
a) 600 HV
b) 700 HV
c) 750 HV
d) 800 HV
Answer: d
Explanation: Steel is used to make slip gauges and should be defect free. It should be hardened uniformly up to the minimum hardness of 800 HV.
8. Which of the following option is correct for given statements?
Statement 1: Slip gauge and its accessories can be used as a limit gauge.
Statement 2: Slip gauge and accessories can be used for the measurement of plug gauge but not for ring gauges.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: a
Explanation: They can be used as a temporary limit gauge. They are used for the measurement of a ring and plug gauges, inspection of precision equipment and for marking out tools etc.
9. What is the value of flatness for the surface upon which slip gauges are wrung?
a) 0.0001 mm
b) 0.001 mm
c) 0.01 mm
d) 0.1 mm
Answer: a
Explanation: Surface should be flat within 0.0001 mm and parallel to the base within 0.0002 mm.
10. Which of the following is incorrect about slip gauge accessories?
a) Sides of the base are relieved
b) Holder holds rigidly the combination of slip gauges
c) Slip gauge accessories are made from suitable hardened steel
d) There is no sliding movement of slip gauges in wringing
Answer: d
Explanation: The sides of base are relieved to provide a convenient finger grip. In wringing operation, first the two surfaces should be slided transversely then twisted together.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Line Standard”.
1. Which of the following is not a line standard?
a) Yard
b) Meter
c) Precision scale
d) Length bar
Answer: d
Explanation: Length bar is an end standard. Yard, meter and precision scale are line standards.
2. What is the length of the Imperial standard yard?
a) 38 m
b) 38 mm
c) 38 inches
d) 38 cm
Answer: c
Explanation: The imperial standard yard is a bar made of bronze of 1 inch square cross section. It is 38 inches long.
3. Which of the following is incorrect about line standard?
a) These are legal standards
b) A round recess, half inch away from the ends is cut at both ends
c) Slope at the ends is zero
d) Points of supports are called ‘Airy’ points
Answer: b
Explanation: A round recess is cut at both ends up to the central plane of the bar. These are one inch away from two ends.
4. Gold plugs are inserted into Yard. How many lines are engraved on a plug?
a) 2 transversely and 2 longitudinally
b) 3 transversely and 2 longitudinally
c) 2 transversely and 3 longitudinally
d) 3 transversely and 3 longitudinally
Answer: b
Explanation: It has two holes at the ends in which gold plugs are inserted. Plugs have 2 lines longitudinally and 3 transversally and lines are in a neutral plane.
5. Which of the following option is correct about straight edges?
a) Deflection be minimum at the centre
b) Deflection be maximum at the centre
c) Deflection be minimum at right most part
d) Deflection be minimum at left most part
Answer: a
Explanation: For straight edges, minimum deflection at centre is desirable. For this, the support should be 0.554 L apart, where L is length of the bar.
6. What is the distance between supports for a simply supported beam?
a) 0.557 L
b) 0.554 L
c) 0.575 L
d) 0.577 L
Answer: d
Explanation: Distance between supports is obtained by expression, (1/√(n 2 -1))*L . Here, n is no. of supports. For simply supported beam, it is equal to *L.
7. Which of the following is incorrect about the metre ?
a) It is inoxidisable
b) Kept at 10 o C
c) Supported by two rollers
d) Have a web type section
Answer: b
Explanation: The bar is kept under atmospheric pressure and at 0 o C. It has a shape of winged section. This section has a web whose surface lines are on a neutral axis.
8. By which material metre bar is made of?
a) Bronze
b) Platinum
c) Platinum-bronze alloy
d) Platinum-iridium alloy
Answer: d
Explanation: Yard is made up of bronze bar. This bar is made of platinum-iridium alloy in which 90% is platinum and 10% iridium. Meter is the distance between two lines which are engraved on a bar surface.
9. Which of the following option is true for given statements about meter ?
Statement 1: Diameter of rollers is 0.5 cm.
Statement 2: Rollers are placed at a distance of 751 mm.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: Metre bar is supported by 2 rollers of diameter not less than 1 cm diameter. They are symmetrically placed in a same horizontal plane at a distance of 751 mm.
10. Which of the following is incorrect about the precision scale?
a) Precision scale of reference standard is of a H section
b) Fine lines are engraved parallel to the longitudinal axis of the bar
c) Lines are engraved by using ruling engine
d) Lines are scribed with a sharp diamond cutter
Answer: b
Explanation: Fine lines are engraved at 90 o to the longitudinal axis of the bar. Lines should be as fine as possible. Taking care of lines in terms of parallelism, uniform thickness and spacing is really important.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “End Standards”.
1. Which of the following is not end standard?
a) Precision scale
b) Length bars
c) Slip gauges
d) Gap gauges
Answer: a
Explanation: Precision scale is based on line standard. We employ end standards in workshops for all practical measurements.
2. What is the diameter of end bars?
a) 10 mm
b) 20 mm
c) 30 mm
d) 40 mm
Answer: b
Explanation: Length bar is the alternate name of end bars. These are round bar made of carbon steel of about 20 mm diameter.
3. What is the hardness of end bar at the ends?
a) 600 HV
b) 700 HV
c) 800 HV
d) 900 HV
Answer: c
Explanation: These are hardened up to 800 HV only at the ends. These are supported by ‘Airy points’.
4. Which of the following option is correct about given statements related to end standards?
Statement 1: It is possible to transfer line standard to end standard.
Statement 2: Size of end bars varies from 5 mm to 100 mm only.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: a
Explanation: Size of end bars or length bars varies from 10 mm to 1200 mm. To transfer line standard correctly to the ends of the bar, Line standard comparator is used.
5. Which of the following is incorrect about end bars?
a) There are 4 grades of accuracy are available
b) Bars above 150 mm generally not found in a majority of engineering work
c) Workshop grades have internal threaded ends
d) Inspection grades have external threaded ends only
Answer: d
Explanation: 4 grades of accuracy are reference, calibration, inspection and workshop. Inspection and workshop both grades have internal threaded ends.
6. What is the range of measurement of slip gauges when they are used with length bars?
a) 1200 mm
b) 1300 mm
c) 1400 mm
d) 1500 mm
Answer: a
Explanation: Slip gauges are used as end standards. When slip gauges are used in combination with end bars, there range of measurement is up to 1200 mm.
7. Which of the following is incorrect about end standards?
a) End of micrometer anvil is the end standard
b) It is difficult to form 2 parallel surfaces at the end of a bar
c) Slip gauges were made of more length than legal line standard
d) It is difficult to heat treat the ends
Answer: c
Explanation: End bars and slip gauges both were made of an equal length to the legal standard. End standards which are used in general measurement applications are very important.
8. Which of the following option is correct for given statements?
Statement 1: Displacement method can be used for comparison of an end gauge with a line standard.
Statement 2: In displacement method, there is no need for a microscope but a spirit level is required.
a) Only statement 1 is correct
b) Only statement 2 is correct
c) Both the statements are correct
d) Both the statements are not correct
Answer: a
Explanation: Displacement method utilizes a microscope. In this method, line standard is placed on a carrier and micrometer readings are taken by moving the carrier. After this, same is done for end standard.
9. Which of the following is correct about brookes level comparator?
a) It is used for sub-division of length standard
b) Must be kept at temperature 10 o C for correct readings
c) A very accurate spirit level is used
d) Spirit level makes line contact on gauges
Answer: c
Explanation: It is used for sub-division of end standards. It is important to keep the room temp constant. This is important because some metals suffer a change in length when the temp is varied. Room must be kept at 20 o C.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Wavelength Standard”.
1. Which of the following is not correct about wavelength standard?
a) Wavelength of monochromatic light is an invariable unit of length
b) Wavelength standard is a physical standard
c) It is a reproducible standard
d) It is a natural unit of length
Answer: b
Explanation: Wavelength standard need not be preserved as it is not a physical one. This is an advantage of wavelength standard over others.
2. What is the error in a reproduction of wavelength standard?
a) 1 part in 100 million
b) 2 parts in 50 million
c) 2 parts in 50 million
d) 1 part in 50 million
Answer: a
Explanation: Wavelength standard is reproducible and error of reproduction is very less i.e. only 1 part in 100 million.
3. Which of the following is the most suitable for wavelength standard?
a) Cadmium 114
b) Krypton 86
c) Mercury 198
d) Any monochromatic light
Answer: b
Explanation: If used in a hot cathode discharge lamp then It is the most suitable element. Temperature should be maintained at 64 o K.
4. Which colour radiation of krypton 86 is selected for measurement?
a) Yellow
b) Green
c) Orange
d) Blue
Answer: c
Explanation: Orange radiation of Kr 86 is selected for measurement. Orange-red line of Kr 86 is produced under some specific conditions like at the temp of 64 o K.
5. Which of the following option is correct for given statements about wavelength standard?
Statement 1: Gas lasers produce 1000 times more intense light than others.
Statement 2: Lasers cannot be used for some interferometers like Pitter-NPL gauge interferometer.
a) T, F
b) F, T
c) F, F
d) T, T
Answer: d
Explanation: Working of Pitter-NPL gauge interferometer is based on 3 or 4 different wavelengths. Laser contains only a single wavelength.
6. Which of the following is not an advantage of gas laser?
a) Bigger size
b) Highly monochromatic light
c) Produce intense light
d) Enormous path difference between interference fringes
Answer: a
Explanation: Bigger size, high cost and effect of temperature and vibration on wavelength, these are the disadvantages of laser.
7. Which of the following option is correct for the given statements?
Statement 1: End and wavelength standards can be compared without any mechanical movement.
Statement 2: Indirect comparison of line standard and wavelength standard involves movement.
a) Only statement 1 is true
b) Only statement 2 is true
c) Both the statements are true
d) Both the statements are not true
Answer: c
Explanation: Comparison of end and wavelength standard does not involve any mechanical movement. Terminal surfaces of end standard can be used as optical reflectors. But in comparison of line and wavelength standard, movement like movement of carriage are involved.
8. What is the path difference between interference fringes, when krypton 86 is used?
a) 500 mm
b) 800 mm
c) 1000 mm
d) 1200 mm
Answer: b
Explanation: Next to laser, Krypton 86 enables maximum path difference i.e. 800 mm between fringes.
9. Which of the following option is correct about wavelength standard?
a) Wavelength does not depend upon the amount of isotope impurity
b) Solid state lasers having high intrinsic noise can be used to study new lines
c) Krypton 86 is produced by neutron bombardment of gold
d) Cadmium 114 is the secondary international length standard
Answer: d
Explanation: Wavelength depends upon the impurity of isotopes. Mercury 198 is produced by neutron bombardment of gold. Cadmium is the only natural material which can produce an almost symmetrical spectral line.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Conditions of Comparison”.
1. What is TEI?
a) UNDE+NDE+TVE
b) UNDE-NDE-TVE
c) UNDE+NDE-TVE
d) UNDE-NDE+TVE
Answer: a
Explanation: NDE is a nominal differential expansion, UNDE is an uncertainty of nominal differential expansion, TVE is temperature variation error. NDE is the difference between the nominal expansion of master and part.
2. What is the maximum limit of TEI after which attention is required?
a) 5% of the tolerance part
b) 10% of the tolerance part
c) 15% of the tolerance part
d) 20% of the tolerance part
Answer: b
Explanation: If the TEI is > 10% of the part of tolerance, then attention is required. In close tolerance works, thermal effect is a single largest source of error. Efforts like applying correction and air conditioning doesn’t always solve the problem.
3. Which of the option is correct about given statements factors affecting standards?
Statement 1: A uniform temperature is important in metrology labs.
Statement 2: Ambient temperature may change by convection, conduction and radiation.
a) Only statement 1 is correct
b) Only statement 2 is correct
c) Both the statements are correct
d) Both the statements are false
Answer: c
Explanation: A uniform temperature is necessary because rate of thermal expansion is different for different materials. Ambient temp may change by convection, conduction and radiation but the effect of radiations is more troublesome.
4. Up to which length of gauges, there is no appreciable change in length with a method of support?
a) 75 mm
b) 100 mm
c) 150 mm
d) 200 mm
Answer: a
Explanation: For small gauges upto 75 mm length, there is no appreciable change in length for a method of supports. But dimensions of long gauges may change even by their own weight.
5. What is the full form of TEI?
a) Total error index
b) Total expansion index
c) Thermal expansion instrument
d) Thermal error index
Answer: d
Explanation: Thermal error index can be reduced by establishing a more accurate coefficient of expansion, making corrections for NDE, minimizing temperature variation from 20 degree C.
6. What is the value of humidity in test laboratories for performing a measurement or any other operation?
a) 35±10%
b) 45±10%
c) 55±10%
d) 65±10%
Answer: b
Explanation: Lower RH value can invalidate measurement by building static charge. High value of RH can cause leakage. It should be maintained at 45±10%.
7. Which of the following statement is correct for given statements?
Statement 1: Nitra-alloy is an ultrastable material.
Statement 2: In steel coefficient of expansion can be increased by adding nickel.
a) F, F
b) F, T
c) T, T
d) T, F
Answer: d
Explanation: Metallurgic compositions also affect the stability of the material. Coefficient of expansion of steel can be reduced by adding nickel. It is desirable to have materials with the same coefficient of expansion.
8. Which of the following statement is not suitable to reduce error produced by temperature variation?
a) Increase rate of air flow
b) Increase the frequency of variation of temperature
c) Increase the amplitude of temperature variation
d) Redesign masters and comparators
Answer: c
Explanation: Decrease in an amplitude of temperature variation is a factor to reduce error produced by temp variations. Redesigning of masters and comparators may reduce this error by balancing time cons. and coefficient of expansion with part to be measured.
9. Which of the following option is correct for given statements about factors affecting accuracy in metrology?
Statement 1: Acoustic noise should be restricted below 45-60 dB.
Statement 2: Humidity corrodes non-ferrous materials only.
a) Only statement 1 is true
b) Both the statements are true
c) Only statement 2 is true
d) Both the statements are not true
Answer: a
Explanation: There is an effect of acoustic noise on sensitive measurement, it value should be less than 45-60 db. Humidity should be maintained at a constant value, it can corrode ferrous materials.
10. Which of the following option is not suitable for environmental conditions in labs?
a) Wet dust particles decrease insulation resistance
b) Dry dust increase surface resistivity
c) A negative air pressure should be maintained in labs
d) Electrostatic precipitators used to collect dust particles
Answer: c
Explanation: A positive air pressure of about 10 to 20 N/m 2 relative to outside area is recommended in labs. Electrostatic precipitators are used to collect and attract dust particles, for this purpose they can be placed in corners.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Metrology in Quality Assurance”.
1. What does QA and QC stand for?
a) Quality Assurance and Queuing Control
b) Quality Adjustment and Quality completion
c) Quality Assurance and Quality control
d) Quality Adjustment and Queuing control
Answer: c
Explanation: QA stands for Quality Adjustment. QA is concerned with the functions related to the attainment of the required quality. QC stands for Quality control. QC is sustaining the product quality practically and ensuring that it meets the requirements given.
2. What is QA?
a) It is the measurement of degree to which a product satisfies the need
b) Any systematic process used to ensure quality in the process
c) Process of identifying defects
d) It is a corrective tool
Answer: b
Explanation: QA is a systematic process which ensures the quality of the product and guarantees to the user that product will be safer and more reliable.
3. Which of the following option is correct regarding QA and QC?
a) QC is an integral part of QA
b) QA is an integral part of QC
c) QA and QC are independent to each other
d) QC may or may not depend on QA
Answer: a
Explanation: QC is based on the measurements as it concerned with practical means. Metrology is an important tool of quality assurance.
4. Which of the following option involves material and component control?
a) Development of standards
b) Development of specification
c) Quality control
d) Feedback
Answer: c
Explanation: Quality and measurement control involves component control. Specification and design involve the development of specifications, designs and standards. Marketing and servicing involves feedback.
5. Arrange the steps of QA in ascending order?
a) Customer needs, material control, design development, process control, marketing
b) Material control, process control, customer need, design development, finished product
c) Customer needs, design development, material control, process control, finished product
d) Material control, servicing, process control, material control, design development
Answer: c
Explanation: Scheme of QA starts with customer need. They have to be converted into the development of a specification, followed by quality and measurement control, material control and convert into the finished product.
6. What is the first step of QA?
a) Development of standards
b) Identification of customer need
c) Servicing
d) Material control
Answer: b
Explanation: Identification of customer need is the first step of QA after which further basic elements of QA are identified. QA depends not only on QC but also on the activities of the entire company.
7. Match the following:
A) Quality assurance - 1) Process oriented
B) Quality control - 2) National physical laboratory
C) Quality management - 3) Product oriented
D) National measurement system - 4) Overall programmer of QA
a) A-3, B-4, C-2, D-1
b) A-2, B-3, C-1, D-4
c) A-1, B-3, C-4, D-2
d) A-4, B-1, C-3, D-2
Answer: c
Explanation: A quantitative management is a management representative, responsible for resolving all matters pertaining to quality and independent of other functions.
8. Which of the following is an example of QA?
a) Verification
b) Software testing
c) Validation
d) Documentation
Answer: a
Explanation: Software testing and validation are the examples of QC. Validation is an example of QA. QC is a system for coordinating the efforts of groups in an organization to improve quality.
9. Which of the following option is not correct regarding QA and QC?
a) Process capabilities should be monitored on intermittent basis
b) Measuring equipment’s must have a calibration certificate
c) Normally many inspections are done during the process of manufacturing
d) QA depends on the activities of the entire company
Answer: a
Explanation: Process capabilities are controlled on a continuous basis. These are used to eliminate and detect potential causes of non-conformance.
10. Where the nodal point for National Measurement System is located?
a) Bangalore
b) Patna
c) Bombay
d) New Delhi
Answer: d
Explanation: Nodal point for national measurement system is NPL and located in New Delhi. It has responsibilities like the development and management of national standards, evaluation of measuring techniques etc.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Tolerances”.
1. What are the functional dimensions?
a) Have to be machined and fit with other mating components
b) Which have no effect on the performance of quality
c) Need not to be machined to an accuracy of the high degree
d) Function is more important than accuracy
Answer: a
Explanation: Non-functional dimensions have no effect on the performance of quality of the assembly or component. Non-functional dimensions need not to be machined to higher accuracy.
2. Why tolerances are given to the parts?
a) Because it’s impossible to make perfect settings
b) To reduce weight of the component
c) To reduce cost of the assembly
d) To reduce amount of material used
Answer: a
Explanation: Tolerances are provided to the parts because variations in the material properties introduce errors and production machines themselves have inherent inaccuracies. Another reason to introduce tolerance is that it is not possible to make perfect settings by operator so some tolerances are provided.
3. What is bilateral tolerance?
a) Total tolerance is in 1 direction only
b) Total tolerance is in both the directions
c) May or may not be in one direction
d) Tolerance provided all over the component body
Answer: b
Explanation: Total tolerance is specified on both the sides of the basic dimension. This usually have + and – tolerance of equal amount.
4. Which type of tolerance provided in drilling mostly?
a) Bilateral
b) Unilateral
c) Trilateral
d) Compound
Answer: b
Explanation: Mostly unilateral tolerance is provided in drilling as dimension is allowed to vary in one direction only. Hole is always oversize, not undersize.
5. What is mean clearance?
a) Maximum size of hole minus maximum size of shaft
b) Minimum size of hole minus minimum size of shaft
c) Mean size of hole minus mean size of shaft
d) Average of both size of shaft and hole
Answer: c
Explanation: Statistical approach allows wider tolerances compared to complete interchangeability approach. Methods used by statistical approach are usually permits cheaper production. Mean clearance is equal to .
6. Which of the following is incorrect about tolerances?
a) Too loose tolerance results in less cost
b) Tolerance is a compromise between accuracy and ability
c) Too tight tolerance may result in excessive cost
d) Fit between mating components is decided by functional requirements
Answer: a
Explanation: Loose tolerance results in increase in cost, assembly problems and poor performance of the product. Tight tolerance results in unnecessary machining and inspection time.
7. Quality control charts doesn’t depend on which factor?
a) Normal distribution
b) Random sampling
c) Independence between samples
d) Binomial distribution
Answer: d
Explanation: In establishing of realistic specifications, control charts are considered as a good guide for the design office. Quality control charts are based on the assumptions of random sampling and normal distribution.
8. Which of the following option is true for given statements?
Statement 1: Bilateral tolerances are used in mass production techniques.
Statement 2: The basic size should be equal to upper and lower limits.
a) T, T
b) F, F
c) T, F
d) F, T
Answer: c
Explanation: Bilateral tolerances are preferred in mass production techniques where setting of a machine is done for the basic size. If unilateral tolerances are specified in place of bilateral, then basic size should be changed to make it bilateral. Basic size is in half way between lower and upper limits.
9. If a clearance fit is present between shaft and hole, what is the tolerance on shaft or hole for a complete interchangeable approach?
a) ½ of maximum clearance – ½ of minimum clearance
b) ¼ of maximum clearance – ¼ of minimum clearance
c) Maximum clearance – minimum clearance
d) ¾ of maximum clearance – ¾ of minimum clearance
Answer: a
Explanation: There are two approaches for deciding of tolerances and shafts i.e. statistical and complete interchangeable approach. There is no risk is taken about a single non-conforming assembly in complete interchangeable approach.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Interchangeability”.
1. Which of the following option is incorrect about interchangeability?
a) Increase output
b) Increase cost of production
c) Useful in mass production
d) Assembly time increases
Answer: d
Explanation: An interchangeable part is one that can be replaced with a similar part manufactured to the same drawing. It can be used in mass production with an economic oriented approach. Assembly time decreases as mating parts are interchangeable.
2. What are the main considerations for deciding the limits of a particular part?
a) Functional requirement
b) Economics and interchangeability
c) Interchangeability and functional requirement
d) Interchangeability, functional requirement and economics
Answer: d
Explanation: Functional requirements are related to the function of a component that is what is required to do. Interchangeability is for ease of replacement of part. Economics is related to the minimum cost and time.
3. For full interchangeability, what is the relation between the process capability of a machine and manufacturing tolerance of the part?
a) Process capability = Manufacturing tolerance
b) Process capability ≥ Manufacturing tolerance
c) Process capability > Manufacturing tolerance
d) Process capability ≤ Manufacturing tolerance
Answer: d
Explanation: For full interchangeability, only such machines are selected for manufacturing whose process capability ≤ manufacturing tolerance. If this condition is satisfied, then the component will meet the desired tolerance and capable of mating with other.
4. Which of the following option is correct in given statements about interchangeability?
Statement 1: Standardisation is not so much of importance for interchangeability.
Statement 2: Interchangeability follows ‘normal distribution’.
a) F, T
b) T, T
c) F, F
d) T, F
Answer: a
Explanation: Standardisation is important in interchangeability. It is essential to follow a common standard by all, only then interchangeability is possible. All standards used by the manufacturing unit are traceable to international standards.
5. Which of the following option is not correct for ‘full interchangeability’?
a) This type of interchangeability is not feasible sometimes
b) Requires machine which can maintain low process capability
c) Machines with very high accuracy are necessary
d) For interchangeable production, this type of interchangeability is not must
Answer: b
Explanation: Full interchangeability is also known as universal interchangeability. Many times, universal interchangeability is not feasible because it requires machine capable of maintaining very high accuracy and high process capability.
6. What is the main use of automatic gauge in selective assembly?
a) Check accuracy of parts
b) Check parallelism of parts
c) Divide group of parts with some tolerance in smaller groups
d) Use to check errors in parts
Answer: c
Explanation: If parts to be assembled have normal tolerance of 0.01 mm then a gauge can be divided them into 10 different groups of 0.001 mm, this gauge is known as automatic gauge. It is for selective assembly of different parts.
7. What is the correct formula to find no. of groups in selective assembly?
a) Process capability / Tolerance desired
b) Tolerance desired / Process capability
c) Tolerance desired * Process capability
d) Tolerance desired + Process capability
Answer: a
Explanation: No. of groups segregated in selective assembly depends upon desired tolerance and process capability of machine. Conditions like high quality and low cost can be achieved by selective assembly technique.
8. What is a limit system?
a) Series of tolerances
b) Series of fits
c) Series of clearances
d) Series of limits
Answer: a
Explanation: Limit system is a series of tolerances arranged to suit a specific range of size. By this, limits of size are selected and given to mating parts to ensure specific classes of fit.
9. Which of the following is correct for selective assembly?
a) Not suitable for industrial purposes
b) Cost increases due to automatic gauging
c) Wastage is high due to selective selection
d) This method is followed in ball and roller bearing units
Answer: d
Explanation: Selective assembly technique is widely used in industries. It is followed in automobile, air craft industries and in ball and roller bearing units. Tolerances desired in these industries are very narrow.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Terminology”.
1. What does ‘50’ represents in 50H8/g7?
a) Basic size
b) Actual size
c) Maximum limit of size
d) Minimum limit of size
Answer: a
Explanation: 50 represent the basic size of the hole and shaft. H and g are the positions of tolerance zone with respect to zero line for hole and shaft respectively. 8 and 7 are the tolerance size.
2. What is ‘Go limit’?
a) Lower limit of shaft and upper limit of hole
b) Lower limit of shaft and hole
c) Upper limit of shaft and lower limit of a hole
d) Upper limit of shaft and hole
Answer: c
Explanation: ‘Go limit’ deals with upper limit of shaft and lower limit of hole and refers to the maximum material condition. ‘No-go’ limits deals with lower limit of shaft and upper limit of hole and refers to the minimum material condition.
3. Which of the following is incorrect regarding terminology?
a) Grades of tolerances decides manufacture’s accuracy
b) For any basic size there are 20 different shafts
c) Line of zero deviation is known as zero line
d) Tolerance has no sign
Answer: b
Explanation: For any basic size, there are 25 different shafts. These are designated by small letters from a to zc. Each shaft has 20 tolerance grades. Tolerance is the algebraic difference between lower and upper deviation.
4. What is the actual deviation?
a) Algebraic sum between actual size and corresponding basic size
b) Algebraic difference between actual and corresponding basic size
c) Average of actual and basic size
d) Algebraic difference between upper and lower deviation
Answer: b
Explanation: Algebraic difference between a size and a corresponding basic size is called deviation. Limit deviations are upper and lower deviations. Algebraic difference of actual size with basic size is called actual deviation.
5. What is the condition for a positive upper deviation?
a) Maximum limit of size > basic size
b) Maximum limit of size is < basic size
c) Minimum limit of size > basic size
d) Maximum limit of size < basic size
Answer: a
Explanation: Upper deviation is positive when maximum limit of size > its basic size and negative when maximum limits size < basic size. For lowers deviations, it is a positive quantity when minimum limit size is more than its corresponding basic size.
6. How many holes are there for any basic size?
a) 22
b) 24
c) 26
d) 28
Answer: d
Explanation: There are 28 different holes for any basic size. These are designated by capital letters. A, B, CD, C, D, E, EF, F, FG, G, H, JS, J, K, M, N, P, R, S, T, U, V, X, Y, Z, ZA, ZB, ZC these are the 28 holes.
7. What does ES represent in terminology as per IS: 919?
a) Lower deviation of hole
b) Upper deviation of shaft
c) Lower deviation of shaft
d) Upper deviation of hole
Answer: d
Explanation: ‘ES’ and ‘es’ represents upper deviation for hole and shaft respectively. ‘EI’ and ‘ei’ represents lower deviation for hole and shaft respectively.
8. What is ‘IT01’?
a) Basic size of hole
b) Basic size of shaft
c) Tolerance grade
d) Standard tolerance factor
Answer: c
Explanation: ‘IT’ refers to the standard tolerance which belongs to any standard grade of tolerance. Tolerance grades are designated by ‘IT’ letters followed by a number. For example, IT01 is a tolerance grade.
9. For tolerance grades 5 to 16, what is the formula for standard tolerance factor?
a) 0.45 1/3 + 0.001D
b) 10*D
c) 0.45 3 + 0.001 D
d) 20*D
Answer: a
Explanation: For tolerance grades 5 to 16 the value of tolerance magnitude is in terms of standard tolerance factor, i = 0.45 1/3 + 0.001 D. For grade IT6, tolerance is 10i. Above it, at each 5 th step the tolerance magnitude is multiplied by 10.
10. What is the hole size which is covered by IT05?
a) 500 mm
b) 600 mm
c) 700 mm
d) 800 mm
Answer: a
Explanation: There are 7 finest tolerance grades from 1T01 to IT05. It covers sizes up to 500 mm. There are 11 coarsest grades which cover sizes up to 3150 mm. Tolerance grades depend upon shaft or hole size.
This set of Engineering Metrology Questions and Answers for Freshers focuses on “Guide for Selection of Fits”.
1. Which of the following is not true for hole and shaft basis systems?
a) Hole basis system is generally preferred over shaft basis system
b) Shaft basis system can be used when products are made from bright drawn bars
c) Choice of the system depends upon nature of the product
d) In hole basis system, allowances are applied to the hole
Answer: d
Explanation: Hole basis system is preferred because it is easy to produce a shaft with specified tolerances than hole. In hole basis system, all tolerances are applied to shaft and hole size is taken as basic size.
2. Which of the following grade of a hole is mostly used for non-circular fits?
a) H5
b) H6
c) H7
d) H9
Answer: d
Explanation: H9, H5, H6, H7 these all are the grades of a hole. H9 can be obtained by reaming and boring. It is used for non-circular fits. H5 can be obtained by honing or internal grinding. H7 can be produced by broaching and grinding.
3. Which of the following option is incorrect for clearance fits?
a) Shaft ‘a’ gives a large clearance
b) Shaft ‘n’ is used for clearance fits
c) Shaft ‘d’ can be used for loose pulleys
d) Shaft ‘g’ is expensive to manufacture
Answer: b
Explanation: Shaft ‘n’ gives transition fit. It gives clearance to only extreme sizes. It is recommended for tight fits. Grades 5, 6 and 7 are available. Shafts a, b and c gives clearance fit. They all gives large clearance so they are not widely used.
4. What is the range of shafts which produce transition fits?
a) Shaft ‘a’ to ‘h’
b) Shaft ‘e’ to ‘n’
c) Shaft ‘d’ to ‘h’
d) Shaft ‘j’ to ‘n’
Answer: d
Explanation: ‘a’ to ‘h’ shafts produces clearance fits with H7 basic hole. ‘j’ to ‘n’ produce transition fit with H7 basic size. Transition fits may result in either interference or clearance fit. It will depend upon the actual size of tolerance of mating component.
5. Which grades are available in shaft ’j’ assembly?
a) 1 to 5
b) 2 to 6
c) 3 to 7
d) 5 to 11
Answer: d
Explanation: Shaft ‘j’ is a transition fit and available in grades 5 to 11. It is good for location fits which require less clearance than ‘h’ and also where a slight interference is permitted. It can be used in gear rings clamped to steel hubs.
6. Which of the following grade is never used for fits?
a) H10
b) H11
c) H8
d) H9
Answer: b
Explanation: H5, H6, H7, H8, H9, H10, H11 these are the hole grades. H10 is not used for diameter fits. It can be used for milled widths. H11 is never used for fits because this grade is very coarse. H11 is useful only for coarse punched holes or drilled holes.
7. Which of the option is correct about the preference of shaft and holes in machine tool industries?
a) ‘A11’ is of first preference in shafts
b) ‘B9’ is of first preference in holes
c) ‘c2’ is of first preference in shafts
d) ‘b11’ is of second preference in holes
Answer: c
Explanation: a11, c2, d9, d11, e8 etc. are the first preference for shafts and b9, b11, c8, c11, d8 etc. are the second preferences for shafts. First preference of holes are A11, D11, E11, F7, F8 etc. and B9, B11, C9, C11, D9 etc. are the second preferences for holes.
8. Which of the following option is correct for given statements regarding the selection of fits?
Statement 1: Shaft ‘h’ is an interference fit and used only for running parts.
Statement 2: Shaft ‘k’ is the true transition fit.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: Shaft ‘h’ gives clearance fit and available in grades 5 to 11. It is useful for spigot fits. Shaft ‘k’ is a transition fit and it is best suited for location fits. Grades available for this category are also 5 to 11.
9. Which shaft is used in valve shaftings?
a) Shaft ‘s’
b) Shaft ‘f’
c) Shaft ‘b’
d) Shaft ‘t’
Answer: a
Explanation: Shaft ‘s’ gives interference fit. It is used for semi-permanent or permanent assemblies of cast iron and steel members. It can be used for valve shafting’s and collar pressed on the shaft.
10. Which of the following gives interference fit?
a) Shaft ‘n’
b) Shaft ‘p’
c) Shaft ‘m’
d) Shaft ‘g’
Answer: b
Explanation: Shaft ‘p’ gives a true interference fit and available in grades 6 or 7. With hole of grade 8 it behaves as transition fit. It is a standard fit for cast iron and steel. It can be used for fixing of a bush on a gear. Shaft ‘g’ gives clearance fit. Shaft ‘m’ and ‘n’ gives transition fit.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Plain Gauges”.
1. Which of the following is not correct about plain gauges?
a) Used to check threaded portions
b) There is no scale in plain gauges
c) Indicates actual value of the inspected dimension
d) Can be used to check dimension of manufactured part
Answer: c
Explanation: These gauges do not have any scale. These gauges are used only for determining that the inspected part is within a specified limit or not. They do not use to indicate actual value. Plain gauges are mostly used to check unthreaded shafts and holes.
2. What of the following option correctly define a solid gauge?
a) Gauging portion and handle separately manufactured
b) Gauge integral with the handle
c) Gauges with suitable locking devices
d) Gauges that are not used for cylindrical holes
Answer: b
Explanation: When the whole gauge is made from one single piece of metal or gauging portion is integral with the handle, such type of gauges are called solid gauges. Gauging portion and handle of ‘renewable type of gauge’ is separately manufactured.
3. What is the hardness of gauging portion in plain plug gauges?
a) 450 HV
b) 550 HV
c) 650 HV
d) 750 HV
Answer: d
Explanation: Gauging surfaces of plain plug gauges are suitably stabilized, lapped and ground. These surfaces are normally hardened to not less than 750 HV. For sizes up to 63 mm, double ended type of plug gauges are used, and for above 63 mm single ended are used.
4. Which of the following is not true for fixed gauges?
a) Independent of availability of power supply
b) These are not expensive
c) Chances of human errors are more
d) Provide uniform reference standard
Answer: c
Explanation: Fixed gauges are generally error free due to drift of the original adjustment, effect of variation of power, non-linear response etc. Human errors are almost nil except for careful handling. Auxiliary equipment and setups are not required.
5. Up to which diameter, bar type plug gauges are used?
a) 20 mm
b) 40 mm
c) 75 mm
d) More than 75 mm
Answer: d
Explanation: Plain plug gauges which are heavy or diameter more than 75 mm, it is common to use bar type or segmental gauges in this case. Gauge efficiency decrease if sensitiveness of user is impaired by weight.
6. What is the suitable material for small plain plug gauges?
a) Any type of steel
b) Light metal alloys
c) Non-metallic handles may be used
d) Aluminum
Answer: c
Explanation: Suitable wear resisting steel is used to make gauging members of plain plug gauges. For heavy plain plug gauges, handle made of light metal alloys are used. For small plain plug gauges, suitable non-metallic handles may be used.
7. What is the colour of the band at ‘no go’ side of plain gauges?
a) Red
b) Blue
c) Green
d) Yellow
Answer: a
Explanation: To identify which end of the gauge is ‘No Go’ or ‘Go’ end, sometimes ‘No Go’ side is painted with red colour. Otherwise, the work ‘Go’ and ‘No Go’ are written on the handle of ‘Go’ and ‘No Go’ side respectively.
8. What is the range of size that can be checked by double-ended Rib type snap gauges?
a) 1 mm to 10 mm
b) 10 mm to 20 mm
c) 20 mm to 50 mm
d) 3 mm to 100 mm
Answer: d
Explanation: It is convenient to use double ended type rib snap gauges to check sizes of 3 mm to 100 mm. For size, 100 to 250 mm single ended progressive type snap gauges are used. Gauging surface are hardened up to 720 HV. Other surfaces are of smooth finish.
9. Which of the following option is correct regarding anvils of ‘adjustable type gap gauges’?
a) Gauging anvil has only sliding movement
b) Gauging anvil has only rotating movement
c) Gauging anvil has both sliding and rotating movement
d) Anvils are of non-adjustable type
Answer: a
Explanation: In adjustable type gap gauges, gauging anvils are adjustable endwise in the horse shoe frame. The gauging anvils of adjustable type snap gauges have only sliding movement that is no rotating movement for adjustment. A sufficient distance should be present between ‘Go’ and ‘No Go’ anvil.
10. What is the main use of contour gauges?
a) Check shape of irregular work
b) Check profiles
c) Check distance between surfaces
d) Check position of work
Answer: a
Explanation: Contour gauges are generally used to check dimensional accuracy and shape of irregular work e.g. radius gauges are used to check fillet shape. Simple contour gauges are used for thread pitches, form gear tooth profiles etc.
11. Which of the following option is correct for the given statements about plain plug gauges?
Statement 1: Cylindrical plugs are used for diameter above 100 mm.
Statement 2: For very large holes, spherically ended rods are used.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: Cylindrical plugs are not suitable for above 100 mm diameter, it is suitable to use spherical ended rods for such cases. Go gauges of 100 to 200 mm diameter can take the form of a cylindrical ended bar.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Gauge Design”.
1. Which principle is related to Gauge design?
a) Rankin principle
b) Position principle
c) Taylor’s principle
d) Carnot Principle
Answer: c
Explanation: According to Taylor’s principle, “‘No Go’ and ‘Go’ gauges are designed to check the minimum and maximum material limits”. In gauge design, simplicity is the main aim as simple gauge can take measurements accurately and continuously.
2. ‘Go limit’ applied to which limit condition?
a) Maximum material limit
b) Minimum material limit
c) Lower limit of shaft and upper limit of hole
d) Moderate material limit
Answer: a
Explanation: ‘Go’ limit is applied to the limit corresponds to maximum material limit condition that is lower limit of hole and upper limit of shaft while ‘No Go’ limit is applied to minimum material condition that is upper limit of a hole and lower limit of a shaft.
3. Which of the following is true for plug gauges?
a) Size difference between ‘Go’ and ‘No Go’ plug gauges is greater than the tolerance of tested shaft or hole
b) Size difference between ‘Go’ and ‘No Go’ plug gauges is Equal to the tolerance of tested shaft or hole
c) Size difference between ‘Go’ and ‘No Go’ plug gauges is less than the tolerance of tested shaft or hole
d) Size difference between ‘Go’ and ‘No Go’ plug gauges more or less than the tolerance of tested shaft or hole
Answer: b
Explanation: In case of standard gauges, size difference between ‘Go’ and ‘No Go’ plug and snap gauges is equal to tolerance. To maintain size and adequate functioning of snap gauges, robustness and rigidity are the main features.
4. Which of the following is incorrect for the gauging faces of snap gauges?
a) Parallel to each other
b) Square to each other
c) Gauging point and work are in same plane
d) Work and gauging faces are at 60 degree
Answer: d
Explanation: Gauging faces of a gap and snap gauges are square and parallel to each other. If gauging diameter of component is larger than gap setting then it will produce welding action may lead to distortion in gauge are incorrect interpretation of reading.
5. Which of the following can’t be done by ‘Go’ plug gauges?
a) Ensure bore alignability
b) Controls diameter
c) Check straightness of hole
d) Check degree of ovality
Answer: a
Explanation: ‘Go’ plug gauge is preferably full length of hole hence straightness can be checked. ‘Go’ gauges can’t check degree of ovality. ‘No Go’ plug gauges are short and its function depends on the diameter and circularity of hole.
6. What is the effect of wear on the size of ‘Go’ snap gauges?
a) Decrease
b) Increase
c) May increase or decrease
d) No effect
Answer: b
Explanation: Due to wear, size of ‘Go’ plug gauge decreased while size of ‘Go’ snap gauge is increased. Absolute accurate gauge can’t be made by gauge makers. So, it is important to assign some deviation to gauges.
7. What is the use of ‘No Go’ gauges?
a) Check a single element of a feature
b) Check several dimensions simultaneously
c) Check roundness and size at the same time
d) Check location and size at the same time
Answer: a
Explanation: ‘No Go’ gauge should check only one feature at a time. A separate ‘No Go’ gauge is needed for each different individual dimension. ‘Go gauges’ are complex gauges can check several related dimensions simultaneously.
8. Which deviations are provided to a new ‘Go’ plug gauge from the nominal size?
a) One positive deviation
b) One negative deviation
c) Two positive deviations
d) Two negative deviations
Answer: c
Explanation: A new ‘Go’ snap gauge is made with two negative deviations while a new ‘Go’ plug gauge is made with two positive deviations from the nominal size.
