Power Plant Engineering Pune University MCQs

Power Plant Engineering Pune This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Steam Power Plant”. University MCQs

Power Plant Engineering Pune University MCQs

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Steam Power Plant”.

1. Which of these is a ‘fissile fuel’?

a) Thorium

b) Carbon

c) Potassium

d) Graphite

Answer: a

Explanation: A fissile fuel is one that is based on a sustained chain reaction with neutrons of any energy.

2. Which of these is a ‘working fluid’ in liquid phase?

a) Water

b) Steam

c) Mercury

d) Oxygen

Answer: a

Explanation: The working fluid is water in liquid phase & steam in gas phase.

3. Which of these is an output of a ‘Furnace’?

a) Fuel gas

b) Air

c) Flue gases

d) Water Vapor

Answer: c

Explanation: A furnace takes in a Fuel gas, Air & Water Vapour while it gives off Flue Gases.

4. What kind of energy output is obtained from a ‘Steam Power Plant’?

a) Heat energy

b) Sound energy

c) Electricity

d) Thermal energy

Answer: c

Explanation: A ‘Steam Power Plant’ is used primarily for electricity generation.

5. What kind of a process does a ‘Steam Power Plant’ undergoes?

a) Adiabatic

b) Cyclic

c) Irreversible

d) Expansion

Answer: b

Explanation: As the internal energy change in the ‘Steam Power Plant’ is ZERO. Hence, the entire plant obeys a Cyclic Process.

6. Water that is fed back to the boiler by the pump is called?

a) Adsorbate

b) Absorbate

c) Condenset

d) Condensate

Answer: d

Explanation: The water feedback is from condenser & its called condensate.

7. The net change in internal energy in a steam power plant is?

a) Positive

b) Negative

c) Zero

d) None of the mentioned

Answer: c

Explanation: As the steam power plant is based on a cyclic process. A cyclic process has a net change in internal energy=0.

8. The product of efficiency & heat transferred to the working fluid is?

a) Net temperature change

b) Net work done

c) Net enthalpy change

d) None of the mentioned

Answer: b

Explanation: The formula of efficiency of a steam power plant is,

Efficiency = net work done/net heat transferred

9. What are the components of a Steam Power Plant?

a) Evaporator, Condenser, Boiler, Expansion valve

b) Evaporator, Condenser, Boiler, Turbine

c) Boiler, Turbine, Condenser, Pump

d) Boiler, Turbine, Pump, Expansion valve

Answer: c

Explanation: A Steam Power Plant has the sequence,

Boiler, Turbine, Condenser, Pump.

10. Shaft work is fed to __________ for getting an electrical output.

a) Motor

b) Generator

c) Rotor

d) Accelerator

Answer: b

Explanation: The flow in a Steam Power Plant follows the sequence,

Source-Shaft-Generator.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Rankine Cycle and Carnot Cycle”.

1. Ideal ‘Rankine Cycle’ is a __________ process.

a) Reversible

b) Irreversible

c) Reversible & Irreversible

d) None of the mentioned

Answer: a

Explanation: Ideal Rankine Cycle is a reversible process.

2. For analytical purposes, the Rankine Cycle is assumed to be in _____________

a) Unsteady flow operation

b) Turbulent flow operation

c) Steady flow operation

d) Laminar flow operation

Answer: c

Explanation: For analytical purposes, always steady flow operation is considered, as in unsteady flow, the various fluid properties vary considerably which remain same when the steady flow operation is assumed.

3. The net work done in a Rankine Cycle is the difference of _____________

a) Condenser work & Boiler work

b) Boiler work & Pump work

c) Turbine Work & Pump work

d) Condenser work & Pump work

Answer: c

Explanation: The net work done in a Rankine Cycle is given by,

W net = W t – W p .

4. In a Rankine Cycle, heat input is provided to ___________

a) Condenser

b) Pump

c) Turbine

d) Boiler

Answer: d

Explanation: As the heating of the liquid working fluid occurs in the Boiler, the heat input is provided to the Boiler for the same.

5. In a Rankine Cycle, heat output is obtained from ___________

a) Condenser

b) Boiler

c) Turbine

d) Pump

Answer: a

Explanation: As the heated water comes to the condenser, it loses its heat & gets condensed. The heat output is obtained from Condenser.

6. The water that flows from the Pump is?

a) Compressible

b) Incompressible

c) Unsteady

d) None of the mentioned

Answer: b

Explanation: The water flowing through the pump is incompressible so as to extract work from the turbine.

7. Steam Rate is the reciprocal of _________

a) Net work done

b) Heat extracted from condenser

c) Heat given to reciprocal

d) Work done by turbine

Answer: a

Explanation: Steam Rate is given by,

Steam Rate = 1/W net .

8. Which of these is sometimes neglected?

a) Turbine work

b) Pump work

c) Condenser heat

d) Boiler heat

Answer: b

Explanation: Pump Work is very small as compared to Turbine Work & so is often neglected.

9. Efficiency of a Rankine Cycle is also expressed as __________

a) Capacity Ratio

b) Heat Rate

c) Heat Ratio

d) Steam Rate

Answer: b

Explanation: The relation between Heat Rate & Efficiency is,

Heat Rate = Efficiency of a Rankine Cycle.

10. Steam Power Plants are more popular in electric power generation because ___________

a) Work output of turbine is very large than work input to the pump

b) Work output of turbine is very small than work input to the pump

c) Work output of turbine is equal to work input to the pump

d) None of the mentioned

Answer: a

Explanation: In a Steam Power Plant, the positive difference of turbine work & pump work makes it useful in electricity generation.

11. Which is the most common type of Evaporator?

a) Flooded Evaporator

b) Plate Evaporator

c) Coil Evaporator

d) Brine Evaporator

Answer: b

Explanation: The most common type is a coil winding on a plate & so the name ‘plate evaporator’.

12. In Rankine Cycle, water is converted to saturated liquid in ___________

a) Evaporator

b) Economizer

c) Superheater

d) Preheater

Answer: b

Explanation: The saturation of water occurs in an Economizer in a Rankine Cycle.

13. If Evaporator & Condenser pressures are p & q, the intercooler pressure P is given as?

a) P = pq

b) P = p/q

c) P =

d) P = p 2 q

Answer: c

Explanation: The relation between Intercooler pressure, Evaporator & Condenser is,

P = .

14. Phase change at constant pressure takes place in _____________

a) Economiser

b) Evaporator

c) Superheater

d) Air-Preheater

Answer: c

Explanation: Superheater undergoes a change in phase at constant pressure.

15. Which of these factors don’t cause Internal Irreversibility of a Rankine cycle?

a) Throttling

b) Mixing

c) Fluid Friction

d) Fluid flow

Answer: d

Explanation: The Rankine cycle is an Irreversible cycle. For a cycle to be irreversible naturally throttling, mixing & friction in fluids are the factors that cause this Irreversibility.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Rankine cycle”.

1. What is the unit of Heat rate?

a) kJ/KW

b) KW/kJ

c) kJ

d) KW

Answer: a

Explanation: Heat rate is the rate of input required to produce unit shaft output.

2. Rankine cycle operating on low pressure limit of p1 and high pressure limit of p2 ___________

a) has higher thermal efficiency than the Carnot cycle operating between same pressure limits

b) has lower thermal efficiency than Carnot cycle operating between same pressure limits

c) has same thermal efficiency as Carnot cycle operating between same pressure limits

d) may be more or less depending upon the magnitudes of p1 and p2

Answer: a

Explanation: Area under P-V curve for Rankine will be more as compared to Carnot cycle.

3. Rankine efficiency of a Steam Power Plant ___________

a) improves in Summer as compared to that in Winter

b) improves in Winter as compared to that in Summer

c) is unaffected by climatic conditions

d) none of the mentioned

Answer: b

Explanation: In winters, the temperature of cooling water is low, which increases Condenser’s efficiency.

4. Rankine cycle comprises of ___________

a) two isentropic processes and two constant volume processes

b) two isentropic processes and two constant pressure processes

c) two isothermal processes and two constant pressure processes

d) none of the mentioned

Answer: b

Explanation: Rankine cycle is a reversible cycle which have two constant pressure and two constant temperature processes.

5. In Rankine cycle, the work output from the turbine is given by ___________

a) change of internal energy between inlet and outlet

b) change of enthalpy between inlet and outlet

c) change of entropy between inlet and outlet

d) change of temperature between inlet and outlet

Answer: b

Explanation: Work output = h1 – h2.

6. Which of the following contributes to the improvement of efficiency of Rankine cycle in a Thermal Power Plant?

a) reheating of steam at intermediate stage

b) regeneration use of steam for heating Boiler feed water

c) use of high pressures

d) all of the mentioned

Answer: d

Explanation: The regenerative features effectively raise the nominal cycle heat input temperature, by reducing the addition of heat from the Boiler/fuel source at the relatively low feedwater temperatures that would exist without regenerative feedwater heating.

7. Match the following:

i) Boiler A. reversible adiabatic expansion of steam

ii) turbine B. constant pressure heat heat addition

iii) Condenser C. reversible adiabatic compression

iv) pump D. constant pressure heat rejection

a) i-B ii-A iii-D iv-C

b) i-A ii-C iii-D iv-A

c) i-B ii-D iii-C iv-A

d) i-A ii-D iii-B iv-C

Answer: a

Explanation: Working fluid in Rankine cycle undergoes 4 processes, expansion in turbine, heat addition in Boiler, heat rejection in Condenser and compression in pump.

8. What is the actual turbine inlet temperature in Rankine cycle?

a) 700C

b) 800C

c) 550C

d) 1150C

Answer: c

Explanation: The TIT is of the range 500-570C.

9. Rankine cycle efficiency of a good Steam Power Plant may be in the range of?

a) 15 to 20%

b) 35 to 45%

c) 70 to 80%

d) 90 to 95%

Answer: b

Explanation: Efficiency of Rankine cycle in actual working condition is found to be between 35 to 45%.

10. A simple Rankine cycle operates the Boiler at 3 MPa with an outlet temperature of 350°C and the Condenser at 50 kPa. Assuming ideal operation and processes, what is the thermal efficiency of this cycle?

a) 7.7

b) 17.7

c) 27.7

d) 37.7

Answer: c

Explanation: Fixing the states; h1 = 340.5 kJ/kg, h2 = h1 + v1 = 343.5 kJ/kg, h3 = 3115.3 kJ/kg, s3 = 6.7428 kJ/kg – K, x4 = 0.869, and h4 = 2343.9 kJ/kg. Thus, η = 1 – Qout / Qin = 1 – / = 27.7%.

11. A simple Rankine cycle produces 40 MW of power, 50 MW of process heat and rejects 60 MW of heat to the surroundings. What is the utilization factor of this co generation cycle neglecting the pump work?

a) 50

b) 60

c) 70

d) 80

Answer: b

Explanation: Application of the first law to the entire cycle gives Qin = Qp + Qreject + W = 150 MW. The utilization factor is then = / Qin = 60%.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Brayton Cycle”.

1. A gas turbine works on __________

a) Carnot cycle

b) Brayton cycle

c) Dual cycle

d) Rankine cycle

Answer: b

Explanation: A gas turbine works on 2 isentropic and 2 isobaric processes which is nothing else but Brayton cycle.

2. What is the range of Thermal efficiency in the Brayton cycle?

a) 30-35%

b) 40-45%

c) 50-55%

d) 50-60%

Answer: c

Explanation: Efficiency of Brayton cycle in actual working condition is found to be between 35 to 45%.

3. What is the maximum possible TIT?

a) 1000 K

b) 1500 K

c) 950 K

d) 1300 K

Answer: d

Explanation: The maximum temperature is limited by metallurgical conditions.

4. A simple Brayton cycle uses Helium as the working fluid, has a maximum temperature of 1000 K, and a pressure ratio of 4. At the start of the compression, the Helium pressure and temperature are 50 kPa and 250 K. Based upon cold-air standard analysis assumptions, the thermal efficiency of the cycle is?

a) 0.13

b) 0.23

c) 0.43

d) 0.53

Answer: d

Explanation: Using the pressure ratio = 1 – rp / k.

5. A simple Brayton cycle has a pressure ratio of 5 and a maximum temperature of 900 K. Air enters the compressor at 100 kPa, 300 K. Based upon cold-air standard analysis assumptions, the back-work ratio of this cycle is?

a) 0.23

b) 0.53

c) 0.48

d) 0.36

Answer: b

Explanation: Using the pressure ratio and isentropic process relations, T2 = T1rp / k = 475 K and T4 = T3rp / k = 568 K. Application of the first law to the compressor and turbine processes and substituting the results into the back-work ratio definition produces rb = / = 0.53.

6. Which of the following methods can be used to increase efficiency of a Brayton cycle?

a) Regeneration

b) Increasing pressure ratio

c) Heat exchanger

d) All of the mentioned

Answer: d

Explanation: A heat exchanger that acts as a counter-flow energy recovery device positioned within the supply and exhaust air streams of an air handling system, in order to recover the waste heat.

7. For the same maximum pressure and heat input, the most efficient cycle is?

a) Brayton cycle

b) Carnot cycle

c) Rankine cycle

d) Dual cycle

Answer: a

Explanation: Efficiency of a Brayton cycle is directly proportional to pressure ratio.

8. The compression ratio is the ratio of ____________

a) Swept volume to total volume

b) Total volume to swept volume

c) Total volume to clearance volume

d) None of the mentioned

Answer: a

Explanation: According to definition, compression ratio is the ratio of swept volume to total volume.

9. A Sterling engine uses an energy source whose temperature is 727°C and an energy sink whose temperature is 27°C. How much heat must be added to the engine to produce 1 unit of work?

a) 1.10

b) 1.19

c) 1.43

d) 2.0

Answer: c

Explanation: Since the Sterling engine is totally reversible, its thermal efficiency is the same as that of a Carnot engine, η = 1 – Tl / Th = 0.7. Now, the definition of the thermal efficiency gives Qin / Wout = 1 / η = 1.43.

10. Which of the following is not a component of Brayton cycle?

a) Compressor

b) Combustion Chamber

c) Turbine

d) Pump

Answer: d

Explanation: Pump is used in Rankine cycle to circulate water from Condenser to Boiler.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Mean Temperature of Heat Addition – 1”.

1. For a given value of mean temperature of heat addition is?

a) efficiency of Rankine is more if turbine exit temperature is less

b) efficiency of Rankine is less if turbine exit temperature is less

c) efficiency does not depend on turbine exit temperature

d) none of the mentioned

Answer: a

Explanation: Efficiency = 1 – Tmin / Tm.

2. Mean temperature of heat addition can be increased by?

a) decreasing the amount of heat added

b) increase the amount of heat added

c) increase condensor pressure

d) decreasing Turbine Inlet Temperature

Answer: c

Explanation: Increasing condensor pressure decreases turbine exit temperature which in turn increases mean temperature of heat addition.

3. Internal irreversibility of Rankine cycle is caused by?

a) fluid friction

b) throttling and mixing

c) expansion and compression process are quite rapid

d) all of the mentioned

Answer: d

Explanation: Practical analysis shows that Internal irreversibility of Rankine cycle depends upon above stated factors.

4. Which of the following statement is true?

a) efficiency is directly proportional to mean temperature of heat addition

b) efficiency is inversely proportional to mean temperature of heat addition

c) efficiency is exponential function of mean temperature of heat addition

d) efficiency does not depend on mean temperature of heat addition

Answer: a

Explanation: Efficiency = 1 – Tmin / Tm.

5. Pulverized coal is ____________

a) coal free from ash

b) non-smoking coal

c) coal which bums For long time

d) coal broken into fine particles

Answer: d

Explanation: Pulverized coal also known as powdered coal or coal dust since it is as fine as face powder in cosmetic make-up.

6. What is caking in Power Plants?

a) making cakes of coal out of fine powders

b) a variety of free burning coals

c) coal produced from burning of wood in inert atmosphere

d) in boiler furnace some coals become plastic and form lumps or masses of coal

Answer: d

Explanation: When many bituminous coals are heated, they soften and form a plastic mass that swells and re solidifies into a porous solid.

7. Water gas is a mixture of ___________

a) CO 2 and O 2

b) O 2 and H 2

c) H 2 , N 2 and O 2

d) CO, N 2 and H 2

Answer: b

Explanation: Water gas is basically HHO that is H 2 and O 2 .

8. Critical pressure of water is ___________

a) 1 kg / cm 2

b) 100 kg / cm 2

c) 155 kg / cm 2

d) 217.7 kg / cm 2

Answer: d

Explanation: The critical pressure of a substance is the pressure required to liquefy a gas at its critical temperature.

9. Coal used in power plant is also known as ___________

a) steam coal

b) charcoal

c) coke

d) soft coal

Answer: a

Explanation: Because this coal is used to generate steam.

10. The temperature to which air must be cooled in order to become saturated is the ___________

a) minimum temperature

b) dew point temperature

c) wet-bulb temperature

d) freezing point

Answer: b

Explanation: The dew point is the temperature at which the water vapour in air at constant barometric pressure condenses into liquid water at the same rate at which it evaporates.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Mean Temperature of Heat Addition – 2”.

1. Mean Temperature of Heat Addition is the ratio of ____________

a) Difference of temperatures to difference of entropies

b) Difference of enthalpies to difference of entropies

c) Difference of temperatures to difference of enthalpies

d) Difference of entropies to difference of enthalpies

Answer: b

Explanation: The formula for Mean Temperature of Heat Addition is given by,

T ml = (h 1 – h 4 )/(s 1 – s 4 ).

2. If T 2 is the temperature of heat rejection, T ml is the mean temperature of heat addition, the efficiency n of a Rankine Cycle is given by which of the expressions?

a) n = 1-(T 2 /T ml )

b) n = 1+(T 2 /T ml )

c) n = (T 2 /T ml )

d) n = 1/(T 2 /T ml )

Answer: a

Explanation: The expression for the efficiency of a Rankine Cycle is given as,

n = 1-(T 2 /T ml ).

3. The saturation pressure corresponding to the minimum practicable temperature of heat rejection is a function of?

a) Temperature of heat rejection

b) Temperature of surroundings

c) Mean temperature of heat addition

d) None of the mentioned

Answer: c

Explanation: The relation between saturation pressure & mean temperature of heat addition is given by,

Efficiency Rankine = f(T ml )

where, T ml = Mean temperature of heat addition.

4. What is the effect of the increase in the superheat at constant pressure?

a) Decreases cycle efficiency

b) Increases mean temperature of heat addition

c) Decreases mean temperature of heat addition

d) None of the mentioned

Answer: b

Explanation: As there is an increase in superheat at constant pressure, the cycle efficiency increases & hence there is an increase in the mean temperature of heat addition.

5. PWR stands for?

a) Pressurized Water Relator

b) Pressurized Water Reheater

c) Pressurized Water Reactor

d) Pressurized Water Refractory

Answer: c

Explanation: PWR stands for Pressurized Water Reactor which does not use Superheat.

6. The maximum temperature of steam that can be used is fixed from metallurgical considerations. This temperature limit is called?

a) Mining Limit

b) Metallurgical Limit

c) Metallic Limit

d) None of the mentioned

Answer: b

Explanation: ‘Metallurgical Limit’ is defined as the lowest temperature limit of usable steam fixed by metallurgical considerations.

7. Most of the turbine expansion takes place in ____________

a) Liquid Region

b) Solid Region

c) Vapour Region

d) Plastic Region

Answer: c

Explanation: Most of the turbine expansion should take place in the vapour region, so as to increase the life of the blades of the turbine.