9. Which of the following option is correct for the given statements about Gauge design?
Statement 1: ‘No Go’ gauges should put in the condition of maximum impassability in the inspection.
Statement 2: ‘Go’ plug gauge corresponds to a minimum limit.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: c
Explanation: ‘Go’ plug gauge corresponds to the minimum limit of the hole, while the ‘No Go’ gauge is the size of maximum limit. But ‘Go’ snap gauge is of maximum limit of shaft and ‘No Go’ corresponds to a minimum limit.
10. If work tolerance is less than 0.09 mm then how much wear tolerance is applied to ‘Go’ gauge?
a) 10%
b) 20%
c) 30%
d) 40%
Answer: a
Explanation: There is no need of giving allowance for wear when work tolerance is less than 0.09 mm. But, if work tolerance is more than 0.09 mm then 10% tolerance is only given to the ‘Go’ gauge for wear.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Gauges for Tapers”.
1. What is important in testing a tapered job?
a) Check the diameter at smaller end
b) Change of diameter per unit mass
c) Change in length per unit weight
d) Change of diameter per unit length
Answer: d
Explanation: Taper plug and ring gauges are used to test tapers. A taper has two ends, one of bigger diameter and other of smaller diameter. To test a tapered job it is important to check the bigger diameter and also the change of diameter per unit length.
2. How correctness of taper can be checked?
a) Draw a single line of Persian blue along the length
b) Draw two lines of Persian blue at any distance along the diameter
c) Draw three lines of Persian blue at equidistant along the length
d) No need of Persian blue, it can be checked simply by seeing the rotation of spindle
Answer: c
Explanation: 3 lines are drawn with Persian blue along the length on the plug gauge or spindle to test the taper. It is fitted in the gauge and rotated once or twice. If these marks of Persian blue are not rubbed evenly then the taper is not correct.
3. What is the tolerance for a bigger diameter of taper in limit gauges?
a) ± IT4
b) ± IT5
c) ± IT6
d) ± IT7
Answer: c
Explanation: Bigger diameter is situated in the gauge plane. Tolerance on both bigger and smaller diameter will be ± IT6 on the basic size. It can be calculated from taper ratio.
4. What is the distance of bigger diameter from face if the value of diameter is 200mm?
a) 5 mm
b) 7 mm
c) 10 mm
d) 12 mm
Answer: d
Explanation: Distance of diameter at the bigger end from face depends upon the value of diameter itself. For example, if the value of diameter is 200 mm then this distance will be 2 mm or varies between 0.5 to 2 mm.
5. What is the value of hardness for plug and ring gauges used for self-holding tapers?
a) 750 to 860 HV
b) 120 to 540 HV
c) 550 to 740 HV
d) 900 to 1200 HV
Answer: a
Explanation: Good quality steel is used for making these gauges and these are suitably heat treated to give hardness of 750 to 860 HV and for stabilization. Gauges surfaces should be free from rust, crack and burrs.
6. Which of the following option is true for given statements regarding gauges for tapers?
Statement 1: Use of double ended gauges is very important in limit gauges for tapers.
Statement 2: Gauges should be packed in non-absorbent paper.
a) T, T
b) F, T
c) T, F
d) F, F
Answer: b
Explanation: Use of double ended gauges is unnecessary in this case because the diameter difference between low and high limit of the tolerances is converted into lengthwise dimension. Thus hole will be within the tolerance. Diameter at the large end of hole falls between gauge plane and other line at distance Z from it.
7. What is the tolerance for plug gauge on basic size?
a) + IT5
b) – IT7
c) + IT8
d) – IT9
Answer: a
Explanation: Distance between gauge plane and a free end in plug gauges is sometimes denoted as ‘a’. Distance ‘a’ varies between 2 mm to 12 mm. IT5 is the tolerance for plug gauges on the basic size.
8. Which of the following is incorrect about gauges?
a) Wear allowance is of main consideration in limit gauges for tapers
b) Cylindrical ring gauges can be used for gauging external diameters
c) Position gauges can be used to check the geometric relationship of features
d) Workshop and inspection gauges with same tolerance limits are more beneficial
Answer: a
Explanation: Wear allowance is not considered on the gauges. It is because of high cost is involved in manufacturing to that level of accuracy. If the tolerance limit of workshop and inspection gauges is same then the same gauges can be used for both the purposes.
This set of Engineering Metrology Interview Questions and Answers for freshers focuses on “Plug and Ring Gauges for Self holding Tapers”.
1. What is the not true for plug and ring gauges for self-holding tapers?
a) These tapers can be used for accurate alignment of tool
b) Can be used for the purpose of transmitting the torques
c) Use of these gauges helps in arriving at absolute deviation
d) Tapers can be external or internal
Answer: c
Explanation: Self holding tapers are mostly used in the tool shanks and machine spindle noses. Purpose of using these is an accurate alignment of tools and torque transmission. Both plug and ring gauges are used to check tapers because tapers can be both external and internal.
2. Which of the following option is correct for plug gauges, Plain?
a) Have only one ring marked on the gauge plane
b) Have only one ring indicates maximum depth
c) Have two rings
d) Have only one ring indicates minimum depth
Answer: c
Explanation: These gauges have two rings. One ring is marked on the gauge plane. Another ring is used to indicate minimum depth of the taper or internal taper. These rings are also present in tanged plug gauges.
3. What is the alternative name of self-holding tapers?
a) Small tapers
b) Fast tapers
c) Self-releasing taper
d) Large tapers
Answer: a
Explanation: Self-holding tapers are used not only to provide perfect alignment in the machine tools but also to provide a firm seat for driving the tools. Self-holding tapers are also known as slow and small tapers. They have very shallow angle.
4. In which of the following a limit step is present?
a) Plain plug gauge
b) Tanged plug gauge
c) Plain ring gauge
d) Tanged ring gauge
Answer: d
Explanation: A limit step is present in the tanged ring gauge at the small end of the taper. It is used to verify shank length from the gauge plane and also to verify the combined effect of thickness of tang and its offsets.
5. How much extra thickness is added to tang thickness in tanged plug gauge?
a) 0.1 mm
b) 0.05 mm
c) 0.01 mm
d) 0.5 mm
Answer: c
Explanation: 0.01 mm is added to the tank thickness to allow for the tang eccentricity of the plug gauge itself. Tanged plug gauges are used to verify internal tapers in machine sockets or tools and also to ensure that tang will be accepted by tang slot.
6. What is the angle of self-holding tapers?
a) 2 to 3 degrees
b) 7 to 8 degrees
c) 10 to 15 degrees
d) 15 to 17 degrees
Answer: a
Explanation: Self holding tapers have a shallow angle of about 2 to 3 degrees. Morse tapers, Brown and sharp tapers, jarno taper are the type of self-holding taper.
7. Which of the following option is correct for given statements about plug gauges for self-holding tapers?
Statement 1: Plug is inserted with high pressure for checking taper.
Statement 2: Morse taper is a type of self-holding taper.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: The plug gauge is inserted with light pressure as far as it goes, for checking internal tapers. At extreme point the large end face of internal taper shall lie within the marks of two rings given on the plug gauge.
8. Which of the following taper is used for ‘shanks of the twist drills’?
a) Morse taper
b) Brown taper
c) Sharpe taper
d) Jarno taper
Answer: a
Explanation: Morse taper is exclusively used on the shanks of the twists drills. For a different type of morse taper, taper is slightly different. In most of the cases, taper is 5/8 inch per foot.
9. Straight edge is generally used in which gauge for testing taper?
a) Plain plug gauge
b) Plain ring gauge
c) Tanged plug gauge
d) Tanged ring gauge
Answer: b
Explanation: In plain ring gauge, to check external taper of a plain or tapped shank, ring gauge is inserted with light pressure. At the extreme position, taper’s small end shank under test should lie short of the ring gauge face on the small end. It is verified by using a straight edge.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Uses of Comparators”.
1. Which of the following is true for uses of comparators?
a) Can’t be used in mass production
b) Not suitable for inspection purposes
c) Can be used as working gauge
d) Slow rate of working
Answer: c
Explanation: Comparators are used in mass production where components are checked at a fast rate. These can be used as inspection purposes, laboratory standards and working standards or gauges.
2. What is the principle of ‘The Johansson Mikrokator’?
a) Button spinning on a loop of string
b) Principle of interference
c) Optical magnification
d) Principle of transformer
Answer: a
Explanation: Johansson Mikrokator is a mechanical comparator used to obtain mechanical magnification. Principle of Johansson Mikrokator is ‘spinning of a button on a loop string’. Magnification of this comparator is of the order of 5000.
3. From which category ‘Sigma comparator’ belongs?
a) Optical comparator
b) Mechanical comparator
c) Mechanical-optical comparator
d) Pneumatic comparator
Answer: b
Explanation: Sigma comparator is a mechanical comparator. Components of sigma comparator are a plunger, knife edge, cross strip hinge, Y-shaped arm, driving drum, slit diaphragm, a scale and a pointer etc.
4. What is the advantage of mechanical comparator over others?
a) Less moving parts
b) No need of external supply
c) No error due to parallax
d) Large range of instrument
Answer: b
Explanation: Mechanical comparator is cheaper as compared to others. Mechanical comparators have more moving parts due to this friction is more and accuracy is less. External supply is not required. Moving pointer moves over a fixed scale hence error due to parallax is possible.
5. Which of the following is true for ’Cross strip’ in sigma comparator?
a) Has two moving members
b) Cross strip is hinged
c) Two members are at 45 o to each other
d) A flexible strip is attached to any one of the members of cross strip
Answer: b
Explanation: A hinged cross strip is present in sigma comparator which has a fixed and a moving member. These are connected to by thin flexible strips and right angle to each other. External force is applied on the moving member.
6. Which colour of light is filtered by filter present in Zeiss Ultra-optimeter?
a) Red
b) Blue
c) Green
d) Yellow
Answer: c
Explanation: Zeiss ultra-optimeter gives a high degree of magnification. This instrument has an optical system involves a double reflection of light. A green filter is present which filters all but the green light which is less fatiguing to the eye.
7. Which of the following is true for Eden-Rolt Millionth Comparator?
a) Utilise both mechanical and optical magnifications
b) Only mechanical magnification
c) Only optical magnification
d) Only electrical magnification
Answer: a
Explanation: Eden-Rolt Millionth is a comparator which utilizes both optical and mechanical magnification that means it can utilize advantages of both optical and mechanical comparators hence it is a highly sensitive comparator. Design of this comparator is economical and simple.
8. Which of the following option is correct regarding the characteristics of comparators?
a) Minimum inertia
b) Minimum compensation for temperature effect
c) High measuring pressure
d) Minimum versatility
Answer: a
Explanation: Design of the instrument must be such that it can be used for wide range of operations which means instrument must have highest versatility. Instrument should be free from wear effects and from backlash and inertia of the system should be minimum.
9. What is the use of bleed valve in flow type pneumatic comparator?
a) Zero adjustment
b) Measurement of size
c) Connect passage of air from plastic tube to gauging head
d) Used with pressure reducing unit
Answer: a
Explanation: Bleed valve in pneumatic comparator is used for zero adjustment. A screw is also present at the inlet of tapered glass tube by which magnification can be changed by passing some air supply from it.
10. What is the order of overall magnification in Eden-Rolt Millionth Comparator?
a) 50
b) 400
c) 20,000
d) 800
Answer: c
Explanation: Mechanical and optical magnification of this instrument is of the order of 400 and 50 respectively. Thus, the overall magnification of Eden-rolt millionth comparator is of the order of about 20,000.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Pneumatic Comparators”.
1. Which of the following is not correct for pneumatic comparator?
a) Independent of operator skill
b) Loss of accuracy due to gauge wear
c) Speedy operation
d) Total life cost is less
Answer: b
Explanation: In pneumatic comparator, there is no physical contact with setting gauge or part being measured. Due to this reason, there is no loss of accuracy due to gauge wear. It is an accurate, universal, reliable and speedy device.
2. What is the order of magnification in flow type pneumatic gauge?
a) 100 to 1000 times
b) 500 to 5000 times
c) 50 to 500 times
d) 100 to 2000 times
Answer: b
Explanation: Velocity type pneumatic gauge have quick response. It can permit a large clearance between object surface and nozzle which results in less wear in gauging members. Less air consumption. So, the magnification of the order to 500-5000 times is possible.
3. Which of the following is true for Pneumatic sensitivity in pneumatic comparators?
a) Directly proportional to operating pressure
b) Inversely proportion to operating pressure
c) Directly proportional to geometrical area of orifice
d) Independent of area of orifice and operating pressure
Answer: a
Explanation: Pneumatic sensitivity in the pneumatic comparator is directly dependent upon the operating pressure and inversely proportional to the geometrical area of the orifice. It can be represented as dp/dM.
4. What is the formula for overall magnification of pneumatic comparator?
a) 0.4*λ/L a
b) 0.7*λ/L a
c) 0.4*λ*L a
d) 0.7*λ*L a
Answer: a
Explanation: Overall magnification depends upon pneumatic sensitivity, sensitivity of pressure measuring device that is rate of change of reading w.r.t. varying pressure and upon rate of change of geometrical area of orifice w.r.t. ‘L’.
5. What is the relation between overall magnification and pneumatic sensitivity in pneumatic comparators?
a) Independent of each other
b) Overall magnification is directly dependent on the square of pneumatic sensitivity
c) Overall magnification is inversely proportional to the pneumatic sensitivity
d) Overall magnification is directly dependent on the pneumatic sensitivity
Answer: d
Explanation: Overall magnification is the rate of change of linear movement of the pointer to the change in the dimension which produces it and represented as dR/dL. It is directly proportional to the pneumatic sensitivity.
6. Which of the following option is correct for velocity type pneumatic gauge?
a) Operate by sensing momentary rate of flow of air
b) Response speed is less than back pressure type
c) Low amplification
d) Filter is placed after pressure reducing unit
Answer: a
Explanation: It is operated by sensing momentary air flow rate. This flow can be sensed by a tapered glass tube which is mounted on a graduated scale. Inside this bore a float is present which is lifted by the air flow.
7. Which of the following statement is true for pneumatic gauges?
Statement 1: Can be used to check multiple dimensions.
Statement 2: A float is present inside the bore.
a) T, T
b) F, T
c) F, F
d) T, F
Answer: a
Explanation: It is best suited to check multiple dimensions in the least possible time. While measuring a bore it can reveal complete story of size, straightness, taper, bell mouth etc. It is independent of operator skill.
8. In Back pressure type pneumatic gauge, there are two orifices. What is the relationship between upstream pressure of first orifice and pressure between two orifices?
a) Depends upon the distance between two orifice
b) Depends upon relative size of orifice
c) Only on geometric area of first orifice
d) Distance between pressure source and first orifice
Answer: b
Explanation: Upstream pressure and pressure between both orifices, they both are measured with reference to atmospheric pressure. The relationship between both the pressures depends upon relative sizes of the two orifices.
9. After which frequency range, pneumatic measuring system is not correctly measured displacements?
a) 5 cycles/second
b) 4 cycles/second
c) 3 cycles/second
d) 2 cycles/second
Answer: d
Explanation: Pneumatic measuring system can’t measure displacements correctly after 2 cycles/second because its response spend is slow. Its response is slower than electrical systems. Response time of back pressure type can be improved by using filled system pressure gauge.
10. For which diameter range of parts pneumatic gauges can be used?
a) 50 to 500 mm
b) 0.5 to 900 mm
c) 50 to 700 mm
d) 100 to 600 mm
Answer: b
Explanation: Pneumatic gauge can be used for parts of diameter 0.5 mm to 900 mm having tolerance 0.05 mm or less. It can be easily used for on line measurement of parts.
11. Which of the following is measuring head sensitivity with the variation of diameter of measuring orifice?
a) πD
b) πDL
c) πDL 2
d) πD 2 L
Answer: a
Explanation: Measuring head sensitivity is represented by ‘dM/dL’. ‘M’ is the diameter of measuring orifice which is equal to πDL. By differentiating ‘M’w.r.t ‘L’ we get πD. Hence ‘dM/dL’ = πD.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Multicheck Comparators”.
1. Which of the following option is incorrect for multicheck comparators?
a) Economical procedure
b) Inspection of all dimensions at the same time
c) Used where all dimensions are independent with each other
d) These are used to save time of inspection
Answer: c
Explanation: Multicheck comparators are desired in those places where various dimensions have some relationship with each other for example concentricity and diameter measurement. It is an economical procedure.
2. How many electrical check heads are incorporated in electric multicheck?
a) 1
b) 2
c) 5
d) 20
Answer: d
Explanation: Electrical multi check comparator is a combination gauge. 20 or more electrical-check heads are incorporated in electrical multi check comparator to measure a number of dimensions simultaneously.
3. Which of the following is not a requirement for automatic gauging?
a) High speed interface
b) High power and low heat
c) Compact size
d) Validate with safety requirements
Answer: b
Explanation: Automatic gauging machines are very accurate machines. They eliminate manual inspection of parts. All dimensions of part are inspected simultaneously and segregated and classified automatically.
4. Which of the following is incorrect for electric multicheck?
a) High production rate
b) Less chances of error
c) Eliminate manual inspection
d) Increase accuracy
Answer: c
Explanation: The instrument is used in high production checking. To check a dimension a master signal light is used to integrate all individual lights. Inspector has to watch only one light. Instrument is used for all sizes of works.
5. How many measuring heads are present in electric check for each dimension?
a) 1
b) 2
c) 3
d) 4
Answer: a
Explanation: For each dimension, signal lights and one measuring head are used for each dimension which indicates whether It is with in the tolerance limit, oversized or undersized.
6. Which of the following statement is true for multi check gauging?
Statement 1: In air multichecks, it is difficult to set air comparators.
Statement 2: Mass inspection is possible in air multichecks.
a) T, F
b) F, T
c) F, F
d) T, T
Answer: b
Explanation: In air multicheck comparators, group of air comparators are used. It is difficult to set these comparators initially to check various dimensions and to arrange them in compact form. But once this set up is done, other things become very easy.
7. Which of the following comparator is most accurate for mass inspection?
a) Electric multicheck comparator
b) Air multicheck comparator
c) Air electric multicheck comparator
d) Automatic gauging machines
Answer: d
Explanation: Automatic gauging machines are most accurate among them. These are similar to multicheck devices and incorporate comparator amplifying methods. Less skilled operator is required as all the inspection is done automatically.
8. If an air electric multicheck comparator is used to check dimensions of shafts then which of the following option is correct?
a) Air comparators are used for checking concentricity only
b) Air comparators are used for checking concentricity and diameter
c) Electric multicheck is used to check diameter only
d) Electric multicheck is more convenient to check concentricity and diameter
Answer: b
Explanation: Both the air multicheck comparator and electric multicheck comparator are used in this type of comparator. It is convenient and easy to use air comparator to check diameter and concentricity and for other measurements, electric-checks are used.
This set of Engineering Metrology Questions and Answers for Experienced people focuses on “Interferometry Applied to Flatness Testing”.
1. Which of the following is the incorrect condition for a perfectly flat surface when tested for interferometry?
a) Monochromatic light is used
b) Viewing angle should be greater than 0 o
c) Optical flats are important in light wave measurement
d) For perfect flat surface alternate light and dark bands are observed
Answer: c
Explanation: Angle at which bands are viewed is called viewing angle. Viewing angle should be 0 o that is line of sight should be at 90 degrees to the reference surface of optical flats. As this angle increases it will cause error.
2. If the angle at which bands are viewed is 30o in flatness testing with interferometry, what is the possible error?
a) 0%
b) 15%
c) 30%
d) 45%
Answer: b
Explanation: If the viewing angle is 30 degrees then three fringes may be seen as 2.5 that is it will cause error of 15 %. If the viewing angle is 45 degrees then three fringes may be seen as 1.75 that is it will cause nearly 40% error.
3. What is the range of the diameter of optical flats?
a) 10 to 50 mm
b) 50 to 100 mm
c) 100 to 200 mm
d) 25 to 300 mm
Answer: d
Explanation: Optical flats are the circular pieces of optical glass with a high degree of finish on the working surfaces. Its two plane faces are flat and parallel to each other. Optical flats varies from the size of 25 to 300 mm.
4. In flatness testing with interferometry, if surfaces are perfectly wrung. Then which option is correct regarding fringe pattern?
a) No fringe pattern
b) Fringes are closer
c) Fringes are at great distance
d) Indistinguishable pattern
Answer: a
Explanation: If the surface between optical flat and work surface are perfectly wrung together then there will be no air gap between the surfaces and fringe pattern will be not observable.
5. Which of the following is true for quartz flats?
a) Have 200 to 400 % more wearing quality than optical flats
b) Have 10 % more wearing quality than optical flats
c) Have 10 % less wearing quality than optical flats
d) Have 200 to 400 % less wearing quality than optical flats
Answer: a
Explanation: Quartz flats have more wearing qualities than optical flats. It is 200 to 400 percent more than optical flats. Working surfaces are finished to a high optical degree of flatness.
6. Which of the following option is incorrect for flatness testing by interferometry?
a) For checking concave or convex surface optical flat is pressed lightly
b) If angle between optical flat and work surface reduces, then fringe spacing decreases
c) For perfectly flat surface condition of complete interference satisfies
d) Only one point contact between optical flat and surface is possible in some cases
Answer: b
Explanation: If ‘θ’ that is the angle between optical flat and work surface whose flatness to be measured reduces then the fringe space increases and if ‘θ’ increases then fringes brought more closer that is fringe spacing decreases.
7. If the angle between optical flat and surface to be tested is very small, then what is the difference of separation between optical flat and surface between two similar adjacent fringes?
a) λ
b) λ/2
c) λ/3
d) 3λ/2
Answer: b
Explanation: Change in separation between surface and optical flat between 2 adjacent and similar fringes is equal to = λ/2.
8. What is the pattern of fringes, if an optical flat is resting on any hill?
a) Central band dark
b) Concentric dark and light band fringes
c) Straight dark fringes
d) Central band may be light or black
Answer: b
Explanation: If surface has a large number of valleys and hills. Generally, optical flat makes contact with hills. Then it will just behave as if it was placed on the convex surface. There will be concentric bright and dark fringes with central bright fringe.
9. Which of the following option is correct for the given statements about interferometry applied to flatness testing?
Statement 1: If the angle between optical flat and surface is too large then there will be largely spaced fringe pattern is observed.
Statement 2: Quartz flats are very sensitive to heat.
a) T, T
b) F, T
c) T, F
d) F, F
Answer: d
Explanation: If ‘θ’ angle between optical flat and surface whose flatness to be measured is too large then fringes will be too closely placed as to be indistinguishable. Quartz have minimum expansion due to heat.
10. Which of the following option is true for optical flats used in flatness testing?
a) Type A optical flats has only one surface flat
b) Optical flats are better than quartz flats
c) White light source is very important in measurement by light wave interference
d) Working surfaces of optical flats are cylindrical
Answer: a
Explanation: Type A optical flats have only one flat surface. Working surface in such type of optical flats is indicated by an arrow head on the cylindrical surface. This arrow head is pointing towards the working surface.
11. To distinguish hill and valley one surface of optical flat is lightly pressed. Which of the following option is for the valley?
a) Number of fringes increases
b) Fringes move apart
c) Fringes brought closer
d) Centre of fringes is displaced
Answer: b
Explanation: In case of hill or convex surface, centre of fringes is displaced and fringe space decreases. But if by light pressure number of fringes decreased and fringes move apart it is a valley or concave surface.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Surface Contour Test”.
1. Which is the wavelength of a spectrum which is used in surface contour test?
a) 0.0005 mm
b) 0.005 mm
c) 0.05 mm
d) 0.5 mm
Answer: a
Explanation: Surface contour test is used to study surface contours and an optical flat is kept at some inclination over the surface. Generally, daylight is used for this test. Wavelength of the spectrum of daylight is 0.0005 mm.
2. How much change is the elevation of surface corresponds to the single fringe interval in surface contour test?
a) 0.0005 mm
b) 0.0025 mm
c) 0.025 mm
d) 0.05 mm
Answer: b
Explanation: In surface contour test, the change in elevation of surface corresponds to each fringe interval shows clearly the precision of this method. Value of this change in elevation is 0.0025 millimeter.
3. If any surface has a scratch on it and surface is tested by surface contour test then, what is the depth of scratch?
a) *
b) *
c) *
d) *
Answer: b
Explanation: Surface contour method is used for many purposes. It is possible to determine depth of the scratch, high and low spots or hills and valleys, and surface worn at the edges. These all can be determined by this method.
4. What is the method to find low and high spots?
a) Pressure by weight test
b) Volume test
c) Pressure test
d) Density test
Answer: c
Explanation: Two low or high spots can be checked by pressure test. If pressure is applied at a point and fringes move closure than the surface is valley. By applying pressure if fringes move apart then the surface is hill.
5. Which of the following option is true for given statements about surface contour test?
Statement 1: In a monochromatic light, bands are lighter near the point of contact.
Statement 2: To study surface contour it is important to know the point of contact with optical flat.
a) T, T
b) F, F
c) F, T
d) T, F
Answer: c
Explanation: For study, it is important to know where surface and optical flat are in contact. Point of contact is usually where a pressure is applied and air film is squeezed at this place.
Bands are sharper near the point of contact in monochromatic light.
6. Curvature of bands is more. What does this statement indicate when surface is tested under surface contour test?
a) More convexity
b) More concavity
c) Flat surface
d) More scratches
Answer: a
Explanation: The magnitude of concavity and convexity can be had by bands curvature. If the band curvature is more it shows more convexity and opposite to this indicates concavity. So we can have an idea of concavity or convexity by this.
7. Which of the following is not true for optical flats used in surface contour test?
a) Colourless
b) Always wrung on the work piece
c) Work piece and optical flat should be free from dust, dust and fingerprints
d) Optical flat should always be lifted from work piece
Answer: b
Explanation: Optical flats should never be wrung on surface to be measured because it scratches too readily. Optical flats should be rested on work piece carefully. It should be clean and free from dust.
8. What is the nature of the surface if curve bands around the line of contact when the surface is tested under surface contour test?
a) Convex surface
b) Concave surface
c) Flat surface
d) May be convex or concave
Answer: a
Explanation: If band curves around the line of contact or point then the given surface is convex but if the band curves opposite to the line of contact or point then the surface is a concave surface.
9. Given figure is a surface to be tested by surface contour test. How much lower or higher is B than Z in this given figure?
engineering-metrology-questions-answers-surface-contour-test-q9
a) λ/4
b) λ/2
c) 3λ/2
d) 3λ/4
Answer: b
Explanation: In the given figure, BYB is the contour. Y and Z are at the centre of two contours. The edge B is either higher or lower than Z by λ/2. The air gap will increase if we move away from X-X. BYB represents points at equal height, it means that B is higher than Z.
10. How much height intervals relative to optical flat is represented by a spacing of fringes?
a) λ/3
b) λ
c) λ/2
d) λ/6
Answer: c
Explanation: Contour of every fringe lies on points of equal height relative to the surface of optical flat. So, the fringe pattern viewed through optical flat will represent the contour map of the surface under test and spacing of fringes will represent height intervals relative to the optical flat of λ/2.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Optical Flats”.
1. How many types of optical flats are present?
a) 2
b) 1
c) 4
d) 3
Answer: a
Explanation: Optical flats are cylindrical in shape and generally have 2 types i.e Type A and Type B. Type A has only one surface flat. Working surface of Type-A is indicated by an arrow. Type B has both surface flat and parallel to each other.
2. Which of the following is used to make optical flats?
a) Toughened glass
b) Glass wool
c) Fused quartz
d) Porous glass
Answer: c
Explanation: Optical flats are generally made from fused quartz or borosilicate glass as they have the least coefficient of linear expansion. This glass is colourless and free from defects like bubbles, internal strains and extraneous matter.
3. What is the coefficient of linear expansion of fused quartz used to make optical flats?
a) 0.6 x 10 -6 / degree
b) 0.6 x 10 -5 / degree
c) 0.6 x 10 -4 / degree
d) 0.6 x 10 -3 / degree
Answer: a
Explanation: Fused quartz has 0.6 x 10⁻⁶/degree at standard temperature of 20 ° C. This low coefficient of linear expansion accounts for its remarkable ability to undergo large, rapid temperature changes without cracking. Borosilicate glass has coefficient of linear expansion not more than 3.6 x 10 -6 /degree.
4. To what degree the edges of optical flats are bevelled?
a) 30 o
b) 45 o
c) 60 o
d) 90 o
Answer: b
Explanation: Edges of optical flats are generally bevelled to 45 o by suitable grinding and polishing to make edges free from any chips. Working surfaces of optical flats are finished by polishing and lapping process and the cylindrical surfaces are finished by grinding.
5. Working surfaces of Type-B optical flats are inclined to each other at which angle?
a) 5 minute
b) 10 minute
c) 15 minute
d) 20 minute
Answer: a
Explanation: The inclination for measuring surfaces of each type of Type-B optical flat is 5 minutes. Optical flats are usually stored in the wooden box to avoid shocks, dust and moisture during storage and transportation.
6. What is the tolerance on flatness for Type-A optical flats of sizes up to 100 mm?
a) 0.05 cm
b) 0.05 µm
c) 0.05 mm
d) 0.05 m
Answer: b
Explanation: Tolerance on flatness for Type-A opticals flats is 0.05 µm for grade optical flats of size upto 100 mm only. But for the size between 101 mm to 200 mm the tolerance should be 0.10 µm. For grade II, it is 0.01 µm for size upto 100 mm and 0.20 for 101-200 mm.
7. Which of the following is not the dimension of optical flat Type A as per IS : 5440—1969 in mm ?
a) 25 x 10
b) 50 x 30
c) 30 x 10
d) 125 x 30
Answer: c
Explanation: As per IS : 5440-1969 , Optical flats of Type-A have dimensions 25 x 10, 30 x 10, 50 x 15, 75 x 20, 100 x 25, 125 x 30, 160 x 35 for both grade I and II.
8. What is the tolerance on thickness for Type-B opticals flats?
a) 0.05 µm
b) 0.15 µm
c) 0.20 µm
d) 0.30 µm
Answer: c
Explanation: Tolerance on flatness, parallelism and thickness for type-B optical flats is 0.05 µm, 0.15 µm and 0.20 µm respectively for grade I and 0.10 µm, 0.20 µm and 0.30 µm for grade II respectively.
9. Which of the following statement is true for optical flats?
Statement 1: Type-A optical flats are tested for parallelism of working surfaces.
Statement 2: Flatness of working surface is tested by comparing with a master flat.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: Type-A optical flats are used are used to test flatness of working faces and Type-B flats are used to test parallelism of working faces, flatness of working faces and also thickness.
10. Which of the following is the method to test parallelism in Type-B optical flats?
a) Hawking interferometer
b) Enrico interferometer
c) Fizeau interferometer
d) Stephan interferometer
Answer: c
Explanation: Fizeau interferometer is used to test parallelism in optical flats. In this test a light from mercury vapour lamp is focused on eye-piece. Beam splitter is used to reflect the beam which strikes the collimating lens. It collimates the beam and throw it on the surface under test.
11. Type-B optical flat is tested for parallelism. What is the formula for the difference of the thickness of the flat at 2 points on the adjacent fringe? µ
a) λ/2*µ microns
b) λ/4*µ microns
c) λ*µ microns
d) λ*µ microns
Answer: a
Explanation: λ/2*µ microns, this is the formula for the difference of the thickness of the flat at two points on the adjacent fringes. This is obtained by Fizeau interferometer test. This gives the optical parallelism. This parallelism is also represented as geometrical parallelism as flat is made of material of uniform refractive index.
12. Which of the following is the dimension for Type-B optical flats?
a) 25.0 x 12.000 mm
b) 25.0 x 23.000 mm
c) 26.0 x 24.000 mm
d) 26.0 x 24.250 mm
Answer: a
Explanation: Type-B optical flats have dimensions 25.0 x 12.000, 25.0 x 12.125, 25.0 x 24.250, 25.0 x 12.375, 25.0 x 24.000,25.0 x 24.125, 25.0 x 24.250 and 25.0 x 24.375 respectively.
13. Which of the following is the use of Type-A optical flats?
a) Testing parallelism of measuring devices
b) Testing parallelism of measuring anvils
c) Testing micrometer measuring surfaces
d) Testing the flatness of measuring table
Answer: d
Explanation: Type-A optical flats are used to test the flatness of slip gauges, measuring tables, precision measuring surfaces of flats. Type-B are used to test flatness and parallelism of measuring surfaces of anvils. Micrometer etc.
14. Which of the following is of more important in case of Type-B optical flat?
a) Thickness
b) Diameter
c) Length
d) Area
Answer: a
Explanation: For optical flats of Type-A, grades and optical flats are important that means it is usually designated by these two and for Type-B, thickness and grades are important, therefore it is designated by these two.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Scales and Gratings”.
1. What is the range of line spacings in gratings?
a) 4 to 200 per mm
b) 200 to 400 per mm
c) 10 to 500 per mm
d) 500 to 600 per mm
Answer: a
Explanation: Gratings plays an important role in rotary as well as linear measurements. Gratings have line spacing from 4 per mm to 200 per mm in lengths up 4 meters or so. These are usually employed with photoelectric readouts.
2. What is the alternate name of amplitude grating?
a) Ronchi ruling
b) Prismatic grating
c) Phase grating
d) Index grating
Answer: a
Explanation: Grating which has plane lines is called amplitude grating or Ronchi grating. It is a constant interval bar with equal line and space pattern. These are generally used for optical testing purposes and metrology applications.
3. Which of the following option is true for scales and gratings?
a) Ruling in scales are closely spaced
b) Ruling in gratings is far apart
c) Vernier device is required with scales
d) Ruling in scale forms a periodic pattern
Answer: c
Explanation: Scales have lines marked on them that is rulings. Scales are usually made of steel. Lines in scales are spaced far apart so that interpolating devices e.g. vernier device are used to make accurate settings.
4. What is the length of Prismatic grating?
a) 500 mm
b) 400 mm
c) 300 mm
d) 200 mm
Answer: d
Explanation: Prismatic grating is also known as phase grating. Prismatic grating contains triangularly shaped and contiguous grooves. Prismatic grating has 100 to 200 grooves and its length is limited to 200 mm.
5. Which of the following option is true for the given statements?
Statement 1: Stainless steel has a high thermal coefficient of expansion than cast iron hence used to make scales.
Statement 2: Most of the scales are produced by duplicating from master scale.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: stainless steel is used for making metal scales. It is stable with time if properly heated, have good finish, resistant to tarnishing but its coefficient of thermal expansion is less than the cast iron and steel.
6. Which type of visual scale line setting against an index is widely used in sophisticated machines?
a) Simple superposition type
b) Alignment of vernier setting
c) Symmetrical forming between two index marks
d) Asymmetrical forming between index marks
Answer: c
Explanation: Index mark is utilized by all scale readouts, with reference to which reading of scale is noted. Symmetrical forming between two index marks is the type which is mostly used in sophisticated machines due to high setting precision.
7. For how much travel length, metal reflecting gratings are used?
a) 600 mm
b) 900 mm
c) 1700 mm
d) Greater than 1800 mm
Answer: d
Explanation: Three types of gratings are commonly used in more fringe system gratings. Phase transmission grating, Metal reflecting grating and line and space transmission grating. Metal reflecting grating is used for travel length more than 1800 mm.
8. What is the condition to obtain fringes of high intensity?
a) Distance between scale and index grating is as far as possible
b) Distance between scale and index grating is minimum
c) Scale and index grating should be overlapped
d) Scale and index grating should be at the right angle
Answer: b
Explanation: Fringes of high intensity means good contrast. It is the essential condition for obtaining good electrical signals. It can be obtained only when the distance between the scale and index grating is minimum.
9. Which of the following is not true for glass scales?
a) Graduations can be produced by depositing material
b) Easily polished
c) Able to work in case of reflected light but not in transmitting light
d) Ordinary glass has 15-30% less thermal coefficient of expansion than steel
Answer: c
Explanation: Glass scales are stable, and are able to work in both transmitting and reflected light. Graduation on these scales can be produced by etching through ruled wax, by depositing material in the form of thin lines and by depositing photographic emulsions.
10. For bi-directional fringe counting, how many detectors are placed for better balance?
a) 3
b) 4
c) 5
d) 6
Answer: b
Explanation: For bi-directional fringe counting, better balance is obtained when four detectors are placed at 0, 90, 180, 270 phase degree of fringe in which counting intervals of one-quarter of the scale interval are provided.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Straightness”.
1. Who gave the fundamental principle of straightness measurement?
a) Bryan
b) Moire
c) Euler
d) Amedeo
Answer: a
Explanation: Fundamental principle of measurement of straightness is given by Bryan. According to this principle, “A straightness measurement system should be in line with the point at which it is to be measured”.
2. Which of the following represents the quality of straightness in precision engineering?
a) Spirit level
b) Straight edge
c) Autocollimator
d) Dial indicator
Answer: b
Explanation: At many places, it is necessary that the surface must be straight e.g. in lathe machine it is required that the tool must move in straight path. Straight line is the basis of most methods of measurements.
3. What is the tolerance of the straightness of a line?
a) Maximum deviation from the straight line joining two extremities
b) Maximum deviation from the middle point of straight line joining two extremities
c) Minimum deviation from the straight line joining two extremities
d) Minimum deviation from the middle point of straight line joining two extremities
Answer: a
Explanation: The tolerance on the straightness of a line can be defined as the maximum deviation in
relation to the reference straight line joining the two extremities of the line to be checked. Tolerance is used to confirm that a part is uniform over a surface. More straightness is present with less tolerance.
4. For checking straightness, straight edge is placed over a surface and these two are viewed against the light. Which of the following option true if colour of light is red?
a) Gap between 0.12 to 0.17 mm
b) Gap between 0.2 to 0.7 mm
c) Gap between 1.7 to 2 mm
d) Gap between 0.0012 to 0.0017 mm
Answer: d
Explanation: Straight edge and surface are viewed against the light. The gap between surface and straight edge should be negligible small for perfect straight surfaces and the measurement of straightness is observed by seeing the colour of light produced due to interference caused by diffraction of light.
5. What is the name of a pair of straight edges?
a) Drum sticks
b) Lower pair
c) Winding sticks
d) Self closed pair
Answer: c
Explanation: Straight edge is a measuring tool consist of a steel and is used to check the straightness. Straight edges are used in machining industry and automotive service. Winding stick is a pair of straight edges which are used in woodwork.
6. What is the position of straightness interferometer in straightness measurement optics?
a) Before laser head
b) After straightness reflector
c) Between laser head and straightness reflector
d) No need of interferometer
Answer: c
Explanation: Straightness interferometer is placed between laser head and reflector. Beam from the laser passes through the interferometer which splits it into two beams which diverge at an angle and are directed to the reflector. The beams are then reflected from the reflector and return to the interferometer along a new path.
7. What is the range of straightness measurement in straightness measurement optics?
a) ±2.5 mm
b) ±5 mm
c) ±10 mm
d) ±20 mm
Answer: a
Explanation: To measure straightness errors in a linear axis, straightness measurement optics are used. For both short range and long range measurement, length of straightness measurement is ±2.5 mm.
8. Which of the following is not the factor affecting the accuracy of straightness measurement by optics?
a) Air turbulence
b) Optics fixed rigidly
c) Slope error
d) Localised heat sources
Answer: b
Explanation: Factors affecting the accuracy of straightness measurement by optics are Air turbulence, Mechanical vibrations, Optic errors, Slope errors, Optics not fixed in the correct position, Optics not fixed rigidly, Localised heat sources etc.
9. At which part of the precision straight edge is generally lapped?
a) Edges only
b) Base only
c) Base and edges both
d) All over the surface
Answer: a
Explanation: Straight edges are extremely useful for setting up machines such as planers. Precision straight edges are hardened and lapped on the edges by a small radius, which makes a blunt knife edge straight to a few thousands of an mm.
This set of Engineering Metrology Interview Questions and Answers for Experienced people focuses on “Test for Straightness by using Spirit Level and Autocollimator”.
1. How the straightness of any surface can be determined with the help of spirit level?
a) By finding relative angular positions at extreme sections of the surface
b) By finding relative linear distance at middle of the surface
c) By finding relative angular positions at adjacent section
d) By finding relative angular positions at any point
Answer: c
Explanation: In case of the spirit level, the angular variations are measured by the sensitive level on it which gives the difference of height between two points by knowing the spirit level’s least count.
2. At what distance instrument is placed when straightness is determined with the help of autocollimator?
a) 0.5 to 0.75 mm
b) 0.5 to 0.75 cm
c) 0.5 to 0.75 m
d) 0.5 to 0.75 µm
Answer: c
Explanation: In determining the straightness with the help of autocollimator instrument is placed at a distance of 0.5-0.75 m on any rigid support and it is completely independent of the surface to be tested.