8. Pelton Wheel Turbine is suited for ____________

a) high heads

b) low heads

c) medium heads

d) zero heads

Answer: a

Explanation: A Pelton wheel turbine is based on the principle of changing Kinetic Energy of fluid into output work.

9. A Hydraulic Ram Pump is based on the principle of ____________

a) Wind Hammer

b) Water hammer

c) Wind gushing

d) None of the mentioned

Answer: b

Explanation: A Hydraulic Ram Pump is based on the principle of Water Hammer. This principle states that “When a flowing fluid is stopped suddenly, the kinetic energy of the rapidly moving fluid decreases to zero & in turn, increases the pressure which pulls the fluid to high heads.

10. Which of the following diagrams are used while analyzing the effect of superheat & Inlet Pressure on mean temperature of heat addition?

a) P-V diagram

b) T-S diagram

c) P-T diagram

d) V-T diagram

Answer: b

Explanation: Using the T-S diagram gives us an overview as to where a particular process occurs, i.e., it is within the solid region, the gaseous region or the vapour region. So, here, we prefer T-S diagram for analysis process.

11. Which of these constitute a Carnot Cycle?

a) 2 reversible isotherms & 2 reversible adiabatics

b) 1 reversible isotherms & 2 reversible adiabatics

c) 2 reversible isotherms & 1 reversible adiabatics

d) 1 reversible isotherms & 2 reversible adiabatics

Answer: a

Explanation: A combination of 2 reversible isotherms & 2 reversible adiabatics gives a Carnot Cycle .

12. Work input and work outputs are given & obtained in ____________

a) 2 reversible adiabatics

b) 2 reversible isotherms

c) 1 reversible isotherm & 1 reversible adiabatic

d) 2 reversible isotherms & 1 reversible adiabatic

Answer: a

Explanation: The work input & output are both in the 2 reversible adiabatics .

13. Heat input & output is obtained in ____________

a) 2 reversible adiabatics

b) 2 reversible isotherms

c) 1 reversible isotherm & 1 reversible adiabatic

d) 2 reversible isotherms & 1 reversible adiabatic

Answer: b

Explanation: The heat inputs & outputs are in 2 reversible isotherms .

14. The elements of a Carnot heat engine are ____________

a) Heat Exchangers, Turbine, Pump

b) Heat Exchangers, Turbine, Evaporator

c) Heat Exchangers, Turbine, Condenser

d) Heat Exchangers, Turbine, Superheater

Answer: a

Explanation: There are 2 heat exchangers, a turbine & a pump in a Carnot heat engine.

15. Which of these shouldn’t be there in the pipelines of working fluid for achieving the conditions of Carnot Cycle?

a) Heat Transfer

b) Insulation

c) Lubrication

d) Zero Friction

Answer: a

Explanation: Heat Transfer & Friction are the factors affecting the conditions of a Carnot Cycle.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Effect of variation of Steam Condition on Thermal Efficiency”.

1. The cycle efficiency ________________ with the _____________ of condenser pressure.

a) decreases, decrease

b) increases, decrease

c) remains same, decrease

d) does not vary, decrease

Answer: b

Explanation: As the decrease in condenser pressure mainly depends on the available cooling water temperature & thus on the climatic conditions of the place. Hence, cycle efficiency being a function of condenser pressure has an inverse relation with the condenser pressure.

2. What is the relation between cooling water temperature (t c1 ) & condenser pressure (p c )?

a) t c1 is directly proportional to p c

b) t c1 is directly proportional to 2xp c

c) t c1 is directly proportional to 5xp c

d) t c1 is directly proportional to 6xp c

Answer: a

Explanation: Cooling water temperature is directly proportional to condenser pressure 1xp c .

3. An increase in inlet steam temperature ___________ the heat rate.

a) lowers

b) increases

c) does not have any effect on

d) temperature has no significance in heat rate

Answer: a

Explanation: An increase in inlet steam temperature, i.e. an increase in superheat at constant inlet steam pressure & condenser pressure gives a steady improvement in cycle efficiency & lowers the heat rate due to an increase in the mean temperature of heat addition.

4. What is the effect of increasing superheat at constant inlet steam pressure & condenser pressure on cycle efficiency?

a) Steady decrement in cycle efficiency

b) Steady improvement in cycle efficiency

c) No effect on cycle efficiency

d) None of the mentioned

Answer: b

5. What is the effect of increasing superheat at constant inlet steam pressure & condenser pressure on mean temperature of heat addition?

a) increases

b) decreases

c) remains same

d) none of the mentioned

Answer: a

6. What is the effect of increasing steam inlet temperature on turbine internal efficiency?

a) it remains same

b) it increases

c) it decreases

d) none of the mentioned

Answer: b

Explanation: Increasing the inlet steam temperature decreases the wetness of the steam in the later stages of the turbine & improves the turbine efficiency.

7. What is the percentage drop in the ultimate strength of unalloyed steels when the steam temperature is raised from 400-500 degree Centigrade?

a) 20%

b) 30%

c) 40%

d) 60%

Answer: b

Explanation: The ultimate strength of unalloyed steels is 30% when the steam temperatures are in the range 400-500 degree Centigrade. Alloying can increase this strength.

8. Apart from alloying, name a material that is used instead of ferritic steels to increase the ultimate strength of unalloyed steels.

a) Chromium

b) Molybdenum

c) Austenitic steel

d) None of the mentioned

Answer: c

Explanation: The use of Austenitic steels increases the ultimate strength of unalloyed steels at high temperatures. The temperature limits are in the range 538-565 degree Centigrade.

9. Which of these cases will have a higher cycle efficiency?

a) Condenser Pressure = 25 mm of Hg; Cooling Water Temperature = 12 degree Centigrade

b) Condenser Pressure = 50 mm of Hg; Cooling Water Temperature = 27 degree Centigrade

c) Condenser Pressure = 75 mm of Hg; Cooling Water Temperature = 36 degree Centigrade

d) Condenser Pressure = 100 mm of Hg; Cooling Water Temperature = 45 degree Centigrade

Answer: a

Explanation: In identical steam conditions cycle efficiency is inversely proportional to cooling water temperature.

10. For the given values of efficiency, inlet steam pressure and quality of steam, pressure limits can be determined by?

a) Mollier Charts

b) Gantt Charts

c) Mollier & Gantt Charts

d) None of the mentioned

Answer: a

Explanation: The pressure limits can be readily determined by drawing the corresponding expansion line of the turbine om a Mollier Diagram.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Reheating of Steam – 1”.

1. Why Reheating of steam is used?

a) to increase efficiency

b) to increase work output

c) to increase Turbine Inlet Temperature

d) to reduce amount of fuel used

Answer: b

Explanation: Work output = work done by turbine – work done by compressor.

2. Reheating of steam _____________

a) decreases steam rate

b) increases steam rate

c) no effect on steam rate

d) none of the mentioned

Answer: a

Explanation: Since work output increases the steam rate decreases.

3. Efficiency of cycle will increase due to Reheating if _____________

a) mean temperature of heat addition in boiler is higher than in reheat process

b) mean temperature of heat addition in boiler is lower than in reheat process

c) it will increase without any conditions

d) it will not increase

Answer: a

Explanation: Efficiency = work output / heat supplied, heat supplied is less in this condition only.

4. Why don’t we use more than two reheats?

a) not economical

b) increased mechanical stresses

c) net efficiency is decreased

d) all of the mentioned

Answer: d

Explanation: The mechanical stresses increases in much higher proportion than the pressure because of the prevailing high temperature.

5. The cycle efficiency in a single reheat plant is influenced by _____________

a) pressure at tubine inlet

b) pressure at which steam is reheated

c) temperature at which steam is reheated

d) temperature at tubine inlet

Answer: b

Explanation: The cycle efficiency is a function of the ratio of reheat to initial pressure.

6. The optimum reheat pressure for most of the modern power plants is ___________ of the initial steam pressure.

a) 0.1-0.5

b) 0.2-0.3

c) 0.2-0.25

d) 0.25-0.3

Answer: c

Explanation: In this range of reheat pressure efficiency is maximum.

7. What is the effect of reheat on steam quality?

a) increases

b) decreases

c) does not change

d) depends on several parameters

Answer: a

Explanation: Because this steam is undergoing expansion two times.

8. What should be the dryness fraction at the time of exhaust?

a) 0.88

b) 0.80

c) 0.90

d) 0.75

Answer: a

Explanation: For modern turbines the admissible dryness fraction of exhaust steam should be not less than x = 0.86 to 0.88.

9. Reheat is preferred for the plants having efficiency greater than _____________

a) 150MW

b) 200MW

c) 100MW

d) 250MW

Answer: c

Explanation: For producing power less than this reheat will not be economical.

10. Which one of the following is an advantage of reheat cycle?

a) the size of the Low pressure turbine blades is reduced because specific volume is reduced by 7 to 8%

b) the reheating reduce 4 to 5% fuel consumption with a corresponding reduction in the fuel handling

c) lower steam pressures and temperatures and less costly materials can be used to obtain the required thermal performance

d) all of the mentioned

Answer: d

Explanation: Reheat increases work output.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Reheating of Steam”.

1. The product of steam rate & network when the steam rate is expressed in kg/kWh is equal to?

a) 36

b) 360

c) 3600

d) 60

Answer: c

Explanation: The Steam Rate in terms of kJ/kWh is given by the expression,

Steam Rate = (3600/W net ) kg/kWh.

2. The product of heat rate & efficiency when the heat rate is expressed in kJ/kWh is equal to?

a) 60

b) 36

c) 360

d) 3600

Answer: d

Explanation: The heat rate in terms of kJ/kWh is given by the expression,

Heat Rate = kJ/kWh

where, n = efficiency.

3. What is the effect of reheat pressure on mean temperature of heat addition T ml ?

a) Reheat pressure is directly proportional to T ml

b) Reheat pressure is inversely proportional to T ml

c) Reheat pressure is equal to T ml

d) T ml is independent of reheat pressure

Answer: a

Explanation: As cycle efficiency is reduced with a decrease in reheat pressure. Hence, the mean temperature of heat addition also decreases.

4. Why is the steam not allowed to expand deep into the two phase region before it is taken to reheating?

a) to control flow rate

b) to control phase change

c) to protect reheat tubes

d) none of the mentioned

Answer: c

Explanation: The steam is not allowed to expand deep into the two phase region before it is taken to reheating, because the moisture particles in the steam while evaporating would leave behind solid deposits in the form of scale which is difficult to remove. Hence, when the steam expands, the reheat tubes are damaged.

5. Net Work output of the plant __________ with reheat.

a) decreases

b) increases

c) remains same

d) none of the mentioned

Answer: b

Explanation: With reheat, the area under the curve increases in comparison to what it was without reheat. Hence, Net Work output of the plant increases.

6. Which of the following problems are posed by increasing the number of reheats?

a) Cost & Fabrication problems arise

b) Heat transfer problems arise

c) Frictional losses arise

d) None of the mentioned

Answer: a

Explanation: Higher the number of Reheats, still higher steam pressures could be used, but mechanical stresses increase at a higher proportion than the increase in pressure, because of the prevailing high temperature. The cost & fabrication difficulties will also increase.

7. What is the effect of decrease of reheat pressure on the quality of steam at turbine exhaust?

a) decreases

b) increases

c) remains same

d) none of the mentioned

Answer: b

Explanation: For too low a reheat pressure, the exhaust steam may even be in the superheated state which isn’t good.

8. The optimum reheat pressure for most of the power plants is how many times of the initial steam pressure?

a) 0.1-0.15

b) 0.2-0.20

c) 0.2-0.25

d) 0.1-0.10

Answer: c

Explanation: The efficiency increases as the reheat pressure is lowered & reaches a peak at a pressure ratio between 0.2-0.25.

9. What is the most preferable dryness fraction of the exhaust steam?

a) 0.99

b) 0.77

c) 0.66

d) 0.88

Answer: d

Explanation: The dryness fraction of the exhaust steam is in the range of 0.86-0.88 for modern turbines.

10. For pressure ratio = 1, efficiency = 0, then?

a) reheat is used

b) reheat is not used

c) only reheat is used

d) none of the mentioned

Answer: b

Explanation: There cannot be any reheat cycle employed when the cycle efficiency is zero and the pressure ratio is equal to 1.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Regeneration – 1”.

1. What is the basic principle of regeneration?

a) Steam after coming out of condenser is circulated to boiler

b) Steam after coming out of condenser is circulated to turbine

c) Steam after coming out of turbine is circulated to boiler

d) Two stage turbine is used

Answer: b

Explanation: In regeneration steam from condenser is circulated through turbine to increase steam temperature before it enters boiler.

2. Ideal regenerative rankine cycle _______

a) Increases efficiency

b) Increases work output

c) Increases the heat supplied

d) Does not effect efficiency

Answer: a

Explanation: Feedwater is preheated so as to decrease the fuel consumption which increases efficiency.

3. Mean temperature of heat addition is _______ due to Regeneration.

a) Decreases

b) Not effected

c) Increases

d) Varied exponentially

Answer: c

Explanation: Since less heat is required in the boiler so mean temperature of heat addition increases.

4. Name the coolants commonly used for fast breeder reactors?

a) Liquid metal Na K)

b) Helium

c) Carbon dioxide

d) All of the mentioned

Answer: d

Explanation: Liquid metals are commonly used, in some plants He and CO 2 are also used.

5. Why trash rack is used?

a) To prevent the entry of debris

b) To prevent steam overflow

c) It is used as an insulter

d) Prevents back flow

Answer: a

Explanation: The trash rack is used to prevent the entry of debris, which might damage the turbine runners and chock up the nozzle of impulse turbine.

6. What is the use of surge tank?

a) To store condensate

b) To prevent surging

c) To provide better regulation of water pressure in the system

d) To prevent chocking

Answer: c

Explanation: The surge tank controls the water when the load on the turbine decreases and supplies water when the load on the turbine increases.

7. What is the function of Fore bay?

a) Temporary water storage

b) Steam passage

c) Water flow in penstock

d) Condensate storage

Answer: a

Explanation: It is temporary water storage when the load on the plant is reduced and provides water for initial increment on increasing load.

8. What is the use of draft tube?

a) To regain kinetic energy

b) To regain potential energy

c) Passage for water

d) Stores energy

Answer: a

Explanation: The draft tube is used to regain the kinetic energy of water coming out of reaction turbine. It enables the reaction turbine to be placed over tailrace level.

9. Is regenerative cycle alone useful?

a) yes

b) no

c) may be

d) depends on other factors

Answer: a

Explanation: Feedwater is preheated so as to decrease fuel consumption which increases efficiency.

10. What is the function of surge tank?

a) Regulation of water pressure

b) Regulation of steam pressure

c) Storage

d) Regulation of lubricants

Answer: a

Explanation: The surge tank controls the water when the load on the turbine decreases and supplies water when the load on the turbine increases

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Regeneration – 2”.

1. External Thermal Irreversibility can be removed by which of the following process?

a) Reheat

b) Regeneration

c) Pre-heat

d) None of the mentioned

Answer: b

Explanation: In the process of regeneration, energy is exchanged internally between the expanding fluid in the turbine & the compressed fluid before heat addition.

2. When is the relation between mean temperature of heat addition with regeneration & without regeneration?

a) (T ml ) with regeneration is independent of (T ml ) without regeneration

b) (T ml ) with regeneration > (T ml ) without regeneration

c) (T ml ) with regeneration < (T ml ) without regeneration

d) (T ml ) with regeneration = (T ml ) without regeneration

Answer: b

Explanation: The efficiency of the regenerative cycle will be higher than that of the Rankine cycle. Hence, the relation between mean temperature of heat addition (T ml ) with regeneration & without regeneration is,

(T ml ) with regeneration > (T ml ) without regeneration .

3. What is the relation between energy gain of feedwater & energy given off by vapour in condensation?

a) energy gain of feedwater > energy given off by vapour in condensation

b) energy gain of feedwater < energy given off by vapour in condensation

c) energy gain of feedwater = energy given off by vapour in condensation

d) none of the mentioned

Answer: c

Explanation: Here heaters are assumed to be adequately insulated, & there is no heat gain from or heat loss to, the surrounding.

4. The product of Steam rate & the difference of work done between turbine & pump, when the steam rate is expressed in kg/kWh is equal to?

a) 36

b) 60

c) 360

d) 3600

Answer: d

Explanation: The steam rate in terms of kg/kWh is given by the expression as,

Steam Rate = 3600/(W t – W P ) kg/kWh.

5. The product of cycle efficiency & heat input is given by which of the following relations?

a) W t – W P

b) W t x W P

c) W t / W P

d) none of the mentioned

Answer: a

Explanation: The expression for cycle efficiency n is given by the following expression,

n = (W t – W P )/(Q 1 ).

6. What is the effect of increase in regeneration on steam rate?

a) decreases

b) remains same

c) increases

d) none of the mentioned

Answer: c

Explanation: More steam has to circulate per hour to produce unit shaft output.

7. What is the relation between efficiencies of Carnot cycle & the ideal Sterling Engine?

a) Both are equal

b) Carnot cycle efficiency > Efficiency of Sterling Engine

c) Carnot cycle efficiency < Efficiency of Sterling Engine

d) No relation between Carnot cycle efficiency & efficiency of Sterling Engine

Answer: a

Explanation: All the heat is added reversibly & all the heat is rejected reversibly. Hence, the efficiency of Carnot Cycle is equal to efficiency of Sterling Engine.

8. Heat transfer taking place in the turbine is?

a) from the vapour to the condensate

b) from the condensate to the vapour

c) no heat transfer

d) none of the mentioned

Answer: a

Explanation: Following the Stirling cycle, in the ideal regenerative cycle the condensate after leaving the pump circulates around the turbine casing so that heat is transferred from the vapour expanding in the turbine to the condensate circulating around it.

9. The heat transfer taking place in the turbine is?

a) irreversible

b) reversible

c) irreversible & reversible

d) none of the mentioned

Answer: b

Explanation: At each point the temperature of the vapour is only infinitesimally higher than the temperature of the liquid.

10. The relation between the steam rate of ideal regenerative cycle & steam rate of rankine cycle is?

a) steam rate of ideal regenerative cycle = steam rate of rankine cycle

b) steam rate of ideal regenerative cycle > steam rate of rankine cycle

c) steam rate of ideal regenerative cycle < steam rate of rankine cycle

d) no relation

Answer: b

Explanation: Net Work output of the ideal regenerative cycle is less & hence, its steam rate will be more.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Regenerative Feedwater Heating”.

1. In an ideal regenerative cycle, heat input is at?

a) Boiler

b) Turbine

c) Condenser

d) Pump

Answer: a

Explanation: In a regenerative cycle, the heat input is at Boiler .

2. In an ideal regenerative cycle, heat output is at?

a) Boiler

b) Turbine

c) Condenser

d) Pump

Answer: c

Explanation: In a regenerative cycle, the heat output is at the Condenser .

3. In an ideal regenerative cycle, the work output is at?

a) Boiler

b) Turbine

c) Condenser

d) Pump

Answer: b

Explanation: In a regenerative cycle, the work output is at the Condenser .

4. In an ideal regenerative cycle, the work input is at?

a) Boiler

b) Turbine

c) Condenser

d) Pump

Answer: d

Explanation: In a regenerative cycle, the work input is at the Condenser .