3. For testing straightness with the help of spirit level, what is the length of each surface section?
a) Equal to spirit level base length
b) Greater than spirit level base length
c) Less than spirit level base length
d) Doesn’t depend upon spirit base length
Answer: a
Explanation: For determining straightness, a straight line is drawn on the surface. It is divided into sections, the length of individual section is equal to the length of the base of spirit level or the base of a reflector in case of autocollimator.
4. For which surfaces, spirit level is used for testing straightness?
a) Both horizontal and vertical surfaces
b) Vertical surfaces
c) In any plane
d) Horizontal surfaces
Answer: d
Explanation: In testing straightness, spirit level is used only for the horizontal surfaces while autocollimator can be used in any plane. In the case of spirit level, angular variations are measured by placing level on it.
5. Which of the following option is true for autocollimators?
Statement 1: Electronic autocollimator has more resolution than visual autocollimator.
Statement 2: Observations are taken using precision level.
a) F, F
b) F, T
c) T, T
d) T, F
Answer: c
Explanation: Electronic autocollimator has 100 times more resolution than visual autocollimator. Visual autocollimator can measure small angles like 0.5 arc minute. Electronic autocollimator can be used for stable platform applications.
6. 1 sec of arc will correspond to how much rise or fall in surface, when surface straightness is tested by autocollimator?
a) 0.000006λ
b) 0.00006λ
c) 0.00006λ
d) 0.0006λ
Answer: a
Explanation: In this method, reading of tilt of the reflector is taken in seconds from the eyepiece. 1 second of arc is 0.000006 mm/mm. It also depends upon the distance between feel centres in millimeter.
7. Which of the following is not true for autocollimator?
a) Contact measurement
b) Use for small tilts
c) High sensitivity
d) Used to determine parallelism
Answer: a
Explanation: Autocollimator is used in many applications like in shop floors and metrology labs. Used for precision measurement of parallelism, straightness, flatness, perpendicularity etc. It is a not-contact optical instrument.
8. Which of the following method is used for the mathematical treatment of determination of straightness with the help of autocollimator?
a) Taylor’s principle
b) Least square method
c) Bryan method
d) Average method
Answer: b
Explanation: According to the least square method, ‘sum of the deviations of the points from the best line is zero and the sum of square of deviations from the best line is minimum’. First the best line is determined and then applies to this method.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Flatness Testing”.
1. For checking the flatness, which of the following is used to mark the surface?
a) Scriber
b) Prussian blue
c) Alcohol
d) Ruler
Answer: b
Explanation: Prussian Blue is used to mark the surface. When rubbed against another flat surface, the distribution of color on the other surface gives a rough idea of flatness of the surface.
2. Determination of flatness using Prussian blue is used for which kind of surfaces?
a) Small surfaces
b) Large surfaces
c) Both large and small surfaces
d) For surfaces with fine smoothness
Answer: a
Explanation: This method is suitable for small surfaces rather than large surface. This method is assumptious and may give more errors in determination of flatness in large surfaces.
3. As per IS: 2063-1962, which surface is considered as a flat surface?
a) When variation of perpendicular distance from geometrical reference plane remains above a given point
b) When variation of diagonal distance from geometrical reference plane remains below a given point
c) When variation of perpendicular distance from geometrical reference plane remains below a given point
d) When variation of sides distance from geometrical reference plane remains above a given point
Answer: c
Explanation: As per IS: 2063-1962, a surface is considered flat when the variation of perpendicular distance from geometrical reference plane parallel to the general trajectory same as the surface to be tested remains below a given point. The reference plane can be represented by means of surface plane or family of straight lines.
4. When the flatness is measured with the use of optical flats, at what distance bands should be viewed?
a) Distance 10 times the diameter of optical flats
b) Distance 5 times the diameter of optical flats
c) Distance 8 times the diameter of optical flats
d) Distance 2 times the diameter of optical flats
Answer: a
Explanation: The bands are viewed from a distance at least 10 times the optical flat diameter and with the line of vision are perpendicular to the flat. If the bands observed are parallel, straight and evenly spaced, the surface is flat otherwise not.
5. Which of the following method is used for the determination of flatness when the surface is irregular?
a) Half grid method
b) Grid method
c) Contact method
d) Non contact method
Answer: c
Explanation: When the surface is irregular, contact method of testing for flatness is used. In the contact method there is a most intimate possible contact between flat and work piece and there will be attempt to maintain a wedge.
6. Which of the following option is true for given statements for flatness testing?
Statement 1: Straight edges can be used to check flatness.
Statement 2: Single ended straight edge can be used to determine flatness of the surface.
a) T, T
b) F, F
c) T, F
d) F, T
Answer: a
Explanation: Straight edges can be used to test flatness and straightness of the surfaces. Single-edged straight edge can be used to determine flatness by applying it at different places in different directions on the tested surface.
7. Which of the following option is not true for flatness testing?
a) Geometrical plane can be represented by a family of straight lines
b) Flatness can be tested by grid and half grid method
c) Three and four edge type straight edge cannot be used for this purpose
d) Geometrical plane can be represented by a surface plane
Answer: c
Explanation: Three and four edges straight edges can be used to test flatness by applying prussian blue on the working edges and then drawing the straight edge across the surface.
8. What are the requirements for the measurement of flatness using light?
a) Monochromatic light and a pair of optical flats
b) Dichromatic light and sets of optical flats
c) White light and a pair of optical flats
d) Monochromatic light and sets of optical flats
Answer: d
Explanation: Monochromatic light and sets of optical flats are required for measurement of flatness using light. Monochromatic light is used to get none overlapping, clear interference pattern.
9. What is flatness error?
a) Maximum separation of a pair of parallel planes which will contain all points on the surface
b) Minimum separation of a pair of parallel planes which will contain all points on the surface
c) Minimum separation of a pair of perpendicular planes which will contain all points on the surface
d) Maximum separation of a pair of perpendicular planes which will contain all points on the surface
Answer: b
Explanation: Flatness error can be defined as the minimum separation of a pair of parallel planes which will contain all points on the surface. Deviations of large surfaces from true plane are determined by using autocollimator and spirit level.
10. Which of the following is true for testing flatness with optical flats?
a) Too large angle of work with flat is desirable
b) Number of bands appears is an indication of flatness
c) Bands are viewed as perpendicularly as possible
d) Quartz flats are very sensitive to temperature changes
Answer: c
Explanation: Due to very great angle between work and flats, bands will be close together and are nearly invisible. Number of bands appear is not an indication of the surface flatness but relates only to the wedge steepness.
11. What is the range of the diameter of optical flats used in testing the flatness?
a) 25mm to 300mm
b) 1mm to 100mm
c) 50mm to 500mm
d) 1mm to 10mm
Answer: a
Explanation: Size of optical flats used varies from 25mm to 300mm diameter. The range is selected to get a proper interference pattern using light.
This set of Advanced Engineering Metrology Questions and Answers focuses on “Parallelism, Equidistance and Coincidence”.
1. Which of the following is true for testing parallelism between two trajectories?
a) Dial indicator is attached on a fixed machine component
b) Moving parts are moving in different directions in testing the parallelism
c) The two parts are moved by the same amount
d) Parts are moving together
Answer: c
Explanation: The dial indicator is attached to one of the moving machine components and its feeler rests against a specified point on the other moving part. The two parts are moved together by the same amount in the same direction and the variations in the reading are noted.
2. Which of the following is true for coincidence between two axes?
a) Light weight dial indicator is used
b) Direction of measurement doesn’t varies
c) There is no effect of gravity force
d) Mandrel is used to represent the plane
Answer: a
Explanation: Light weight dial indicator is used in this test. The direction of the measurement varies during rotation in relation to the gravity direction. The sensitivity of the apparatus to the gravity force is taken into account.
3. Which of the following is true to check parallelism between two straight lines formed by the intersection of two planes?
a) V-blocks are used for large distance between two lines
b) No need of V-blocks
c) If there is a small distance between straight lines then use of V-blocks is the most necessary
d) It can be checked only by a straight edge
Answer: a
Explanation: If the distance between two lines is not small or large then the V-blocks are used. V- blocks are covered by a straight edge is used. Check for this is made by spirit level. For small distance there is no need of these.
4. What is the tolerance of parallelism of straight lines?
a) 0.015 on 300 mm
b) 0.15 on 300 mm
c) 0.015 on 600 mm
d) 0.15 on 600 mm
Answer: a
Explanation: Permissible deviations or tolerance of parallelism of two plane surfaces or straight lines is 0.015 mm on 300 mm. Free end of the spindle relative to the table surface is in upward direction only.
5. Which of the following is not true for coincidence?
a) Two axes merged in each other
b) Coincidence and perpendicularity are same
c) One axis extends beyond the other
d) Sometimes coincidence is used with is used with more general meaning of parallelism
Answer: b
Explanation: Two lines or axes are said in alignment or coincident when their distance apart at several points is measured over a specified length and this distance doesn’t exceed a specified value. The measured distance may be located either on the actual lines or on their prolongation.
6. Which of the following is true for measurement of equidistance?
a) Related to distance between two axes
b) Related to distance between two planes
c) Related to distance between reference plane and the axes
d) There is no relation with axes and planes
Answer: c
Explanation: When plane passing through the axes is parallel to the reference plane then there is an equidistance. It is related to the distance between reference plane and the axes. It may be different axes, or the same axis.
7. Test for parallelism of 2 planes is carried out in two different directions. What is correct for these directions?
a) Parallel to each other
b) Perpendicular to each other
c) At 45 degree to each other
d) At 60 degree to each other
Answer: b
Explanation: Two planes are parallel when the difference between the maximum and minimum dimension obtained that is maximum error over a given length does not exceed a specified value. The test is carried out in two directions which are perpendicular to each other.
8. Which of the following is not true for mandrel?
a) It represent the axis of rotation of spindle
b) Mandrel is always centred
c) Axis of rotation of mandrel may be hyperboloid
d) Axis of rotation of mandrel may be conical
Answer: b
Explanation: When a mandrel has represented the axis of rotation of spindle etc. It is not necessary that mandrel have been exactly centred and under such conditions the axis of the rotation of mandrel may describe a conical or hyperboloid.
9. Which of the following option is correct for given statements about parallelism?
Statement 1: A dial indicator is used to test parallelism of two planes.
Statement 2: Parallelism defines the distance between two surfaces that are parallel to each other and the datum surface.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: d
Explanation: To test the parallelism, dial indicator can be used. The dial indicator is held on a support with base or flat base and is moved in one plane over a specified length, and the feeler is made to rest against the 2nd plane and the deviations are noted down.
10. How many minimum sides to be measured of a cylinder to test parallelism?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: Parallelism can be defined as the tolerance which controls the parallelism between two features. It is possible to find the parallelism of the cylinder by measuring the two sides of a cylinder.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Vernier and Optical Bevel Protractor”.
1. What is the range of bevel protractor?
a) 0-90°
b) 0-180°
c) 0-360°
d) 90-270°
Answer: c
Explanation: Bevel protractor is the simplest instrument for measuring angles. It measures an angle between two faces of a component. It is used to test angle for very close tolerances. The range of bevel protractor is 0-360°.
2. Where will be the vernier scale is present?
a) Base plate
b) Circular plate
c) Adjustable plate
d) Main body
Answer: b
Explanation: It has a base plate which is attached to the main body. Circular plate contains vernier scale. It contains 24 divisions coinciding with 23 main scale divisions. One full rotation of adjustable blade increase one division in main scale.
3. What is the least count of vernier bevel protractor?
a) 10’
b) 5’’
c) 5’
d) 10’’
Answer: c
Explanation: The least count of bevel protractor is 5’. It is commonly used for angular measurements where more precision is required like for angular measurement in workshops. Optical bevel protractors are the recent development of vernier bevel protractors.
4. Which of the following is correct about the adjustable blade?
a) Adjustable blade is attached to main body
b) Adjustable blade is capable of rotating freely about the centre
c) Adjustable blade is capable of rotating freely about the free edge
d) Adjustable blade is attached to base plate
Answer: b
Explanation: Adjustable blade is attached to the circular plate. It is capable of rotating freely about the centre of the main scale. Main scale is engraved on the main body of the instrument. It can be locked in any position.
5. Upto which value optical bevel protractor can take the readings?
a) 10’
b) 5’
c) 2’
d) 15’
Answer: c
Explanation: Circular graduations can be viewed by a small microscope which is fitted on it. It is possible to read by estimation to about 2 minutes of arc with the help of microscope in optical bevel protractor.
6. Which of the following are the types of mechanical bevel protractor?
a) A, B only
b) A, B, C and D only
c) A, B, C, D and E only
d) A, B and C only
Answer: b
Explanation: There are four types of mechanical bevel protractors i.e. A, B, C, and D. The vernier can read to 5 minutes of arc in A and B type of mechanical bevel protractor whereas in case of type C, the scale can be read in degrees.
7. What is the difference between type A and type B?
a) Least count is 5’ in type A and 10’ in type B
b) Type A is provided with fine adjustment device whereas type B is not
c) Type B is provided with fine adjustment device whereas type A is not
d) The vernier scale is different in both types
Answer: b
Explanation: The difference between type A and Type B is that type A has a fine adjustment device or acute angle attachment whereas type B is not. The scales of all the types of mechanical bevel protractor are graduated either as semicircle marked 0—90—0 with two verniers 180° apart or as a full circle.
8. What are the dimensions of working edge of stock ?
a) 90mm*7mm
b) 100mm*10mm
c) 7mm*90mm
d) 90mm*10mm
Answer: a
Explanation: The working edge of the stock is about 90 mm long and 7 mm in thickness. It is essential that it’s working edge should be perfectly straight and in case departure is there, it should be in the form of concavity.
9. Which of the following is a general dimension of blade?
a) 250mm*3mm
b) 100mm*2mm
c) 150mm*3mm
d) 150mm*2mm
Answer: c
Explanation: It is about 150 or 300 mm in length, 3 mm wide. It is 2 mm in thickness. Its ends are bevelled at angles of 45 degrees and 60 degrees within the accuracy of 5 minutes of arc.
10. What is the parallel limit of blade of optical bevel protractor?
a) 0.003mm
b) 0.02mm
c) 0.002mm
d) 0.03mm
Answer: d
Explanation: Blade is moved along the turret. Working edge of blade should be parallel upto 0.03 mm and straight up to 0.02 mm and over the entire length of 300 mm. Blade can be clamped in any position.
11. What is the flatness tolerance of acute angle attachment?
a) 0.005mm
b) 0.0005mm
c) 0.5mm
d) 0.00005mm
Answer: a
Explanation: Acute angle attachment can be fitted into the body. It can be clamped in any position. Working edge of acute angle attachment should be parallel to the working edge of the stock within 0.015 mm and flat to within 0.005 mm over the entire length of attachment.
12. Which of the following is not true for type D mechanical bevel protractor?
a) It is not provided with vernier
b) Graduated in degrees
c) Have a fine adjustment device
d) Doesn’t have acute angle attachment
Answer: c
Explanation: Type D mechanical bevel protractor is read in degrees. It is not provided with acute angle attachment. It doesn’t contain a vernier or fine adjustment device.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Sine Principle and Sine Bars”.
1. Up to which angle sine bars can measure the angles?
a) 45 degree
b) 60 degree
c) 90 degree
d) 120 degree
Answer: a
Explanation: The sine bars become impractical and inaccurate as the angle exceeds 45° because the bar is physically clumsy to hold in that position and even a slight error of the sine bar can cause large angular errors after this angle.
2. What is the permissible tolerance on flatness of side faces of sine bars of 100 mm as per IS 5359-1969?
a) 0.001 mm
b) 0.005 mm
c) 0.01 mm
d) 0.05 mm
Answer: b
Explanation: As per IS 5359-1969, the flatness of side faces of sine bars of size 100 mm is 0.005 mm and the tolerances of squareness for side faces to upper face and parallelism of side faces to the roller axes are 0.003/25 mm and 0.01/25 mm respectively.
3. Which of the following is not used in making of sine bars?
a) High carbon
b) High chromium
c) Corrosion resistant steel
d) Aluminium
Answer: d
Explanation: Sine bars are used to measure angles accurately or locating any work to a specified angle within a close limit. Sine bars are made from high chromium, high carbon, corrosion resistant steel, ground, hardened and stabilised.
4. Which of the distance of the axes of two cylinders of sine bar?
a) 20 inches
b) 50 inches
c) 5 inches
d) 25 inches
Answer: c
Explanation: In British system, the distance between the axes of the two cylinders is 10 or 5 inches, and in metric system the distance between axes of cylinders is 100, 200 and 300 millimeter.
5. Which of the following is incorrect regarding sine bars?
a) Sine bar is itself a complete measuring instrument
b) Some holes are drilled in the body
c) It can be used to locate any work to a given angle
d) It is capable of self generation
Answer: a
Explanation: The sine bar is itself not a complete instrument or complete measuring instrument. Another datum like surface plates are needed. Some holes are drilled in the bar body. It is to facilitate handling and reduce weight.
6. What are the characteristics permissible tolerance flatness of upper and lower surface of 100mm sine bar I.S. 5359—1969?
a) 0.001mm
b) 0.01mm
c) 0.005mm
d) 0.05mm
Answer: a
Explanation: The permissible tolerance of flatness of upper and lower surfaces of sine bars is 0.001 mm and the tolerance for parallelism of upper and lower surfaces with respect to datum surface is also 0.001 mm.
7. Which of the following is true for the given statements about sine bars?
Statement 1: Grade A sine bars are less accurate than grade B.
Statement 2: Grade B sine bars are accurate up to 0.01 mm/m of length.
a) T, F
b) T, T
c) F, T
d) F, F
Answer: d
Explanation: Sine bars are graded as of A or B grade depending upon the accuracy of the centre distance. B grade of sine bars are accurate up to 0.02 mm per m of length but B grade is less accurate than A grade. A grade sine bars are accurate up to 0.01 mm per m of length.
8. What is the parallelism tolerance of end faces of axes of rollers in sine bar according to British Standards?
a) 0.013mm per 50mm
b) 0.01mm per 25mm
c) 0.013mm per 25mm
d) 0.13mm per 25mm
Answer: c
Explanation: According to British standard, parallelism tolerance of end faces to the axis of the hinge roller is within 0.013 mm/ 25 mm and the accuracy of distance between rollers axes is 0.0025, 0.005 and 0.008 mm for 100 mm, 200 mm and 300 mm bars.
9. What is sine centre?
a) Centre of sine bar
b) Sine bar with block holding centres
c) Sine bar with hole in centre
d) Sine bar with hollow rod in centre
Answer: b
Explanation: A sine bar with block holding centres is known as sine centre. It can be rigidly clamped and adjusted in any position. Sine centres can be used for inspection of the conical objects between centres.
10. As per IS 5359-1969, what is the permissible tolerance on mean diameter of the rollers in 100mm sine bars?
a) 0.005 mm
b) 0.001 mm
c) 0.002 mm
d) 0.01 mm
Answer: c
Explanation: As per IS 5359-1969, the permissible tolerances for mean diameters of rollers and distance between roller axes are 0.002 mm and ±0.03 mm respectively for sine bars of size 100 mm.
11. Which of the following is true for sine table?
a) Sine table is most convenient for the light workpieces
b) Procedure of setting angle is not same as sine bars
c) Table may be safely swung from 0 to 90 degrees
d) Error caused by clamping mechanism is very large
Answer: c
Explanation: Sine table is the development of the sine bar. It is the most accurate and convenient design for heavy workpieces. The principle of setting sine table at any angle is same as for sine bars.
12. Upto which inclination sine centres can be used?
a) 45 degree
b) 90 degree
c) 120 degree
d) 60 degree
Answer: d
Explanation: These are used up to 60 degree angle. Rollers are clamped firmly to the body. Sine centre is a very useful device for testing the conical work centered. The principle of setting sine centre is same as of sine table.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Rotary Tables”.
1. Which of the following is used in mechanical type rotary tables?
a) Bevel gear
b) Spur gear
c) Worm and gear
d) Pinion gear
Answer: c
Explanation: Mechanical rotary table which is cam compensated employs worm and gear as the angle measuring element but cam-compensation of gear error established the final accuracy of this type of rotary table.
2. What is the principle on which precision index table works?
a) Circle divider
b) Taylor’s principle
c) Principle of least square
d) Interference principle
Answer: a
Explanation: Rotary tables are the best-known and widely used circle dividing instrument. Precision index table is a type of rotary table. It is a serrated tooth table which is based on the principle of circular divider.
3. How many teeths are present in the serrated divider in precision index table?
a) 360
b) 720
c) 1000
d) 500
Answer: a
Explanation: The indexing in precision index table corresponds to the number of teeth through which the table is indexed. The serrated divider is limited to 360 teeth. Serrated teeth indexer has been developed in 0.25° increment with accuracy of ± 0.1 second of arc.
4. By which curve, the small increments of angles are achieved in averaging type optical rotary machines?
a) Tan curve
b) Cos curve
c) Sine curve
d) Cot curve
Answer: c
Explanation: Smaller increments of angle are achieved by the sine curve which is generated by electronic or optical pulsing in the averaging type optical rotary table. The circular scale could be read by electrical or by Moire fringe method.
5. How the final unresolved error can be overcome in a mechanical cam compensated rotary table?
a) By the perfection of gear
b) By compensation
c) There is no unresolved final error
d) Perfection of gear is the better in this case than compensation
Answer: b
Explanation: In mechanical cam-compensated type rotary table, accuracy depends upon the accuracy of the worm and gear. Compensation is used to overcome the final unresolved error, rather than perfection of the gear.
6. How many face gears are used by precision index table?
a) 5
b) 4
c) 3
d) 2
Answer: d
Explanation: Precision index table uses two face gears. Both the gears have serrated teeth. Both gears are same in diameter, shape and number of teeth. When both face gears are brought into contact root to crest, then lock together and prevent rotation.
7. Which of the following is not true for the periodic error in worm and gear rotary table?
a) It can be affected by tooth spacing of the gear
b) This error is not taken into consideration
c) It can be affected by the thread form
d) It is the error within two turn of the hand wheel
Answer: d
Explanation: The periodic error is the error within one turn of the hand wheel. It is not taken into consideration. This error is affected by factors like the thread form and tooth form, drunkenness, line up, runout of worm, errors of eccentricity, and spacing of tooth of the gear.
8. What is the effect of lack of true spindle rotation in accurate worm and gear rotary table?
a) Angular error
b) Centre distance error
c) Both angular and centre distance error
d) Decrease repeatability
Answer: c
Explanation: Lack of true spindle rotation in accurate worm and gear rotary table results in both angular error and centre distance error. Rotary table has the advantage of trouble free operation and good repeatability.
9. Which of the following option is true about rotary tables?
Statement 1: Index is not used with optical rotary table.
Statement 2: Accurate worm and gear rotary table can be used with an index plate.
a) T, T
b) T, F
c) F, T
d) F, F
Answer: a
Explanation: It can be used with an index plate to divide the circle, without the loss of accuracy and necessity of reading angle. Optical rotary table cannot use index, because it’s worm and gear is not accurate.
10. Which of the following is true for accurate worm and gear rotary tables?
a) Bidirectional approach is used for setting
b) Can be used for inspection of angles
c) Can’t be used for generation of angles
d) Worm and gear are highly accurate
Answer: b
Explanation: A unidirectional approach is used in accurate worm and gear type table for setting to take care of unavoidable presence of backlash. The accurate worm and gear has an advantage for the inspection and generation of angles.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Clinometers”.
1. At which part spirit level is present in the clinometers?
a) On a rotary member
b) On the fixed member
c) On the base
d) On the circular scale
Answer: a
Explanation: A special case of the application of spirit level is a clinometer. The spirit level is mounted on a rotary member present in the clinometer carried in housing. One face of the housing forms the base of the clinometer.
2. At which interval, circular glass is divided in Hilger and Watts type clinometers?
a) 3’
b) 5’
c) 10’
d) 2’
Answer: c
Explanation: Hilger and Watts type is the most commonly used clinometer. The circular glass scale is enclosed. It is divided from 0 degree to 360 degree at 10′ intervals. An optical micrometer can be used for the subdivision of 10′.
3. Which of the following is not a common function of clinometers?
a) Determine included angle of two adjacent faces
b) Checking angular faces
c) Checking relief angles on small cutting tools
d) Setting inclination table
Answer: c
Explanation: Clinometers can be used for checking relief angles on large cutting tools, for checking angular faces and milling cutter inserts. These can also be used on jig boring machines for setting inclination table and on grinding machines for angular work.
4. What is the range of readings which can be read directly in precision microptic clinometer?
a) 0 o to 180 o
b) 0 o to 270 o
c) 0 o to 90 o
d) 0 o to 360 o
Answer: d
Explanation: Precision microptic clinometer can be used for direct reading over the range 0° – 360°. Special feature of precision microptic clinometer are optical reading system, totally enclosed glass circles, slow motion screw for fine adjustments, eyepiece rotatable to most convenient viewing position.
5. Which of the following is used to illuminate scale in precision microptic clinometer?
a) An integral low voltage lamp
b) An integral high voltage lamp
c) An ordinary lamp
d) A high voltage bulb
Answer: a
Explanation: The scales of precision microptic clinometer are illuminated by an integral low voltage lamp. Daylight illuminated bubble unit is present, but is also provided with a lamp. It is for alternative illumination.
6. What is the purpose of slow motion screw in precision microptic clinometer?
a) To set tool head initially
b) Same function as of locating face
c) Final adjustment to centre the bubble
d) Measure angle between the surfaces
Answer: c
Explanation: The clinometer can be used as a precision setting tool. It can be used to set a tool head or table at a given angle. Micrometer scale is set firstly. Then the glass scale is rotated. It is to bring the relevant graduation to the index, for final adjustment the slow motion screw is used.
7. Which of the following is not a part of index head of centers used in clinometer?
a) Indexing plate
b) Camshaft
c) Crank
d) Worm and worm wheel
Answer: b
Explanation: The index head of the centers mainly consists of indexing plate, a crank and worm and worm wheel. The crank is attached to a worm. Worm is in mesh with the worm wheel.
8. Index centres are actually meant to use on which machine?
a) Milling machines
b) Planer machines
c) Lathe machines
d) Shaper machines
Answer: a
Explanation: Index centres were meant for the use on milling machines. But now their application is extended to inspection work. In such cases, where the measurement of a large number of angular dimensions about a common centre is required, index centres are best suited.
9. What is the purpose of locating face present on the back of the precision microptic clinometer?
a) Allows instrument to be used vertically
b) Allows instrument to be used at an angle
c) Allows instrument to be used horizontally
d) Allows the setting of inclination table
Answer: c
Explanation: With the suitable accessories these clinometers can be used for measuring angular displacements of small part. A locating face is present on the back of the precision microptic clinometer which allows the instrument to be used horizontally with the reflector unit or accessory worktable.
10. What is the use of worm and quadrant arrangement in clinometers?
a) Reading up to 5’ is possible
b) Reading up to 1’ is possible
c) Reading up to 10’ is possible
d) Reading up to 0.1’ is possible
Answer: b
Explanation: Worm and quadrant arrangement is provided in some instruments so that reading up to 1′ is possible. There is no bubble present in some clinometers but a graduated circle is present and it is supported on accurate ball bearings.
11. Which of the option is true for the given statements about clinometers?
Statement 1: Bubble vial is the reference for inclination.
Statement 2: It can’t be used for angular work on grinding machines.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: a
Explanation: Bubble vial is the reference for inclination. To measure the inclination of a surface, the vial is turned until it is approximately level. After this, the slow motion screw is used to centre the bubble.
This set of Engineering Metrology test focuses on “Optical Instruments for Angular Measurement”.
1. Which of the following is not true for autocollimators?
a) Has an infinity telescope
b) Has an autocollimator
c) For smaller angle it is not accurate
d) Very high sensitivity
Answer: c
Explanation: Autocollimator is an optical instrument which is used for the measurement of small angular differences. Autocollimator provides a very sensitive and accurate approach for small angular measurements. Autocollimator is an infinity telescope and a collimator combined into one instrument.
2. What is the relationship between the linear displacement of the graticule image in the eyepiece plane and reflector tilt?
a) Both are independent of each other
b) Linear displacement is directly proportional to the reflector tilt
c) Linear displacement is inversely proportional to the reflector tilt
d) Linear displacement is directly proportional to the square of the reflector tilt
Answer: b
Explanation: Linear displacement of the graticule image is directly proportional to tilt of the reflector. It can be measured by an eyepiece graticule, electronic detector system or optical micrometer, scaled directly in angular units.
3. Up to which accuracy length can be measured by laser interferometer?
a) 1 part in 10 8
b) 2 part in 10 8
c) 1 part in 10 6
d) 2 part in 10 6
Answer: c
Explanation: It is possible to measure length to accuracy of 1 part in 10 6 with laser interferometer. With two retro-reflectors that are placed at a fixed distance, and a length measuring laser interferometer the angle change can be measured to an accuracy of 0.1 second.
4. Which of the following option is correct for the given statements about optical instruments for angular measurements?
Statement 1: Laser interferometer with two-retro reflector uses sine principle.
Statement 2: Photoelectric microptic autocollimator can be used as a visual collimator.
a) F, F
b) T, F
c) F, T
d) T, T
Answer: d
Explanation: Laser interferometer uses the Sine principle. The line which joins the poles of the reflectors makes the hypotenuse of the right triangle. Photoelectric collimator can be used as a visual autocollimator and is available with a dark field graticule.
5. Which of the following is true for automatic position sensing autocollimator?
a) Accuracy is affected by normal mains fluctuations
b) There is no effect of lamp ageing on the accuracy of this instrument
c) Instrument measure in all planes simultaneously
d) It is not ideal for the repetitive checking
Answer: b
Explanation: Accuracy of automatic position sensing autocollimator is not affected by lamp ageing or normal mains fluctuations. Automatic autocollimators are ideal for the repetitive checking of the components.
6. How many pads are included for use under the foot screws in leveling base of autocollimator?
a) 2
b) 3
c) 4
d) 5
Answer: b
Explanation: Three pads are present in the leveling base of autocollimator for use under the foot screws. There is no requirement to remove the autocollimator after use as the autocollimator case is constructed to take both items.
7. What is the main use of steel cube reflector in autocollimator?
a) To provide a 90 degree standard in 3 planes
b) For general bench use
c) Calibrate surface plate
d) For setting but not checking perpendiculars
Answer: a
Explanation: Steel cube reflector can be used as a general purpose reflector. It can be used for providing a 90 degree angle standard in three planes. It can be used for setting or checking perpendiculars.
8. What is the range of readings up to distance of 9 metres in microptic autocollimator?
a) 15 minutes of arc
b) 20 minutes of arc
c) 5 minutes of arc
d) 10 minutes of arc
Answer: d
Explanation: A pair of target wires is used in this instrument. These wires are placed in the focal plane of a collimating lens. It is possible to read the tilt of reflector to normal upto 1/2 sec. of arc with the help of micrometer. The instrument has a range of readings of 10 minutes of arc up to 9 meter distance.
9. Which of the following used moire gratings for angular measurements?
a) Laser interferometer
b) Microptic autocollimator
c) Precision polygons
d) Goniometer
Answer: d
Explanation: Goniometer constitutes the continuously rotating Moire gratings for angular measurements with high accuracy. Two radial gratings are employed in goniometers which are rotating in unison.
10. Which of the following is true for Reading heads present in goniometer?
a) There is only one reading head which is stationary
b) Two readings heads and both are stationary
c) There is only one reading head which is moving with a rotatable work table
d) Two reading heads, one is stationary and other is rotating with work table
Answer: d
Explanation: Two reading heads are present in the goniometer. One head remains stationary while other moving with a rotatable work table. The phase difference between the outputs of heads varies continuously as the second head attached to the rotary table is moved.
11. How much angle accuracy is possible with a goniometer fitted with two 32400 lines radial grating?
a) 0.1 second of arc
b) 1 second of arc
c) 2 second of arc
d) 0.5 second of arc
Answer: a
Explanation: Advantage of goniometer is that grating errors are entirely averaged to zero during the time of measurement thus giving the inherent accuracy. With a goniometer which is fitted with two 32400 lines radial gratings, it is possible to obtain angle measurements to an accuracy of 0.1 second of arc.
12. Which of the following is not true for angle dekkor?
a) It is a type of autocollimator
b) It can be used as a comparator
c) It is a more precise instrument than autocollimator
d) It has a wide field of application without the operation of a micrometer
Answer: c
Explanation: It is a type of collimator and contains a small illuminated scale. The instrument measures by comparing the readings obtained from a standard. This is less precise instrument than autocollimator but it has wide field of application for general angular measurement.
13. What is the alternate name of constant deviation prism?
a) Optical square
b) Dowell prism
c) Circular prism
d) Reflector prism
Answer: a
Explanation: Constant deviation prism is also known as optical square. The special property of optical square is that it always reflects the ray through the same angle, which means doesn’t depend on the angle of incident.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Precision Polygons”.
1. What is the maximum overall diameter for precision polygons?
a) 100 mm
b) 200 mm
c) 300 mm
d) 400 mm
Answer: c
Explanation: Precision polygons are also known as multifaced polygons. These can be used for calibration of rotary tables, dividing head. The overall diameter of polygons should not exceed 300 mm for convenient handling.
2. What are the maximum numbers of faces a precision polygon can have?
a) 30
b) 60
c) 90
d) 72
Answer: d
Explanation: The minimum size of the reflecting face of the precision polygons should be approximately 13 mm x 13 mm. Thus a maximum number of faces of polygons can be seventy two, corresponding to an included angle of 5 degree.
3. How many holes are provided in precision polygons for clamping purpose?
a) 1
b) 2
c) 3
d) 4
Answer: d
Explanation: About four holes are provided in the polygons for the clamping purposes. These holes are plain in the type-1 polygon and threaded in type-2 and type-3 precision polygon respectively.
4. What is the dimension of polygon between top and supporting surfaces for a type 2 precision polygon as per IS: 6987-1973?
a) 75 mm
b) 150 mm
c) 300 mm
d) 600 mm
Answer: b
Explanation: As per IS : 6987-1973, there are three types of precision polygons that is ‘type-1’, ‘type-2’ and ‘type-3’. The dimension of polygon between the top surface and the supporting surface is 75 mm for type -1,150 mm for type-2 and 300 mm for type-3.
5. What is the accuracy of top and supporting surface of type 3 precision polygon as per IS: 6987-1973?
a) 0.005 and 0.04 mm
b) 0.0025 and 0.005
c) 0.007 and 0.0035
d) 0.001 and 0.002 mm
Answer: a
Explanation: The top surface and supporting surface are made flat and parallel to accuracies of 0.0025 and 0.005 mm for type-1 and 0.007 mm and 0.0035 for type-2, 0.005 and 0.04 mm for type-3 and departure from flatness is permissible in concave direction only.
6. What is the primary consideration in the accuracy of precision polygons?
a) How closely the mirror agrees with nominal angle
b) How closely the reflecting surface agrees with nominal angle
c) Primary consideration for precision polygons is how square and flat it is or its surface
d) How many sides polygon has having
Answer: c
Explanation: The primary consideration in accuracy for the certainty of calibration is not how closely reflecting faces or mirror agrees with the nominal angle, but how flat and square it is.
7. Which of the following option is true for the given statements about precision polygons?
Statement 1: It may have unequal angles.
Statement 2: Polygon with 12 sides is used for most of the works.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: c
Explanation: The polygons mostly have equiangular faces but unequal angles can also be provided for some special purposes. These are generally about 15 mm in thickness and 75 mm across flats and have a central hole for mounting purposes.
8. To what accuracy all face of a precision polygon made square to the bottom supporting surface?
a) 2.5 µm
b) 3.5 mm
c) 2.5 mm
d) 3.5 µm
Answer: a
Explanation: All faces of polygon are made square to the bottom surface to an accuracy of 2.5µm. The error in angle between any two adjacent working faces should not be more than 10 seconds of arc.
9. What is the flatness of reflecting faces of precision polygons?
a) Within 0.0002 mm
b) Within 0.0001 mm
c) Within 0.0003 mm
d) Within 0.0004 mm
Answer: b
Explanation: The reflecting faces of precision polygons should be flat with in 0.0001 mm. If individual mirrors are used then they should be mounted in such a way that there is no distortion. The mirror position should be fixed or there should be no possibility of alterations of mirror position from bumping or poor mounting.
10. Which of the following is true for precision polygons?
a) It is not possible to make a full calibration of the rotary table with one polygon
b) Correction factor is applicable for reference to the exact centering
c) Reflecting surfaces should be within 6 to 7 seconds of nominal angle
d) Correction factor is not applicable when the centre of the mirror is used in calibration
Answer: a
Explanation: It is not possible to make a full calibration of the rotary table with only one polygon because of the limited sides. Thus all the lines of the circular scale of an optical rotary table are not inspected for error.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Caliper Principle”.
1. Why is the caliper principle used?
a) For circular divisions
b) For checking flatness
c) For measuring dimensions with vernier caliper
d) For measuring dimensions with micrometer
Answer: a
Explanation: Caliper principle is used for the circular division or to divide a circular disc in number of divisions. Circular division deals with the continuous division of a Circle and measurement. The level of accuracy of circular division depends only on the precision of the equipment and the techniques used.
2. According to caliper principle, complete circular division of a circle must be equal to which angle?
a) 120
b) 180
c) 90
d) 360
Answer: d
Explanation: There are some angles which are not an exact fractional circle division, but is considered as a combination of angles which are uniform divisions. By caliper principle complete circular division of a circle must be equal to 360°.
3. How many microscopes are required to marking a circular disc into 90 o divisions?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: If the caliper principle is applied for marking a circular disc into 90 degree divisions. Then, in this method, we require the use of two microscopes for taking readings at two different positions simultaneously.
4. How many trial lines are marked firstly when caliper principle is used to mark a circular disc into 90 o divisions?
a) 5
b) 4
c) 3
d) 2
Answer: d
Explanation: Firstly two trial lines namely ‘1’ and ‘2’ are marked approximately at 180 degree and the two microscopes A and B are set against these marks. This practice is to divide a circle into two equal halves.
5. How many marks are needed to mark a circular table into 180 o divisions using caliper principle?
a) 1
b) 2
c) 3
d) 4
Answer: d
Explanation: 2 lines are marked at approx. 180° and individual microscopes set against these marks, let microscope A for mark 1 & B for 2. The position below B is noted & marked as 3. If the line division of 1 & 2 was exactly 180°, then the difference between 1 and 3 is the twice the error from 180° which can be measured. The space between 1 and 3 is divided by 4. Then 2 and 4 divide the circle into 180° divisions.
6. Which of the following statement is true for the circular division by caliper principle?
Statement 1: An arbitrary standard of angle is required.
Statement 2: All angles are obtained by the uniform division of the dividing circle.
a) F, T
b) T, T
c) T, F
d) F, F
Answer: a
Explanation: The main advantage of circular division and angular measurements is that, there is no need of arbitrary standard of angle but all angles can be obtained by uniform division of the circle.
7. How many marks are needed to mark a circular table into 90o divisions?
a) 2
b) 4
c) 6
d) 8
Answer: d
Explanation: Eight marks are required to divide a circular table into 90 degree division. Four marks are required to divide it correctly 180 degree say 0 to 180 and then another four marks are needed to divide it in 90 to 270 degree. By this table is divided into 90 degree divisions.
8. Which of the following option is true for caliper principle?
Statement 1: This principle can be used to calibrate precision polygons.
Statement 2: Fully calibrated lines can be correctly engraved after marking the circular table and also after calibration of lines.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: c
Explanation: Caliper principle can also be used to calibrate the polygons. After dividing the circles, lines can be correctly engraved on the disc at given intervals. By using the calibration of lines and it’s known for errors of setting.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Calibration of Polygons”.
1. How many auto-collimators are required when the polygons are calibrated by using only auto-collimators?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: Any precision polygon is usually calibrated by two autocollimators before using, in order to know the errors. For this method, precision polygon is mounted on a table and this table is a rotating table.
2. What is the accuracy of comparison method used for calibration of polygons?
a) ±0.1 seconds
b) ±0.2 seconds
c) ±0.3 seconds
d) ±0.4 seconds
Answer: c
Explanation: If all the exterior angles of the upper polygon are compared with the angle between any two faces of the lower polygon then by comparison method of calibration of polygons, the accuracy of ± 3 seconds can be obtained.
3. What is the relation between angle of two autocollimators and angle between polygon faces when polygon is calibrated? (R 1 , R 2 are the readings.)
a) P = R + (R 1 +R 2 )
b) P = R + (R 2 -R 1 )
c) P = R – (R 1 +R 2 )
d) P = R – (R 1 -R 2 )
Answer: b
Explanation: The angle between two polygon face is P and between two autocollimators is R. Readings are taken by using autocollimators let readings are R 1 and R 2 . Then the angle between polygon face is equal to autocollimator angle plus difference in readings.
4. How many auto-collimators are required for comparison method of calibration of polygons?
a) 1
b) 2
c) 3
d) 4
Answer: a
Explanation: In comparison method of calibration of polygons, two polygons which are identical to each other and one table which can rotate is used. For viewing purpose a single autocollimator is used.
5. Which of the following is the correct option for given statements about calibration of polygons?
Statement 1: Autocollimators angle is constant during calibration.
Statement 2: Wild rotary table can be used as the base of precision polygons.
a) F, F
b) T, T
c) F, T
d) T, F
Answer: b
Explanation: Angle between two autocollimators is constant that is ∑R/n is equal to R where n is the number of polygon faces. Precision polygons are placed on a rotary table for calibration and wild type is used in many places.
6. What is formula for the angle between autocollimator when polygon is calibrated by using two autocollimators?
a) (360 0 /n)-∑(R 2 -R 1 )/n
b) (180 0 /n)-∑(R 2 -R 1 )/n
c) (360 0 /n)-∑(R 2 -R 1 )*n
d) (180 0 /n)-∑(R 2 -R 1 )*n
Answer: a
Explanation: Summation of angle between polygon faces is equal to 360 degree. If there be n number of sides in a polygon then dividing the equation throughout by n that is (360 0 /n)-∑(R 2 -R 1 )/n.
7. Which of the following option is true for calibration of polygons by using auto-collimators?
Statement 1: Imperfect centering has a great effect on calibration.
Statement 2: This method gives a high degree of accuracy without reference to any angular standard.
a) T, T
b) T, F
c) F, T
d) F, F
Answer: c
Explanation: It is not necessary for calibration of polygons that the autocollimators be aimed at the centre of polygons as there is no effect of imperfect centering in this method of calibration or autocollimators.
8. By computed least square method, what is the accuracy obtained for polygons up to 12 faces?
a) ±1.0 second
b) ±2.0 second
c) ±3.0 second
d) ±4.0 second
Answer: a
Explanation: If each faces pair of the upper polygon is compared with all the faces of the lower polygon and the angles are computed by the least square method then the better accuracy will achieve. By this, the accuracy of ± 1.0 second may be obtained for up to 12 faces polygons.
9. Which of the following is not true for comparison method used for calibration of polygons?
a) Identical polygons are used
b) Polygons are mounted one above the other
c) Polygons are mounted on the fixed table
d) Reflecting faces of both the polygons are viewed simultaneously
Answer: c
Explanation: Two identical polygons are mounted one above the other on a table which can rotate. The autocollimator is placed in a position that it views simultaneously the reflecting faces of both the polygon.
10. What is correct for the angle of autocollimators used for calibration of polygons?
a) Angle between autocollimators is equal to the nominal angle between adjacent faces
b) Angle between autocollimators is more than the nominal angle between adjacent faces
c) Angle between autocollimators is less than the nominal angle between adjacent faces
d) Angle between autocollimators is more or less to the nominal angle between adjacent faces
Answer: a
Explanation: The angle between autocollimators are set such that the angle is equal to the nominal angle between adjacent faces of the polygon, it is to give reflections from adjacent faces of the polygon.
This set of Engineering Metrology Problems focuses on “Check the Angle of a Tapered Hole”.
1. How many balls are needed in the method to check the angle of a tapered hole?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: In the method of checking the angle of a tapered hole, there is a need for two balls. Depth gauge and height gauge are also required. This method is suitable for checking the angle of a tapered ring gauge.
2. At what position a smaller ball is placed in the hole to check the angle of a tapered hole?
a) Lower position
b) Upper position
c) Middle position
d) At any position
Answer: a
Explanation: In the method to check the angle of tapered hole, Firstly the small ball of radius let R is inserted in lower position in the hole and depth H from the upper surface of tapered hole to the top of the ball is measured.
3. Which of the following gauge is generally used to measure distance between top of ball and tapered hole in the method of checking angle of a tapered hole?
a) Depth gauge
b) Slip gauge
c) Height gauge
d) Angle gauge
Answer: c
Explanation: In this method of checking the angle of tapered hole the bigger ball of radius let R is placed in the hole and distance H. The distance between tapered hole and the top of the ball is measured with height gauge.
4. Which of the following is correct about smaller ball using in the method of checking angle of tapered hole by using balls?
a) Small ball should be of the size so that it will be seated somewhere in between hole
b) Small ball should be of the size so that it will be seated at the bottom most position in the hole
c) Small ball should be of the size so that it will be seated at the top most position in the hole
d) There is no effect of ball position on the method
Answer: a
Explanation: In this method to check the angle of tapered hole, balls are used. Smaller ball is of such size that it will be seated somewhere between the hole that is not at the bottom and not at the top. Above it bigger ball will be placed.
5. Which of the following is true about the method of checking the angle of a tapered hole?
Statement 1: Balls of different sizes are used.
Statement 2: This method can be used to check relief clearance of dies.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: c
Explanation: To check the angle of tapered hole, balls of different size are used. This method is suitable for checking the angle of a tapered ring gauge and very suitable for measuring the relief clearance of dies.
6. What is the formula to find angle of tapered hole?
a) CosA/2 = (R 1 -R 2 )/(H 1 +H 2 +R 1 -R 2 )
b) SinA/2 = (R 1 -R 2 )/(H 1 +H 2 +R 1 -R 2 )
c) TanA/2 = (R 1 -R 2 )/(H 1 +H 2 +R 1 -R 2 )
d) CotA/2 = (R 1 -R 2 )/(H 1 +H 2 +R 1 -R 2 )
Answer: b
Explanation: SinA/2 = (R 1 -R 2 )/(H 1 +H 2 +R 1 -R 2 ) this is the formula to find angle of tapered hole where A is the angle of tapered hole. R 1 and R 2 is the radius of smaller and bigger ball respectively. H 1 and H 2 are the heights.
7. Which of the following is true for the measurement of small tapers by balls?
a) Weight of the ball cause no effect on the accuracy of reading
b) Measuring pressure exerted can cause axial movement
c) Measuring pressure exerted cause no effect on the accuracy of reading
d) Accuracy of small taper measurement is same as large taper
Answer: b
Explanation: A precaution is needed when the small taper is measured with the help of balls. If the ball is allowed to drop in the hole, it will wedge the taper of the hole. Ball weight and measuring pressure that is exerted over it can cause appreciable axial movement and can give inaccurate readings.
8. What is the modified formula of checking angle of tapered hole when both the balls lie inside the groove?
a) SinA/2 = (R 2 -R 1 )/(H 1 +R 2 -(H 2 +R 2 ))
b) SinA = (R 2 -R 1 )/(H 1 +R 2 -(H 2 +R 2 ))
c) SinA/2 = (R 2 -R 1 )/(H 1 -R 2 -(H 2 +R 2 ))
d) SinA = (R 2 +R 1 )/(H 1 +R 2 -(H 2 +R 2 ))
Answer: a
Explanation: When both smaller and bigger ball are inside the groove then the formula to find angle of tapered hole will modify. The modified formula is SinA/2 = (R 2 -R 1 )/(H 1 +R 2 -(H 2 +R 2 )), where A is the angle of tapered hole.
This set of Engineering Metrology Quiz focuses on “Determine the Included Angle of an Internal Dovetail”.
1. Which of the following is not correct for dovetail joints?
a) Sloping sides act as a guide
b) The slope is 1:5 for softwoods
c) Used in box constructions
d) Difficult to make manually
Answer: b
Explanation: In dovetail joint, the sloping sides acts as guide and during the mating operation prevent the lifting of the female mating part. The slope is 1:6 for softwoods and 1:8 for hardwoods.
2. Which of the following statement is correct regarding the dovetail joint?
Statement 1: Angle between sloping face and imaginary centre plane is important.
Statement 2: It is difficult to pull apart the joint when glue is added.
a) F, F
b) F, T
c) T, F
d) T, T
Answer: d
Explanation: In case of dovetail the angle between sloping face and an imaginary vertical centre plane is important. The dovetail joints are very strong due to the shape of ‘tails’ and ‘pins’. This makes it difficult to pull the joint apart and it is nearly impossible when glue is added to the joint.
3. How many pins are used in the method of determination of an angle of a dovetail?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: To measure the angle of an internal dovetail, there is a need for two pins. These pins are of equal size. Along with the pins, slip gauges and micrometer is also used in this method.
4. What is the shape of tails and pins in an internal dovetail joint?
a) Circle
b) Square
c) Rectangle
d) Trapezoidal
Answer: d
Explanation: The shape of tails and pins in dovetail joint is trapezoidal. A dovetail joint or simply is a joinery technique which is most commonly used in woodworking e.g. furniture, timber framing etc.
5. Which of the following is true about pins the method which is used to determine the included angle of an internal dovetail?
a) Pins touch both the sides of dovetail
b) Pins touches only one side of dovetail
c) Pins are of different size is used
d) Balls of different size is used
Answer: a
Explanation: In this method of checking the included angle of an internal dovetail, firstly the two pins are placed in the position such that touches both the sides of dovetail and then distance across the pins is measured.
6. Which of the following is not a name of dovetail joint?
a) Swallowtail joint
b) Fantail joint
c) Profile joint
d) Culvertail joint
Answer: c
Explanation: In Europe, dovetail joint is also known as swallowtail joint and a fantail joint. In pre dates history, dovetail joint is also called Culvertail joint. Profile joint is not the name of dovetail.
7. Which of the following formula is true for the angle of internal dovetail?
a) Tan A = (l 2 -l 1 /2) / h
b) Sin A/2 = (l 2 -l 1 /2) / h
c) Cos A = (l 2 -l 1 /2) / h
d) Sin A = (l 2 -l 1 /2) / h
Answer: a
Explanation: Formula for finding the angle of an internal dovetail is Tan A = (l 2 -l 1 /2) / h where l 1 and l 2 are the distance across the pins and h is the height of slip gauges. Thus by knowing these three parameters, angle A can be calculated.
8. Which of the following is used to measure the distance across the pins when included angle of the dovetail is determining by using pins?
a) Vernier
b) Micrometer
c) Screw gauge
d) Slip gauge
Answer: b
Explanation: Micrometer is used to determine the distance across the pins. For setting pins at required height slip gauges are used.
Dovetail joints can be used in jet engines for attaching turbine blades to the shaft in jet engines and also for clockmaking, joining adjacent sections etc.
9. The method used for determining the angle of internal dovetail for some measurements. Which of the following is suitable for this method?
a) Angle of taper plug gauge
b) Any round taper work which can be placed on a surface
c) Any flat tapered work which can be placed on a surface
d) Angle of taper ring gauge
Answer: d
Explanation: This method is suitable to check angle of a plug gauge which is tapered and any round and flat tapered work which can be placed on a surface. Angle of taper ring gauge can be determined by the method of finding the angle of tapered hole by using balls.
10. Which of the following option is not true for the given statement about the method of determination of angle of internal dovetail by using pins?
Statement 1: Pins should extend above the top surface of a dovetail.
Statement 2: Pins are raised on slip gauges.
a) T, T
b) F, F
c) F, T
d) T, F
Answer: c
Explanation: The pins used in this method are raised on two sets of slip gauge blocks which are of equal heights. In this method one care should be taken that the pins do not extend above the dovetail’s top surface.
This set of Engineering Metrology MCQs focuses on “Measure an Internal Taper in Blind Hole”.
1. Which of the following is used to measure an internal taper in a blind hole?
a) One pin
b) Two balls
c) Single ball
d) Two pins
Answer: b
Explanation: For this method of measurement of internal taper of blind holes, generally two steel balls are used. These balls are generally made up of steel.
2. Which of the following is the first step in the method of measuring an internal taper in a blind hole?
a) Balls are placed in bottom of the taper
b) All the balls are placed over the support
c) Pins are placed in bottom of the tape
d) All the pins are placed over the support
Answer: a
Explanation: In the method of measurement of internal taper of blind hole the first step is that the two balls which are of equal diameter are placed in the bottom. Each ball is placed in bottom corner of the internal taper of blind hole.
3. Which of the following is used to fill the gap between the balls?
a) Combination of pins
b) Combination of balls
c) Slip gauges
d) Plug gauges
Answer: c
Explanation: In this method, after placing the balls the gap between the balls is filled with the combination of the slip gauges. The length of slip gauges between the balls should be noted very carefully.
4. Which of the following is the blind hole?
a) All ordinary holes are called blind holes
b) Those hole which has specified depth without breaking through the other side
c) Those holes which goes all the way through metal
d) Clearance holes are the blind holes
Answer: b
Explanation: Blind holes are those which are drilled or reamed etc. at a specified depth. It is drilled without breaking through the other side. Those holes which go all the way through the work piece are known as through holes.
5. How the error in angle measurement can be decreased when the internal taper of the blind hole is measured?
a) Increase the height of slip gauge combination
b) Decrease the height of slip gauge combination
c) In place of balls, pins are used
d) Balls of different diameter are used
Answer: a
Explanation: When the internal taper of blind hole is measured by using balls then the error in the angle measurement of taper can be decreased by choosing the height of slip gauge combination as large as possible.
6. Which of the following is true for the measurement of internal taper in the blind hole?
a) Roller of large radius should be used
b) No effect of roller size
c) Roller of small radius should be used
d) Both the rollers are of different size
Answer: c
Explanation: In this method of measurement of internal taper, the radius of rollers should be small so that the contact between the flanks of sloping sides and rollers is made in a plane which is near to the base.
7. What is the formula for the internal tapered angle of blind hole?
a) Sin A/2 = (l 1 -l 2 )/2h
b) Cot A/2 = (l 1 -l 2 )/2h
c) Cos A/2 = (l 1 -l 2 )/2h
d) Tan A/2 = (l 1 -l 2 )/2h
Answer: d
Explanation: Tan A/2 = (l 1 -l 2 )/2h or A = 2 tan -1(l 1 -l 2 )/2h is the formula to measure the internal tapered angle of the blind hole where (l 1 -l 2 ) is the different in length of slip gauges and h is the height of slip gauges upon which balls are placed.
8. Which of the following is used as a support in the blind hole when the internal taper is measured by using balls?
a) Wooden block
b) Slip gauges
c) Balls of larger diameter
d) Internal taper itself acts as a support
Answer: b
Explanation: A combination of slip gauges of height let ‘h’ is prepared and placed in the hole as support. Now, place the two balls in the upper position. Each ball touched the tapered side of the hole and space is filled with another combination of slip gauges.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Measure the Angle of a V-Groove”.
1. Which of the following is used for measuring the angle of V-groove?
a) Two discs of same size
b) Two pins of different size
c) One disc only
d) One pin only
Answer: b
Explanation: For measuring the angle of V-groove, two discs or two pins are used. These pins or discs are of different size. There is also a need of height gauge in this angle measurement method.
2. What is the first step in the measurement of angle of the V-groove?
a) Small disc is placed in the groove
b) Flatness of groove is tested
c) Bigger disc is placed in the groove
d) Both discs are placed simultaneously
Answer: a
Explanation: In the method of measuring the angle of V-groove, First step is that the small disc is placed in the groove. After that height of the smaller disc above the surface plate is measured with the help of height gauge.
3. Which of the following is true about the method of measuring the angle of V-groove?
a) Larger disc is placed over the smaller disc in groove
b) Larger disc is placed in the groove after removing the smaller disc
c) Smaller disc is placed below the smaller disc
d) Larger disc is placed in the groove without removing the smaller disc
Answer: b
Explanation: After removing the smaller disc from the groove, bigger disc is placed in the groove. The height of disc let ‘h2’ is again measured with the help of height gauge.
4. Which of the following is not true for the high accuracy in the method of finding the angle of V-groove?
a) Height of smaller should be measured by sensitive indicator
b) Height of larger discs should be measured by using slip gauges
c) Use of height gauge give more accuracy than slip gauges
d) Use of both slip gauge and sensitive indicator increase accuracy
Answer: c
Explanation: To increase the accuracy of the method or for higher accuracy, height of the smaller and bigger disc let h1 and h2 respectively can be measured by using sensitive indicator. Use of slip gauges for this purpose will also improve accuracy.
5. Which of the following statement is true for the measurement of angle of V-groove using discs?
Statement 1: This method is good for the measurement of the angle of machine tool sides.
Statement 2: Discs should always touch the sloping sides of the groove.
a) T, T
b) F, T
c) T, F
d) F, F
Answer: a
Explanation: This method which is used to measure angle of V-grooves is also very suitable for measuring the angle of profile and angle of machine-tool slides.
The discs used in this method should be of such diameter that they always touch the sloping sides of the groove only.
6. Which of the following can be used in the case of threads to measure the difference in heights of discs when the angle of V-groove?
a) Slip gauges
b) Height gauges
c) Screw gauges
d) Dial indicator
Answer: d
Explanation: This method is also very suitable for measuring the angle of shallow grooves and threads.
To measure the difference of disc height say, in case of threads, can be measured by dial indicator.
7. What is the formula of the angle of a V-groove?
a) Sin A/2 = (d 2 -d 1 )/2 ÷ (h 2 -h 1 )-((d 2 -d 1 )/2)
b) Tan A/2 = (d 2 -d 1 )/2 ÷ (h 2 -h 1 )-((d 2 -d 1 )/2)
c) Cot A/2 = (d 2 -d 1 )/2 ÷ (h 2 -h 1 )-((d 2 -d 1 )/2)
d) Cos A/2 = (d 2 -d 1 )/2 ÷ (h 2 -h 1 )-((d 2 -d 1 )/2)
Answer: a
Explanation: Sin A/2 = (d 2 -d 1 )/2 ÷ (h 2 -h 1 )-((d 2 -d 1 )/2) is the formula of angle of groove where A is the angle of V-groove, d 2 and d 1 are the diameters of discs and h 2 and h 1 are the height of discs from surface plate.
8. What is the formula of distance between centre of discs in the method of measurement of the angle of V-grooves using discs?
a) (h 2 +h 1 )-((d 2 -d 1 )/2)
b) (h 2 -h 1 )-((d 2 -d 1 )/2)
c) (h 2 -h 1 )+((d 2 -d 1 )/2)
d) (h 2 -h 1 )-((d 2 +d 1 )/2)
Answer: b
Explanation: If O 1 and O 2 are the centres of the two balls used in this method and O 1 B is drawn parallel to one of the inclined surfaces & O 2 B is perpendicular to O 1 B. Then, O 2 O 1 B equals half the angle of V-groove and the distance between centres i.e. O 1 O 2 is given by (h 2 -h 1 )-((d 2 -d 1 )/2).
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Calibration of Linear and Angular Measuring Instruments”.
1. What is the relation between variation due to observation, manufacturing process and measuring process of a product?
a) σ observation = σ process + σ measurement
b) σ observation = σ process – σ measurement
c) σ observation = σ process * σ measurement
d) σ observation = σ process / σ measurement
Answer: a
Explanation: The variation in the observation depends upon the variation in the product due to manufacturing process and variation due to measuring process. In order to keep σobservation minimum measurement should be kept minimum so that product as a whole is reliable.
2. What is the maximum permissible error for class I micrometers?
a) 0.002 mm
b) 0.004 mm
c) 0.008 mm
d) 0.016 mm
Answer: b
Explanation: In micrometers, to cover the entire range the error in readings is checked by slip gauges. The maximum permissible error for class I micrometers is 0.004 mm and 0.008 mm for class II micrometers.
3. What is the permissible error in the perpendicular motion of ocular microscope column w.r.t. The work stage over 100 mm movements?
a) 0.04 mm
b) 0.05 mm
c) 0.07 mm
d) 0.06 mm
Answer: d
Explanation:The permissible error in the perpendicular motion of ocular microscope column w.r.t. The work stage over 100 mm movements is 0.06mm.
4. Which of the following is used to check change in ocular lines position due to column rotation in universal micrometer?
a) Dial indicator
b) Slip gauges
c) Control shaft
d) Universal microscope
Answer: c
Explanation: A special control shaft is used to check this where a right angled blade is provided at right angle to shaft diameter line. The ocular line is made to coincide with the blade and the column is titled, the shift in position of the ocular line is noted, this shift is the required error.
5. What is the least count of clinometer which is used to check reading of column rotation used for setting of helix angles in universal micrometer?
a) 1’
b) 2’
c) 3’
d) 4’
Answer: a
Explanation: The permissible error which is allowed in the entire range of column rotation is ± 5′. A clinometer is used to check this which is of 1′ least count. The clinometer is put over column top. Given Inclination is further checked with clinometer.
6. Which of the following is true for the calibration of instruments?
a) In casting and fabrication shops the measurements made are of more precise nature as compared to those made in machine shop and tool room
b) Periodical calibration is made for optical measuring instruments
c) There is no need of periodic calibration in universal microscope
d) Preventive maintenance is not necessary for optical measuring instruments
Answer: b
Explanation: In machine shop and tool room the measurements made are of more precise than those made in casting and fabrication shops, so instruments used in these shops require more frequent calibration. Annual programme can be made for periodical calibration and for general preventive maintenance in optical measuring instruments like universal microscope.
7. What is the permissible error in straight movement of longitudinal and transverse table in horizontal plane?
a) 0.002 mm
b) 0.003 mm
c) 0.004 mm
d) 0.005 mm
Answer: a
Explanation: The permissible error in straight movement of longitudinal and transverse table is 0.002 mm in horizontal plane and 0.005 mm in vertical plane. This can be checked by using a rectangular straight edge and a dial indicator of least count 0.001 mm with an attachment for fixing dial indicator.
8. Which of the following is true for checking the Relative perpendicular motion of the longitudinal and transverse carriage?
a) The permissible error allowed is 0.005 mm in 2500 mm length.
b) This is checked using a slip gauges
c) Precision square of class I or 0 is used
d) Maximum error in precision error is of ± 10″ in squareness
Answer: c
Explanation: The permissible error allowed in this case is 0.005 mm in 1100 mm length. This can be done by using a precision square of class I or class 0 accuracy having a maximum error of ± 10″ in squareness.
9. What is the maximum permissible error in wear of centres?
a) 0.04 mm
b) 0.03 mm
c) 0.02 mm
d) 0.01 mm
Answer: d
Explanation: The centres are set and checked for straightness. It can be observed while rotating the centres. The maximum error permissible for wear of centres is 0.01 mm.
10. What is the least count of dial indicators which can be calibrated using passmeter?
a) 0.01 mm
b) 0.03 mm
c) 0.05 mm
d) 0.07 mm
Answer: a
Explanation: The dial indicators of least count 0.01 mm can be calibrated by using passmeter or by micrometer dial comparator of least count 0.002 mm. The dial indicators can also be calibrated using slip gauges.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Measurements of Limit Gauges”.
1. Which of the following is generally used to check the hardness of the gauging surface of screw ring gauges?
a) Rockwell hardness testing machine
b) Charpy hardness testing machine
c) Diamond pyramid machine
d) Scratch test
Answer: d
Explanation: The hardness of the gauging surface of limit gauges may be generally measured on a hardness testing machine, preferably on the diamond pyramid machine. In certain types of gauges like screw and plane ring gauges, hardness is checked by means of a scratch test.
2. Up to which accuracy small gap gauges can be measured by using slip gauges?
a) ± 0.001 mm
b) ± 0.002 mm
c) ± 0.003 mm
d) ± 0.004 mm
Answer: a
Explanation: Small gap gauges can be measured to an accuracy of ± 0.001 mm by using slip gauges and length bars but the accuracy of measurement of larger gap gauges is not so high, due to probable springing open of jaws when inserting the slip gauge combination.
3. What is the advantage of the use of slip gauge standards for dial comparators?
a) Size of the standard is equal to one of the limits of the plug gauge size
b) Size of the standard is greater than one of the limits of the plug gauge size
c) Size of the standard is less than one of the limits of the plug gauge size
d) Slip gauges are more accurate
Answer: a
Explanation: The advantage of the slip gauge standards for dial comparators is that size of the standard is equal to one of the limits of the plug gauge size and hence the effect of errors of the comparator scale graduations is minimised.
4. Which of the following is not used to measure the plain plug gauges if the tolerance less than 0.025 mm?
a) Bench micrometer
b) Diameter measuring machine
c) Hand micrometer
d) High magnification dial comparator
Answer: c
Explanation: If the tolerance on the plug gauge is less than 0.025 mm then, it is important to use more accurate measurement method. In such cases, bench micrometer or high magnification dial comparator or diameter measuring machine should be employed. In this case, hand micrometer can only measure over a limited range of size.
5. Which of the following is most convenient to measure the cylindrical ring gauges?
a) Slip gauges
b) Micrometer
c) Measurement by using rollers
d) Pneumatic comparators
Answer: d
Explanation: Cylindrical ring gauges are most conveniently measured on pneumatic comparators; the taper and ovality of the gauges is quickly investigated and accuracy of the order of ± 0.001 mm is obtained by using pneumatic comparators.
6. What is the standard magnification used by an optical projector to inspect form of profile gauges?
a) 50
b) 100
c) 150
d) 200
Answer: a
Explanation: Profile gauges are most conveniently inspected by optical projection at a standard magnification. The standard magnification mostly used is 50. Another standard magnification which can be used is 100 but it is generally not used due to reduced intensity of illumination at the projector screen, it is generally not greater than 50.
7. Which of the following statement is true for measurement of height and depth gauges?
Statement 1: These can be measured by comparators.
Statement 2: Gap of light method is not good for depth gauges.
a) T, T
b) T, F
c) F, F
d) F, T
Answer: b
Explanation: Height and depth gauges can be measured by depth micrometers, bench micrometers or comparators. The recommended method for depth and height gauges is ‘gap of light’ method.
8. Which of the following is true for parallel screw plug gauges?
a) The minor diameter is measured by making a measurement on a diameter measuring machine between the flat ends of Vees
b) The flank angle is measured by making a measurement on a diameter measuring machine between the flat ends of Vees
c) The effective diameter is measured by making a measurement on a diameter measuring machine between the flat ends of Vees
d) Pitch is measured by making a measurement on a diameter measuring machine between the flat ends of Vees
Answer: a
Explanation: The major diameter is obtained on the diameter measuring machine which is standardised in a similar way as bench micrometer. The minor diameter is measured on a diameter measuring machine between the flat ends of Vees which are placed in the thread groove on the gauge’s opposite sides.
9. Which of the following is best gauge/machine to inspect the parallel screw ring gauges?
a) Hand micrometer
b) Plug check gauges
c) Comparators
d) Bench micrometer
Answer: c
Explanation: Screw ring gauges inspection by plug check gauges verifies that the ring gauges lie between their size limits. The major diameters are measured by inspection of the thread form which provides an indirect verification.
10. Which of the following is true for the measurement of taper ring gauges?
a) Taper ring gauges of sizes above the diameter of 20 mm are best measured by inserting precision balls of different sizes in the gauge
b) Taper ring gauges of sizes below the diameter of 20 mm are best measured by inserting precision balls of different sizes in the gauge
c) Taper ring gauges of size equal to the diameter of 20 mm are best measured by inserting precision balls of different sizes in the gauge
d) Taper ring gauges of all sizes are best measured by inserting precision balls of different sizes in the gauge
Answer: b
Explanation: Taper ring gauges of diameter below than 20 mm are best measured by inserting precision balls of different sizes in the gauge and the distance between the top of each ball and one of the end faces of the gauge is measured.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Checking of Slip Gauges”.
1. Which of the following is generally used to calibrate slip gauges?
a) Micrometer
b) Collimator
c) Interferometer
d) Gap gauge
Answer: c
Explanation: As a result of handling in the labs or inspection workshops, slip gauge is responsible for displaying the signs of wearing after the appreciable period of use and therefore, should be checked or re-checked at regular intervals. It can be easily done with the help of millionth measuring machine such as Newall Interferometer.
2. Which of the following is true for checking of slip gauges with interferometer?
a) Both ends of gauges examined simultaneously
b) Right end is examined first
c) Left end is examined first
d) Any end can be examined after one another
Answer: a
Explanation: The absolute measurement and gauge comparison are done by an interferometer. It consists of a higher interferometer arranged in such a way that both ends of this type of gauge are checked simultaneously in the same area of view.
3. Up to which accuracy differences in length can be measured when slip gauges are calibrated by interferometer?
a) 0.02 mm
b) 0.002 mm
c) 0.0002 mm
d) 0.00002 mm
Answer: d
Explanation: The gauges show interference fringes across the faces at both ends after simple adjustment, and from the relative positions of these differences in length accuracy achieved is 0.00002 mm.
4. Which of the following is used to compute absolute length when slip gauges are calibrated by interferometer?
a) Scale
b) Slide rule
c) Scriber
d) Caliper
Answer: b
Explanation: The absolute length is computed with the special slide rule provided for this purpose and in Zeiss interferometer the corresponding linear measurement in microns is determined by special slide rule.
5. Which of the following is not a part of the instrument used for checking slip gauges?
a) Collimator
b) Monochromatic light source
c) White light source
d) Lens
Answer: d
Explanation: Arrangement contains a dual collimator, white light source and slit which provides white light. A monochromatic light source, condenser and a slit which provide monochromatic light.
6. How are mirrors arranged when lengths of two slip gauges are compared?
a) Mirrors are arranged in such a manner that both the end faces of slip gauges appear to overlap
b) Mirrors are arranged in such a manner that both the end faces of slip gauges appear separately
c) Lenses are arranged in such a manner that both the end faces of slip gauges appear to overlap
d) Lenses are arranged in such a manner that both the end faces of slip gauges appear separately
Answer: a
Explanation: Mirrors are arranged in such a manner that both the end faces of slip gauges appear to overlap, when lengths of two slip gauges are compared.
7. What is the main purpose of micrometer eyepiece in the instrument used to compare the lengths of two slip gauges?
a) Measure the fraction of bands
b) To read the fringe
c) Measure the length
d) To measure the width of fringe
Answer: a
Explanation: In the instrument used to compare lengths of two slip gauges a micrometer eyepiece is present which accurately measure the fractions of bands, but it is better to estimate the fraction.
8. Under what condition white light bands appear when a comparison of lengths of two slip gauges takes place?
a) Optical paths from dividing mirror are less
b) Optical paths from dividing mirror are more
c) Optical paths from dividing mirror are equal
d) Optical paths from dividing mirror can be more or less
Answer: c
Explanation: The standard gauge is adjusted so that the end faces of slip gauges are at an optical path distance from the dividing mirror when illuminated by the source of white light. Under these conditions the interference fringes appear are known as ‘white light band’. These are produced when the optical paths from the dividing mirror are same or equal.
9. Which of the following indicate the exact point of equality when the comparison of lengths of two slip gauges takes place?
a) A prominent white band
b) A prominent black band
c) A prominent black & white band
d) A prominent grey band
Answer: b
Explanation: A prominent black band indicates the exact point of equality which has other bands, fringed with colour on either side, successive bands being of minimised intensity until invisible.
10. Which of the following statement is true regarding Zeiss interferometer used for the measurement of slip gauges?
Statement 1: Zeiss interferometer is used for relative comparative measurement of slip gauges.
Statement 2: It uses three wavelengths of cadmium light.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: Zeiss interferometer is a compact instrument which is used for absolute comparative measurement of slip gauges. The absolute length of a slip gauge by this method can be determined by three methods First is by comparison with a standard block. second is by a combined measurement of 3 gauge blocks. and the third is by measurement with a wrung-on gauges block.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Automatic Inspection Machines”.
1. Which of the following is not true about automatic inspection machine?
a) Human intervention is required to judge the quality
b) Consists a logic system
c) Self diagnostic system is present
d) Microprocessors are present
Answer: a
Explanation: Automatic inspection machines are very economical in high production manufacturing facilities for final inspection. Human intervention is not required to judge the quality. One or more measuring stations are required for the inspection of parts.
2. What is not a use of rocker-arm components in automatic gauging system?
a) Amplify motion
b) Enable probe to reach very difficult areas
c) Enable positioning of part
d) Transfer movement from datum through not more than one pivot points
Answer: d
Explanation: Rocker-arm components could be used for more accuracy to transfer movement from the datum through one or more pivot points to the probe. Advantage of such a system amplifies the motion, enables probe to areas which are difficult to reach, and enables positioning of part.
3. Which of the following is true about the self-diagnostic system present in automatic inspection machines?
a) Increase downtime
b) Easy but slow identification
c) Improved efficiency of maintenance
d) Increase settling time
Answer: c
Explanation: Self-diagnostic systems are used in automatic inspection machines and these systems allow easy and fast identification of circuits which are faulty, reducing downtime and improving maintenance efficiency.
4. What is done to avoid out-of-sequence mishaps in automatic inspection machine?
a) Clamping between centres and sequence of part lifting are linked on different controls
b) Clamping between centres and gauge fixtures are linked on different controls
c) Sequence of part lifting and gauge fixtures are linked on different controls
d) Sequence of part lifting, clamping between centres and gauge fixtures are linked on same controls
Answer: d
Explanation: To avoid out-of-sequence mishaps, clamping between centres, the sequence of part lifting and the gauge fixtures moving down and up, etc. are linked by a single control mechanism. All movements of the gauge structures are cam operated in each gauging station and powered by a electric motor reducer.
5. Which of the following is true about probes used in automatic inspection machines?
a) Retractable type
b) Non-retractable type
c) Auxiliary probe is not used
d) Heads of probes are not held back till the part is in gauging position
Answer: a
Explanation: The probes should be made retractable type as far as possible, to prevent possible damage and wear to the probes. The probe heads are held back till the part is in a position of gauging.
6. Which of the following statement is true for automatic inspection machines?
Statement 1: Measurement information is displayed on the screen.
Statement 2: Bad parts are not segregated automatically.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: a
Explanation: Bad parts or faulty parts are segregated and discharged into the reject chute. This is done to avoid any possibility of using them in a final assembly. Automatic or semi-automatic mastering of the system is present in automatic gauging machine and is easily performed.
7. Why retooling is fast and less expensive in automatic inspection machines?
a) Only hardware changes are needed
b) Both hardware and software changes are needed
c) No hardware changes are needed
d) Software program doesn’t need any change
Answer: c
Explanation: Retooling is fast and not much expensive because no hardware changes are required and the software program is able to achieve these. Electronic gauging machines provide information that can be interfaced with computers or CRT or analysers.
8. Which of the following is true about the design of structure of automatic inspection machine?
a) Separate structure is designed for transportation and gauging system
b) Same structure is designed for transportation and gauging system
c) Anti vibration mounts are placed only one leg of gauging structure
d) Anti vibration mounts are placed only on two front legs of gauging structure
Answer: a
Explanation: The design of structure of the machine is to be completely separate for the transportation system and also separate for the gauging system. Anti-vibration mounts are used on each of the supporting leg of the structure of gauging. These are used to insulate the gauging fixture from any possible vibrations.
9. Which of the following option is true for given statements about automatic inspection machines?
Statement 1: Safety devices are incorporated to avoid damage to the gauging fixture.
Statement 2: Gauging devices entering the part is positively pushed.
a) T, T
b) T, F
c) F, T
d) F, F
Answer: b
Explanation: The gauging devices entering the part should be spring loaded into their proper position and not positively pushed. If excessive force is needed anywhere then the further operation is stopped to avoid damage.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Electronic Gauging”.
1. What is the relation between e.m.f. and displacement in electronic gauging systems?
a) E.m.f is directly proportional to displacement
b) E.m.f is inversely proportional to displacement
c) E.m.f is independent to displacement
d) E.m.f is directly proportional to cube of displacement
Answer: a
Explanation: Mostly the electric gauging systems are based on the principle of displacement transducer e.g. LVDT which produces an e.m.f. This is linearly proportional to the displacement.
2. For which purpose indicating instrument is used in electronic gauging?
a) To display calculations
b) To display dimensions
c) To display electrical pulse
d) To display part number
Answer: c
Explanation: By using electronic techniques or electronic gauging systems the speed of gauging increased. The electrical impulse produced in electronic gauging system is generally displayed by an indicating instrument.
3. What is the operating speed of tolerance boundary circuits in electronic gauging?
a) 5 millisec or faster
b) 5 millisec
c) Below 5 millisec
d) Below 2 millisec
Answer: a
Explanation: Response time in electronic gauging systems is very fast. Tolerance boundary circuits are available in these gauging systems. These circuits operate in about 5 milliseconds or faster.
4. Which of the following is true about sensing devices used in electronic gauging systems?
a) Large size
b) Large size and expensive measuring fixture
c) Large size and inexpensive measuring fixture
d) Small size and inexpensive measuring fixture
Answer: d
Explanation: Sensing devices used in electronic gauging systems are of smaller size permitting use of a measuring fixture which is simple and less expensive. Accuracy of measurement in these systems is very high.
5. What is the range of high resolution transducers used in electronic gauging systems?
a) 1.5 mm
b) 2.5 mm
c) 3.5 mm
d) 4.5 mm
Answer: b
Explanation: High resolution transducers are used in electronic gauging systems. These transducers have a linear measuring range of 2.5 mm which may have a resolution of the order 0.00003 millimeter.
6. Which of the following option is correct for given statements about electronic gauging systems?
Statement 1: Size control systems are based on the principle of electronic gauging.
Statement 2: Gauging reliability is high.
a) T, T
b) F, F
c) T, F
d) F, T
Answer: a
Explanation: The size control system and automatic inspection have been developed based on the principles of electronic gauging systems. In these systems, it can be possible to set the desired dimension very precisely.
7. Which of the following is not true when electronic gauging is used for the adjustments when grinding operation is carried out?
a) Corrective actions can’t be carried out during grinding operation
b) Machine can stop automatically when necessary
c) Machine can recognise that components are falling in reject limits
d) Accuracy is very high
Answer: a
Explanation: It is possible to take the corrective actions on the grinding machine during operation of grinding and also possible to stop the machine automatically if the dimension of the component falls in the incorrect limits.
8. Which of the following option is true for the given statements about electronic gauging systems?
Statement 1: Capacitive pick-ups used in electronic gauging systems which make contact with the measuring tip.
Statement 2: Arithmetic operation can be carried out on electrical signals.
a) F, F
b) F, T
c) T, T
d) T, F
Answer: b
Explanation: Capacitive pick-ups do not make any contact so there is no wear problem on the tip or measuring tip. It is also possible to carry out simple arithmetic operations on the electrical signals which are generated by transducers.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Meaning of Surface Texture”.
1. What is the importance of the valley in any irregular surface?
a) Reduce metal to metal contact
b) Retain film of lubricating oil
c) Reduce stress concentration
d) Improve surface texture
Answer: b
Explanation: The hills in any irregular surface helps in reducing metal to metal contact and valleys are useful to retain the film of lubricating oil on the surface otherwise it will be difficult to maintain lubricating oil film on the surface.
2. What is the relation between rate of wear and contact surface area?
a) Rate of wear is inversely proportional to the contact surface area
b) Rate of wear is directly proportional to the contact surface area
c) Rate of wear is inversely proportional to the square of contact surface area
d) Rate of wear is directly proportional to the square of contact surface area
Answer: b
Explanation: If any surface has large number of irregularities i.e. hills and valley then the surface will obtain good bearing properties. Rate of wear is proportional to the load per unit area and surface area in contact.
3. Which of the following option is true for given statements about surface texture?
Statement 1: Concept of surface roughness is sensory.
Statement 2: Failure due to fatigue starts always at sharp corners.
a) T, F
b) F, T
c) F, F
d) T, T
Answer: d
Explanation: Concept of a roughness of surface is sensory. Surface roughness has been understood by a sense of touch and light. Failure due to Fatigue starts at sharp corner because at sharp corners stress concentration is more and that part fails earlier.
4. Which of the following is not true about first order irregularities?
a) Arising due to irregularities in machine tool itself
b) Arising due to weight of material itself
c) Arise due to vibrations
d) May arises due to deformation of work under action
Answer: c
Explanation: First order irregularities includes the irregularities arising out of inaccuracies in the machine tool itself. This includes the irregularities on surface arising due to work deformation under the action of cutting forces and the material weight itself.
5. Under which group, does waviness in surface falls?
a) Primary texture
b) Secondary texture
c) Tertiary texture
d) Quaternary texture
Answer: b
Explanation: If the hills and valleys are not close to each other or they both are far apart, it is due to the machine tool imperfections and this is referred to as waviness or secondary texture.
6. In how many categories, geometrical irregularities can be classified?
a) 3
b) 2
c) 4
d) 5
Answer: c
Explanation: Geometrical irregularities can be classified into four categories i.e. First Order, Second Order, Third Order, Fourth Order and these four categories are further grouped under two groups.