5. What effect does the heating of feedwater by steam ‘bled’ from the turbine has on the Rankine Cycle?

a) it rankinises the Rankine Cycle

b) it carnotinises the Rankine Cycle

c) it reheats the Rankine Cycle

d) none of the mentioned

Answer: b

Explanation: The heating of feedwater by steam ‘bled’ from the turbine, known as regeneration, carnotinises the Rankine cycle.

6. What is the effect of increase in regeneration on steam rate?

a) steam rate increases

b) steam rate decreases

c) steam rate isindependent of regeneration

d) none of the mentioned

Answer: a

Explanation: More steam has to circulate per hour to produce unit shaft output.

7. If h 1 & h 10 are the enthalpies at the inlet & at the exhaust, s 1 & s 10 are the enthalpies at the inlet & exhaust, the mean temperature of heat addition, T ml with regeneration is?

a) (h 1 + h 10 )/(s 1 + s 10 )

b) (h 1 + h 10 )/(s 1 – s 10 )

c) (h 1 – h 10 )/(s 1 + s 10 )

d) (h 1 – h 10 )/(s 1 – s 10 )

Answer: d

Explanation: The expression for mean temperature of heat addition is given as,

T = (h 1 – h 10 )/(s 1 – s 10 ).

8. If Q represents the heat input, P represents the heat output; the efficiency n in terms of Q & P is given by?

a) n = QP

b) n = /Q

c) n = /Q

d) n = Q/

Answer: b

Explanation: The expression of efficiency in terms of heat input & output is given by,

n = /Q.

9. If q represents the work output, r represents the work input, Q represents the heat input, the efficiency n in terms of q & r is given by?

a) n = /Q

b) n = /Q

c) n = /Q

d) n = /Q

Answer: a

Explanation: The efficiency in terms of work input, work output & heat input is given by,

n = /Q.

10. What is the effect of increase in steam rate on boiler size?

a) boiler size increases

b) boiler size increases

c) boiler size is independent of steam rate

d) none of the mentioned

Answer: a

Explanation: Increase in steam rate increases by regeneration, i.e., more steam has to circulate per hour to produce unit shaft output. Hence, it increases boiler size.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Feedwater Heaters – 1”.

1. Feedwater heaters are of two types, they are ____________

a) natural and forced

b) saturated and non saturated

c) open and close

d) water driven and steam driven

Answer: c

Explanation: Feedwater heaters are classified by the methods of mixing steam and feedwater.

2. In open feedwater heater __________

a) the extracted steam is allowed to mix with feedwater

b) feedwater flows through tubes and steam is condensed outside

c) steam flows outside tubes and feedwater inside

d) steam flows inside tubes and outside inside

Answer: a

Explanation: In a closed heater, the extracted steam is allowed to mix with feedwater and both leave the heater at a common temperature.

3. Closed heaters are also called __________

a) contact type heater

b) shell and heat exchanger

c) drip heaters

d) shell and tube heater

Answer: b

Explanation: Closed heaters are also called shell and heat exchanger where the feedwater flows through the tubes.

4. Expand TTD?

a) turbine temperature difference

b) total temperature difference

c) terminal temperature difference

d) turbine terminal difference

Answer: c

Explanation: Terminal temperature difference = saturation temperature of bled steam – exit water temperature.

5. The value of TTD varies with __________

a) heater pressure

b) heater temperature

c) turbine inlet temperature

d) independent of all mentioned

Answer: a

Explanation: The value of TTD varies with heater pressure. heaters receiving wet steam, the TTD is positive.

6. Why at least one open heater is used?

a) installed vertically

b) feedwater deaeration

c) less cost

d) increase efficiency

Answer: b

Explanation: The open heater works as a deaerator.

7. What are the advantages of open heater?

a) lower cost

b) high heat transfer capacity

c) high feedwater temperature

d) all of the mentioned

Answer: d

Explanation: Open heaters are cheap as compared to closed heaters, in closed heaters feedwater temperature is not high.

8. What do you mean by heater drip?

a) condensate

b) heater failure

c) extract

d) maximum temperature

Answer: a

Explanation: Saturated water at the steam extraction pressure.

9. Which of the following material can be used as a moderator?

a) Beryllium

b) Graphite

c) Heavy water

d) All of the mentioned

Answer: d

Explanation: A neutron moderator is a medium that reduces the speed of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction involving uranium-235.

10. Closed heaters are __________

a) horizontal

b) vertical

c) inclined

d) depends on the requirement

Answer: d

Explanation: Closed heaters are mostly horizontal. Sometimes, they are made vertical to reduce the floor areas.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Feedwater Heaters – 2”.

1. Feed water heaters are of how many types?

a) One

b) Two

c) Three

d) Four

Answer: b

Explanation: There are two types of feed water heaters-

1) Open Heater

2) Closed Heater.

2. What is the other name of the open heater?

a) shell & tube heat exchangers

b) contact type heaters

c) regenerative heat exchangers

d) closed heaters

Answer: b

Explanation: Open heaters are also known as contact type heaters where the extracted steam is allowed to mix with feedwater & both leave the heater at a common temperature.

3. What is the condition of the fluids in closed heaters?

a) they are separate

b) they are mixed

c) they are partially mixed

d) none of the mentioned

Answer: a

Explanation: The fluids in a closed heater are un-mixed or separated. Closed heaters are heat exchangers.

4. Closed heaters are ______________ heat exchangers.

a) parallel flow

b) shell-and-tube

c) counter flow

d) cross- flow

Answer: b

Explanation: Closed heaters are shell-and-tube heat exchangers where the feedwater flows through the tubes & the extracted steam condenses outside the walls in the shell. The heat released by condensation is transferred through the walls of the tubes.

5. What is the other name of the condensate obtained after condensation in a shell-and-tube heat exchanger type closed heaters?

a) Heater rise

b) Heater fall

c) Heater drip

d) None of the mentioned

Answer: c

6. What is the function of the trap applied to the condensate?

a) the trap stops the condensate fully

b) the trap stops only vapour & allows liquid to pass through it

c) the trap stops only liquid & allows vapour to pass through it

d) none of the mentioned

Answer: b

Explanation: The main function of the trap applied to the flow of condensate is to stop vapour & allow liquid to flow through it.

7. Which of these is the correct expression for terminal temperature difference?

a) TTD = saturation temperature of ‘bled’ steam – exit water temperature

b) TTD = saturation temperature of ‘bled’ steam + exit water temperature

c) TTD = saturation temperature of ‘bled’ steam x exit water temperature

d) TTD = saturation temperature of ‘bled’ steam / exit water temperature

Answer: a

Explanation: The expression for terminal temperature difference for a closed heater is given as,

TTD = saturation temperature of ‘bled’ steam – exit water temperature.

8. If terminal temperature difference is too small, what will be its impact on plant efficiency?

a) it increases

b) it decreases

c) it remains same

d) none of the mentioned

Answer: a

Explanation: The formula for TTD is given as,

TTD = saturation temperature of ‘bled’ steam – exit water temperature.

9. If plant efficiency is high, what will be its effect on heater size?

a) it remains same

b) it increases

c) it decreases

d) none of the mentioned

Answer: b

Explanation: Too small a value of TTD, it is good for plant efficiency & consequently, this would require a larger heater.

10. When is a drain-cooler used?

a) when the extracted steam upon condensation gets subcooled

b) when the extracted steam upon subcooling gets condensed

c) the extracted stream has no dependence on drain-cooler

d) none of the mentioned

Answer: a

Explanation: When extracted steam gets subcooled upon condensation, a drain cooler may be used.

11. Which of these is a disadvantage of open heater?

a) simplicity

b) lower cost

c) high heat transfer capacity

d) none of the mentioned

Answer: d

Explanation: The disadvantage is the necessity of a pump at each heater to handle the large feedwater stream.

12. Which of the following is not an advantage of an open heater?

a) simplicity

b) lower cost

c) high heat transfer capacity

d) necessity of a pump at each heater to handle the large feedwater stream

Answer: d

Explanation: The disadvantage is the necessity of a pump at each heater to handle the large feedwater stream.

13. The number of pumps required by a closed heater for pumping the main feedwater stream is?

a) 1

b) 2

c) 3

d) 4

Answer: a

Explanation: A closed heater requires only a single pump for the main feedwater stream regardless of the number of heaters.

14. What is the purpose of using open heaters in steam power plants?

a) feedwater purification

b) feedwater esterification

c) feedwater deaeration

d) feedwater carbonisation

Answer: c

Explanation: In most steam power plants, closed heaters are more favored than open heaters & so are used primarily for the purpose of feedwater deaeration.

15. Why are closed heaters sometimes made vertical?

a) to reduce weight of heaters

b) to reduce floor areas for installations

c) to minimize losses due to weight

d) none of the mentioned

Answer: b

Explanation: Closed heaters are mostly horizontal. Sometimes, they are made vertical to reduce the floor areas needed for their installations.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Carnotinization of Rankine Cycle”.

1. In the T-S diagram of a Rankine cycle, the abscissa represents?

a) total entropy of turbine steam

b) partial entropy of turbine steam

c) partial enthalpy of turbine steam

d) none of the mentioned

Answer: a

Explanation: The T-S diagram of a Rankine Cycle has total entropy of turbine steam in the abscissa & temperature on the ordinate.

2. After the expansion of throttle steam, why is some steam extracted?

a) so that the total amount of steam in the entire system remains same

b) so that the variation in temperature is constant

c) so that pressure variation is constant

d) so that the total entropy is reduced

Answer: d

Explanation: The expansion of throttle steam is mainly to reduce the total entropy & the heat given up by this steam is added to feed water, thereby heating it.

3. The heat given up by the expansion of throttle steam is utilised in?

a) maintaining the heat flow in the system

b) reducing temperature variation in the system

c) heating the feedwater

d) cooling feedwater

Answer: c

Explanation: The expansion of throttle steam is mainly to reduce the total entropy & the heat given up by this steam is added to feed water, thereby heating it.

4. “Regenerative feedwater heating by turbine extraction” is often termed as?

a) Electrophoresis of Rankine cycle

b) Sterlinisation of Rankine cycle

c) Carnotization of Rankine cycle

d) None of the mentioned

Answer: c

Explanation: In the T-S diagram, the area of the parallelogram representing the cycle output will be equal to the area of the rectangle representing the output of the Carnot cycle. That is why we often term regenerative feedwater heating by turbine extraction as carnotization of rankine cycle.

5. A regenerative feedwater heating cycle with an infinite number of feedwater heaters has efficiency equal to?

a) Brayton cycle

b) Carnot cycle

c) Diesel cycle

d) Otto cycle

Answer: b

Explanation: In the T-S diagram, the area of the parallelogram representing the cycle output will be equal to the area of the rectangle representing the output of the Carnot cycle. Thus, the efficiency of a regenerative feedwater heating cycle with an infinite number of feedwater heaters is equal to that of a carnot cycle.

6. In the T-S diagram, the process of heating from condenser to boiler saturation temperature when the number of turbine extraction stages are finite is?

a) Reversible

b) Irreversible

c) Adiabatic

d) None of the mentioned

Answer: b

Explanation: When the number of extraction stages are finite, the process is irreversible. On the contrary, when there are infinite extraction stages, the process becomes reversible.

7. For the process of heating from condenser to boiler saturation temperature to be reversible, the number of extraction stages involved in the entire cycle should be?

a) Zero

b) One

c) Infinite

d) Finite

Answer: c

Explanation: When the number of extraction stages are finite, the process is irreversible. On the contrary, when there are infinite extraction stages, the process becomes reversible.

8. Which of the processes immediately follows the expansion of throttle steam?

a) heat given up by the steam is added to feedwater

b) heating from condenser to boiler saturation temperature

c) carnotization of rankine cycle

d) none of the mentioned

Answer: a

Explanation: The expansion of throttle steam is mainly to reduce the total entropy & the heat given up by this steam is added to feed water, thereby heating it.

9. The output from boiler goes to?

a) Turbine

b) Condenser

c) Pump

d) Economiser

Answer: a

Explanation: The sequence of flow is

Boiler, Turbine, Condenser, Pump, Economiser.

10. The area of parallelogram in the T-S diagram representing the cycle output is equal to?

a) area of rectangle representing the output of the Carnot cycle

b) area of the triangle representing the output of the Carnot cycle

c) area of the square representing the output of the Carnot cycle

d) none of the mentioned

Answer: a

Explanation: From the T-S diagram the area of parallelogram representing the cycle output is equal to the area of rectangle representing the output of the Carnot cycle.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Optimum Degree of Regeneration”.

1. What is the value of “beta” if h represents the local enthalpy on the given expansion line at a given pressure & h f is the enthalpy of saturated water at that pressure?

a) h + h f

b) h x h f

c) h – h f

d) none of the mentioned

Answer: c

Explanation: The expression for the value of “beta” if h represents the local enthalpy on the given expansion line at a given pressure & hf is the enthalpy of saturated water at that pressure is given as,

Beta = h – h f .

2. The expression for temperature rise t in feedwater heater when a & b are the temperatures of boiler saturation & condenser respectively, is given by which of the following expression?

a) t = 0.5

b) t = 0.5

c) t = 0.5

d) t = 0.5

Answer: d

Explanation: The expression for temperature rise t in feedwater heater when a & b are the temperatures of boiler saturation & condenser respectively, is given by,

t = 0.5 .

3. What happens to the feedwater that enters the economiser?

a) Feedwater is heated to the saturation temperature at the boiler pressure

b) Feedwater is heated to the boiler temperature at the saturation pressure

c) Feedwater is cooled to the saturation temperature

d) Feedwater is cooled at the boiler pressure

Answer: a

Explanation: The function of an economiser is to heat the feedwater to the saturation temperature at the boiler temperature. Naturally, this is what happens to the feedwater in the Economiser.

4. The economiser can also be assumed as?

a) Feedwater cooler

b) Feedwater heater

c) Economiser has nothing to do with Feedwater

d) None of the mentioned

Answer: b

Explanation: The function of an economiser is to heat the feedwater to the saturation temperature at the boiler temperature. Hence, it is assumed as ‘feedwater heater’.

5. The feedwater in the Economiser _________

a) is heated by bled turbine steam

b) is cooled by bled turbine steam

c) is heated by outgoing flue gases

d) is cooled by outgoing flue gases

Answer: c

Explanation: The function of an economiser is to heat the feedwater to the saturation temperature at the boiler temperature. This heating of feedwater occurs by the heat given to the feedwater by outgoing flue gases.

6. The temperature rise from condenser to boiler saturation is divided __________ among the feedwater heaters for maximum gain in efficiency.

a) unequally

b) partially

c) equally

d) remains undivided

Answer: c

Explanation: The total enthalpy rise or the temperature rise from condenser to boiler saturation is divided equally among the feedwater heaters for maximum gain in the efficiency.

7. What is the expression for enthalpy of each heater h per heater if a represents the enthalpy of heated feedwater from the economiser and b represents the enthalpy at condenser & n represents the number of heaters?

a) h per heater = /

b) h per heater = x

c) h per heater = +

d) h per heater = –

Answer: a

Explanation: the expression for enthalpy of each heater h if a represents the enthalpy of heated feedwater from the economiser and b represents the enthalpy at condenser & n represents the number of heaters is given by,

h per heater = / .

8. If n denotes the number of heater, t OA denotes the overall temperature difference & T fw denotes the total temperature rise of feedwater. The expression for T fw is?

a) ) x t OA

b) ) x t OA

c) ) / t OA

d) ) – t OA

Answer: a

Explanation: If n denotes the number of heater, t OA denotes the overall temperature difference & T fw denotes the total temperature rise of feedwater. The expression for T fw is given by the following relation,

T fw = ) x t OA .

9. The expression for the overall temperature difference T OA is given by?

a) t OA = boiler saturation temperature – condenser temperature

b) t OA = boiler saturation temperature + condenser temperature

c) t OA = boiler saturation temperature x condenser temperature

d) t OA = boiler saturation temperature / condenser temperature

Answer: a

Explanation: The expression for the overall temperature difference t is given by,

t OA = boiler saturation temperature – condenser temperature.

10. Efficiency gain follow the law of ____________

a) diminishing forward motion

b) increasing return

c) decreasing return

d) none of the mentioned

Answer: c

Explanation: The gain in cycle efficiency is proportional to the gain in feedwater temperature, the efficiency gain thereby follows the law of diminishing return with the increase in the number of heaters.

11. The number of heaters for a plant is fixed by?

a) Mass Balance

b) Energy balance

c) Heat balance

d) None of the mentioned

Answer: b

Explanation: The number of heaters for a plant is fixed by Energy Balance of the whole plant when it is found that cost of adding another heater does not justify the saving in heat supply or marginal increase in cycle efficiency.

12. The effect on the degree of regeneration due to an increase in feedwater temperature is?

a) degree of regeneration increases

b) degree of regeneration decreases

c) degree of regeneration remain same

d) degree of regeneration is optimised

Answer: d

Explanation: An increase in feedwater temperature reduces the heat absorption from the outgoing flue gases in the economiser & may cause a reduction in boiler efficiency. The number of heaters & the degree of regeneration thus get optimised.

13. The expression for efficiency when a & b are two constants corresponding to alpha & beta and c corresponds to gamma, is?

a) Efficiency = 1 – ((b 2 ))/))

b) Efficiency = 1 + ((b 2 ))/))

c) Efficiency = ((b 2 ))/))

d) Efficiency = 1 / ((b 2 ))/))

Answer: a

Explanation: The expression for efficiency when a & b are two constants corresponding to alpha & beta and c corresponds to gamma, is given as,

Efficiency = 1 – ((b 2 ))/)).

14. What is the relation between a & c if a & c correspond to alpha & gamma respectively, for maximum efficiency of a cycle?

a) a = 3c

b) c = 2a

c) c =

d) a = 2c

Answer: d

Explanation: The relation between a & c if a & c correspond to alpha & gamma respectively, for maximum efficiency of a cycle is given by,

c = .

15. The expression for efficiency gain due to regeneration if a, b, n correspond to alpha, beta, cycle efficiency respectively, is?

a) n = / 2 ))

b) n = / 2 ))

c) n = / 2 ))

d) n = / 3 ))

Answer: a

Explanation: The expression for efficiency gain due to regeneration if a, b, n correspond to alpha, beta, cycle efficiency respectively is given by,

n = / 2 )).

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Supercritical Pressure Cycle and Layout of a Stem Power Plant”.

1. Steam is generated in a _____________ boiler at a pressure above the critical point.

a) simple

b) once through

c) superficial

d) thrice through

Answer: b

Explanation: The steam generation in a supercritical pressure cycle is in a once through boiler when the steam is heated at a pressure above the critical point.

2. Apart from feedheating, what should a plant have to obtain a gain in thermal efficiency?

a) Lubrication

b) Differential heating

c) Reheating cycles

d) Regenerative cycles

Answer: c

Explanation: To obtain a gain in thermal cycle efficiency, apart from the feedheating, there should be multiple number of reheats.

3. The increment in thermal efficiency compared to the corresponding Subcritical cycle is gained at the expanse of?

a) compactness of the plant

b) simplicity of the plant

c) complexity of the plant

d) expanse of the plant

Answer: c

Explanation: The increment in thermal efficiency compared to the corresponding Subcritical cycle is gained at the expanse of complexity of the plant. Naturally, more the complexity, more this increment.

4. Which of the following needs to be incorporated to prevent the low pressure turbine exhaust wetness from being excessive?

a) Double regeneration

b) Double carnotization

c) Double reheat

d) Double cooling

Answer: c

Explanation: Incorporating double reheat is one way to prevent the low pressure turbine exhaust wetness from being excessive.