7. Match the following order with their irregularities.
A. First Order - 1. Feed marks of cutting tool
B. Second Order - 2. Lack of straightness of guideways
C. Third Order - 3. Rupture of material during chip removal
D. Fourth Order - 4. Vibrations
a) A-3, B-2, C-4, D-1
b) A-2, B-4, C-1, D-3
c) A-2, B-4, C-3, D-1
d) A-1, B-2, C-4, D-3
Answer: b
Explanation: Second order Irregularities caused by vibrations due to any reason such as chatter marks. If the machine is perfect and free of vibrations, some irregularities can be caused by machining itself due to the characteristic of the process, such type of irregularities include third order. Fourth order includes the irregularities due to rupture of the material during the chip removal.
8. Under which group, does third order irregularities fall?
a) Primary group
b) Secondary group
c) First group
d) Second group
Answer: d
Explanation: Irregularities of small wavelength falls under second group and caused by the direct action of the cutting element or by some disturbance such as friction. It includes irregularities of third and fourth order.
9. Which type of irregularities comes under the first group?
a) First and second order
b) Second and third order
c) Third and fourth order
d) First and fourth order
Answer: a
Explanation: First group includes irregularities of considerable wave-length. These errors include irregularities of first and second order. These are mainly due to misalignment of centres. These errors are also referred to as Waviness.
10. Which of the following is true about texture in case of finishing process?
a) Directional and irregular
b) Regular and directional
c) Irregular and non-directional
d) Regular and non-directional
Answer: c
Explanation: In case of finishing process, the texture is non-directional and non regular while if the surface is machined by a single point cutting tool then the surface will have roughness which is directional and uniformly spaced.
11. Under which category, does the error arises due to non-linear feed motion falls?
a) Second group
b) Primary texture
c) Waviness
d) Roughness
Answer: c
Explanation: The error caused by lack of straightness of guide-ways and non-linear feed motion are also referred to as Waviness or Secondary Texture. These errors or irregularities are of considerable wavelength.
12. Which of the following option is true if hills and valleys on any surface are very close?
a) Wavelength is more
b) Wavelength is small
c) Surface appears more wavy
d) Surface appears rough but wavelength is more
Answer: b
Explanation: If the hills and valleys are close to each other on any surface then the wavelength is very small and the surface appears rough and if they are far apart then the wavelength is more and appears more wavy.
13. Which term is used for errors of first and second order?
a) Micro geometrical error
b) Macro geometrical error
c) Mini geometrical error
d) Mili geometrical error
Answer: b
Explanation: The error or irregularity falls under first and second order are also termed as macro-geometrical errors and the irregularities or error of third and fourth order are termed as micro-geometrical errors.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Surface Roughness”.
1. What is meant by roughness?
a) Minute succession of hills of different height
b) Minute succession of valleys and hills of different height and varied spacing
c) Minute succession of valleys and hills of same height and same gap
d) Minute succession of valleys of different depth
Answer: b
Explanation: Imperfections are bound to be on surface and they take the form of succession of hills and valleys which vary in height and spacing which result in irregularity of the surface. Roughness is the form of these minute imperfections.
2. Surfaces produced by straight and cylindrical grinding tools tend to create which type of roughness?
a) Regularly spaced but directional roughness
b) Regularly spaced but non directional roughness
c) Irregularly spaced but directional roughness
d) Irregularly spaced but non directional roughness
Answer: c
Explanation: The roughness on the surface tends to be both irregularly spaced and directional in straight and cylindrical grinding and in the case of boring or lapping process the surface roughness tends to be irregular and non-directional in nature.
3. Which of the following is necessary for the complete study of surface roughness?
a) Measurement of all the components of elements
b) Analysis of all the component element
c) Assessment of the effects of combined texture
d) Measurement and analysis of all the components and assessment of combined texture
Answer: d
Explanation: For the complete study of the surface roughness, it is important that the analysis and measurement of all the component elements be made and an assessment of the effects of the combined texture be made.
4. Which of the following is true for measurement of surface roughness?
a) 3 dimensional geometry can be easily measured
b) Direction of measurement is perpendicular to the lay
c) Direction of measurement is parallel to the lay
d) Direction of measurement is parallel to the direction of the predominant surface marking
Answer: b
Explanation: There are difficulties in the measurement of surface roughness in three dimensional geometry, but for simplification purposes, it is reduced into two dimensional geometry. To measure, the direction is generally perpendicular to the direction of the predominant surface markings or “lay”.
5. How much a stylus instrument can be magnified to plot or find minute irregularities?
a) 50 times
b) 500 times
c) 5000 times
d) 50,000 times
Answer: d
Explanation: The shape of the hills and valleys is best studied in a cross-section normal to the surface using a stylus instrument which plots a graph in which even the minute irregularities are magnified upto 50,000 times whereas the length over which observations are made is magnified only by 50-300 times.
6. Which of the following is true about Tomlinson surface meter?
a) It is a mechanical instrument
b) It is an electrical instrument
c) It is a mechanical cum optical instrument
d) It is an optical instrument
Answer: c
Explanation: The Tomlinson surface meter uses mechanical cum optical means for magnification. It has a diamond stylus on the surface finish recorder. This instrument is given reliable results.
7. What do you mean by dominant spacing?
a) Distance between successive peaks when irregularities are comparatively uniform in shape and size
b) Distance between middle point of successive hills when irregularities are comparatively uniform in shape and size
c) Distance between middle point of successive valleys when irregularities are comparatively uniform in shape and size
d) Distance between successive peaks when irregularities are regardless of shape and size
Answer: a
Explanation: When the irregularities are uniform in shape and size, then the distance between the peaks or successive peaks is described as pitch or dominant spacing. These spacings are measured by using an instrument.
8. Which of the following is used for the direct measurement of surface quality and commonly used in U.S.A.?
a) Profilometer
b) Tomlinson surface meter
c) Talysurf
d) Replica method
Answer: a
Explanation: Profilometer is most commonly used in U.S.A. It is used for direct measurement of surface quality. It is a dynamic instrument and principle is similar to the gramophone pick-up.
9. Which of the following parameter is important for specifying surface roughness?
a) Size of irregularity
b) Spacing of irregularity
c) Height of irregularities
d) Height, spacing and form of irregularities
Answer: d
Explanation: The surface roughness is concerned with both the size and the shape of the irregularities. Both size and shape i.e. height of irregularities, their spacing and form are important for specifying surface roughness.
This set of Engineering Metrology online test focuses on “Terminology as per Indian Standards”.
1. What do you mean by Geometrical Surface?
a) Surface prescribed by design without any errors of form or surface roughness
b) Surface limiting the body and separating it from surrounding
c) Close representation of real surface
d) Outer surface of the body
Answer: a
Explanation: Geometrical surface is the surface prescribed by design or by process of a manufacturer, neglecting errors of form or surface roughness. Real surface is the surface limiting the body and separating it from surrounding surface.
2. Under which category, does the scratches falls?
a) Lay
b) Effective surface
c) Flaws
d) Geometrical surface
Answer: c
Explanation: Flaws are the type of irregularities which occur at one place or at relatively infrequent or at very widely varying intervals in surface. Scratches, cracks, random blemishes etc. are the type of flaws.
3. Which of the following statement is wrong about sampling length?
a) It is the length of profile necessary for evaluation of irregularities to be taken account
b) It is known as cut off length in regard to measuring instruments
c) It is measured in a direction parallel to general direction of profile
d) It is the length of profile necessary for evaluation of surface roughness parameters
Answer: d
Explanation: Sampling length is the profile length which is necessary for the evaluation of the irregularities. This is also called as the ‘cut-off length’ in regard to the measuring instruments. It is measured in parallel direction to the direction of the profile.
4. What is the general instrument cut off for majority engineering work?
a) 0.08 mm
b) 0.8 mm
c) 0.1 cm
d) 0.5 mm
Answer: b
Explanation: For majority of the engineering work, 0.8 mm is considered to be quite satisfactory for instrument cut-off and for most waviness measurements upper limit of about 25 mm is suitably accepted.
5. What is the upper limit that is commonly accepted for waviness measurement?
a) 10mm
b) 20mm
c) 25mm
d) 15mm
Answer: c
Explanation: There is no theoretical value that could be assigned to maximum spacing for waviness as higher value of waviness tends to merge with other general errors in geometric forms. 25mm is the upper limit commonly accepted as suitable for waviness measurement.
6. What is the correct formula for average wavelength to describe surface roughness? (Where, R a is the arithmetic mean deviation from the mean line of profile)
a) 2π x R a / Mean slope
b) 2π x R a x Mean slope
c) 2π / R a x Mean slope
d) 2π / R a / Mean slope
Answer: a
Explanation: R t is the maximum height of peak to valley within the assessment length. R t measurement is valuable for providing guidance for planning metal-cutting operations and analysing finish. Average wavelength = 2π x R a / Mean slope.
7. Which of the following is an effective surface as per Indian standard?
a) A real surface is an effective surface
b) It is the direction of predominant surface pattern
c) Close representation of real surface
d) Real surface which doesn’t represent instrumental means
Answer: c
Explanation: A real surface is the surface which limiting the body and separating it from the surface of surrounding and effective surface is the close representation of real surface which is obtained by instrumental means.
8. Which of the following is true for a mean and center line of profile?
a) When the waveform is repetitive then there is some difference between mean and centre line
b) Mean line of profile is the mean distance between more prominent irregularities
c) Mean line profile is the average value of ordinates from mean line
d) Centre line of profile is the line which is parallel to the direction of profile and area embraced above and below the line is equal
Answer: d
Explanation: Mean line of the profile is the line which have the form of the geometrical profile. Mean line of profile divides the effective profile so that the sum of the squares of distances between effective points and the mean line is a least. When the waveform is repetitive, the centre and mean line are equivalent.
9. What is ten point height of irregularities?
a) Average difference between 10 highest peaks
b) Average difference between 10 deepest valleys
c) Average difference between 5 highest peaks and 5 deepest valleys
d) Average difference between 10 highest peaks and 10 deepest valleys
Answer: c
Explanation: Ten point height of irregularities is represented by R z and defined as the average difference between the 5 highest peaks and the 5 deepest valleys within the sampling length measured from a line, not crossing the profile and parallel to the mean line.
10. Which of the following is a criterion of a good bearing surface?
a) Positive skew
b) Negative skew
c) Negative peak roughness
d) Positive start up length
Answer: b
Explanation: Skew will show whether porous, sintered and cast iron surfaces will yield a meaningful Ra measurement. Negative value of skew is the criterion for a good bearing surface.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Methods of Measuring Surface Finish”.
1. Which of the following is the best for the examination of surface finish?
a) Touch inspection
b) Visual inspection
c) Scratch inspection
d) Microscopic inspection
Answer: d
Explanation: Microscopic inspection is the best method for examining the surface finish. Visual, touch and scratch inspection methods are not as accurate as microscopic. In these methods, minute flaws can’t be detected.
2. Upto which limits irregularities can be detected with touch inspection of a surface?
a) 0.0001 mm
b) 0.001 mm
c) 0.01 mm
d) 0.1 mm
Answer: c
Explanation: Touch inspection method can tell which surface is rougher. In this method, the finger-tip is moved along the surface at a speed of about 25/sec and the irregularities of about 0.01 mm can be easily detected.
3. Which of the following material is not used for rubbing on the surface to be inspected in scratch inspection?
a) Softer material
b) Hard material
c) Plastic
d) Lead babbitt
Answer: b
Explanation: In scratch inspection method, a softer material like plastic or lead babbitt is rubbed over the surface to be inspected. It carries the impression of the scratches on it which can be easily visualised.
4. Which of the following option is true for given statements about method of measurement of surface finish?
Statement 1: Minute flaws can be easily detected by touch inspection.
Statement 2: Direct instrument measurement is enabled to determine a numerical value of surface finish.
a) F, T
b) T, F
c) F, F
d) T, T
Answer: a
Explanation: The main limitation of the method of inspection by touch is that the degree of surface roughness can not be assessed by this and also the minute flaws can’t be detected by the only touch.
5. What is the limitation of microscopic inspection to check surface finish?
a) An average value is needed
b) Small portion of surface can be detected at a time
c) A master finish surface is also needed
d) It is necessary to inspect whole surface together
Answer: b
Explanation: Microscopic inspection method have some limitation that at a time only a small portion of the surface can be inspected. So for inspection, several readings are required in this method to get an average value.
6. In the method of microscopic inspection what is the angle of beam light with the work?
a) 20 0
b) 30 0
c) 60 0
d) 90 0
Answer: c
Explanation: In one method of microscopic inspection, a straight edge is placed on the surface to be inspected and a beam of light is projected at about 60 degree to the work. The shadows cast into the surface scratches are magnified and studied.
7. Which of the following is true for a method of measurement of surface finish with surface photographs?
a) Different type of illumination is needed
b) No effect of type of illumination
c) Same type of illumination is needed
d) Monochromatic light is needed
Answer: a
Explanation: In the method of surface inspection with magnified photographs of the surface are taken with different types of illumination. After this photographs with different illumination are studied and compared.
8. In case of vertical illumination in measuring surface finish with surface photographs, which will appear as bright area?
a) Flat portion
b) Scratch
c) Irregularity
d) Hills
Answer: a
Explanation: In the inspection of surface with photographs if we use vertical illumination, then irregularities and scratches appear as dark spots and flat portion of the surface as bright area. But in case of oblique illumination, the case is reverse.
9. Which of the following method use pendulum in measuring the surface finish?
a) Micro interferometer
b) Wallace surface dynamometer
c) Reflected light intensity method
d) Microscopic inspection
Answer: b
Explanation: Wallace surface dynamo meter is like a friction meter which consists a pendulum in which the testing shoes are present which are clamped to a bearing surface and a spring pressure which is predetermined can be applied.
10. Which of the following is not true for the method of measurement of surface finish by micro interferometer?
a) Optical flat is used
b) Monochromatic source of light is used
c) Depth of defect can’t be measured
d) Interference lines plays an important role in identification of the defect
Answer: c
Explanation: In the method of inspection of surface by using micro interferometer, an optical flat is used which is placed on the surface to be examined and illuminated by using monochromatic light. Interference bands are studied by using a microscope. Defects or scratches appear as interference lines extending from the dark bands into the bright bands.
11. Which of the following is the direct measure of surface finish in Wallace surface dynamometer?
a) Time of swing
b) Angle of swing
c) Length of swing
d) Height of swing
Answer: a
Explanation: In the case of Wallace surface dynamometer, if the surface to be tested is smooth, there will be less friction and pendulum swings for a longer time period. So, time of swing of pendulum is a direct measure of surface finish.
12. Which of the following is a destructive method in measuring surface finish?
a) Gloss measurement
b) Taper sectioning
c) Diffraction technique
d) Micro interferometer
Answer: b
Explanation: In taper sectioning method, a section is cut through the surface to be inspected at a shallow angle, thus magnifying height variations by a factor of cot theta, and the section is studied by optical microscope. It is an accurate but destructive method.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Advantages of Dial Indicators”.
1. Which of the following is true for the use of dial indicators?
a) Skilled labour is necessary
b) Useful for quantity control in inspection room
c) Useful for quality control in inspection room
d) Considerable practice is required before use
Answer: c
Explanation: Ease of reading in a dial indicator is the best advantage over other conventional type gauges of linear measuring instruments, for which before the proficiency of use requires a degree of skill and considerable practice.
2. Which of the following is provided in dial gauge to raise the plunger?
a) A finger lever
b) Probe
c) Spring
d) A pointer
Answer: a
Explanation: The dial gauge instrument is used in such a way that plunger move sharply in either direction. So the instrument should be made so that by such movement, it will not be damaged and its accuracy and setting will not be spoiled. A knob or finger lever is provided for raising the plunger.
3. What is the relation between accuracy attained and range of travel in measurement with dial gauges?
a) Accuracy attained is directly proportional to the range of travel
b) Accuracy attained is inversely proportional to the range of travel
c) Accuracy attained is directly proportional to the square of a range of travel
d) Accuracy attained is independent to the range of travel
Answer: b
Explanation: When a measurement is done by using dial indicators then the accuracy achieved in measurement is inversely proportional to the range of travel in measurement. There is no need of very large range to attain high accuracy.
4. What is the range of dial indicators?
a) 1 mm
b) 5 mm
c) 7 mm
d) 10 mm
Answer: d
Explanation: Range of travel of dial indicator is of the order of 10 mm. On finished work, dial gauges are mostly used as comparators and a narrow range is needed to have high accuracy.
5. Which of the following is not an advantage of dial indicator?
a) Use in mass production
b) Suited for precision dimensional control
c) Specialised skilled labour helps in attain greater accuracy
d) Versatile
Answer: c
Explanation: Dial gauges are best suited for precision dimension control where tolerance is very little. Over a long period dial gauge instrument is capable of giving trouble-free and dependable measurements.
6. How much operating pressure is required on a measuring head to obtain the zero reading in dial indicators?
a) 20 oz
b) 40 oz
c) 60 oz
d) 80 oz
Answer: d
Explanation: On a measuring head, the required operating pressure in dial gauges to obtain the zero reading is of the order of 80 oz and should remain constant over the whole range.
7. Which of the following is a problem in using dial gauges?
a) Gauge wear
b) Effect of temperature variation
c) Economy
d) Oscillation in the pointer
Answer: d
Explanation: Other advantages of dial gauges over conventional gauges are that it is not subjected to the gauge wear and there is no effect of temperature variation on the instrument. It is a versatile and economic instrument.
8. Which of the following option is true for the given statements about dial indicators?
Statement 1: Dial indicators can inspect dimensional variation.
Statement 2: It is not suitable to use to check out of roundness.
a) T, F
b) F, T
c) F, F
d) T, T
Answer: a
Explanation: Dial indicator is able to inspect dimensional variations which are very difficult to detect by conventional gauges. Type of roundness and taper can be detected with the help of roundness.
9. Which of the following is true for the advantages of dial indicators?
a) Slow speed but good adaptability
b) Adaptability and positive visibility
c) Positive visibility and expensive set ups
d) Use of different inspectors but inexpensive set-ups
Answer: b
Explanation: In addition to the speed of the dial indicator gauge, positive visibility and adaptability, economy and accuracy, place them in the category of a precision measurement instrument.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Working Mechanism of Dial Indicators”.
1. Which of the following is necessary for the working mechanism of dial indicators?
a) High magnification ratio
b) Low magnification ratio
c) Moderate magnification ratio
d) Good magnification ratio is achieved by using gear and pinions in a large area
Answer: a
Explanation: High magnification ratio is important in this instrument which is achieved by the use of an arrangement of gears and pinions in a small area. Gear train is arranged in a manner similar to a clock movement.
2. What is the purpose of a pin which is located in a slot in rack guide in dial indicator?
a) Prevent movement of plunger perpendicular to its own axis
b) Prevent rotation of plunger about its own axis
c) Prevent plunger displacement
d) Prevent movement of plunger in case of misalignment
Answer: b
Explanation: The plunger rotation about its own axis is prevented by a pin which is located in a slot in a rack guide carries a rack accurately meshing with the pinion. The plunger is a perfect sliding fit in its bearings.
3. What is the pressure exerted by spring in dial gauge?
a) 2 oz
b) 3 oz
c) 4 oz
d) 6 oz
Answer: d
Explanation: In order to keep the plunger in a normal position or extended position a spring is used. This spring is a light coil spring and the pressure exerted by this spring is of about 6 oz.
4. Why rotatable bevels are used in dial indicators?
a) Facilitate the work of machine setting
b) Acts as an offset attachment
c) Prevent shocks
d) For making final zero setting
Answer: d
Explanation: Most of the dial indicators include a rotatable bezel. Rotatable bezel is used to make the final zero setting at any position in the full circle. A clamp is also provided for locking it in any position.
5. Which of the following is attached to dial face for rapid checking of parts?
a) Tolerance pointers
b) Contact points
c) Special stems
d) Lever attachments
Answer: a
Explanation: Tolerance pointers can be attached to the dial face for rapid checking of the parts. These pointers can be used to clearly indicate any tolerance, whether bilateral or unilateral, on the dial gauge.
6. What is the purpose of lever attachment used in dial indicators?
a) Checking of parts
b) Transfer motion at the right angle to the spindle
c) Transfer motion at the 180 degree to the spindle
d) Transfer motion at the 60 degree to the spindle
Answer: b
Explanation: Lever attachments are very useful part in a dial indicator. The attachment transfers motion 90 degree directly to the indicator spindle. There is provision to avoid any type of errors caused due to play in bearings and wear.
7. Which of the following is used to inspect deep recesses by dial indicators?
a) Rotatable bezels
b) Cushioned pointers
c) Stem indicators
d) Contact points
Answer: c
Explanation: Dial indicators can also be used inspect deep recesses but in this case, an additional part attachment is required i.e. a stem indicator. Long stem indicators are used where deep recesses are to be inspected.
8. Which of the following option is true for given statements about dial indicators?
Statement 1: Gears are precision cut to prevent backlash.
Statement 2: Change of contact points make dial indicators more versatile.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: d
Explanation: To take up the backlash, a hair spring is fitted to the dial gauge gear trains by a gear and pinion meshing. The gears are precision cut and the movement assembly resembles that of high-grade watch to prevent the gear from backlash.
9. Why a revolution counter is used in dial gauge?
a) To withstand sudden shock
b) To indicate correctly the number of revolution
c) To count and display the number of revolutions
d) To transfer motion at right angle
Answer: b
Explanation: A revolution counter is present in dial gauge, if the pointer makes more than one revolution, it will correctly indicate the number of revolutions and enable a complete reading to be made when the indicator is used for direct measurement.
This set of Tough Engineering Metrology Questions and Answers focuses on “General Care of Dial Gauges”.
1. Which of the following statement is true for dial indicators?
a) It can be used as a direct measuring instrument
b) It can only be used as a comparator
c) There is no effect on accuracy if the surface of contact point worn out
d) Test for repeatability is done only once at the starting
Answer: b
Explanation: Dial gauges are only used as comparators and should not be used as direct measuring instruments. It provides only relative measurement. These are used to check consistency and accuracy in manufacturing processes.
2. What will happen if plunger lifting lever released suddenly?
a) Break the plunger
b) Lever will break
c) No effect
d) Distort rack teeth
Answer: d
Explanation: When the plunger lifting lever raised to allow work to be inserted under the contact point, then after completing this it must be released slowly. Sudden release will distort the rack teeth.
3. Which of the following is true for plunger used in dial indicator?
a) It should never be greased or oil
b) It should be greased monthly
c) It should be oil or greased after every use
d) It should be oiled weekly
Answer: a
Explanation: Oiling and greasing are not desirable in plunger of dial indicator. Oiling of plunger will only result in picking up of dust and sticking. The plunger should never be greased or oiled.
4. When does the back mounting used in dial indicators?
a) When space is limited and positive clamping is not required
b) When space is more and positive clamping is required
c) Space is limited and positive clamping is required
d) Space is more and positive clamping is not required
Answer: c
Explanation: A dial indicator could be mounted either by the back or by the stem. Back mounting of dial indicator provides more positive clamping. It is preferred where fixture design mount permits adjustment and space is limited.
5. Which of the following is not true about the clamping force and clamping of dial indicators?
a) Too great clamping force may jam the plunger
b) Clamp should be loose in case of back lug
c) Tight clamp will always cause slip
d) Steel stem are best for clamping
Answer: a
Explanation: If the dial gauge is clamped by the steel stem, then a great a clamping force will cause the jamming of plunger in the stem. The fixture hole must be smooth and true to avoid distortion, locking and binding of stem in it.
6. Which of the following is not true for contact points used in dial indicators?
a) These are generally blackened
b) Made of hardened steel
c) General purpose contact point is of square form
d) Contact end is polished
Answer: c
Explanation: The contact points are made of hardened steel and blackened to avoid rusting. To prevent scratching of workpiece, the contact end is polished. The general purpose contact point is of spherical shape.
7. What is the accuracy of dial indication for 2.3 turns?
a) Within ±1 graduation
b) Within ±0.1 graduation
c) Within ±2 graduations
d) Within ±0.2 graduations
Answer: a
Explanation: The dial indicator should be accurate to within ±1 graduation with 2.3 turns, that is the variation of the actual object size with the setting master is displayed by the pointer position with a maximum error of ± 1 graduation, at any position within 2.3 turns.
8. Which of the following is true for flat surface of flat contacts in dial gauges?
a) Should be parallel to the plunger
b) Should be truly square to the measuring surface of fixture
c) Should be square to the plunger
d) Should be perpendicular to the measuring surface of plunger
Answer: c
Explanation: If contact points of dial gauge are worn, then it should be replaced as early as possible. The surface of flat contacts should be square truly to the plunger and for accurate reading should be parallel to the measuring surface of the fixture.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Test Indicators”.
1. Which of the following has a maximum sensitivity?
a) Vernier caliper
b) Test indicator
c) Dial indicator
d) Passmeter
Answer: b
Explanation: Accuracy, dependability, performance of test Indicators are outstanding and also long life. Maximum sensitivity and accuracy ensured by jewel mounting of the movement in conjunction with gears and pinions which are precision ground.
2. Which type of housing is used in the test indicator?
a) Box type
b) Spherical
c) Split type
d) Detachable
Answer: a
Explanation: Test indicator is a self-contained instrument, a separate unit which can be easily replaced and removed when in a case or need of repair or for maintenance. The housing of test indicator is of box type.
3. Which of the following is the difference between test indicator and dial indicator?
a) Test indicator has lever type contacts
b) Dial indicator is lighter than test indicator
c) Dial indicator is smaller than test indicator
d) Stylus is present in dial indicator but not in test indicator
Answer: a
Explanation: Test indicators are different from the dial indicators. The obvious difference between these two is that dial indicators have plunger-type contacts and test indicators have lever-type contacts. Test indicators are also lighter and smaller than dial indicators.
4. Which of the following is true about housing of test indicator?
a) Opens at the bottom only
b) Opens at the top only
c) Opens at bottom and top both
d) Opens at front only
Answer: d
Explanation: The housing of test indicator opens at the front only. Single piece construction of side panels and also of bottom surface. The housing encloses totally the movement. It provides maximum protection against shock and damages.
5. Which of the following option is true for the given statement about test indicators?
Statement 1: It can’t measure depth of holes.
Statement 2: Spring force is low.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: The test indicators cannot measure the depth of the holes as dial indicators can. On the test indicator the spring force is very lower, which is desirable while measuring deformable materials.
6. Which of the following is true about the material used for making parts in test indicators?
a) No part is made of plastic
b) All parts are made of hardened steel
c) Cover over the dial face is made of hardened metal
d) Cover over the dial face is made of plastic
Answer: d
Explanation: Plastic parts are not used on this instrument but there is an exception of the cover over the dial face which is made up of plastic. Easy to read by sharply defined dial face is present with contrasting numerals.
7. What is the shape of the front end of the housing of a test indicator?
a) Rectangle
b) Shape of a fork
c) Square
d) Shape of a round ball
Answer: b
Explanation: The design of front end of the housing is of the shape of a fork and between this fork the axis of the stylus is mounted, thus providing added shock resistance and stability. The precision alignment of the 2 mounts also insures maximum accuracy.
8. Which of the following option is true about the guideways present is test indicator?
a) Dovetail guideways are present only at the top of the housing
b) Dovetail guideways are present only at the bottom of the housing
c) Dovetail guideways are present at the top and bottom of the housing
d) Square guideways are present only at the top of the housing
Answer: c
Explanation: Dovetail guideways are present at top and bottom of the housing which permits easy movement of the mounting shanks. By simply tightening a clamp nut which is knurled they can be clamped at any desired point. No need of separate tool.
9. Which of the following is not an advantage of automatic reversing in test indicators?
a) Error free reading
b) Less effort
c) Eliminate reversing lever
d) Indicator hand always move anti-clockwise
Answer: d
Explanation: Automatic reversing is present in test indicator which eliminates the need of reversing lever. The indicator hand present in it always moves in clockwise direction which ensures error-free readings.
10. Which of the following option is true for the given statements about test indicators?
Statement 1: Housing has a satin chrome finish.
Statement 2: Stylus is made of stainless hardened steel.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: c
Explanation: It has a Corrosion-proof housing with satin chrome finish and stainless hardened steel for the stylus. Test indicators are of unique quality and durability. Even after millions of measurement test indicators are still accurate and meet specifications.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Indicators Gauges”.
1. What is the alternative name of passmeter?
a) Dial-type adjustable ring gauge
b) Dial-type adjustable snap gauge
c) Dial-type adjustable plain gauge
d) Dial-type adjustable plug gauge
Answer: b
Explanation: Passmeter is also called as a dial-type adjustable snap gauge. Passmeter instrument is quite similar to the micrometer screw gauge. A passmeter has very big scale present in its frame on which a pointer moves.
2. Which of the following is used for magnification purpose in passmeter?
a) Lever and gear movement
b) Anvil and lever
c) Anvil and gear
d) Clamping screw and anvil
Answer: a
Explanation: The lever and gear movement are used for magnification purposes in a passmeter. It is an indicator gauge and even much more accurate than the dial indicator instrument.
3. Which of the following is a part of internal dial gauge?
a) Solid body and clamping screw
b) Solid tube body and lever
c) Solid tube body with finger probe
d) Hollow tube body and lever
Answer: d
Explanation: Internal dial gauges is a comparison gauge and used to check bore diameters by the comparative method. The instrument consists of a hollow tube body which contained a lever pivoted.
4. What is the range of measurement in a single setting of internal dial gauge with scale division value of 0.002 mm?
a) ±0.06 mm
b) ±0.02 mm
c) ±0.01 mm
d) ±0.1 mm
Answer: a
Explanation: The range of measurement in a single setting of internal dial gauge is approximately ± 0.06 with scale division value of 0.002 mm and ± 0.22 millimeter for scale division value of 0.01 millimeter.
5. What is the smallest size that can be measured by internal dial gauge?
a) 5 to 10 mm in diameter
b) 7 to 10 mm in diameter
c) 11 to 18 mm in diameter
d) 5 to 18 mm in diameter
Answer: c
Explanation: The contacts present in internal dial gauge are interchangeable having extension rods to broaden the measurement range. This instrument can check the smallest size of the order or 11 to 18 mm in diameter.
6. How many tolerance pointers are provided on the scale of passmeter?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: There are two tolerance pointers are present on the scale of passmeter which can be set in any position just by unscrewing the cap which is present on the cover and by using a special setting wrench.
7. What is the value of pressure applied by the spring on the back of the movable anvil in passmeter?
a) 500±50 grammes
b) 100±5 grammes
c) 500±100 grammes
d) 700±200 grammes
Answer: d
Explanation: A detent is present in the passmeter which is used for retracting the movable anvil while taking the measurement. The spring which is present at the back of the movable anvil exerts a contact pressure of about 700 ± 200 grammes.
8. What is the diameter of the contact point of a spindle in dial pipe gauge?
a) 2.5 mm
b) 3.5 mm
c) 4.5 mm
d) 5.5 mm
Answer: a
Explanation: Dial pipe gauge is specially used for easy measurement of pipe’s wall thickness. It is a dial thickness gauge. Diameter of a contact point of the spindle is 2.5 mm. Minimum measurable inside diameter of pipe is about 3.5 mm.
9. What is the largest size range that can be checked by internal dial gauges?
a) 156 to 200 mm
b) 106 to 200 mm
c) 86 to 120 mm
d) 56 to 120 mm
Answer: c
Explanation: The largest size range that can be checked by internal dial gauge is from 86 to 120 mm. It has lever whose one end of the lever is attached to the movable contact of this instrument and other end actuates the pointer.
10. How many contacts are present in internal dial gauges?
a) 1 which is fixed
b) 2, one fixed and other movable
c) 3, two fixed and one movable
d) 4, two fixed and two movable
Answer: c
Explanation: The internal dial gauge instrument has three contacts which are spaced equally along the circumference of the head. Out of three contacts, one is movable and the other two are fixed or non-movable type.
11. Which of the following is not true about passmeter?
a) Fixed spindle
b) Adjustable anvil
c) Used for external measurement
d) Movable pointer
Answer: a
Explanation: An adjustable anvil is present in passmeter. The adjustment of this anvil is done by first removing the protecting cover from the frame and then releasing the clamping screw. A movable spindle is present in passmeter.
12. Upto which depth dial caliper gauge can reach?
a) 60 mm
b) 80 mm
c) 20 mm
d) 10 mm
Answer: b
Explanation: Internal caliper gauge is used for comparison of inside diameter quickly. It can reach 80 mm of depth. It is a comparison gauge and can be used with micrometer or master ring for zero setting.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Screw Threads Terminology”.
1. What is the name of screw thread which is formed on a cone?
a) Parallel screw thread
b) Straight screw thread
c) Tapered screw thread
d) Cylindrical screw thread
Answer: c
Explanation: A screw thread is formed by forming a continuous helical groove on the external or internal surface of cylinder. The screw thread formed on frustum of a cone or a cone is called as tapered screw thread.
2. What type of thread is formed on female screw gauge?
a) External thread
b) Internal thread
c) Both internal and external
d) Major screw thread
Answer: b
Explanation: An internal thread is that which formed on the inside of a workpiece e.g. on female screw gauge or a nut. An external thread is that which formed on the outside of a workpiece e.g on bolts or studs.
3. Which of the following option is true for truncation?
a) Thread can be tranculated at crest only
b) Thread can be tranculatd at root only
c) Thread can be tranculated at crest and root both
d) Thread can’t be tranculated at crest and root both
Answer: c
Explanation: A thread is truncated sometimes at the crest or at the root or at both root and crest and root. The radial distance from the crest to the nearest apex of the fundamental triangle is truncation at the crest is and at the root it is the radial distance from the root to the nearest apex.
4. What is dedendum for external threads?
a) Radial distance between pitch and minor cylinder
b) Radial distance between major and pitch cylinder
c) Radial distance between major and minor cylinder
d) Axial distance between major and pitch cylinder
Answer: a
Explanation: Addendum for an external thread is defined as the radial distance between the major cylinder and pitch cylinder and for internal addendum is the radial distance between the minor cylinder and pitch cylinder. Dedendum for external thread is the radial distance between the pitch cylinder and minor cylinder and this is the radial distance between the major and pitch cylinders for internal thread.
5. Which of the following is not a name of the major diameter of an external thread?
a) Outside diameter
b) Crest diameter
c) Full diameter
d) Cone diameter
Answer: d
Explanation: For a straight thread, Major diameter is the diameter of the major cylinder. It is also known to as the outside diameter or full diameter for external threads. Sometimes it is also called crest diameter.
6. Which of the following is not true about the axial thickness of screw thread?
a) Measured in direction perpendicular to the axis of thread
b) Measured on pitch cylinder
c) Distance between opposite faces of same thread
d) Measured at the same thread
Answer: a
Explanation: In a screw thread axial thickness is the distance between the opposite faces of the same thread. It is measured on the pitch cylinder and in a direction parallel to the thread axis.
7. What is the alternative name of functional diameter?
a) Cone diameter
b) Virtual diameter
c) Root diameter
d) Inside diameter
Answer: b
Explanation: Functional diameter is also known as virtual diameter. For an internal or external thread, this is the pitch diameter of the enveloping thread, lead and flank angles having the full depth of engagement but not at roots and crests.
8. What is a thread per inch in screw thread?
a) Pitch in inches
b) Axial distance moved by threaded part
c) Reciprocal of pitch in inches
d) Radial distance moved by threaded part
Answer: c
Explanation: Thread per inch is the reciprocal of the pitch. The angle made by the thread helix at the pitch line with plane perpendicular to the axis is known as lead angle. Lead angle is measured in an axial plane.
9. Which of the following is not true about effective diameter?
a) Also known as pitch diameter
b) It decides quality of fit between nut and screw
c) This is the diameter of minor cylinder
d) It is a very important dimension for screw threads
Answer: c
Explanation: In case of straight thread, effective diameter is the diameter of the pitch cylinder and is also called as pitch diameter. Effective diameter is the most important dimension at it decides the quality of the fit between the nut and the screw.
10. Which of the following is true for the multiple start screw threads?
a) It is produced by a single helical groove
b) Grooves should be different in spacing
c) It gives a quick transverse
d) It is formed in a transverse section on a cylinder
Answer: c
Explanation: Multiple start screw threads is produced by forming two or more than two helical grooves, equally spaced and similarly formed in an axial section on a cylinder. This gives a ‘quick traverse’ without sacrificing core strength.
11. Which of the following statement is true for screw threads?
Statement 1: Flank angle of symmetrical thread is known as thread’s half-angle.
Statement 2: It is measured parallel to the axis of a thread.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: a
Explanation: In a screw thread the angles between individual flanks and perpendicular to the thread axis which passes through the vertex of the fundamental triangle are called flank angles. The flank angle of a symmetrical thread is called as the half-angle of a thread.
12. Flanks of the threads connect the crest with the roots.
a) True
b) False
Answer: a
Explanation: Flanks of thread are straight edges which connect the crest and the root. Angle of thread is the angle between the flanks or slope of the thread measured in an axial plane and also known as the included angle.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Effect of Pitch Errors”.
1. What is the effect of pitch error?
a) Increase effective diameter of bolt
b) Decrease effective diameter of screw
c) Increase effective diameter of nut
d) Increase effective diameter of both nut and screw
Answer: a
Explanation: An error in pitch increases the effective diameter of a screw or bolts virtually and virtually decreases the effective diameter of a nut. The meaning of the virtual change is that if any screw is perfect except for pitch error, if its effective diameter is not reduced, it will not easily screwed into a perfect ring gauge of same nominal size.
2. What is the virtual change in effective diameter caused by pitch error in whitworth thread?
a) 1.821 X pitch error
b) 1.921 X pitch error
c) 1.111 X pitch error
d) 1.211 X pitch error
Answer: b
Explanation: If p is the error in a pitch for a whitworth thread, then the virtual increase or decrease in the thread effective diameter in case of bolt or nut is given by the formula: Virtual change in effective diameter = 1.921 x p.
3. What is the virtual change of effective diameter of bolt or nut in case of whitworth thread in terms of error in flank angle?
a) 0.1921 X p(θ 1 + θ 2 )
b) 0.182 X p(θ 1 + θ 2 )
c) 0.0195 X p(θ 1 + θ 2 )
d) 0.0105 X p(θ 1 + θ 2 )
Answer: d
Explanation: A Corresponding reduction in the effective diameter is also needed for the errors in flank angles, if the screw or nut is to fit a perfect ring gauge of the same nominal size. Formula for virtual change in effective diameter is : 0.0105 X p(θ 1 + θ 2 ). Where p is the normal pitch and θ 1 and θ 2 are the error in flank angles.
4. Which of the following is periodic pitch error?
a) Successive portion of thread is longer than the mean
b) Successive portion of thread is shorter than the mean
c) Successive portion of thread is longer or shorter than the mean
d) Successive portion of thread is neither longer nor shorter than the mean
Answer: c
Explanation: Periodic pitch error repeats itself along the thread at regular intervals of time. In this type of error, successive thread portions are either shorter or longer than the mean. It occurs when the tool velocity work ratio s not constant.
5. What is the formula of virtual effective diameter in case of unified threads?
a) Simple effective diameter + [ + 0.0098 p (θ 1 + θ 2 )].
b) Simple effective diameter – [ + 0.0098 p (θ 1 + θ 2 )].
c) Simple effective diameter + [ + 0.0098 p (θ 1 + θ 2 )].
d) Simple effective diameter – [ + 0.0098 p (θ 1 + θ 2 )].
Answer: a
Explanation: For unified thread total virtual effective diameter is Simple effective diameter + [ + 0.0098 p (θ 1 + θ 2 )] while in case of metric thread it is Simple effective diameter + [ + 0.0131 p (θ 1 + θ 2 )].
6. Which of the following is not correct when minor and major diameter have errors?
a) Will cause interference between mating parts
b) Flank contact increases
c) Less root section
d) Less wall thickness
Answer: b
Explanation: Errors on the minor and major diameters will cause interference in the mating thread. Due to errors in minor and major diameter, the wall thickness and root section will be less, also the flank contact will be decreases and the component will be weak in strength.
7. Which of the following are main elements, error in any of these can cause rejection of thread?
a) Major diameter and minor diameter
b) Major diameter, minor diameter and effective diameter
c) Major diameter, minor diameter, effective diameter and pitch
d) Major diameter, minor diameter, effective diameter, angle of thread and pitch
Answer: d
Explanation: In case of plain holes and shafts, there is one dimension only which has to be considered i.e. diameter. Errors in diameter if exceed the permissible tolerance, will result in rejection of part. But in case of screw threads there are minimum 5 important elements which are Major diameter, minor diameter, effective diameter, angle of thread and pitch and error in any one of these will result rejection of the thread.
8. What is the nature of the graph between cumulative pitch error and length of thread in case of progressive pitch error?
a) Straight line
b) Parabolic
c) Hyperbolic
d) Exponential
Answer: a
Explanation: Progressive pitch error can be caused due to pitch error in any generating machine or in the lead screw of a lathe. The graph between cumulative pitch error and thread length in progressive pitch error is a straight line.