5. What is the critical point of steam generation in a “once through” boiler?

a) 221.5 bar

b) 221.4 bar

c) 221.3 bar

d) 221.2 bar

Answer: d

Explanation: Steam generation in a “once through” boiler is at the critical point of 221.2 bar.

6. In a typical layout of a 215MW reheat power plant, the feed in the boiler is at?

a) 280 degree Centigrade

b) 230 degree Centigrade

c) 238 degree Centigrade

d) 250 degree Centigrade

Answer: c

Explanation: In a typical layout of a 215MW reheat power plant, the feed in the boiler is at 238 degree Centigrade.

7. The input to the deaerator is from a __________ pressure feedwater heater.

a) high

b) low

c) medium

d) none of the mentioned

Answer: b

Explanation: The deaerator input is at low pressure feedwater heater and so the working of the deaerator comes into play.

8. The input to the low pressure feedwater heater is from?

a) Drain heater

b) Drain cooler

c) Drain pipe

d) None of the mentioned

Answer: b

Explanation: The input to the low pressure feedwater heater comes from the drain cooler which goes to the deaerator.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Steam Power Plant Appraisal”.

1. The thermal efficiency of a Watt’s Beam Engine is about?

a) 50%

b) 100%

c) 5%

d) 2%

Answer: d

Explanation: From the performance table consisting of performance data of various steam power plants, the efficiency of Watt’s Beam Engine is about 2%.

2. The thermal efficiency of a 1 MW locomotive steam engine is about?

a) 2%

b) 3%

c) 6%

d) 7%

Answer: d

Explanation: From the performance table consisting of performance data of various steam power plants, the efficiency of 1 MW locomotive steam engine is about 7%.

3. The number of feedwater heaters required in a Watt’s Beam Engine is?

a) 0

b) 4

c) 6

d) 8

Answer: a

Explanation: A Watt’s Beam Engine does not employ any feedwater heaters & hence the number of feedwater heaters in a Watt’s Beam Engine is ZERO.

4. Among 1 MW, 2 MW, 30 MW & 660 MW locomotive steam engines, the highest efficiency is?

a) 1 MW

b) 2 MW

c) 30 MW

d) 660 MW

Answer: d

Explanation: From the performance table consisting of performance data of various steam power plants, the efficiency of 1 MW locomotive steam engine is about 7%, 2 MW locomotive steam engine is about 20%, 30 MW locomotive steam engine is about 35%, 660 MW locomotive steam engine is about 44%.

5. The initial pressure of a Watt’s Beam Engine is about?

a) 1 bar

b) 2 bar

c) 3 bar

d) 4 bar

Answer: b

Explanation: From the performance table consisting of performance data of various steam power plants, the pressure of a Watt’s Beam Engine is about 2 bar.

6. What is the exhaust condition of a Watt’s Beam Engine?

a) near saturation

b) dry

c) wet

d) 0.9 dry

Answer: c

Explanation: From the performance table consisting of performance data of various steam power plants, the exhaust condition of a Watt’s Beam Engine is wet.

7. The number of feedwater heaters required for a 660 MW locomotive steam engine is?

a) 4

b) 0

c) 7

d) 8

Answer: c

Explanation: From the performance table consisting of performance data of various steam power plants, the number of feedwater heaters required by a 660 MW locomotive steam engine are 7.

8. Among 1 MW, 2 MW, 30 MW & 660 MW locomotive steam engines, the highest initial pressure is?

a) 1 MW

b) 2 MW

c) 30 MW

d) 660 MW

Answer: d

Explanation: From the performance table consisting of performance data of various steam power plants, the initial pressure of 1 MW locomotive steam engine is about 15 bar, 2 MW locomotive steam engine is about 15 bar, 30 MW locomotive steam engine is about 40 bar, 660 MW locomotive steam engine is about 160 bar.

9. Among 1 MW, 2 MW, 30 MW & 660 MW locomotive steam engines, the highest initial temperature is?

a) 1 MW

b) 2 MW

c) 30 MW

d) 660 MW

Answer: d

Explanation: From the performance table consisting of performance data of various steam power plants , the initial temperature of 1 MW locomotive steam engine is about 300 degree Celsius bar, 2 MW locomotive steam engine is about 250 degree Celsius, 30 MW locomotive steam engine is about 450 degree Celsius, 660 MW locomotive steam engine is about 540 degree Celsius.

10. Common size unit of a Steam Power Plant is?

a) 30 MW

b) 300 MW

c) 500 MW

d) 150 MW

Answer: c

Explanation: The most common size steam power plant is of 500 MW. Further large size plants have been built, but aren’t found in common usage.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Deaerator – 1”.

1. Deaerator is an ___________

a) closed heater

b) open heater

c) surface heater

d) none of the mentioned

Answer: b

Explanation: One of the feedwater heater is a contact type open heater, known as deaerator.

2. What is the purpose of deaerator?

a) to remove the dissolved oxygen and carbon dioxide

b) to remove the dissolved nitrogen

c) to remove the dissolved impurities

d) to supply more oxygen to feedwater

Answer: a

Explanation: Purpose of deaerator is to remove the dissolved oxygen and carbon dioxide in water which makes water corrosive.

3. What do you mean by vent condenser?

a) a condensing unit

b) a temperature measuring instrument

c) a heat exchanger

d) dissolves oxygen

Answer: c

Explanation: Feedwater is passed through a heat exchanger commonly called as vent condenser.

4. How dissolved oxygen and carbon dioxides are removed?

a) by allowing it to fall from height

b) by series of chemical reactions

c) by condensing feedwater

d) by heating feedwater to saturation temperature

Answer: d

Explanation: The solubility of these gases decreases with an increase in temperature.

5. What chemicals are added for residual dissolved oxygen and carbon dioxide?

a) sodium sulphite

b) hydrazine

c) alum

d) all of the mentioned

Answer: d

Explanation: Na 2 SO 3 and N 2 H 4 are used to remove residual gasses.

6. Why deaerator is installed at a certain height from the pump?

a) to provide a net positive suction head

b) to maintain less pressure

c) to avoid leakage

d) to maintain pressure

Answer: a

Explanation: Deaerator is installed at a certain height from the pump so as to maintain a optimum pressure before suction.

7. Why deaerator is not used in water cooled and moderated nuclear power plant?

a) radioactivity

b) not economical

c) not safe

d) not mechanically possible

Answer: a

Explanation: deaerator is not used in water cooled and moderated nuclear power plant because of the concern regarding radioactivity release with deaeration.

8. What is the location of high pressure heaters?

a) after the deaerator

b) before the deaerator

c) middle of deaerator

d) depends on pressure conditions

Answer: b

Explanation: The feedwater heaters before the deaerator are often called high pressure heaters.

9. What is the location of low pressure heaters?

a) after the deaerator

b) before the deaerator

c) middle of deaerator

d) depends on pressure conditions

Answer: a

Explanation: The feedwater heaters after the deaerator are often called low pressure heaters.

10. Steam used to heat water comes from?

a) boiler

b) turbine

c) condenser

d) external power source

Answer: b

Explanation: Steam from turbine is at high pressure and temperature.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Deaerator – 2”.

1. Which of the following type heater is known as deaerator?

a) Contact-type open heater

b) Contact-type closed heater

c) Closed heater

d) None of the mentioned

Answer: a

Explanation: A deaerator is a closed-type open feedwater heater while all the other heaters are closed heaters.

2. What is the solubility of dissolved gases at boiling or saturation temperature?

a) Positive

b) Negative

c) Zero

d) None of the mentioned

Answer: c

Explanation: The solubility of dissolved gases in water decreases with an increase in pressure and becomes zero at boiling or saturation temperature.

3. In the deaerator, the feedwater is heated to the saturation temperature by the steam extracted from?

a) compressor

b) turbine

c) pump

d) none of the mentioned

Answer: b

Explanation: The steam extracted from the turbine is used to heat the feedwater to the saturation temperature.

4. The heat exchanger after passing through which, the feedwater is sprayed from the top is called?

a) Vent condenser

b) Vent evaporator

c) Vent economiser

d) Vent heater

Answer: a

Explanation: Feedwater after passing through a heat exchanger, is sprayed from the top & bled steam from the turbine is fed from the bottom.

5. What kind of steam comes through the other side of the feedwater spray?

a) pure steam

b) bled steam

c) saturated steam

d) superheated steam

Answer: b

Explanation: Feedwater after passing through a heat exchanger, is sprayed from the top & bled steam from the turbine is fed from the bottom.

6. The chemical injected into the feedwater at the suction of the boiler feed pump is?

a) Sodium Sulphide

b) Sodium Sulphate

c) Sodium Sulphite

d) Sodium Hydride

Answer: c

Explanation: To minimise the effect of the residual dissolved oxygen & carbon dioxide gases in water, Sodium Sulphite & Hydrazine are injected in suitable calculated doses into the feedwater at the suction of the boiler feed pump.

7. Why is Sodium Sulphite added into the feedwater at the suction of the boiler feed pump?

a) to maximise the effect of dissolved gases

b) to minimise the effect of dissolved gases

c) to increase feedwater concentration

d) none of the mentioned

Answer: b

8. Name another chemical apart from Sodium Sulphite which is into the feedwater at the suction of the boiler feed pump?

a) Calcium peroxide

b) Hydroxide

c) Hydrazine

d) Oxymes

Answer: c

9. Where is the deaerator placed in the feedwater system?

a) in the beginning

b) in the middle

c) at the end

d) there is no deaerator in the feedwater system

Answer: b

Explanation: The deaerator is usually placed in the middle of the feedwater system so that the total pressure difference between the condenser & the boiler is shared equally between condensate pump & boiler feed pump.