9. Which of the following is the correct option for given statements about the effect of pitch error?
Statement 1: Pitch error can cause progressive tightening on assembly.
Statement 2: Tool work velocity ratio will play an important role to prevent pitch errors.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: d
Explanation: The threads are commonly generated by a point cutting tool. For pitch to be correct, the ratio of the tool linear velocity and work’s angular velocity must be correct and constant, otherwise pitch errors will occur.
10. Which of the following is not related to the drunken thread?
a) Periodic pitch error
b) Erratic pitch error
c) Progressive pitch error
d) Irregular pitch error
Answer: c
Explanation: Drunken thread has erratic pitch, in which the advance of the helix is irregular in thread’s 1 complete revolution. Thread drunkenness is a case of a periodic pitch error recurring at regular intervals of 1 pitch.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Gauge Wear”.
1. In which gauges wear takes place more rapidly?
a) Screw thread gauges
b) Plain gauges
c) Profile gauge
d) Go/nogo gauge
Answer: b
Explanation: Screw thread gauges wear more rapidly than plain gauges. When effective diameter NOT GO and full form GO ring gauges are used, manufacturing tolerance of work is reduced by the amount that must be allowed for wear in the full form ring gauges.
2. What is the common range of wear in ring thread gauge?
a) 0.0025mm – 0.005mm
b) 0.025mm – 0.05mm
c) 0.0025mm – 0.0075mm
d) 0.025mm – 0.075mm
Answer: d
Explanation: It is common for a hardened ring thread gauge to wear from 0.025 mm to 0.075 mm during a few days of operation. Gauge tolerance is adjusted in such a way that takes wear allowance into account.
3. What is the wear allowance recommended by BSI for solid ring and plug gauges?
a) 0.01mm
b) 0.5mm
c) 0.05mm
d) 0.001mm
Answer: c
Explanation: The allowance recommended by B.S.I, for wear on generally used solid ring and plug gauges is 0.002 inch . Frequent checking of solid pattern gauges is necessary in order to obviate this effect.
4. What is the relation between the effective diameter of a thread hole and an effective diameter of the screw in screw thread gauge?
a) minimum effective diameter of a thread hole must necessarily be greater than the maximum effective diameter of the screw
b) maximum effective diameter of a thread hole must necessarily be greater than the minimum effective diameter of the screw
c) minimum effective diameter of a thread hole must necessarily be lesser than the maximum effective diameter of the screw
d) maximum effective diameter of a thread hole must necessarily be greater than the minimum effective diameter of the screw
Answer: a
Explanation: The minimum effective diameter of a thread hole must necessarily be greater than the maximum effective diameter of the screw. The pitch diameter of a parallel thread is the diameter of the imaginary co-axial cylinder which intersects the surface of the thread in such a manner that the intercept on a generator of the cylinder.
5. Which of the following statement is incorrect about adjustable thread gauges?
a) It is used for precision gauging purposes
b) It shows more gauge wear than solid gauge wear
c) It overcome the disadvantages by solid gauge wear
d) Its wear allowance is 0.0125mm
Answer: b
Explanation: In order to overcome the disadvantages of solid gauge wear, the adjustable pattern screw thread gauge was evolved which is widely employed for precision gauging purposes. Although wear can be compensated for but the B.S. allowance of 0.002″ for solid gauges is reduced by about 0.0005″.
6. What is the provision for wear of Go gauges is made by?
a) A margin greater than maximum metal limit of work
b) A margin greater than tolerance zone of gauge
c) A margin lesser than maximum metal limit of work
d) A margin between tolerance zone of gauge and maximum metal limit of work
Answer: d
Explanation: ‘Go’ gauges provision for wear is made by the introduction of a margin between the maximum metal limit of the work and tolerance zone for the gauge. Wear should not be permitted beyond the maximum metal limit of the work, when the limit is of critical importance.
7. What is the magnitude of wear allowance in Go gauges in present British System?
a) One-fifth of gauge tolerance
b) One-third of gauge tolerance
c) One-tenth of gauge tolerance
d) One-fifteenth of gauge tolerance
Answer: c
Explanation: Wear allowance magnitude is one-tenth of the gauge tolerance. In British system dispenses with workshop and inspection gauges and we give the same tolerance limits on workshop and inspection gauges and the same gauges can be used for both purposes.
8. If work tolerance is less than 0.09mm, then how much wear allowance is given to Go gauge?
a) 5% gauge tolerance
b) No allowance
c) 1% gauge tolerance
d) 2.5% gauge tolerance
Answer: b
Explanation: When work tolerance is less than 0.09 mm there is no need of giving allowance for wear. 10% gauge tolerance is given only on ‘Go’ gauge for wear if work tolerance is more than 0.09 mm.
9. Where should tolerance zone is placed for Go Gauges in present British System?
a) Inside work limits
b) Outside work limits
c) Equal to work limits
d) Regardless to work limits
Answer: a
Explanation: The tolerance zone for the ‘Go’ gauges should be placed inside the work-limits. In First System, tolerances on the workshop gauge are arranged to fall inside the work tolerance, further ‘Go’ gauge should eat away 10% of work tolerance.
10. Where should tolerance zone is placed for No-Go Gauges in present British System?
a) Inside work limits
b) Outside work limits
c) Equal to work limits
d) Regardless to work limits
Answer: b
Explanation: The tolerance zone for the ‘No Go’ gauges should be placed outside the work-limits. In First System, inspection gauge tolerances fall outside the work tolerance and tolerance on No Go’ gauge should be one-tenth of work tolerance.
This set of Engineering Metrology online quiz focuses on “Tolerance for Screw Thread Gauges and Screw Threads”.
1. How many variables are taken into consideration for the calculation of effective diameter tolerance?
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: The screw threads combination is very much complex. There is a complicated interplay between pitch, thread angle and effective diameter. The effective diameter tolerance must take into consideration the three variables i.e. the major diameter, the length of thread engagement, the pitch.
2. What is the formula for tolerance on effective diameter ?
a) a∛D +b√L +c√p
b) a∜D +b√L +2c√p
c) a∛D +b√2L +c√p
d) 2a∛D +2b√L +3c√p
Answer: a
Explanation: Effective diameter tolerance depends on the Diameter, length of thread, pitch. It depends on them non linearly. Equation of tolerance is a∛D +b√L +c√p where D = major diameter, L = length of engagement, p = pitch, a, b, c are constants.
3. How the values of constants affect the accuracy of tools?
a) Decrease in accuracy will increase the value of constants
b) Increase in accuracy will increase the value of constants
c) Decrease in accuracy will reduce the value of constants
d) Increase in accuracy will reduce the value of constants
Answer: d
Explanation: The value of these constants will depend upon the prevailing accuracy of tools and machines used to produce the screw threads. Increase in accuracy will reduce the value of constants. The specifications provide for three grades of fits, close, medium, free.
4. What are the values of constants for whit worth threads?
a) a=0.003 b=0.005, c=0.002
b) a=0.002, b=0.003, c=0.005
c) a=0.004, b=0.005, c=0.006
d) a=0.001, b=0.002, c=0.003
Answer: b
Explanation: The value of these constants according to British Standard Specifications for Whitworth threads for medium fit are a=0.002, b=0.003, c=0.005 i.e. the equation of tolerance on effective diameter is 0.002∛D +0.003√L +0.005√p
5. What is the relation between close fit and free fit?
a) Close fit tolerance is one third of free fit
b) Close fit tolerance is one half of free fit
c) Close fit tolerance is two thirds of free fit
d) Close fit tolerance is three fourths of free fit
Answer: c
Explanation: The basic formula gives effective diameter tolerance for medium fit. Close fit tolerances are two-thirds of free fit, and free fit tolerance is one and a half times that of medium fit. This results in tolerance increasing by 50% each time from close-medium-free fit.
6. Match the following fit with their use?
A B
1) Close a) Suitable for bulk of screw threads
2) Medium b) Suitable for screw requiring fine snug fit
3) Free c) Suitable for interchangeable screw threads
a) 1-a, 2-b, 3-c
b) 1-c, 2-b, 3-a
c) 1-b, 2-a, 3-c
d) 1-b, 2-c, 3-a
Answer: d
Explanation: Close fit applies to screw requiring a fine snug fit. Medium fit is suitable for better class of ordinary interchangeable screw threads and free fit is suitable for bulk of screw threads of ordinary commercial quality.
7. What is the major diameter tolerance of effective diameter for external threads?
a) +0.01√p
b) -0.05√p
c) +0.05√p
d) -0.01√p
Answer: a
Explanation: In major diameter, the tolerance is given by expression Effective Diameter tolerance = +0.01√p. It is applicable for all grades of fits for external threads. In major diameter, no such tolerance is laid down for internal threads.
8. What is the minor diameter tolerance of effective diameter for external threads?
a) Effective diameter tolerance+0.03√p & Effective diameter tolerance+0.01√p
b) Effective diameter tolerance+0.02√p & Effective diameter tolerance+0.01√p
c) Effective diameter tolerance+0.013√p & Effective diameter tolerance+0.02√p
d) Effective diameter tolerance+0.01√p & Effective diameter tolerance+0.02√p
Answer: c
Explanation: Minor diameter tolerance for external threads is for close fit and is for external threads in case of medium and free fit.
9. Which of the following is incorrect for the minor diameter tolerance of effective diameter for internal threads?
a) For 26 tpi : Tolerance = 0.2p+0.004”
b) For 26 tpi : Tolerance = 0.2p+0.005”
c) For 22 tpi : Tolerance = 0.2p+0.005”
d) For 26 tpi : Tolerance = 0.2p+0.007”
Answer: b
Explanation: For minor diameter tolerance of internal threads, tolerance for 26 tpi and finer is equal to 0.2p + 0.004”, tolerance for 24 tpi and 22 tpi is equal to 0.2p+0.004”, tolerance for 20 tpi and coarser is equal to 0.2p+0.004”.
10. Why Wide tolerance on core diameter of internal threads is given?
a) To prevent binding at the root of the tap
b) To prevent binding at the crest of the tap
c) To prevent binding at the flank of the tap
d) To prevent binding at the face of the tap
Answer: a
Explanation: To prevent binding at the root of the tap wide tolerance on the core diameter of internal threads is given. It permits a tapping drill being used of ample size. This follows a general practice and results in a flat crest to the root of the thread.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Screw Thread Gauge Tolerance”.
1. How many types of tolerances are there in screw thread gauge tolerance?
a) 2
b) 3
c) 5
d) 4
Answer: b
Explanation: Tolerance for plug and ring screw gauges are covered in three classes, i.e. Reference, Inspection and workshop. Workshop gauges being within the work tolerance, and inspection and reference being outside.
2. What is the reference gauge tolerance for 6” diameter gauge?
a) 0.001”
b) 0.002”
c) 0.003”
d) 0.004”
Answer: a
Explanation: Tolerances were graded in terms of diameter. The workshop and inspection tolerance on gauges for 6” inches is 0.002” on effective diameter. Reference gauge tolerance was half of these tolerances i.e. 0.001” for 6”. This tolerance included the virtual effect of pitch and angle errors.
3. What is the tolerance on effective diameter for gauges upto 1.5” diameter as per B.S.S. No. 919?
a) 0.0002”
b) 0.0003”
c) 0.0004”
d) 0.0005”
Answer: c
Explanation: B.S.S. No. 919 was issued on screw gauge tolerance as an emergency. Specifications widened tolerance more on smaller size than larger. The tolerance was divided into two separate elements. For gauges upto 1.5″ diameter, Tolerance on effective diameter = 0.0004″.
4. What is the equivalent of pitch and angle tolerance on effective diameter for gauges upto 1.5” diameter as per B.S.S. No. 919?
a) 0.0004”
b) 0.0005”
c) 0.0006”
d) 0.0007”
Answer: b
Explanation: For gauges upto 1.5″ diameter, Equivalent of pitch and angle tolerance on effective diameter = 0.0005″. The simple effective diameter tolerance on NO GO gauge was same but virtual tolerance was halved. It is due to the fact that short length of thread is not liable to much pitch error.
5. What is the effect of pitch error upon the effective diameter of a screw thread?
a) D1 = E x K
b) D1 = 2E x K
c) D1 = E x K/2
d) D1 = E x K x 4
Answer: a
Explanation: The compensations for pitch and angle errors are also provided for by the application of corrections for each of these quantities. Effect of pitch error upon effective diameter of a screw thread is
D1 = E x K where D1=Effective dia. equivalent of pitch error, E = max. cumulative pitch error along the thread, K = constant for the shape of thread.
6. A constant ‘K’ is used for defining the shape of thread. What is the value of ‘K’ for Whitworth?
a) 1.5
b) 1.62
c) 1.73
d) 1.92
Answer: d
Explanation: Effect of pitch error upon the effective diameter of a screw thread is D1 = E x K,
K = constant for the shape of thread = 1.92 for Whitworth, = 1.73 for International metric threads and = 2.27 for B.A.
7. What is the compensation for angle error?
a) ΔE=3p*ΔΘ/100
b) ΔE=p*ΔΘ/100
c) ΔE=p*ΔΘ/50
d) ΔE=p*ΔΘ/200
Answer: a
Explanation:The compensation for angle error, ΔE is related to the pitch p as follows: ΔE=p*Θ/100 where ΔΘ is the angle error in degrees. It is necessary that ΔE and p should be expressed in the same measure, i.e. English or metric. The angle error is the arithmetical sum of the errors of the two flank angles irrespective of their signs.
8. Which of the following item must fall within the prescribed limit for plug gauges?
a) Measured effective diameter along the pitch line
b) Measured effective diameter perpendicular to the pitch line
c) Measured minor diameter along the pitch line
d) Measured minor diameter perpendicular to the pitch line
Answer: a
Explanation: There are some requirements on effective dia which must be met before the gauge can be accepted i.e. the measured effective diameter along the pitch line and the measured effective diameter is +ΔE1+ΔE2 for plug gauges.
9. Which of the following item must fall within the prescribed limit for ring gauges?
a) Measured effective diameter +ΔE1+ΔE2
b) Measured effective diameter +ΔE1-ΔE2
c) Measured effective diameter -ΔE1-ΔE2
d) Measured effective diameter -ΔE1+ΔE2
Answer: c
Explanation: For ring gauges, requirements that must met are the measured effective diameter along the pitch line and the measured effective diameter -ΔE1-ΔE2. It should be noted that the max. allowable pitch error or the max. allowable angle error can readily be found from the formulae given, by evaluating ΔE1or ΔE2 to the full effective diameter tolerance allowed on any given size of gauge.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Diameter and Pitch Combinations”.
1. What is the range of diameters that have been specified in IS: 4218 -1976?
a) 1-50mm
b) 1-500mm
c) 1-250mm
d) 1-100mm
Answer: b
Explanation: The diameter and pitch combinations for ISO Metric screw threads in the diameter range of 1 to 500 mm have been specified in the IS: 4218 —1976. This standard specifies several pitches for various diameters.
2. According to IS: 4218 -1976, How many types of pitches are present?
a) 2
b) 1
c) 4
d) 3
Answer: a
Explanation: According to this IS: 4218 -1976, there are two types of pitches i.e. coarse series and fine series. For any diameter in study, coarse pitch is the largest of the pitches associated with that diameter , the rest of the pitches being always finer than the coarse pitch are called fine pitches.
3. How many choices for diameters are present in IS: 4218 -1976?
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: IS: 4218 -1976 gives three choices for diameters i.e. first choice, second choice and third choice, and recommends the use of diameters given in the first choice as far as possible for various applications.
4. How many tolerance grades are there for ISO metric screw threads?
a) 4
b) 5
c) 6
d) 7
Answer: d
Explanation: On ISO metric threads, tolerances are defined by tolerance position and tolerance grades. There are 7 tolerance grades and these are 3, 4, 5, 6, 7, 8, and 9. 3, 4 and 5 are for precision threads and 6 for medium quality and for less precision methods are 7, 8 and 9.
5. For a diameter of 20mm, several pitches given are 1, 1.5, 2 and 2.5mm. Which of the following is coarse pitch?
a) 1mm
b) 2 and 2.5mm
c) 1.5, 2 and 2.5mm
d) 2.5mm
Answer: d
Explanation: For the diameter of 20 mm various pitches allowed are 1, 1.5, 2 and 2.5 mm. Of these 2.5 is coarse pitch, and the 1, 1.5 and 2 are fine pitches. Only largest of the pitches falls under coarse pitch and other remaining comes under fine pitches.
6. What is the symbol designated for the pitch diameter combination of an ISO Metric screw thread by IS: 4218 -1976?
a) M
b) PD
c) DP
d) P
Answer: a
Explanation: According to this IS: 4218 -1976, the pitch diameter combination of an ISO Metric screw thread is designated by the letter M followed by the values of the nominal thread diameter and the pitch.
7. What is the correct way to write pitch diameter combination of thread size 20mm and pitch 2.5mm?
a) M 20:2.5
b) M {20,2.5}
c) M 20×2.5
d) M 20-2.5
Answer: c
Explanation: While the designation of pitch diameter combination of screw thread, letter M is followed by the values of the nominal thread diameter and the pitch, the two being separated by the sign ‘x’. Hence, combination of thread size 20mm and pitch 2.5mm is shown by M 20×2.5.
8. What should M 22 designate in pitch diameter combination?
a) 22mm diameter with lowest fine pitch
b) 22mm diameter with standard coarse pitch
c) 22mm diameter with highest fine pitch
d) 22mm diameter with all pitch
Answer: b
Explanation: When no pitch is mentioned in the designation of pitch diameter combination, it means standard coarse pitch is implied e.g., M 22 shall designate a pitch diameter combination of threads size 22 mm and coarse pitch of 2.5 mm.
9. Which of the following is the first choice of diameter which is indicated by IS?
a) 20
b) 18
c) 17
d) 22
Answer: a
Explanation: The first choice of diameters which are indicated by IS are 1,1.2,1.6,2,2.5,3,4,5,6,8,10,12,16, 20,24, 30, 36, 42, 48, 56, 64, 72, 80, 90, 100, 110, 125, 140, 160,180, 200, 220, 250 and 280.
10. Which of the following tolerance grades can be used for minor diameter and pitch diameter of internal threads?
a) 4, 6, 8
b) 3, 4, 5, 6, 7
c) 3, 4, 5
d) 4, 5, 6, 7, 8
Answer: d
Explanation: The tolerance grades recommended for minor diameter and pitch of internal threads are 4, 5, 6, 7, and 8 and for major diameter of external threads and for pitch diameter of external threads are 4, 6, 8 and 3, 4, 5, 6, 7, 8, 9 respectively.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Involute Curve”.
1. What is the alternative name of involute gears?
a) Straight tooth gear
b) Helical gear
c) Cycloid gear
d) Spiral gear
Answer: a
Explanation: Commonly used forms of gear teeth are:
involute
cycloidal
Involute gears are also called spur gears and straight tooth.
2. Where does involute gear is used?
a) For crude purposes
b) General purpose in precision engineering
c) Where heavy loads comes on machine
d) Where impact loads comes on machine
Answer: b
Explanation: Involute gears are used for general purpose in precision engineering. The cycloidal gears are not used in modern engineering generally, but can be used for some crude purposes where impact and heavy loads come on the machine.
3. What type of teeths is present in involute rack?
a) Spiral
b) Helical
c) Straight
d) Double helical
Answer: c
Explanation: The straight teeth are present in involute rack. Only a simple cutter is needed to form the complex involute form on gear. It is an advantage which is associated with involute curve or profile.
4. Upon which factor, shape of involute curve depends?
a) Base circle diameter
b) Pitch circle diameter
c) Addendum circle diameter
d) Face width
Answer: a
Explanation: The shape of involute curve entirely depends upon the diameter of base circle as involute is generated from a base circle. Pressure angle and pitch also important for the profile of involute.
5. Which of the following is correct about involute curve?
a) Involute curvature increases with increase in base circle diameter
b) Involute is straight line when diameter of base circle is zero
c) Involute curvature increases with increase in pitch circle diameter
d) Involute curvature decreases with increase in base circle diameter
Answer: d
Explanation: The curvature of the involute decreases as the diameter of base circle goes on increasing and when diameter of base circle is infinity then finally involute becomes straight line.
6. What is the standard pressure angle for an involute system?
a) 20 or 14.5 degree
b) 20 or 30 degree
c) 30 or 14.5 degree
d) 40 or 30 degree
Answer: a
Explanation: The involute system has a standard value of pressure angle which is 20° or 14.5° whereas on the cycloidal system does not have a standard pressure angle, it varies from zero at pitch line to a maximum at the teeth tips.
7. Which of the following is true for an involute curve?
a) Tangent to any point on involute is parallel to the generator at that point
b) Tangent to any point on involute is perpendicular to the generator at that point
c) Tangent to any point on involute is at 45 degree to the generator at that point
d) Tangent to any point on involute is at 30 degree to the generator at that point
Answer: b
Explanation: It is important to fulfill the requirements of law of gearing for an involute curve. The tangent at any point on involute will be perpendicular to the generator at that point. This condition fulfils the requirements needed for laws of gearing.
8. What is the effect of centre distance between two gears on velocity ratio of involute gear pair?
a) Less for less velocity ratio
b) Less for more in velocity ratio
c) More or less for more velocity ratio
d) No effect
Answer: d
Explanation: Variations in the centre distance between 2 gears have no effect on the velocity ratio between an involute gears pair. It is an advantage associated with the involute for the flank curve of gear.
9. What is the involute curve?
a) Point Locus on a straight line which rolls around a circle without slipping
b) Point Locus on a straight line which rolls around a line without slipping
c) Point Locus on a circle which rolls around a pitch circle without slipping
d) Point Locus on a circle which rolls around a line without slipping
Answer: a
Explanation: An involute curve is a point locus on straight line which rolls, around a circle without slipping. It could also be defined as the point locus on a piece of string which in unwound from a cylinder or stationary cylinder.
10. Which of the following factor is least important for an involute profile?
a) Number of teeth
b) Pressure angle
c) Pitch
d) Gear it mates with
Answer: d
Explanation: The involute gear profile is important in machine design, since unlike with other gear systems, involute gear tooth profile depends on only the number of teeth on the gear, pitch and pressure angle but does not depend on the gear it mates with.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Terminology of Gear Tooth”.
1. Which of the following is the correct mathematical formula for module?
a) D/N
b) D/2N
c) 2D/N
d) 4D/N
Answer: a
Explanation: Module is defined as the length of the pitch circle diameter / tooth. Thus, if Pitch Circle Diameter of gear is D and number of teeth is N, then module is equal to D/N. It is generally expressed in millimeter.
2. What is the standard value of clearance?
a) 0.572 x m
b) 0.182 x m
c) 0.157 x m
d) 0.821 x m
Answer: c
Explanation: Term clearance used in terminology of gear tooth is the radial distance from the tooth top to the bottom of a mating tooth space when the teeth are engaged symmetrically. Standard value of clearance is 0.157 m where m is module.
3. What is the value of addendum?
a) 1 module
b) 2 modules
c) 3 modules
d) 4 modules
Answer: d
Explanation: This is the radial distance from the pitch circle to the tooth tip. Its value is equal to 1 module. Another term diametral pitch is defined as a number of teeth per inch of pitch circle diameter.
4. What is dedendum?
a) Addendum + 2 x clearance
b) Addendum + clearance / 2
c) 2 x Addendum + clearance
d) Addendum + clearance
Answer: d
Explanation: Dedendum is the radial distance from the pitch circle to the bottom of the tooth space. Dedendum is equal to Addendum plus Clearance = m + 0.157 m = 1.153 m as one addendum is a module and standard value of clearance is 0.157 m.
5. What is the flank of tooth?
a) Part of the surface of tooth which is above the pitch surface
b) Part of the surface of tooth which is below the pitch surface
c) Part of the surface of tooth which is in the middle of top and bottom of the pitch surface
d) Part of the surface of tooth which is at the top of the pitch surface
Answer: b
Explanation: Face of the tooth is that part of the tooth surface which is lying above the pitch surface. Flank of Tooth is that part of the tooth surface which is below the pitch surface.
6. What is tooth thickness?
a) Circular pitch / 2
b) Circular pitch / 4
c) 2x Circular pitch
d) 4 x Circular pitch
Answer: a
Explanation: Thickness of tooth is the distance of arc measured along the pitch circle from its intercept with one flank to its intercept with the other flank of the same tooth.
Tooth thickness = C.P./2 or πm/2.
7. What is the name of angle which is present between line of action and common tangent to the pitch circles?
a) Helix angle
b) Lead angle
c) Pitch angle
d) Pressure angle
Answer: d
Explanation: The angle between the line of action and the common tangent to the pitch circles is called as pressure angle. The standard values of pressure angle are 14.5 degree and 20 degree. Pressure angle is generally represented by φ.
8. Which of the following is not the correct formula for base pitch?
a) Base circumference / Number of teeth
b) π x Base circle diameter / N
c) π x D sinφ / N
d) π x m x cosφ
Answer: c
Explanation: Base pitch is the distance which is measured around the base circle from the origin of the involute on the tooth to the origin of a involute on the next tooth.
Base pitch = Base circumference / Number of teeth
= π x Base circle diameter / N = π x D cosφ / N = π x m x cosφ.
9. What is blank diameter?
a) Pitch circle diameter plus addenda
b) Pitch circle diameter plus twice the addenda
c) Base circle diameter plus addenda
d) Base circle diameter plus twice the addenda
Answer: b
Explanation: Blank diameter is that diameter of blank from which gear is out. Blank diameter is equal to the pitch circle diameter plus addenda.
Blank diameter = mN + 2m = m x .
10. Which of the following is not necessary to find normal module of helical gear?
a) Number of teeth
b) Pitch diameter
c) Helix angle
d) Tooth thickness
Answer: d
Explanation: The formula for normal module of helical gear is m n = cosα where N is number of teeth, D is pitch diameter and α is helix angle. Also, m n = p n /π where p n is normal circular pitch.
11. What is worm lead in worm and worm gear?
a) N w x 2p x
b) N w x 4p x
c) N w x p x
d) N w / p x
Answer: c
Explanation: Worm lead is represented by L and L = N w x p x where, N w is number of threads in worm and is p x axial pitch. Lead angle in worm and worm gear is represented by ψ and tanψ = L/πd where d is pitch diameter.
This set of Engineering Metrology Question Bank focuses on “Sources of Errors in Manufacturing Gears”.
1. Which of the following is true for generating method of gear formation?
a) No use of cutter
b) Profiles of several teeth are formed simultaneously
c) Linear motion of the tool and the blank is not constant
d) Each tool space is cut independently
Answer: b
Explanation: Gear teeth are generally made by two methods, reproducing method and generating method. Method in which the cutting tool forms the several teeth profiles simultaneously during constant relative motion of the blank and tool is known as Generating method.
2. Which of the following is true for high power gears?
a) Operated at low speed
b) Operated at high speed
c) Operated at moderate speed
d) Operated at high or moderate speed
Answer: a
Explanation: High power gears are operated at low speeds generally but it has to transmit large force. Therefore for this purpose the gear teeth should specify fullest possible contact along the tooth length.
3. Which of the following gear is used for counting and timing purposes?
a) High speed gears
b) High power gears
c) Low speed gears
d) Precision gears
Answer: d
Explanation: Constant gearing ratio is the main requirement of the precision gears. Precision gears are generally used for indexing devices and measuring instruments, or in counting and timing purposes, and usually have small face width and small module.
4. What is the kinematic error in gears?
a) Minimum error in gear rotation per gear revolution
b) Accumulated permissible error in gear rotation per gear revolution
c) Maximum error in gear rotation per gear revolution
d) Accumulated permissible error in gear rotation in two gear revolutions
Answer: b
Explanation: Kinematic error is defined as the permissible accumulated error in gear rotation per gear revolution. The kinematic accuracy index is the maximum kinematic error. It can be defined as the maximum angular error in gear rotation, when it meshes in single-profile engagement with a precise gear.
5. What is profile error?
a) The minimum distance of any point on the profile of tooth form and normal to the design profile when the two coincide at the reference circle
b) The minimum distance of any point on the profile of tooth form and parallel to the design profile when the two coincide at the reference circle
c) The maximum distance of any point on the profile of tooth form and parallel to the design profile when the two coincide at the reference circle
d) The maximum distance of any point on the profile of tooth form and normal to the design profile when the two coincide at the reference circle
Answer: d
Explanation: Profile error is a possible error on spur, helical or bevel gear etc. It is the max distance of any point on the profile of tooth and normal to the design profile when two coincide at the reference circle.
6. What is a cyclic error?
a) Mean value of the discrete values of variation in the kinematic error of the gear taken for all cycles during one revolution
b) Mean value of the range of variation in the kinematic error of the gear taken for all cycles during one revolution
c) Mean value of the range of variation in permissible deviations in basic pitch of the gear taken for all cycles during one revolution
d) Mean value of the range of variation in the angular error of the gear taken for all cycles during one revolution
Answer: b
Explanation: The cyclic error is defined as the mean value of the range of variation in the kinematic error of the gear which is taken for all cycles during 1 revolution. It can also be explained as an error which occurs during each revolution of the element under consideration.
7. How bearing contact of mating gears is represented?
a) By the relative size of the bearing contact pattern in mm
b) By the relative size of the bearing contact pattern in cm
c) By the relative size of the bearing contact pattern in meter
d) By the relative size of the bearing contact pattern in percent
Answer: d
Explanation: Bearing contact for mating gears is represented by the relative size of the bearing contact pattern in % and along the length of tool it is represented by the ratio of the traces of contact, subtracting gaps larger than the size of the module, to the full tooth length.
8. Another name for Wobble ______________
a) Radial run-out
b) Eccentricity
c) Composite error
d) Axial run-out
Answer: d
Explanation: Run out is the total range of reading of an indicator with the contact point applied to a rotated surface, without axial movement about an axis which is fixed. Axial runout is the runout measured parallel to the rotation axis, at a specified distance.
9. What is undulation?
a) Departure of the actual tooth surface from design surface
b) Departure of the virtual tooth surface from design surface
c) Departure of the design surface from actual tooth surface
d) Departure of the design surface from virtual tooth surface
Answer: a
Explanation: Undulation is a departure of the actual tooth surface from the design surface and undulation height is the normal distance between 2 surfaces that contain the crests and the troughs of the tooth undulation.
10. Which of the following is true for eccentricity?
a) Half the radial run-out
b) Half the axial run-out
c) Equal to the radial run-out
d) Equal to the axial run-out
Answer: a
Explanation: Radial runout is the runout measured along a perpendicular to the rotation axis. Eccentricity is half the radial run-out.
11. Which of the following can be used to ensure smoothness of gear operation?
a) By limiting the minimum permissible deviation in base circle
b) By limiting the maximum permissible deviation in base circle
c) By limiting the maximum permissible deviation in basic pitch
d) By limiting the minimum permissible deviation in basic pitch
Answer: c
Explanation: Smoothness of gear operation is important to provide for noiseless engagement and longer service life of gearing. The smoothness of gear operation can be ensured by limiting the maximum permissible deviations in basic pitch.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Gear Measurement”.
1. What is the effect of improper alignment of each tooth?
a) Tooth thickness increases
b) Face width decreases
c) Load will not distributed evenly
d) Pitch of teeth reduced
Answer: c
Explanation: Good alignment of each tooth on a gear is essential, as otherwise the load will not be distributed evenly over its face. It is quite probable that the load may be carried by one edge only introducing high bearing stresses, if teeth of a gear are machined poorly.
2. Which of the following is not true about concentricity of teeth?
a) Fluctuating velocity will be noticed when not concentric
b) Can be checked by using projector
c) Inaccuracy of parts when not concentric
d) Should be tested to ensure the proper heat treatment
Answer: d
Explanation: Concentricity of teeth is an important item and should be checked to ensure that the set up and equipment is in good order. When teeth are not concentric then fluctuating velocity will be noticed on the pitch line while transmitting motion.
3. Which of the following option is true about an analytical method of inspection of gears?
a) Analytical method is widely used for industries
b) This method is fast
c) All individual elements of gear teeth are checked
d) More accurate
Answer: c
Explanation: Analytical method is slow and tedious and not of much use for industry. By analytical inspection of gears we mean that all the individual elements of the gear teeth are checked. The discrete error values of pitch, tooth profile etc can’t give a true overall assessment of the accuracy of a gear.
4. Which of the following element is not determined by analytical inspection?
a) Profile
b) Composite vibrations
c) Spacing
d) Pitch
Answer: b
Explanation: The analytical inspection of the gears consists in determination of these Profile, Spacing, Pitch, Backlash, Runout or eccentricity or concentricity, thickness of tooth and Lead. These teeth elements in which the errors are caused due to manufacturing errors are determined by analytical inspection.
5. Which of the following option is correct for given statements about gear measurement?
Statement 1: Improper alignment of each teeth will cause high bearing stresses.
Statement 2: Gear blank should be tested for dimensional accuracy.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: d
Explanation: The gear blank should be tested for dimensional accuracy and eccentricity as outside diameter forms the datum from where the tooth thickness is measured, it forms an important item to be controlled. It is quite probable that the load may be carried by one edge only introducing high bearing stresses, if teeth of a gear be machined poorly.
6. Which of the following is not determined by the functional type of inspection?
a) Lead
b) Noise level
c) Variation in action
d) Vibration
Answer: a
Explanation: The functional inspection consists of carrying out the running test of gear with another gear which is more accurate and is known as master gear or control gear, to determine composite vibration, noise level, or variation in action.
7. Which of the following statement is true about inspection of gear?
a) Profile is determined by functional inspection
b) Backlash is determined by analytic inspection
c) Analytic test require running test of gear
d) Thickness of tooth is measured by functional inspection
Answer: b
Explanation: Functional type of inspection is done by running test of gear with another gear. It is used to determine noise level and composite variation. Analytical method is used to determine backlash, lead and runout.
8. Which of the following machine is used for rolling tests?
a) Parkson gear tester
b) Tooth caliper
c) Base pitch measuring instrument
d) Involute profile testing machine
Answer: a
Explanation: Rolling test is generally performed on Parkson Gear Tester. This test reveals any errors in pitch, tooth form and concentricity of pitch line. Any of the above errors will cause the variation of centre distance, when two gears are in mesh with each other.
9. If reference circle of gear is eccentric then which error is reflected by this eccentricity?
a) Cyclic error
b) Periodic error
c) Pitch error
d) Undulation
Answer: c
Explanation: It must be emphasised that there are some in-built limitations in the gear itself while the accuracy of measurement of gear depends upon the measuring equipment available, such as the inability of a gear to define its own axis of rotation. Thus if the reference circle of gear is eccentric, it would be reflected in pitch error.
10. Which of the following option is true for given statements about gear measurement?
Statement 1: There is no effect of cutter accuracy on the accuracy of gear.
Statement 2: Accuracy of individual elements is necessary for precision gears.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: d
Explanation: The accuracy of any gear mainly depends upon the cutter accuracy and the setting of the machine. Optical projection and rolling tests will suffice for most of the gears. It is necessary to determine the accuracy of individual elements in the manufacture of high precision gears.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Coordinate Measuring Machines”.
1. What precise movement does CMM have?
a) Precise movement in x coordinate
b) Precise movement in x and y coordinates
c) Precise movement in y and z coordinates
d) Precise movement in x, y and z coordinates
Answer: d
Explanation: Co-ordinate measuring machines are useful for three dimensional measurements. These machines have precise movements in x,y and z coordinates which can be easily measured and controlled.
2. Which type of CMM is most suited for large heavy workpieces?
a) Cantilever type
b) Bridge type
c) Horizontal boring mill type
d) Floating bridge type
Answer: c
Explanation: Bridge type CMM is more difficult to load. It less sensitive to mechanical errors. Horizontal boring mill type is best suited for heavy and large workpieces. Highly accurate type is vertical bore mill type but is usually slower to operate.
3. Which direction is sensed by a linear measurement transducer used in CMM?
a) Positive direction only
b) Negative direction only
c) Both positive and negative direction
d) Not used to sense directions
Answer: c
Explanation: Each slide in CMM is equipped with the help of a precision linear measurement transducer in 3 directions. It gives digital display and also senses a positive or negative direction. These are manufactured in both computer-controlled models and manual.
4. What is the accuracy of present day co-ordinate measuring machine?
a) 10 microns
b) 5 microns
c) 2 microns
d) 1 micron
Answer: a
Explanation: Co-ordinate measuring machines of present day are three-axis digital read-out type and these machines work up with an accuracy of 10 microns. Resolution of present day co-ordinate machine is 5 microns.
5. What is the name of an element which uses inductive coupling?
a) Inducto conduct
b) Inductosyn
c) Conductosyn
d) Conducto induct
Answer: b
Explanation: CMM utilize a measuring element known as Inductosyn data element. It uses inductive coupling between conductors and the conductors are separated by a small air gap. As Inductosyn is not subjected to wear, it does not develop inaccuracy.
6. Which principle is used in the three master guideways and probe location?
a) Principle of dynamic design
b) Principle of static design
c) Principle of kinematic design
d) Principle of effective design
Answer: c
Explanation: In the probe location and three master guideways, the principles of kinematic design are used. Whole machine is supported on a 3-point suspension with its massive granite work table.
7. What is the cause of translational errors in CMM?
a) Error in scale division
b) Error in straightness
c) Twisting error
d) Roll error
Answer: b
Explanation: Translational errors result from errors in the division of scale and straightness error perpendicular to the corresponding axis direction. Errors in scale division are known as positional errors. Error in straightness is the cause of translational errors.
8. Which of the following is not related to the geometrical accuracy of CMM?
a) Straightness of axes
b) Squareness of axes
c) Position accuracy
d) Axial length measuring accuracy
Answer: d
Explanation: Geometrical accuracy concerned with the straightness of axes, position accuracy and squareness of axes while total measuring accuracy concerns volumetric length measuring accuracy and axial length measuring accuracy.
9. How many measurement parameters are considered in checking axes accuracy of straightness in CMM?
a) 2
b) 4
c) 6
d) 8
Answer: c
Explanation: Six measurement parameters need to be considered in the straightness of axes. Straightness of x-axis measured in y and z directions. Straightness of z-axis in x and y directions and of y-axis in x and z directions.
10. How many reference gauges are measured for volumetric length measuring accuracy in CMM?
a) 2
b) 3
c) 4
d) 5
Answer: b
Explanation: It is defined as the difference between the reference length of gauges, oriented freely and the corresponding results from the machine. 3 reference gauges are measured. Their lengths corresponding to approx. 1/3, 1/2 and 3/4 of the full travel of the longest axes.
11. Which of the following is true for trigger type probe system used in computer controlled CMM?
a) Bucking mechanism is a 2 point bearing
b) Current coordinate position stored when circuit is close
c) Contacts of point bearing arranged at 90 degree
d) Contacts of point bearing act as electrical micro switches
Answer: d
Explanation: The “buckling mechanism” in trigger type probe system is a 3 point bearing, the contacts of which are arranged around the circumference at 120 degrees. These contacts act as micro switches.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Alignment Tests on Lathe”.
1. What is the purpose of locating cylinder in the test of the true running of the main spindle?
a) To locate the chuck
b) To locate the main spindle
c) To locate the feeler
d) To level the machine
Answer: a
Explanation: Locating cylinder is provided to locate the face plate or chuck. Threads get worn out soon thus, locating surface can not be threaded one. Locating surface should be cylindrical and must run truly.
2. In what direction the parallelism of the main spindle to saddle movement is checked?
a) Vertical direction
b) Horizontal direction
c) Both vertical and horizontal direction
d) At an angle
Answer: c
Explanation: Parallelism of the main spindle to saddle movement is checked in both vertical and horizontal direction. In this method, mandrel is used and this mandrel should be so proportioned that its overhang does not produce sag.
3. What is axial play?
a) Freedom of spindle movement in axial direction
b) Freedom of spindle movement perpendicular to axial direction
c) Freedom of spindle movement in direction of cutting forces
d)Freedom of spindle movement in horizontal direction
Answer: a
Explanation: Meaning of axial play is the indispensable freedom of movement of spindle in the axial direction to prevent it from seizing by heating. It is different from axial slip. Axial slip is the axial movement of spindle which follows the same pattern.
4. What will happen if an axial play is not provided to the spindle?
a) It will try to expand
b) It will try to bend
c) It will shrink in some time
d) It will show fracture
Answer: b
Explanation: If axial play is not allowed, it would try to bend. Thus there will be no adverse effect of axial play if the direction of cutting forces remains constant or same. If this direction of cutting force changes, there would be some error introduced due to axial movement of spindle.
5. In leveling of machine, which direction is more important in horizontal plane?
a) Longitudinal
b) Transverse
c) Both longitudinal and transverse
d) Both longitudinal and transverse direction is not important
Answer: c
Explanation: Both longitudinal and transverse directions are equally important in horizontal plane. It will produce a simple bend and undesirable stresses; if any long lathe bed is not installed truly horizontal then there will be a deflection in bed.
6. What is the effect of axial slip in screw cutting?
a) Pitch will not be uniform
b) Pitch will be uniform
c) Pitch will be short
d) Pitch will be high
Answer: a
Explanation: Due to the axial slip, the pitch will not be uniform in the case of screw cutting. It is due to periodic movement of the spindle. However this is not of so much importance while turning.
7. Which of the following is done for testing the true running of headstock centre?
a) Feeler of dial indicator is pressed perpendicular to the taper surface
b) Feeler of dial indicator is pressed parallel to the taper surface of cent
c) Feeler of dial indicator is pressed at acute angle to the taper surface of cent
d) Feeler of dial indicator is pressed at obtuse angle to the taper surface of cent
Answer: a
Explanation: For testing this error of true running of headstock centre, the feeler of the dial indicator is pressed perpendicular to the centre taper surface, and the spindle is then rotated. The deviation which is indicated by the dial gauge gives the trueness of the centre.
8. Which type of surface is produced in case of deviation from parallelism of spindle axis from bed in vertical axis?
a) Tapered
b) Straight
c) Threaded
d) Hyperboloid
Answer: d
Explanation: A hyperboloid surface is produced due to any type of deviation from parallelism of axis of spindle from bed in the vertical axis. For this test, a mandrel is fitted in the taper socket of the spindle.
9. Which of the following is not used in testing the pitch accuracy of lead screw?
a) A negative stop
b) Slip gauge
c) Length bars
d) Dial gauge
Answer: a
Explanation: Test for pitch accuracy of the lead screw is performed by fixing a positive stop on the lathe bed. Against the stop, the length bars and slip gauges can be located. On the carriage, indicator is mounted and first it makes contact against the length of slip gauges.
10. What is the permissible error in working accuracy of cylindrical turning when a job is held between centers when a practical test is performed?
a) 0.02mm/100 mm
b) 0.01mm/100mm
c) 0.02mm/300 mm
d) 0.01mm/300 mm
Answer: c
Explanation: Working accuracy of machine facing is a permissible error of 0.02 mm over the diameter of test work piece, which is taken as 300 mm for swing over bed of upto 500 mm, and 400 mm for swing over 500 mm. Hence the permissible error is 0.02 mm/300 mm.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Alignment Tests on Milling Machine”.
1. What is the load condition when a relative alignment of machine parts and accuracy of control devices measured?
a) No load condition
b) Half load condition
c) Full load condition
d) One-fourth load condition
Answer: a
Explanation: The relative alignment of all machine parts and the accuracy of the driving mechanisms and control devices are measured under the condition of no load. The result of these measurements must lie within the prescribed limits.
2. What is another name of the axial play?
a) Full play
b) Front play
c) Back play
d) End play
Answer: d
Explanation: Another name of the axial play is end play. End play is important especially on machines of high speed and it should be within the prescribed limits. It is the freedom of spindle moving in axial direction.
3. What is the length of mandrel which is used to test true running of internal taper on milling machine?
a) 50 mm
b) 100 mm
c) 300 mm
d) 1000 mm
Answer: c
Explanation: To test true running of internal taper, a mandrel of 300 mm length is fixed in the taper of spindle. A dial gauge is set on the table of machine and feeler is adjusted to touch the lower surface of this mandrel.
4. What is the error caused when transverse movement is not parallel with spindle axis on milling machine?
a) Milled surface will not be square to base
b) Depth of cut will vary
c) Eccentricity of tapered hole
d) Axial slip
Answer: b
Explanation: To test transverse movement parallel with spindle axis. The table is set in its mean position and dial gauge is fixed. The table is crosswise moved and any deviation on reading of dial gauge is noted. Due to this error when cross slide is moved, the depth of cut will vary.
5. Which of the following is not true about the testing of eccentricity of external diameter?
a) Locating shoulder is fixed
b) Feeler is placed on the surface of shoulder
c) Vibrations are produced due to eccentricity
d) Cutter will float sideways due to eccentricity
Answer: a
Explanation: The feeler is placed on the shoulder surface. The locating shoulder is rotated and a deviation is noted. It is due to eccentricity of the spindle in the hole in which it fits. Vibrations are produced due to eccentricity and the cutter will float sideways and cut oversize, or undersize.
6. What is the length of the bracket which is used for checking the parallelism of centre slot with the longitudinal movement of the table?
a) 50 mm
b) 500 mm
c) 150 mm
d) 750 mm
Answer: c
Explanation: The parallelism of the central slot with the longitudinal movement of the table is checked with the help of a bracket. Length of the bracket is 150 millimeter with a tennon which enters the T-slot.
7. At how many points the axial slip is tested on the collar of the spindle?
a) 2, 180 degree apart
b) 2, 90 degree apart
c) 4, 90 degree apart
d) 3, 60 degree apart
Answer: a
Explanation: In testing cutter spindle axial slip, if the feeler touches at the same spot where the turning tool on the emery wheel has machined the spindle collar in the assembled machine, then the feeler will not show deviation. Therefore, axial slip must be tested at two points 180 degree apart on the collar of the spindle.
8. Which of the following option is true for given statements about alignment test on a milling machine?
Statement 1: Heavy cast iron standards are always rigid sand solid enough to withstand stresses.
Statement 2: Each trial measurement of machines is based on its correct erection.
a) T, T
b) T, F
c) F, F
d) F, T
Answer: d
Explanation: Machine tools are sensitive to shocks and impacts, even heavy cast iron standards are not always rigid and solid enough to withstand all the stresses which can be caused due to falling during transportation and also due to various type of deformations.
9. What is the permissible error for internal taper for true running nearest to spindle nose?
a) 0.02mm – 0.045mm 0.04 mm
b) 0.01mm – 0.025mm 0.03 mm
c) 0.1mm – 0.25mm 0.02 mm
d) 0.0mm – 0.025mm 0.01 mm
Answer: b
Explanation: Permissible error for testing internal taper for true running is 0.01 mm nearest to the spindle nose and this permissible error is 0.025 millimeter at a distance of 300 millimeter.
This set of Engineering Metrology Questions and Answers for Entrance exams focuses on “Alignment Tests on Pillar Type Drilling Machine”.
1. How Flatness of clamping surface of the base test is performed?
a) By placing a straight edge on one gauge block
b) By placing a straight edge on four gauge blocks
c) By placing a straight edge on two gauge blocks
d) By placing a straight edge on three gauge blocks
Answer: c
Explanation: The Flatness of clamping surface test is performed by placing a straight edge on two gauge blocks on the base plate in various positions and the error is noted down by inserting the feeler gauges.
2. What is the maximum error for Flatness of clamping surface?
a) 0.1/1000 mm
b) 0.1/100 mm
c) 0.5/100 mm
d) 0.01/1000 mm
Answer: a
Explanation: The maximum error allowed for Flatness of clamping surface is 0.1/1000 mm clamping surface. The surface should be concave only for correct results.
3. How perpendicularity of drill head guide to the base plate is performed?
a) By placing the frame level with graduations from 0.03 to 0.05 mm/m on spindle table
b) By placing the frame level with graduations from 0.05 to 0.1 mm/m on guide column
c) By placing the frame level with graduations from 0.05 to 0.1 mm/m on spindle table
d) By placing the frame level with graduations from 0.03 to 0.05 mm/m on guide column
Answer: d
Explanation: The perpendicularity of drill head guide to base plate test is performed by placing the frame level on guide column and base plate and the error is noted by noting the difference between the readings of the two levels.
4. In the perpendicularity of drill head guide to base plate test, what is the position of guide column?
a) Inclined at the upper end towards the front only
b) Declined at the upper end towards the front only
c) Inclined at the upper end towards the back only
d) Declined at the upper end towards the front only
Answer: a
Explanation: The error should not exceed 0.25/1000 mm guide column for a vertical plane passing through the axes of both spindle and column and the guide column should be inclined at the upper end towards the front only, and 0.15/1000 mm for a horizontal plane passing through the axes of both spindle and column.
5. What is the maximum error for perpendicularity of spindle sleeve with a base plate?
a) 0.15/1000 mm for plane vertical to plane passing through the axes of both spindle and column
b) 0.15/1000 mm for plane horizontal to plane passing through the axes of both spindle and column
c) 0.5/1000 mm for plane vertical to plane passing through the axes of both spindle and column
d) 0.5/1000 mm for plane horizontal to plane passing through the axes of both spindle and column
Answer: b
Explanation: The error should not exceed 0.25/1000 mm for plane vertical to plane passing through the axes of both spindle and column and the sleeve should be inclined toward column only ; and 0.15/1000 mm for plane horizontal to plane passing through the axes of both spindle and column.
6. In testing of the true running of spindle taper, what is the position of dial indicator?
a) Dial indicator is fixed on the base
b) Dial indicator is placed on the table
c) Dial indicator is fixed on the sleeve
d) Dial indicator is fixed on the table
Answer: d
Explanation: For true running of spindle taper test, the test mandrel is placed in the tapered hole of spindle and a dial indicator is fixed on the table and its feeler made to scan the mandrel.
7. What is the error for the true running of spindle taper for machines with taper larger than Morse No. 2?
a) 0.03/100
b) 0.01/100
c) 0.04/300
d) 0.04/100
Answer: c
Explanation: The error for the true running of spindle taper should not exceed 0.04/300 mm for machines with taper larger than Morse No. 2 and 0.03/100 mm for machines with taper upto Morse No. 2.
8. In how many planes, they test for parallelism of the spindle axis with its vertical movement is performed?
a) In two planes 60° to each other
b) In two planes 30° to each other
c) In two planes 45° to each other
d) In two planes 90° to each other
Answer: d
Explanation: The test for parallelism of the spindle axis with its vertical movement is performed in two planes right angle to each other. The dial indicator is fixed on the table with its feeler touching the mandrel and test mandrel is fitted in the tapered hole of the spindle.
9. For testing squareness of spindle axis with table, when was reading taken down?
a) At every 90° rotation of spindle
b) At every 180° rotation of spindle
c) At every 60° rotation of spindle
d) At every 120° rotation of spindle
Answer: b
Explanation: The dial indicator is fixed in the spindle tapered hole and its feeler touch the straight edge At A and then, reading is noted down. The spindle is rotated by 180° so that the feeler touches at point A’ and again reading is noted down.
10. What is the permissible error for squareness of spindle axis with table test?
a) 0.05/300 mm
b) 0.08/300 mm
c) 0.1/300 mm
d) 0.01/300 mm
Answer: c
Explanation: The difference of two readings gives the error in squareness of spindle axis with table. The permissible errors are 0.08/300 mm with lower end of spindle inclining towards column only to first plane and 0.05/300 mm for plane perpendicular to the previous plane.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Coordinate Measuring Machines”.
1. What precise movement does CMM have?
a) Precise movement in x coordinate
b) Precise movement in x and y coordinates
c) Precise movement in y and z coordinates
d) Precise movement in x, y and z coordinates
Answer: d
Explanation: Co-ordinate measuring machines are useful for three dimensional measurements. These machines have precise movements in x,y and z coordinates which can be easily measured and controlled.
2. Which type of CMM is most suited for large heavy workpieces?
a) Cantilever type
b) Bridge type
c) Horizontal boring mill type
d) Floating bridge type
Answer: c
Explanation: Bridge type CMM is more difficult to load. It less sensitive to mechanical errors. Horizontal boring mill type is best suited for heavy and large workpieces. Highly accurate type is vertical bore mill type but is usually slower to operate.
3. Which direction is sensed by a linear measurement transducer used in CMM?
a) Positive direction only
b) Negative direction only
c) Both positive and negative direction
d) Not used to sense directions
Answer: c
Explanation: Each slide in CMM is equipped with the help of a precision linear measurement transducer in 3 directions. It gives digital display and also senses a positive or negative direction. These are manufactured in both computer-controlled models and manual.
4. What is the accuracy of present day co-ordinate measuring machine?
a) 10 microns
b) 5 microns
c) 2 microns
d) 1 micron
Answer: a
Explanation: Co-ordinate measuring machines of present day are three-axis digital read-out type and these machines work up with an accuracy of 10 microns. Resolution of present day co-ordinate machine is 5 microns.
5. What is the name of an element which uses inductive coupling?
a) Inducto conduct
b) Inductosyn
c) Conductosyn
d) Conducto induct
Answer: b
Explanation: CMM utilize a measuring element known as Inductosyn data element. It uses inductive coupling between conductors and the conductors are separated by a small air gap. As Inductosyn is not subjected to wear, it does not develop inaccuracy.
6. Which principle is used in the three master guideways and probe location?
a) Principle of dynamic design
b) Principle of static design
c) Principle of kinematic design
d) Principle of effective design
Answer: c
Explanation: In the probe location and three master guideways, the principles of kinematic design are used. Whole machine is supported on a 3-point suspension with its massive granite work table.
7. What is the cause of translational errors in CMM?
a) Error in scale division
b) Error in straightness
c) Twisting error
d) Roll error
Answer: b
Explanation: Translational errors result from errors in the division of scale and straightness error perpendicular to the corresponding axis direction. Errors in scale division are known as positional errors. Error in straightness is the cause of translational errors.
8. Which of the following is not related to the geometrical accuracy of CMM?
a) Straightness of axes
b) Squareness of axes
c) Position accuracy
d) Axial length measuring accuracy
Answer: d
Explanation: Geometrical accuracy concerned with the straightness of axes, position accuracy and squareness of axes while total measuring accuracy concerns volumetric length measuring accuracy and axial length measuring accuracy.
9. How many measurement parameters are considered in checking axes accuracy of straightness in CMM?
a) 2
b) 4
c) 6
d) 8
Answer: c
Explanation: Six measurement parameters need to be considered in the straightness of axes. Straightness of x-axis measured in y and z directions. Straightness of z-axis in x and y directions and of y-axis in x and z directions.
10. How many reference gauges are measured for volumetric length measuring accuracy in CMM?
a) 2
b) 3
c) 4
d) 5
Answer: b
Explanation: It is defined as the difference between the reference length of gauges, oriented freely and the corresponding results from the machine. 3 reference gauges are measured. Their lengths corresponding to approx. 1/3, 1/2 and 3/4 of the full travel of the longest axes.
11. Which of the following is true for trigger type probe system used in computer controlled CMM?
a) Bucking mechanism is a 2 point bearing
b) Current coordinate position stored when circuit is close
c) Contacts of point bearing arranged at 90 degree
d) Contacts of point bearing act as electrical micro switches
Answer: d
Explanation: The “buckling mechanism” in trigger type probe system is a 3 point bearing, the contacts of which are arranged around the circumference at 120 degrees. These contacts act as micro switches.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Three Dimensional Measuring Machine”.
1. Which of the following is provided as scales in three dimensional measuring machines?
a) Laser interferometer
b) Straight edge
c) Vernier caliper
d) Screw gauge
Answer: a
Explanation: Laser interferometers are provided as scales in three dimensional measuring machines. A cooling system is also provided in this machine. This cooling system is to reduce the temperature rise when it is in operation.
2. Which motor is used to control axes movement in three dimensional measuring machines?
a) Tachometer
b) Torque motor
c) Induction motor
d) Stepping motor
Answer: d
Explanation: Axes movement in three dimensional measuring machines is controlled by stepping motors. Stepping motors are attached to lead-screws. 3 carriages are provided and mounted upon double V-ways.
3. Which material is used for the base in three dimensional measuring machines?
a) Steel
b) Aluminium
c) Granite
d) Lead
Answer: c
Explanation: The machine base and metrology system should be made independent of each other. The external forces upon the metrology system should be constant. Granite is chosen for building the machine base because of low coefficient of expansion.
4. How many pneumatic isolators are used to support the base of three dimensional measuring machines?
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: Three dimensional measuring machine has pneumatic isolators. The base of the machine is supported on 3 pneumatic isolators. The frame of a machine is built of steel because temperature-controlled oil shower is included.
5. Which of the following is true about electronic gauge stylus used in three dimensional measuring machines?
a) It is ball tipped
b) Tip is trapezoidal
c) Polygonal tip
d) Pointed tip
Answer: a
Explanation: The electronic gauge stylus is ball-tipped. It is a single axis, linear variable displacement transducer carried and positioned by the vertical or we can say ‘z’ slide. The axis of the linear variable displacement transducer is mounted at a 45 degree angle w.r.t the y and z axes.
6. How many laser interferometers are provided on y-axis slide?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: Two laser interferometers are provided on the y-axis slide. These are suitably separated. The difference in readings taken by these 2 lasers is used as a servo input to drive a piezoelectric crystal.
7. Which mounts are used to support frame?
a) Effective mounts
b) Dynamic mounts
c) Static mounts
d) Kinematic mounts
Answer: d
Explanation: Kinematic mounts are used to support the frame inside the machine base. The plane of the supports is coincident with the bending neutral axis of the machine base. Its influence is thereby minimized on the metrology frame.
8. Which drive is used in slide drive system present in three dimensional measuring machines?
a) Rack and pinion drive without gear teeth
b) Rack and pinion drive with gear teeth
c) Worm and worm gear drive without teeth
d) Worm and worm gear drive with teeth
Answer: a
Explanation: A portion of each bearing is evacuated and acts like a vacuum chuck to hold the bearing. The bearing surface balance provides lift. The slide drive system used in three dimensional measuring machines can be considered as a rack and pinion drive without gear teeth.
9. Which of the following option is true for given statements about 3-dimensional measuring machines?
Statement 1: A cooling system is present in 3-dimensional measuring machine.
Statement 2: It is designed for 3-dimensional calibration but not adaptable for computer control.
a) T, T
b) F, F
c) F, T
d) T, F
Answer: d
Explanation: Three dimensional measuring machines are useful in modern sophisticated industry. 3-D measuring machines are designed for 3-dimensional calibration. This machine is also adaptable for computer control.
10. Which type of error is introduced when the travel direction of LVDT is not normal to the part surface?
a) Sine error
b) Cosine error
c) Tangent error
d) Cotangent error
Answer: b
Explanation: When the direction of travel of Linear variable displacement transducer is not normal to the part surface, the cosine error is introduced. A correction is provided in this machine for this cosine error.
11. Which type of pathways is used for laser interferometer present in three dimensional measuring machines?
a) Helium unshielded pathways
b) Neon unshielded pathways
c) Helium shielded pathways
d) Neon shielded pathways
Answer: c
Explanation: Displacement accuracy is achieved by laser interferometers. Laser interferometers are operated in helium-shielded pathways. The interferometers are located in strict accordance with the Abbe principle.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Universal Measuring Machine”.
1. What is the difference between CMM and UMM?
a) UMM can’t inspect geometrical features while CMM does it
b) CMM is more accurate than UMM but can’t inspect geometrical features
c) UMM is more accurate than CMM and can inspect geometrical features
d) CMM is more accurate than UMM but can’t inspect geometrical features
Answer: c
Explanation: Co-ordinate measuring machine doesn’t inspect the geometric features of the part but universal measuring machine does it. Co-ordinate measuring machine is less accurate than a universal measuring machine.
2. Which type of standard is UMM for calibration of hole location gauges?
a) Primary standard
b) Secondary standard
c) Basic standard
d) Reference standard
Answer: a
Explanation: Universal measuring machine is a primary standard for calibration of hole location gauges. A hole-location gauge is calibrated on universal measuring machine and used to inspect a Co-ordinate measuring machine.
3. Which of the following is used to locate awkward shaped workpieces in UMM?
a) Swinging table
b) Tilt table
c) Rotary table
d) Angular table
Answer: c
Explanation: The workpieces of awkward shape can be located by using a rotary table to align reference holes with the measuring axes. When the dimensions are specified with respect to centre hole in the part, then initial line-up is facilitated by using the reference hole in the rotary table centre.
4. Which of the following is used to measure macro-circuit components in UMM?
a) Telescope
b) Microscope
c) Probe tip
d) Capstan
Answer: b
Explanation: For measuring the location of small holes, a microscope is used and also for parts which are damaged by physical contact. Parts like components of macro-circuit, which doesn’t have reference surfaces against which an indicator probe-tip may register, can be measured by a microscope.
5. Which of the following are the foundations of mechanical accuracy in UMM?
a) Geometry and length
b) Roundness, geometry and length
c) Geometry, division of circle and length
d) Roundness, geometry, division of circle and length
Answer: d
Explanation: “Cubic concept” of accuracy in the UMM requires the individual mastery of 4 mechanical arts-Roundness, geometry, division of circle and length. These are the “Foundations of Mechanical Accuracy” truly.
6. Which of the following option is true for given statements about UMM?
Statement 1: Measurement on CMM is faster than UMM.
Statement 2: UMM can resolve the exact nature of error of features of all parts.
a) T, T
b) F, T
c) T, F
d) F, F
Answer: a
Explanation: Universal measuring machine is capable of resolving the exact nature of the error of features of all parts. This machine discloses information about measurement which in turn permits the machine or methods improvement.
7. Which of the following principle is used to derive authority for angles of angle gauges or angular relationships in mechanical parts and assemblies?
a) Self-assessment principle of dividing the circle
b) Self proving principle of dividing the circle
c) Self verification principle of dividing the circle
d) Self explaining principle of dividing the circle
Answer: b
Explanation: Accurate circle division is a requirement of all machine shops and laboratories. The self-proving principle of dividing the circle is used to derive the authority for “angles” of angle gauges, rotary tables, or the angular relationships in mechanical parts and assemblies.
8. Which of the following is the authority for roundness?
a) Precision spindle
b) Probes
c) Dividing circle
d) Rotary tables
Answer: a
Explanation: It is important to achieve roundness for precision machine tools of many mechanical parts and with their spindles especially. A precision spindle is an authority for roundness.
9. Which of the following is not true for UMM?
a) Less skilled operator is needed
b) It is a slow machine
c) Used as a special purpose machine in metrology laboratories
d) A valuable machine for comparing master gauges and length standards
Answer: a
Explanation: UMM is a slow machine. It requires a highly skilled operator to use. The accuracy created in these machines has overcome the needs of most industries. As a result, today UMM is only found as a special-purpose machine in metrology labs.
10. Which of the following is a foundation of all geometrical accuracy?
a) Vertical plane
b) Flat plane
c) Rough plane
d) Oblique plane
Answer: b
Explanation: The foundation of all geometric accuracy is the flat plane. Meehanite cast iron is a prime material component for the elements of geometry because it is available readily, easily cast to shape and relatively uninfluenced by relative-humidity.
This set of Engineering Metrology Questions and Answers for Campus interviews focuses on “Numerical Controlled Coordinate Measuring Machines”.
1. In which of the following numerical controlled CMM used?
a) Workshops
b) Production floors
c) Workshop and production floors both
d) Can be used anywhere
Answer: c
Explanation: CMMs are designed originally for the measurement of high-precision on relatively few workpieces in the metrology labs but are now used both in the workshop and on the production floor.
2. Which of the following technique is used to measure the profile of cams on numerical controlled CMM?
a) Scanning technique
b) Searching technique
c) Standing technique
d) Sorting technique
Answer: a
Explanation: The profile or form of cams and cutting dies, etc., can be measured on numerical controlled CMM by a scanning technique. This technique takes about 50 measurements and processes them every second.
3. Which of the following is responsible to control the processes in numerical controlled machines?
a) Symbols and letters
b) Letters and numbers
c) Numbers and symbols
d) Numbers, symbols and letters
Answer: d
Explanation: Numerical control is a programmable automation of machines and processes in which process is controlled by symbols, letters and numbers. In numerical control program, instruction changes when job changes.
4. Which type of probe system is used in CMM?
a) One dimensional probe system
b) Two dimensional probe system
c) Three dimensional probe system
d) Both one and two dimensional probe system
Answer: c
Explanation: Coordinate measuring machines both portable and bridge-type have a probe system. These probe systems have three dimensional probes which are suitable for dynamic measurements.
5. In CMMs adequate numbers of soft keys are present. What are soft keys?
a) Keys with variable functions
b) Keys not hard to press
c) Soft running keys so that less fatigue to operator
d) Keys made of soft material
Answer: a
Explanation: In CMMs which are installed with microprocessor based controls, suitable number of soft keys are provided. These keys are the keys with variable functions, which handle commands required for man-machine dialogue.
6. Which of the following option is true for given statements about numerical controlled CMM?
Statement 1: Idle time of the production equipment is more.
Statement 2: Software for automatic evaluation is incorporated.
a) T, T
b) F, F
c) T, F
d) F, T
Answer: d
Explanation: In a numerical controlled coordinating measuring machine, software suitable for automatic calibration of the probe, calculation of geometric elements and automatic evaluation and recording is incorporated.
7. What is the use of SPC software in CMMs?
a) Dynamic analysis of measurement
b) Statistical analysis of measurement
c) System analysis of measurement
d) Quality analysis of measurement
Answer: b
Explanation: SPC software is a feature present in CMMs. It is for statistical analysis of measurements. Temperature compensation is also present for a change in the temperature due to various reasons like environmental change.
8. Which of the following is used to inspect nonlinear surfaces in very fast way in CMMs?
a) Laser triangulation probe
b) Impact protection
c) Wave lasers
d) Line laser
Answer: d
Explanation: Laser triangulation probes are used to scan the surface and after scanning it transmits a continuous flow of data. Line lasers are the fastest way to inspect non-linear surfaces. It is widely used in reverse engineering.
9. Which of the following is true for the given statements about numerical controlled CMM?
Statement 1: Command like full 3D alignment is provided.
Statement 2: Repeat function is used to simplify the inspection of features which are similar.
a) T, T
b) F, F
c) F, T
d) T, F
Answer: a
Explanation: Various commands are provided in CMMs. These commands are full 3-D alignment, multipoint measurement of circle centers, choice of 3 working planes, probe diameter compensation etc.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Computers in Metrology”.
1. How a system is used to check the surface finish of a surface by CAI?
a) As a mirror
b) As a lens
c) As a black body
d) As a grey body
Answer: a
Explanation: For checking surface finish of a surface by machine vision or CAI, the surface is treated as a mirror. The vision system looks at an image of a light source reflected in the surface. Changes in that image signify the defective area.
2. How many degrees of freedom is in the robotic arm?
a) 1
b) 2
c) 3
d) 4
Answer: d
Explanation: A robot arm has four degrees of freedom, the motions are three rectangular linear motions and wrist motion. It is brought for the inspection near the equipment while being machined.
3. Which of the following is used to control the robot arm?
a) Microprocessor
b) Keyboard
c) Mouse
d) Computer
Answer: a
Explanation: The motion of the robot arm is controlled by a microprocessor. It performs simultaneous multi-axis control of position, acceleration and speed and provides high dynamic arm performance.
4. How many levels are organized in an inspection data handling?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: The inspection data handling is organized at 2 levels; first is to perform the dimensional analysis of the part to discriminate good parts, bad parts and reworkable parts and second is the inspection data is reduced on real-time statistical basis to derive trends.
5. What is the use of stroboscope technology?
a) Optically freezing the motion of rotating part
b) Mechanically freezing the motion of reciprocating part
c) Optically freezing the motion of reciprocating and rotating part
d) Mechanically freezing the motion of reciprocating and rotating part
Answer: c
Explanation: Stroboscope technology is used for optically freezing the motion of reciprocating or rotating parts. Fibre optics is the main reason for the remote inspection. It is possible by fibre optics.
6. Which of the following is used for automatic inspection?
a) Universal probes
b) Hydrolysis probes
c) Electronic probes
d) Mechanical probes
Answer: a
Explanation: Hundreds of readings may be taken in an automatic process and then processed, analysed and results are produced. Automatic inspection is carried out by universal probes. Operator intervention is not required in a fully automatic inspection.
7. How many points are needed on the circumference to define a circle by computer?
a) One
b) Two
c) Three
d) Four
Answer: c
Explanation: If 3 points on the circumference of a circle are completely defined then a computer can easily define the circle. Manually this work is very painstaking and very time consuming too. Also in gear measuring machine, the use of computer give final results in no time and very accurately.
8. What is another name of computer aided inspection?
a) Computer aided machining
b) Visionary machining
c) Machine vision
d) Visionary inspection
Answer: c
Explanation: Machine vision is a technique which allows a sensor to view a scene and derive a decision logically without further human intervention. Advantages of machine vision systems are consistency, high speed and reliability.
9. Which of the following is mounted on a robot arm for inspecting complicated surfaces?
a) Vision sensor
b) Proximity sensor
c) Heat sensor
d) Touch sensor
Answer: a
Explanation: It’s possible to look directly for defects if the defects are relied upon to have a distinct contrast with the correct surface. The vision sensor can be mounted on a robot arm for inspecting large or complicated surfaces.
10. Which of the following is used to detect the modulated reflected light from any irregularity on the surface?
a) Television camera
b) Light intensity sensor
c) Modulator
d) Video processor
Answer: d
Explanation: When the light beam hits the material then any surface irregularity modulates the reflected light. This is detected by a video processor and also microcomputer in an evaluation unit.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Principles of TQM”.
1. What is the full form of TQM?
a) True quality machining
b) Total quality management
c) True quantitative machining
d) Total queue management
Answer: b
Explanation: Total quality management is a process that promotes unending improvement in the efficiency and effectiveness of all elements of a business. Quality finds the 1st place in the entire business action.
2. Which of the following is correct for TQM?
a) Quality strategy in TQM emanates from top
b) TQM is a static process
c) It is a management approach to short-term success through customer
d) It is used to improve processes not products
Answer: a
Explanation: Quality strategies and values in TQM emanates from top. Strategy of defect prevention leads to plans of action and strategic goals. Customer orientation is also a principle of TQM. Regular feedback is needed to meet the needs of customers.
3. Which part in quality management is the critical part?
a) Process thinking
b) Performance measurement
c) Customer’s view
d) Systematic approach
Answer: d
Explanation: A critical part of quality management is the systematic and strategic approach to achieving an organization’s vision and goals. This process includes the formulation of a strategic plan that integrates quality as a core component.
4. Which of the following is not true for communication in TQM?
a) Three way communication
b) It should be clear
c) Forceful
d) Open involvement
Answer: a
Explanation: Communication is two way in total quality management. It should be forceful, effective, consistent and clear. It is very essential for active and open involvement in all company’s visions.
5. Which of the following is correct option for given statements about TQM?
Statement 1: Design of the formal system is a one time effort.
Statement 2: TQM is a management philosophy.
a) F, F
b) F, T
c) T, T
d) T, F
Answer: b
Explanation: Design of a system is not a onetime effort but it wills changes continuously according to the customer need and organization.
TQM is a management philosophy to a journey of excellence of organization and also to satisfy needs of customer.
6. What are the core principles of the TQM in a company-wide effort?
a) Customer and process orientation only
b) Continuous improvement only
c) Process orientation and continuous improvement only
d) Continuous improvement, process and customer orientation
Answer: d
Explanation: TQM as a company-wide effort emphasizes 3 core principles. These principles are process orientation, customer orientation and continuous improvement. Some core areas are essential to implement these principles that organization need to follow.
7. Which drivers are used in TQM system?
a) Competition, Survival and export drive
b) Teamwork participation and customer satisfaction
c) Quality tools and technique
d) Management commitment and vision
Answer: a
Explanation: Management commitment and vision, teamwork participation, Quality tools and techniques are the system models and competition. Survival, profitability, Customer expectations are the drivers. System models, drivers and TQM all together forms a TQM system.
8. What is included in the quality assessment in TQM?
a) Strategic quality planning
b) Management of process quality
c) Quality and operational results
d) Information and analysis
Answer: b
Explanation: Any TQM company needed a good process management. These include design, R & D, process management quality for all work units and suppliers and also quality improvement and assessment.
9. How many stages are needed for inspection and testing in TQM as per ISO 9001?
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: There are three stages of inspection and testing as per ISO 9001. These stages are receiving inspection and testing, in process inspection and third is testing and final inspection and testing.
10. Which factor is the basis of Decision making in TQM?
a) Facts only
b) Opinions only
c) Facts and opinions both
d) Neither facts nor opinions
Answer: a
Explanation: Decision-making within the organization should be only based on facts. It is not based on opinions like personal interests and emotions. Data should support this type of decision-making process.
This set of Tricky Engineering Metrology Questions and Answers focuses on “Quality Management and Quality System Requirements”.
1. What is the primary focus of the quality management system?
a) Customer focus
b) Engagement of people
c) Process approach
d) Improvement
Answer: a
Explanation: The primary focus of quality management system is to meet the requirements of a customer. The main aspect to sustain success in an organisation is to retain the confidence of customers and other parties on whom it depends.
2. What are the responsibilities of management in quality system management?
a) Frequently change responsibilities of employees for flexibility
b) Frequently change authorities for flexibility
c) Authority changes but fixed responsibility
d) Fix authority and responsibility
Answer: d
Explanation: The management should fix responsibility and authority of every employee to control and detect nonconformity affecting quality. It must provide all the resources like methods, machinery and money of the desired standard to result in quality work.
3. What is not true for the quality system requirements?
a) Generic
b) Depends upon size of organisation
c) Independent of type of organisation
d) Applicable to any organisation
Answer: b
Explanation: All the quality system requirements for organisations as per ISO 9001:2015 are generic. These are intended to be applicable to any organization. It does not depend on organisation type or size, or the products and services it provides.
4. What does quality plans specify in a quality system?
a) Work instructions
b) Checklists
c) Clause to clause interpretation of work
d) All resources and their schedule
Answer: d
Explanation: Quality plans in quality system specified all the resources and their schedule of acquisition to match with desired schedule of activities. Quality manual provides clause to clause interpretation of work in supplier’s context.
5. In how many groups, the quality system and management requirements are divided as per ISO-9001:2000?
a) 2
b) 3
c) 4
d) 5
Answer: d
Explanation: According to ISO-9001:2000, all the quality system and management requirements are considered in 5 heads. These are i) quality management system, ii) resource management, iii) management responsibility, iv) product realisation and v) measurement, analysis and improvement.
6. What is quality control?
a) Process of recognition of entire manufacturing process
b) Concerned with the integration of all the efforts in organisation
c) Detection of defects in a product
d) Minimization of material level
Answer: c
Explanation: Quality control deals with the detection of defects in a product. It also deals with the sorting out rejects. Most of the techniques used in quality control are based on statistical methods.
7. Which option is correct for given statements about quality assurance?
Statement 1: It assures that quality requirements will fulfilled.
Statement 2: Quality assurance is product oriented.
a) F, F
b) T, F
c) T, T
d) F, T
Answer: b
Explanation: Quality assurance is process oriented while quality control is product oriented. Quality assurance is a way of preventing defects and is focused on providing confidence that quality requirements needed will be fulfilled.
8. What is the purpose of ISO standards created for quality management systems?
a) To certify the process
b) To certify the quality of a product
c) To certify the quality of service
d) To certify the quantity used for product
Answer: a
Explanation: The Quality Management System standards created by ISO are meant to certify the processes of an organization but not the product or service itself. Standards of ISO 9000 do not certify the quality of the service or product.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Tools and Techniques of TQM”.
1. Which statistical technique integrates product design and manufacturing process?
a) Tree analysis
b) Problem solving techniques
c) Quality function deployment
d) Taguchi approach
Answer: d
Explanation: Taguchi’s approach for quality combines statistical methods and engineering to achieve rapid movement in quality and cost by optimising the design of a product. It integrates manufacturing process and product design.
2. What is the key step in Taguchi’s approach?
a) Tolerance design
b) System design
c) Parameter design
d) Process design
Answer: c
Explanation: Taguchi’s approach is based on integrating system design , parameter design and tolerance design . Parameter design is the key step as it offers the concept of uncontrollable factor.
3. What is called the stratification of information?
a) Breaking down a whole group into smaller sub groups
b) Isolating the vital few from the trivial many
c) Grouping of scattered information
d) Sequencing of processes in a quality system
Answer: a
Explanation: Stratification of information is one of the statistical tools which means breaking down of the whole group into smaller sub-groups. Run charts, effect diagram, pareto diagram and scatter diagrams are also the statistical tools.
4. Which technique is used to relate complex cause and effect relationships?
a) Affinity diagram
b) Pareto diagram
c) Scatter diagram
d) Interrelationship diagram
Answer: d
Explanation: Interrelationship diagram is a quality improvement technique which shows the relationship between inter-related factors. This diagram displays the factors which are involved in complex problems.
5. What is PDPC?
a) A statistical tool
b) Quality improvement technique
c) Quality assurance technique
d) Statistical process control technique
Answer: b
Explanation: PDPC is process decision program chart which helps in the selection of the best process to obtain desired result. It is a quality improvement technique. It evaluates existing process and also look at alternatives.
6. What is the first step in problem solving process?
a) Plan
b) Do
c) Check
d) Action
Answer: a
Explanation: Problems are best solved by the cycle: Plan-Do-Check-Action. In planning, a course of action is planned according to customer requirement and conditions of service then the process must be executed according to this plan.
7. How many control charts are normally used for statistical control of variables?
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: Three control charts are normally used for statistical control of variables. These are i) Mean chart, ii) Range chart, and iii) standard deviation charts. Control charts help in the understanding of inherent capability of process and bring the process under control.
8. Which tool is used to analyse the effects of a failure of individual components on the system?
a) FTA
b) FMEA
c) Quality circles
d) Fool proofing
Answer: b
Explanation: Failure mode and effect analysis is a statistical tool used to review the new product design with respect to the requirements of customers before it is sent to production. It is used basically to analyse the failure effect of individual components on the system as a whole.
9. What is the formula for process capability index?
a) C p
b) C p
c) (1-C p )K
d) (1+C p )K
Answer: a
Explanation: Process capability index is also known as measure of process capability and denoted by C pk . C pk = *C p . K is the correction factor and always has a positive value. C p is the process capability potential also known as process capability variation and is equal to the .
10. What is arrow diagram in TQM?
a) A diagram used to plan the most appropriate schedule
b) Diagram shows the relationship strength between the variables
c) Used large amount of data and organise it on the basis of natural relationship between items
d) Diagram showing the sequencing and inter relationships between factors
Answer: a
Explanation: Arrow diagram is a statistical tool used to plan the most appropriate schedule for any task and to effectively control it during the progress of the process. Arrow diagram helps in establishing the most suitable plan for a project.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Principle of Working”.
1. What is the use of a laser beam in image formation?
a) Triangulation system for measuring system
b) Reduce glare of image
c) Controls contrast of image
d) Controls brightness of image
Answer: a
Explanation: Laser beam is used for triangulation system for measuring distance. Polarised or ultraviolet light is used to reduce glare or increase contrast. It is important that light source is placed correctly since it influences the contrast of the image.
2. Where is backlighting is best suited?
a) Simple silhouette image is required to obtain minimum image contrast
b) Certain key features on the surface of the object are to be inspected
c) Simple silhouette image is required to obtain maximum image contrast
d) Three-dimensional feature is being inspected
Answer: c
Explanation: Backlighting is suited when a simple silhouette image is required to obtain maximum image contrast. When certain key features on the surface of the object are to be inspected, front lighting is used.
3. Which light is preferred if three dimensional features are being inspected?
a) Front lighting
b) Side lighting
c) Backlighting
d) Any lighting is suited
Answer: b
Explanation: Side lighting or structured lighting may be required when a three-dimensional feature is being inspected. The proper orientation and fixturing of part also deserve full attention. Selection of proper illumination technique is important for any feature.
4. Why do CCD or CID cameras are used?
a) To generate the electronic signal representing the image
b) To generate image’s hard copy
c) To determine lighting of the image
d) To capture heat signature
Answer: a
Explanation: CCD or CID cameras are used to generate the electronic signal that represents the image. The camera collects light from the image scene via lens and uses a photosensitive target to converts it into electronic signal.
5. Where is the Vidicon Camera used?
a) Open-circuit television systems
b) In Image processing
c) In image analysis
d) Closed-circuit television systems
Answer: d
Explanation: Vidicon Camera used in closed-circuit television systems can be used for machine vision systems. An image is formed in camera by focussing the incoming light through a series of lenses onto the photoconductive faceplate of the vidicon tube.
6. What is used in solid state cameras?
a) Image sensor IC
b) CMOS image sensors
c) Charge coupled device image sensors
d) Digital camera image sensor
Answer: c
Explanation: Solid state cameras are generally used in machine vision systems. These uses charge injected device or charge coupled device image sensors. They contain linear or matrix array of small, accurately spaced photo-sensitive elements fabricated on silicon chips using integrated circuit technology.
7. How many detector elements are present in a matrix array solid state camera?
a) 156 x 156 per array
b) 216 x 216 per array
c) 116 x 116 per array
d) 256 x 256 per array
Answer: d
Explanation: A typical matrix array solid state cameras have 256 x 256 detector elements per array. Solid state cameras are small and rugged. Sensors of solid state cameras are do not wear out with use. There is very less image distortion in solid state cameras because of placement of photo detectors accurately.
8. What is the common rate of an image forming in a camera?
a) 20 images per second
b) 30 images per second
c) 25 images per second
d) 50 images per second
Answer: b
Explanation: A camera may typically form an image 30 times per sec i.e. at 33 m sec intervals. At each time interval the entire image has to be captured and frozen for processing by an image processor. An analog to digital converter is used to convert analog voltage of each detector into digital value.
9. What is windowing?
a) Technique used to concentrate the processing in a desired area of an image
b) Technique used for image restoration
c) Technique for image analysis
d) Technique to describe and measure the properties of image features
Answer: a
Explanation: Windowing is a technique used to concentrate the processing in a desired part of image and also ignoring the non-desired part or non-interested part of the image. In this, an electronic mask is created around a small area of an image.
10. Which of the following method is used to reduce processing of image?
a) Triangulation technique
b) Digital imaging technique
c) Run length encoding
d) Stereo vision
Answer: c
Explanation: General techniques to reduce processing are edge detection and run length encoding. In run-length encoding, each line of the image is scanned, and transition points from black to white or vice versa are noted, along with the number of pixels between transitions.
11. What is stadimetry?
a) Direct imaging technique in which distance is judged by apparent object distance
b) Indirect imaging technique in which distance is judged by apparent object distance
c) Direct imaging technique in which distance is judged by actual distance of the object
d) Indirect imaging technique in which distance is judged by actual distance of the object
Answer: a
Explanation: Stadimetry is a technique used to determine the object distance from a vision system camera. It is a direct imaging technique in which distance of the object is determined by the apparent size of object in the field of view of camera.
12. Which method is not used to determine object orientation?
a) Equivalent ellipse
b) Triangulation technique
c) Structured light method
d) Light intensity distribution
Answer: b
Explanation: Measuring the distance of an object from a vision system camera, determining object orientation, and defining object position are three important tasks performed by machine vision systems. The object orientation can be determined by the methods of an equivalent ellipse, the connecting of three points method, light intensity distribution and structured light method.
13. Which method is used for interpreting images?
a) Light intensity distribution
b) Stereo vision
c) Optical computing
d) Template matching
Answer: d
Explanation: Template matching and feature weighing are the most commonly used methods of interpreting images. In template matching a mask is generated electronically to match a standard image of an object.
14. What do you mean by image interpretation?
a) Identification of type of image
b) Identification of an object based on recognition of its image
c) Identification of color content of image
d) Identification of each pixel of image
Answer: b
Explanation: Image interpretation involves identification of an object based on recognition of its image. These results are then compared with a presorted set of standard criteria and the various conclusions are drawn.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Gray Scale Vs Binary Imaging”.
1. Which type of conversion is involved in machine vision inspection system?
a) Continuous tone image into a binary image
b) Binary image into a continuous tone image
c) Binary image into black and white image
d) Low quality grayscale image to high quality grayscale image
Answer: a
Explanation: The machine vision inspection systems involve the conversion of continuous tone image as seen by a B & W television camera into a binary image. Considerable skill are used for this in optics and lighting.
2. How many different values can be picked by gray scale image?
a) 2
b) 125
c) 126
d) 256
Answer: d
Explanation: For a grayscale image, the intensity of the image varies across the brightness spectrum. This variation is gradual. The intensity is a whole number at any point in a range of 0 to 255, thus it can pick a value from 256 different values.
3. What is the meaning of pixel value ‘1’ in binary imaging?
a) Black
b) White
c) Gray
d) Yellow
Answer: b
Explanation: Any image is made of a number of pixels and value of these pixels may vary between a certain range. For binary image, the pixel value is 0 or 1 which means only two shades. 1 is for white and 0 is for black.
4. Which of the following option is correct for the given statements about gray scale and binary imaging?
Statement 1: All binary images are gray scale images.
Statement 2: In gray scale imaging, every pixel is represented by 8 bits.
a) F, F
b) T, F
c) F, T
d) T, T
Answer: d
Explanation: All binary images are grayscale but all grayscale images are not binary images as binary image can take only 2 values. Grayscale have a transition between pure white or pure black.
5. What is the most important characteristic of a binary image?
a) Segmentation
b) Distance transform
c) Dilation
d) Erosion
Answer: b
Explanation: An important characteristic of a binary image is the distance transform. Distance transform gives the distance of every set pixel from the nearest unset pixel. The distance transform can be calculated efficiently.
6. What is the format of binary images?
a) PBM
b) PGM
c) PPM
d) PMP
Answer: a
Explanation: The format of the binary image is PBM or portable bit map and PGM or portable gray map is the format of grayscale images. PPM is also an image format and is known as portable pix map.
7. Which type of display is used to read fonts of character?
a) 2 segment display
b) 4 segment display
c) 6 segment display
d) 7 segment display
Answer: d
Explanation: Fonts of characters are read by a display of 7 segments. It is a form of an electronic display device which is widely used in electronic meters, basic calculators and electronic meters etc.
8. Which is not a part of the parameters used to define grayscale in gray scale model?
a) Hue
b) Contrast
c) Lightness
d) Saturation
Answer: b
Explanation: In some cases, rather than using the RGB or CMY color models to define grayscale, three other parameters are defined. These are hue, saturation and lightness. In a grayscale image, the saturation is apparent color intensity, hue is apparent color shade and lightness is apparent brightness.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Circular Scanning”.
1. What is mathematical morphology?
a) Method of image rendering
b) Method of image processing and analysis
c) Method of image compression
d) Method of image formation
Answer: b
Explanation: Mathematical morphology is a method of image analysis and processing which is based on set theoretical descriptions of image measurements and transformations. It uses the concept of a structuring element, a predefined shape which is employed as a probe to test out the spatial nature of a pattern.
2. What is not true for circular scanning?
a) They are solid state device
b) They are used for line following
c) They are used for surface inspection
d) They are used for evaluation
Answer: d
Explanation: Circular scanning devices are used for surface inspection of bore and cylinder outside diameter, angular position measurement, line following etc. Circular scanning is a solid state device that is configured as a light sensitive discretely segmented annular ring.
3. Circular scanners are consists of which type of diodes?
a) Monolithic arrays of silicon photodiodes
b) Silicon avalanche photodiodes
c) Multi element silicon photodiodes
d) Two dimensional arrays of silicon photodiodes
Answer: a
Explanation: Circular scanners devices consist of monolithic arrays of silicon photodiodes. These are self-scanned photodiode arrays which have their geometry, defined.
4. On which factor does the output of photodiode in circular scanners depends upon?
a) Frequency of illumination incidented
b) Frequency of illumination reflected
c) Amplitude of illumination incidented
d) Amplitude of illumination reflected
Answer: c
Explanation: In circular scanners, each photodiode site will output a signal that is directly proportional in amplitude to the illumination incident upon it. This output is a serial analog data stream whose rate is determined by the input clock frequency.
5. What are the factors which are responsible for the time required to read out the number of elements in a circular scan?
a) Size of scanner
b) Property of photodiode
c) Average scan time for reading
d) Frequency of input clock and number of elements
Answer: d
Explanation: The requirements of light intensity are a function of the circular scan time and the physical size of each photodiode. The total time required to read out the number of elements is a function of the input clock and the number of elements in the array.
6. What is not a function of circular scanning?
a) Tracking
b) Slicing of 3D object into 2D image
c) Displacement
d) Cylindrical bore inspection
Answer: b
Explanation: The various applications of circular scanning could be for detecting presence/absence of a feature, cylindrical bore or other defect inspection, displacement, tracking, location recognition, etc.
7. What is tracking?
a) Obtaining coordinates of a particular object in an image
b) Obtaining a path followed by a moving object
c) Obtaining the coordinate data necessary to position the sensing system along defined patterns
d) Obtaining the coordinates of a frame that is captured
Answer: c
Explanation: Tracking and cylindrical bore or other defect inspections are the applications of circular scanning. In circular scanning, tracking means obtaining the coordinate data necessary to position the sensing system along defined patterns.
8. What is displacement?
a) Calibration, verification, and alignment of an object moving in an angular motion about a pivotal centre
b) Verification and alignment of an object moving in an angular motion about a pivotal centre
c) Calibration and alignment of an object moving in an angular motion about a pivotal centre
d) Calibration and verification of an object moving in an angular motion about a pivotal centre
Answer: a
Explanation: Displacement and location recognition are the applications of circular scanning. Displacement in circular scanning refers to calibration, verification, and alignment of an object moving in an angular motion about a pivotal centre.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Photogrammetry”.
1. How many location photographs are required for photogrammetry?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: In photogrammetry photograph are taken from at least two different locations so that “lines of sight” can be developed from each camera to points on the object. These lines of sight are intersected mathematically to produce the 3-D coordinates of the points of interest.
2. What does the inner orientation of camera define in photogrammetry imaging process?
a) Geometric parameters of the imaging process
b) Location of object points in space
c) View direction
d) Finding fixed points
Answer: a
Explanation: The coordinates of image define the locations of the object points on the film. The exterior orientation of a camera defines location of points in space and direction of view. The inner orientation of camera defines the geometric parameters of the imaging process.
3. What does close range photogrammetry called in computer vision community?
a) Topographic modeling
b) Image-based modeling
c) Aerial photogrammetry
d) Engineering photogrammetry
Answer: b
Explanation: In Terrestrial photogrammetry also known as close-range Photogrammetry, the camera is located on the ground, pole mounted and handheld. This type of photogrammetry is sometimes called Image-Based Modeling in the computer vision community.
4. What is the fundamental principle of photogrammetry?
a) Interference
b) Resection principle
c) Triangulation
d) Intersection principle
Answer: c
Explanation: Photogrammetry is a 3-D coordinate measuring technique that uses photographs as the fundamental medium for metrology. The fundamental principle used by this technique is triangulation or Aerial Triangulation.
5. What is the type of photograph if the tilt of the axis of the camera from the plumb line is 2 degrees?
a) Oblique photograph
b) Horizontal photograph
c) Tilted photograph
d) Vertical photograph
Answer: d
Explanation: If the tilt of the axis of a camera from the plumb line is less than 3 degree then the photograph is vertical photograph but if the tilt of camera axis is more than 3 degree then it is called as tilted photograph.
6. What is the type of photograph on which the apparent horizon doesn’t appear?
a) Low oblique
b) High oblique
c) Tilted
d) All type of oblique photographs
Answer: a
Explanation: Oblique photographs are of two types : High oblique photograph and low oblique photograph. High oblique photograph is an oblique photograph in which the apparent horizon appears while low oblique photograph: is one on which the apparent horizon doesn’t appear.
7. Which is not correct about interpretative photogrammetry?
a) It form basis for remote sensing
b) Involves study of photographic images
c) Involves recognition and identification of objects and judgement of their significance
d) Also involves the use of collected data after analysis
Answer: d
Explanation: Photo interpretation or interpretative photogrammetry involves the study of photographic images but remote sensing involves not only the photograph analysis but also the use of data collected from remote sensing instruments.
8. Which of the following option is true for given statements about photogrammetry?
Statement 1: Both aerial and terrestrial photogrammetry used in Urban planning.
Statement 2: Terrestrial photogrammetry is more suitable for movement related issues.
a) T, T
b) F, F
c) F, T
d) T, F
Answer: a
Explanation: Urban planning takes advantage of terrestrial and aerial methods. Planners and designers collaborate on the best perspective for a specific project using aerial photogrammetry and terrestrial photogrammetry helps to see the interrelation between urban constructions, security issues etc.
9. Which photogrammetry method has topographical mapping as a common application?
a) Interpretative Photogrammetry
b) Metric photogrammetry
c) Aerial Photogrammetry
d) Space Photogrammetry
Answer: b
Explanation: Metric photogrammetry consists of making precise measurements on photographs to determine relative point locations. Common applications of Metric Photogrammetry are topographical mapping and plan metric mapping.
10. Which instrument lets an operator see two photos at once?
a) Goniometer
b) Collimator
c) Theodolite
d) Stereo plotter
Answer: d
Explanation: Stereoscopic plotting instruments or stereoplotters or plotters are the instruments designed to provide accurate solutions for point positions of objects from their corresponding positions of images on overlapping pairs of a photo.
This set of Engineering Metrology Questions and Answers for Aptitude test focuses on “Grazing Incident Technique to Evaluate Surface Flatness”.
1. How many data points can be analyzed in 20 seconds using grazing incidence interferometry?
a) 35,000
b) 45,000
c) 55,000
d) 65,000
Answer: d
Explanation: A laser-based system is developed to view part surface topography using grazing incidence interferometry. It is a microprocessor based system. It can analyze more than 65,000 data points and computer flatness in less than 20 seconds.
2. Which of the following option is true for the evaluation of the surface by using grazing incident technique with laser beam system?
a) It can two dimensional profiles with submicron accuracy
b) It measure half the part surface at a time
c) It can produce three dimensional profiles with submicron resolution
d) Video screen is used to view test results
Answer: b
Explanation: It measures the whole part surface at one time and produces 2 and 3-D profiles with sub-micron resolution and accuracy. Test results can be viewed with the help of video screen and hard copied on a printer.
3. How much a laser beam can be expanded inside interferometer using grazing incidence interferometry?
a) 200 mm
b) 200 nm
c) 400 mm
d) 400 nm
Answer: a
Explanation: In this instrument, inside the interferometer a laser beam can be expanded into 200 mm column of light. The interference pattern obtained by this process represents the shape of the part of the surface.
4. Which system is used to automatically interpret the interference pattern?
a) Phase measuring interferometric system
b) Multi-color microscopic interferometry system
c) Two point distance measuring interferometric system
d) Michelson interferometric system
Answer: a
Explanation: Phase measuring interferometric system or we can say PMI can automatically interpret the interference pattern. It can capture a large number of data samples from test surface.
5. In how many picture elements the test surface is divided if a high contrast video system captures the image of an interference pattern?
a) 455336
b) 55536
c) 65536
d) 75536
Answer: c
Explanation: If a high contrast video system is used to capture images of the interference pattern then it divides the test surface into 65,536 picture pixels or picture elements. The map or pixel map is superimposed over the interference pattern and its intensity profile is recorded.
6. How many data samples can be captured by the PMI system?
a) 1 million
b) 2 million
c) 1.5 million
d) 4 million
Answer: b
Explanation: PMI system or phase measuring interference system can capture over 2 million data samples. After capturing, it interprets them and then compiles the data into a 3-D image of the test surface.
7. From which part the light column is divided into beams in grazing incident technique?
a) At the hypotenuse of the system’s precision prism
b) At base of the system’s precision prism
c) After reflecting from the test surface
d) At perpendicular of the system’s precision prism
Answer: a
Explanation: At the hypotenuse of the precision prism of the system, the light column is divided into two beams i) the reference and ii) test beam. When these beams recombine, they interfere with one another and create a series of light and dark bands or an interference pattern.
8. How the intensity variation appears at each pixel in the grazing incident technique with laser beam system?
a) As a cosine wave
b) As a sine wave
c) Straight line
d) Hyperbolic
Answer: b
Explanation: The intensity variation at each pixel appears as a sine wave and recorded by the microprocessor. It is used to determine its relative phase. The phase differences are used to define the surface topography.
9. Which of the following statement is true about the grazing incident technique used to evaluate surface flatness?
Statement 1: Grazing incidence design turns rough surface into polished mirror surface to facilitate measurement.
Statement 2: It is important to prevent test beam to strike at grazing angle for measurement performance.
a) F, F
b) T, T
c) F, T
d) T, F
Answer: d
Explanation: The performance of measurement can be improved by striking the test beam at a grazing angle. The grazing incidence design turns non-reflective, rough surfaces into a polished mirror surface to facilitate measurement.
10. How many diffraction gratings are used by interferometer in grazing incident technique with laser beam system?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: The interferometer uses 2 linear diffraction gratings. These gratings are used to split and recombine the light into reference and test beams. The diffracted light of first order from the first grating reflects off at a grazing angle and it is the test beam. The zero order diffracted light is reference beam and passes parallel to the surface.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Visual Inspection”.
1. What is the use of an interference microscope?
a) Measure depth of scratches
b) Measure width of crack
c) Develop a permanent visual record
d) Only illuminate the cracks
Answer: a
Explanation: Interference microscope is used to measure the depth of scratches in the finish of finely lapped or polished surfaces. This is a nondestructive technique and is generally used in visual inspection.
2. What is the tube diameter of rigid borescope?
a) 0.1 to 10 mm
b) 0.5 to 90 mm
c) 0.2 to 100 mm
d) 0.9 to 70 mm
Answer: d
Explanation: The borescope’s applications are limited with a straight line path between the observer and surface to be observed. The diameter of tube of rigid borescope may range from 0.9 to 70 mm and length from 0.15 to 30 metres.
3. What is the use of fluorescent penetrants?
a) Develop permanent visual records of a remote object
b) Illuminates and observes internal, closed or inaccessible areas
c) Enhance the observation of surface cracks
d) Evaluate surface finish, shape and microstructure
Answer: c
Explanation: Fluorescent penetrants are generally used for visual inspection. It is used to enhance the observation of cracks. Image sensors are also used for visual inspection which develops permanent visual records.
4. What is the field of view range of borescope?
a) 30 to 180 degree
b) 10 to 90 degree
c) 60 to 360 degree
d) 10 to 180 degree
Answer: b
Explanation: The field of view of borescope can range from 10 to 90°. It is possible to have orbital scan which involves the rotation of the optical shaft for scanning purpose. The illumination system used in bprescope incorporates features like different viewing head, orbital scan, and adjustable focussing of the objective lens.
5. What type of fibre is present in the optical tube of mini borescope?
a) Quartz fibre
b) Asbestos fibre
c) Plastic fibre
d) Resin fibre
Answer: a
Explanation: Mini borescope uses a single image-relaying rod or quartz fibre in the optical tube in place of conventional relay lenses. Mini borescope is a variant of borescope along with hybrid borescopes, extendable borescopes, or rigid chamberscope.
6. Which of the following option is true about hybrid borescopes?
a) Use rod lenses combined with concave lenses
b) Use rod lenses combined with concave mirror
c) Use rod lenses combined with convex lenses
d) Use rod lenses combined with convex mirror
Answer: c
Explanation: Hybrid borescopes uses rod lenses combined with convex lenses to-relay the image. Extendable borescope enable the use of extension tubes. These both are the variants of the borescope and used for visual inspection.
7. Upto which length the flexible fiberscopes are available?
a) 12 m
b) 14 m
c) 16 m
d) 18 m
Answer: a
Explanation: Flexible fiberscopes are available upto 12 m length and in diameter range of 1.4 to 13 mm. Image guide fibres with fibre size 65 to 17 µm and light guide bundle with 30µm diameter fibre are used in flexible fiberscopes.
8. Which of the following option is true for the given statements about flexible fibrescope?
Statement 1: Fibrescope produce higher resolution than videoscope.
Statement 2: Videoscopes have longer working length than fibrescope.
a) T, T
b) T, F
c) F, F
d) F, T
Answer: d
Explanation: Videoscopes produce higher resolution and have longer working length than fiberscope. The display used in this reduces eye fatigue and enables point-to-point measurement on the viewing screen with the help of reticles.
9. For what distance, videoscopes are used with CCD probes for electronic transmission?
a) Less than 15 m
b) More than 15 m
c) Less than 10 m
d) More than 10 m
Answer: b
Explanation: For more than 15 meter distance, videoscopes with CCD probes or charge coupled device probes are used for electronic transmission of black and white or colour images to a video monitor.
10. Which of the following is not true about rigid chamberscope?
a) Enable use of extension tube
b) Have zoom facility
c) Used for rapid inspection
d) Offer greater magnification
Answer: a
Explanation: Chamberscopes offer more magnification than conventional rigid borescopes. They have zoom facility and used for rapid inspection of large chambers. They include variable direction of view with high intensity lightning.
11. Where does the CCD chip is placed in flexible fiberscope?
a) At proximal end
b) Ar median point
c) At the distal end
d) Anywhere between proximal and distal end
Answer: c
Explanation: A CCD chip consists of a large number of light-sensitive picture elements or pixels arranged in a pattern of rows and columns, is placed at the distal end. The objective lens focuses the object image on the surface of the CCD chip.
12. Which type of special purpose system is used for the examination of hazardous process or for extreme radiations?
a) Fibrescope
b) Chamberscope
c) Periscope
d) Vacuum borescope
Answer: c
Explanation: Periscopes allow examination of dangerous or hazardous areas. Periscopes are designed for high pressure and temperature, extreme radiation or underwater applications. Vacuum borescopes recording and observation of images inside vacuum chambers.
13. Which of the following is not true for rigid borescopes?
a) Operates like telescope in reverse
b) Good for rapid examination
c) Video adaptation is present
d) Semi Rigid sheathing is present
Answer: d
Explanation: Semi rigid borescopes are operated like telescope in reverse. A borescope spreads the field of view. Semi Rigid sheathing is present in flexible illuminated fibrescopes and it allows the inspection at most difficult to reach spots.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Laser Inspection”.
1. Which of the following is not true about metrology lasers used in laser inspection?
a) These are high-power instruments
b) Used for rapid non-contact gauging of delicate parts
c) Have low optical cross-talk
d) Wide dynamic range
Answer: a
Explanation: These are low-power instruments. Laser systems have wide dynamic range, high contrast and low optical cross-talk. Laser systems can be used in inspection of surfaces and in dimensional measurements and are very useful in precision and accuracy measurements.
2. What is the wavelength of light produced by He-Ne laser in laser inspection?
a) 6988 Å
b) 5328 Å
c) 5928 Å
d) 6328 Å
Answer: d
Explanation: He-Ne lasers are used in laser inspection. Light produced by He-Ne lasers is at a wavelength of 6328 Å or 0.6 μm and that is in phase and coherent. This source is a 1000 times more intense than other monochromatic sources.
3. Which technique is not suitable to measure large diameter parts or large gaps?
a) Diffraction pattern technique
b) Scanning laser technique
c) Photodiode array imaging
d) Laser triangulation sensor
Answer: a
Explanation: Diffraction pattern technique is not suitable for diameters larger than few mm and is used to measure small gaps and small diameter parts. In this method, a parallel laser beam which is coherent is diffracted by a small part, and the resultant pattern is focussed on a linear diode array by a lens.
4. What is the accuracy of scanning laser gauge for objects of 10-50 mm diameter?
a) ±0.15 μm
b) ±0.25 μm
c) ±0.35 μm
d) ±0.45 μm
Answer: b
Explanation: Scanning laser gauge can provide an accuracy of ±0.25 μm for objects of 10 to 50 millimeter diameter. It can also be used for objects of diameter from 0.05 to 450 millimeter and offers repeatability of 0.1 μm.
5. Which of the following is true about resolution in two frequency laser interferometer?
a) Straightness resolution – 90 nm
b) Angular resolution – 3 arc seconds
c) Flatness resolution – 2 nm
d) Linear resolution – 1 nm
Answer: d
Explanation: The advantage of two frequency laser interferometer technique is that system does not depend upon the beam intensity and provides high sensitivity, it is also independent of noise due to air turbulence. The linear resolution by two frequency laser interferometer technique is 1 nm, angular resolution is 0.03 arc seconds and straightness resolution is 40 nm.
6. How much accuracy can be achieved by photodiode array imaging?
a) ±0.05 μm
b) ±0.15 μm
c) ±0.5 μm
d) ±0.25 μm
Answer: a
Explanation: In photodiode array imaging method which is a laser inspection technique in which the stationary part’s shadow is projected on a solid-state diode array image sensor. For large parts, 2 arrays are used i.e. one array for each edge. Accuracies as high as ±0.05 μm can be achieved by this method.
7. Which application is ideally suited for two frequency laser interferometer?
a) Pitch and yaw measurement
b) Hole diameters
c) Thickness measurement
d) Measurement of edge locations
Answer: a
Explanation: 2 frequency laser interferometer techniques are ideally suitable for measuring linear positioning, pitch, yaw and straightness in two planes. The two-frequency laser head provides, one frequency with a P polarisation i.e. M beam and another frequency with an S polarisation i.e. R beam.
8. The location of the image spot directly depends on which factor in laser triangulation sensor technique?
a) Wavelength of laser
b) Measuring range
c) Standoff distance
d) Focal length of lense
Answer: c
Explanation: The location of the image spot in laser triangulation sensor technique depends directly upon the standoff distance between the sensor and the surface of object. If standoff distance changes, it will result in a lateral shift of the spot along the sensor array.
9. Which technique from given laser inspection techniques is useful for measuring the diameter of hot steel bars?
a) Laser scanning gauge
b) Frequency laser interferometer
c) Laser triangulation sensors
d) Photodiode array imaging
Answer: a
Explanation: The Laser scanning gauge technique is very useful to measure the diameter and roundness of hot steel bars under the vibration conditions to an accuracy of 0.025 millimeter over diameters of 5 to 25 millimeter.
10. Where does wire is placed in a measurement of diameter using the technique of gauging wide diameter from the diffraction pattern formed in a laser beam?
a) Between collimator and lens
b) Between collimator and source
c) Between collimator and plane of measurement
d) Between collimator and detectors
Answer: c
Explanation: Gauging wide diameter is a method of the measurement of the thin wire diameter with the use of the interference fringes resulting from diffraction by the wire in the laser beam. Output variation from the photodetector is caused by changes in fringes.
11. How many sensors are needed to measure part thickness by using laser triangulation sensors?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: It is possible to measure part thickness or the inside bore diameter with the help of 2 sensors in laser triangulation sensor technique. The measurement accuracy and measurement range are directly related.
This set of Basic Engineering Metrology Questions and Answers focuses on “Evaluating Uncertainty in Measurement”.
1. Which type of distribution approach is not followed by systematic error?
a) U-shaped distribution approach
b) Rectangular distribution approach
c) Triangular distribution approach
d) Normal distribution approach
Answer: d
Explanation: Conventional approach used to evaluate measurement uncertainty is based on random error and systematic error. Systematic error follows Rectangular, Triangular or U-shaped distribution approach.
2. Which approach is accepted as an international procedure in evaluating the uncertainty of measurement?
a) Conventional approach
b) Modern approach
c) Experimental approach
d) Observational approach
Answer: b
Explanation: Modern approach is accepted as an international procedure. It is useful even for those problems where limited observations are possible. It is problem specific and defines the method explicitly.
3. How many methods of evaluation of uncertainty are based upon modern approach?
a) 2 methods namely Type-A and Type-B
b) 2 methods namely Type-1 and Type-2
c) 3 methods namely Type-A, Type-B and Type-C
d) 3 methods namely Type-1, Type-2 and Type-3
Answer: a
Explanation: Modern approach is based on Type A method and Type B method. When observations are taken under same measurement conditions, Type A method is used. In type B method of modern approach, the uncertainty in measurement is evaluated by the judgement of the available information.
4. Which of the following option is correct for given statements about evaluation of uncertainty of measurement?
Statement 1: Principle of evaluation of uncertainty by modern approach is approximately the same as conventional approach.
Statement 2: Conventional approach is problem specific.
a) T, F
b) F, F
c) F, T
d) T, T
Answer: a
Explanation: Modern approach defines the method explicitly and is problem specific. In those problems where only limited observations are possible, modern approach is very useful.
5. Which type of approach is followed by random errors?
a) Poisson distribution approach
b) Binomial distribution approach
c) Gaussian distribution approach
d) Polynomial distribution approach
Answer: c
Explanation: Random errors are those which can be caused by little variation in the standard setting of position, operator errors in reading the display of instrument etc. Random error follows the normal frequency or Gaussian distribution approach.
6. What is the main characteristic of random errors used to determine maximum measuring error?
a) Cumulative error
b) Standard deviation
c) Variance
d) Median
Answer: b
Explanation: Random errors are those which are produced due to large number of fluctuating and unpredictable errors that are non controllable in nature. The main characteristic of random errors is standard deviation, used to determine maximum measuring error.
7. What is the relation between maximum error for a measurement method and standard deviation in the case of random errors?
a) Maximum error equal to standard deviation
b) Maximum error is two times of standard deviation
c) Maximum error is three times of standard deviation
d) Maximum error is four times of standard deviation
Answer: c
Explanation: Spread of possible random error values is determined by the maximum error. The maximum error for a measurement method is three times the standard deviation. The maximum error and standard deviation determine the accuracy of measurement.
8. Which of the following error is not a systematic error?
a) Error induced due to stylus pressure
b) Instrument location errors
c) Error due to parallax
d) Error due to play in the instrument’s linkages
Answer: d
Explanation: Systematic errors can be caused due to calibration errors, Stylus pressure, ambient conditions , Avoidable errors and incorrect theory.
9. What is the advantage of statistical methods?
a) Increase the value of
b) Increase the value of
c) Decrease the value of
d) Increase the value of
Answer: a
Explanation: The value of increases with the help of statistical methods which means offer same quality at low cost or good quality at same cost or both i.e. better quality and less cost. Convention approach which is based upon random errors for evaluating the uncertainty of measurement follow the statistical methods.
10. What is true about random errors?
a) Sign of error can be predicted
b) Probability of occurrence of same absolute value is not equal for negative and positive errors
c) Constant in magnitude
d) Arithmetic mean in a measurement series approaches zero as measurement number increases
Answer: d
Explanation: Random errors can be caused by friction and may be due to play in the linkage of instruments. These errors are variable in sign and magnitude. These are sometimes negative and sometimes positive. Its sign cannot be predicted.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Type A Evaluation of Uncertainty”.
1. What do you mean by Type-A evaluation of uncertainty?
a) Involves a series of independent measurements of a quantity
b) Involves a series of dependent measurements of a quantity
c) Uncertainty which is characterized using an assumed probability distribution based on information available
d) Evaluated by judgment of available information
Answer: a
Explanation: Type-A evaluation of uncertainty is mainly based on repeated observations. Type-A evaluation of uncertainty involves making a series of a large number of independent quantity measurements.
2. What is used as an input estimate in Type-A evaluation of uncertainty?
a) Standard deviation
b) Arithmetic mean
c) Variance
d) Geometric mean
Answer: b
Explanation: The arithmetic mean is used as the input estimate in Type-A evaluation of uncertainty, and the standard deviation of the mean is used as the standard uncertainty. Those evaluation of standard uncertainty that is not a Type-A is a Type-B evaluation.
3. What is ANOVA in statistical analysis?
a) Analysis of variance
b) Analysis of various attributes of statistics
c) Analysis of non-observable variables
d) Assessment of various attributes of statistics
Answer: a
Explanation: Type-A evaluation of uncertainty is evaluated by using statistical analysis of series of observations scattered around some mean value which are associated with the ANOVA or analysis of variance.
4. Which is not used to evaluate Type-A uncertainty?
a) Arithmetic mean
b) Standard deviation
c) Sensitivity coefficient
d) Degree of freedom
Answer: c
Explanation: The best way to evaluate Type-A uncertainty data is by calculating the arithmetic mean, standard deviation or degree of freedom. Arithmetic mean is calculated first, followed by standard deviation and degree of freedom is calculated at last.
5. Which of the following is not treated as Type-A uncertainty?
a) Thermal stability
b) Noise
c) Repeatability
d) Resolution
Answer: d
Explanation: Here, the meaning of noise is the effect on a signal due to surrounding electrical interference and magnetic fields. Noise is treated as a random Type-A uncertainty. Other random Type-A uncertainty with a normal distribution is thermal stability and repeatability.
6. Which of the following statement is true about Type-A uncertainty?
Statement 1: Most of the systematic uncertainty is Type-A uncertainty.
Statement 2: Type-A uncertainties vary each and every time a measurement is made.
a) T, T
b) F, T
c) F, F
d) T, F
Answer: b
Explanation: Most of the systematic uncertainty is Type-B uncertainties while most of the random uncertainties are Type-A uncertainties. Every time when any measurement is made, Type-A uncertainty varies.
7. In which guide the symbols, terms and methods used for evaluating measurement uncertainty are described?
a) AUM
b) SUM
c) RUM
d) GUM
Answer: d
Explanation: The symbols, terms and methods used for evaluating measurement uncertainty are described in the GUM or Guide to the Expression of Uncertainty in Measurement, which was published in 1993 by the ISO .
8. What is the equation for experimental variance used in Type-A evaluation of uncertainty?
a) σ = √[ ∑ n i=1 ].
b) σ = √[ ∑ n i=1 2 ].
c) σ = √[ ∑ n i=1 2 ].
d) σ = √[ ∑ n i=1 ].
Answer: b
Explanation: Standard deviation is basically the measurement of the dispersion of a data set from its average. Formula is given by, σ = √[ ∑ n i=1 2 ], where x’ is arithmetic mean and is equal to [ ∑ n i=1 ].
9. How can Type-A uncertainties can be quantify?
a) Using quality transducer
b) Using stepper motor
c) Using LCR meter
d) Using conductivity meter
Answer: a
Explanation: Better quality transducer can be used to reduce Type-A and Type-B elemental uncertainties. Calibration can quantify Type-A elemental uncertainty, but not reduce it. Calibration can quantify as well as reduce the level of Type-B elemental uncertainty.
10. What is the value of the degree of freedom used in evaluation by Type-A method?
a) N
b) N+1
c) N-1
d) N+2
Answer: c
Explanation: The number of degrees of freedom used for evaluation is one less than the number of independent measurements of quantity i.e. if number of independent measurements are 100 then the degree of freedom is equal to .
This set of Engineering Metrology Assessment Questions and Answers focuses on “Type B Evaluation of Standard Uncertainty”.
1. Which type of uncertainty is evaluated in Type-B Evaluation?
a) When observations are taken under same conditions
b) When information has possible variability of input variables
c) When Information is present non continuous manner
d) When information is available and is used as it is without any judgement
Answer: b
Explanation: The standard uncertainty where the available information is present with a possible variability of input variables is evaluated by Type-B method of evaluation. For making Type-B evaluations critical thinking, intellectual honesty and professional skill are required.
2. Type-B method is a type of which evaluation approach?
a) Gaussian approach
b) Triangular distribution approach
c) U shaped distribution approach
d) Modern approach
Answer: d
Explanation: Type-B method is a part of modern approach, it’s another part is Type-A method. Type-B evaluation of uncertainty use manufacturer’s specifications like previous measurement data for material or measuring instrument.
3. What is the coverage factor in a Type-B method?
a) Any numerical value only
b) A multiple of sigma only
c) A numerical value or multiple of sigma
d) Always equal to one
Answer: c
Explanation: The coverage factor is specified either as one numerical value or may be stated at a multiple of sigma. The uncertainty or we can say standard can be obtained by the dividing the given value by the multiple.
4. What value of uncertainty cannot be taken in a Type-B method?
a) Standard uncertainty without certificate
b) Resultant of previous value
c) Evaluated on the basis of experience
d) Reference value from the literature
Answer: a
Explanation: The value of uncertainty may be taken from a reference value from the literature, a resultant value of a previous measurement, using the standard uncertainty for which calibration certificate is available or could be evaluated on the basis of experience.
5. If calibration certificate state the uncertainty at Xσ and quoted uncertainty is N, then what is the value of standard uncertainty?
a) X*N
b) X/N
c) N/X
d) N X
Answer: c
Explanation: The standard uncertainty will be obtained by dividing the given value by the multiple. For example, if a calibration certificate states the uncertainty at 5a, the standard uncertainty is then simply, quoted uncertainty/5.
6. When is rectangular distribution is used in Type-B evaluation method?
a) When value of measurand is equal to upper limit
b) When value of measurand is equal to lower limit
c) When measurand lies anywhere within the limits
d) When no limits can be determined
Answer: c
Explanation: Rectangular distribution is used when the limits can be determined and the value of the measurand is equally likely to lie anywhere within the limits.
7. When is triangular distribution is used in a Type-B method?
a) When most values are near the origin
b) When most values are near the right most position of distribution
c) When most values are near the left most position of distribution
d) When most values are near the centre of distribution
Answer: d
Explanation: Triangular distribution of Type-B evaluation is used when it is known that most of the values used are more likely to be near the centre of the distribution, rather than at the extreme limits.
8. What is the sensitivity coefficient?
a) It describes how sensitive the input data is
b) It describes to what extent output data is influenced with variation in input data
c) It describes to what extent input can change
d) It describes to what extent input data is influenced with variation in the number of observations
Answer: b
Explanation: The sensitivity coefficient describes to what extent the output estimate is influenced by variation of the input estimate. The sensitivity coefficient can be calculated by varying the quantity over range of uncertainty list and measuring its influence on the measurand.
9. Which of the following is not treated as Type-B uncertainty?
a) Hysteresis
b) Common Mode Voltage
c) Nonlinearity
d) Repeatability
Answer: d
Explanation: Resolution, Scale Size and Quantization, Hysteresis, Common Mode Voltage, Installation, Nonlinearity or Linearity, Spatial Variation, Loading uncertainties, Sensitivity and Zero offset, these all are Type-B uncertainties.
10. Which distribution is related to U-probability distribution of Type-B evaluation of uncertainty?
a) Arcsin distribution
b) Binomial distribution
c) Poisson distribution
d) Bernoulli distribution
Answer: a
Explanation: U-probability distribution of Type-B evaluation method of uncertainty is used when the values are at extreme limits and values are least at mean for example Arcsin distribution. Standard uncertainty = a/√2.
This set of Engineering Metrology Multiple Choice Questions & Answers focuses on “Expanded Uncertainty”.
1. What is the actual definition of expanded uncertainty?
a) Uncertainty of the measurement result expressed as a standard deviation
b) Quantity defining an interval about the measurement result
c) Evaluation method of uncertainty by the statistical analysis of series of observations
d) Uncertainty Evaluation method by other than the statistical analysis
Answer: b
Explanation: The quantity that defines an interval about the measurement outcome which can be expected to include a large portion of the distribution of values that could be attributed to the measurand.
2. What is the relation of expanded uncertainty with coverage factor and combined uncertainty?
a) Expanded uncertainty = Coverage factor * Combined uncertainty
b) Combined uncertainty = Coverage factor * Expanded uncertainty
c) Coverage factor = Combined uncertainty * Expanded uncertainty
d) Coverage factor * Combined uncertainty * Expanded uncertainty = 1
Answer: a
Explanation: The equation which is used to calculate expanded uncertainty is a very basic equation. To calculate expanded uncertainty, one will need to multiply a coverage factor by the combined uncertainty.
3. What is the confidence interval for the value of coverage factor ‘2’?
a) 95 %
b) 94 %
c) 95.45 %
d) 94.45 %
Answer: c
Explanation: Confidence interval for the value of coverage factor 2 is generally taken as 95 % but it is not the actual value. The actual value for this is 95.45 %. For 95 % confidence interval, actual ‘k’ or coverage factor is 1.96.
4. Which table is generally used to find the coverage factor?
a) Student’s T table
b) F distribution table
c) Wishart distribution table
d) Tau distribution table
Answer: a
Explanation: Student’s T table is generally used to find coverage factor. The values are generally found at the bottom of the table especially the last row and it is generally marked with the infinity symbol.
5. What is the value of coverage factor which is generally used in the manufacturing industry?
a) 2
b) 2.89
c) 3
d) 3.89
Answer: d
Explanation: In the manufacturing industry, the main aim is for a failure rate of 1 in ten thousand or a coverage factor ‘k’ of 99.99% confidence, where coverage factor = 3.89. However, Confidence intervals can be greater or smaller for different industries depending on acceptable failure rates.
6. Which of the following option is true for given statements about expanded uncertainty and coverage factor?
Statement 1: Last calculation is the expanded uncertainty when estimating uncertainty in measurement.
Statement 2: In metrology industry, the mostly used value of the coverage factor is 2.
a) T, F
b) F, F
c) T, T
d) F, T
Answer: c
Explanation: In metrology industry, a typically estimate of uncertainty to 95.45% confidence and coverage factor where k=2 is used. It can vary according to requirement. Last calculation is generally the expanded uncertainty while estimating measurement uncertainty.
7. Which option is not correct about coverage factor?
a) It is a number which is generally larger than 1
b) Range – 2 to 7
c) Can be calculated by using MS excel
d) Depends on the selected coverage probability
Answer: b
Explanation: The coverage factor generally depends upon the probability distribution type of the output measurement quantity in the measurement model and on the selected coverage probability. Its range is generally between 2 to 3, can be more for special purposes.
8. What is the formula for relative expanded uncertainty?
a) U r = U/| y |
b) U r = U/y
c) U r = U*| y |
d) U r = U*2y
Answer: a
Explanation: In analogy with relative standard uncertainty U r and relative combined standard uncertainty U c,r the relative expanded uncertainty of a measurement result y is U r = U/ | y |, y is not equal to zero and U is expanded uncertainty.