10. Why is the deaerator placement in the feedwater system so important?

a) to maximise pressure difference between the condenser & the boiler

b) to minimise pressure difference between the condenser & the boiler

c) to make the pressure difference between the condenser & the boiler Zero

d) none of the mentioned

Answer: c

11. Which gases are vented out of the deaerator?

a) Oxygen only

b) Carbon dioxide only

c) Oxygen & Carbon dioxide

d) None of the mentioned

Answer: c

Explanation: The exhaust of the feedwater deaerator contains Oxygen & Carbon dioxide both.

12. Net positive suction head is provided because?

a) to prevent vapour lock

b) to prevent cavitation

c) to prevent friction

d) none of the mentioned

Answer: b

Explanation: In order to prevent the cavitation arising, a net positive suction head is provided for the pump. The deaerator is placed at a sufficient height from the basement.

13. The output of the boiler heat pump is to?

a) the high pressure heater

b) the low pressure heater

c) simultaneously to the low & high pressure heaters

d) none of the mentioned

Answer: a

Explanation: The Boiler feed pump give an output which goes to the high pressure heater.

14. Why is the deaerator not employed in water cooled & moderated nuclear power plant?

a) due to radioactivity release in degeneration

b) due to emissivity of degeneration

c) due to reheating

d) due to regeneration

Answer: a

Explanation: The deaerator is not employed in water cooled & moderated nuclear power plant because of the radioactivity released in degeneration.

15. Which among the following goes to the Vent Condenser along with Oxygen & Carbon dioxide?

a) Sodium sulphite

b) Carbon monoxide

c) Water vapour

d) None of the mentioned

Answer: c

Explanation: The gases Oxygen, Carbon dioxide & Water vapour are subjected to the vent condenser wherein the moisture gets absorbed & so the exhaust gases vented out are Oxygen & Carbon dioxide.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Efficiencies in a steam power plant – 1”.

1. What percentage of fuel energy is actually converted to electrical energy?

a) 50%

b) 40%

c) 34%

d) 25%

Answer: c

Explanation: In overall process due to losses the 66% of energy is lost.

2. Maximum energy of a power plant is lost in __________

a) condensor

b) pump

c) boiler

d) environment

Answer: a

Explanation: In a condensor heat is rejected to cooling water. This is the loss due to heat to work energy conversion in the cycle.

3. The lower is the value of heat rate __________ is the efficiency.

a) lower

b) higher

c) same

d) depends on further parameters

Answer: b

Explanation: The parameter that readily reflects the fuel economy is the heat rate, which is inversely proportional to the efficiency.

4. Overall efficiency is the ratio of power available at generator terminals to rate of energy released by combustion of fuel.

a) true

b) false

c) can’t say

d) not true for all conditions

Answer: a

Explanation: Efficiency is power generated / power supplied.

5. The steam from steam generator of a nuclear power plant is best described as __________

a) superheated steam

b) supercritical steam

c) saturated dry steam

d) saturated wet steam

Answer: d

Explanation: Steam contains moisture after coming out of boiler.

6. Under certain conditions, the specific enthalpies of dry steam, saturated water and wet steam are 2783 kJ/kg, 1219 kJ/kg and 2750 kJ/kg respectively. Determine the dryness fraction of wet steam.

a) 0.01

b) 0.02

c) 0.021

d) 0.03

Answer: c

Explanation:Specific enthalpies of saturated water and dry steam are 1219 kJ/kg and 2783 kJ/kg. Substituting these values in the equation “hws= xdhg+hl” gives the dryness fraction as 0.021.

7. What includes fixed cost?

a) cost of land, Cost of building, Cost of equipment, Cost of installation

b) interest

c) management cost

d) all of the mentioned

Answer: d

Explanation: These are the parameters that cannot be neglected and come under the fixed cost.

8. Name the major isotope present in steam generated in a Boiling Water Reactor.

a) N-16

b) D-32

c) N-32

d) D-16

Answer: a

Explanation: It is more economical and more efficient.

9. Efficiency of a power plant is more in summers or winters?

a) summers

b) winters

c) same in both

d) depends on variation

Answer: b

Explanation: In summers the heat loss is more so efficiency is less.

10. What is the mechanical efficiency of turbine?

a) brake output / internal output

b) internal output / brake output

c) blade energy / energy supplied

d) none of the mentioned

Answer: b

Explanation: None.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Efficiencies in a Steam Power Plant – 2”.

1. The steam power plant is a bulk energy converter where fuel energy is converted to?

a) heat energy

b) electrical energy

c) chemical energy

d) none of the mentioned

Answer: b

Explanation: Energy conversion in a steam power plant is as below

Fuel energy to Electricity.

2. Rate of energy released by the combustion of the fuel is given by?

a) Fuel burning rate x Calorific Value of the fuel

b) Fuel burning rate / Calorific Value of the fuel

c) Fuel burning rate + Calorific Value of the fuel

d) Fuel burning rate – Calorific Value of the fuel

Answer: a

Explanation: Rate of energy released by the combustion of the fuel is given by,

Fuel burning rate x Calorific Value of the fuel.

3. The overall efficiency n overall of a steam power plant is given by?

a) n overall = )

b) n overall = )

c) n overall = )

d) none of the mentioned

Answer: a

Explanation: The overall efficiency n overall of a steam power plant is given by,

n overall = ).

4. Which of the following shows the correct relation? (n boiler denotes efficiency of a boiler)

a) n boiler =

b) n boiler =

c) n boiler =

d) n boiler =

Answer: a

Explanation: The efficiency of a boiler is given by the following expression,

n boiler = .

5. The mechanical efficiency of a turbine is given by? (n tm denotes the mechanical efficiency)

a) n tm =

b) n tm =

c) n tm =

d) n tm =

Answer: c

Explanation: The expression for the turbine mechanical efficiency is given by,

n tm = .

6. If Q 1 represents the rate of heat addition to the cycle and W net represents net cycle work output, the expression for net cycle heat rate is?

a) Q 1 + W net

b) Q 1 / W net

c) Q 1 / (1/W net )

d) Q 1 x W net

Answer: b

Explanation: The expression for the net cycle heat rate is given by,

Net cycle heat rate = Q 1 / W net .

7. The generator efficiency n of the electric alternator is?

a) n =

b) n =

c) n = )

d) none of the mentioned

Answer: a

Explanation: The generator efficiency of the electric alternator is defined as the ratio of electrical output at generator terminals to the brake output of the turbine.

8. Which of these is not an auxiliary equipment in a power plant?

a) Fans

b) Crushers

c) Galvanisers

d) Conveyors

Answer: c

Explanation: The auxiliary equipment in a power plant are those equipment which are driven by the electricity taken from the generated power of the plant.

9. Which of these shows the formula for the efficiencies of the auxiliaries n 1 ?

a) n 1 =

b) n 1 =

c) n 1 =

d) n 1 =

Answer: c

Explanation: The auxiliary equipment or auxiliaries in a power plant are those equipment which are driven by the electricity taken from the generated power of the plant. Their efficiency is given by,

n 1 = .

10. What approximate percentage of energy in the fuel is converted to electricity?

a) 55%

b) 45%

c) 35%

d) 25%

Answer: c

Explanation: Only 34% of the energy stored in the fuel is converted to electricity & 66% is lost. The maximum loss of energy takes place in the condenser where heat is rejected to cooling water.

11. Heat rejection in a condenser is to?

a) cooled water

b) coolant

c) cooling water

d) none of the mentioned

Answer: c

Explanation: The maximum loss of energy takes place in the condenser where heat is rejected to cooling water. This is the loss due to heat to work energy conversion in the cycle or the loss due to second law.

12. Heat rate indicates?

a) heat added per unit volume

b) heat added per unit of work produced

c) heat added per unit of mass stored

d) heat added per unit area

Answer: b

Explanation: The parameter which readily affects the fuel economy is the heat rate which is inversely proportional to the efficiency, and hence the lower its value the better. It broadly indicates the heat added per unit of work produced.

13. Which of the following parameters affects the fuel economy?

a) heat constant

b) specific heat

c) heat rate

d) heat consumption

Answer: c

14. Gross cycle heat rate is equal to?

d) none of the mentioned

Answer: a

Explanation: The gross cycle heat rate is given by,

Gross cycle heat rate = .

15. The relation between heat rate & efficiency is?

a) both are directly proportional

b) both are inversely proportional

c) they are independent of each other

d) heat rate is also called efficiency

Answer: b

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Cogeneration of Power & Process Heat”.

1. Having two separate units for process heat and power is?

a) useful

b) useless

c) pollution reducing

d) none of the mentioned

Answer: b

Explanation: Having two separate units for process heat & power is wasteful, for of the total heat supplied to the steam generator for power purposes, a greater part will normally be carried away by the cooling water in the condenser.

2. A plant producing both, electrical power & process heat simultaneously is?

a) Cogenital plant

b) Cogenerial plant

c) Cogeneration plant

d) Conglomerate plant

Answer: c

Explanation: Cogeneration plant is defined as a plant which produces electrical power and processes heat simultaneously.

3. In a back pressure turbine _____________

a) pressure at the exhaust from the turbine is the saturation pressure corresponding to the temperature desired in the process

b) pressure at the entrance of the turbine is the saturation pressure corresponding to the temperature desired in the process

c) pressure at the exhaust from the turbine is the saturation pressure corresponding to the pressure desired in the process

d) none of the mentioned

Answer: a

Explanation: The name back pressure turbine is given because pressure at the exhaust from the turbine is the saturation pressure corresponding to the temperature desired in the process.

4. In a by-product power cycle?

a) the power is produced initially

b) power production is in the middle stages of the cycle

c) power production is after the cycle has ended

d) none of the mentioned

Answer: c

Explanation: When the process steam is the basic need, and the power is produced incidentally as a by-product, the cycle is often called as the by-product power cycle.

5. Back pressure turbines are usually _________________ with respect to their power output.

a) large

b) small

c) very large

d) very small

Answer: b

Explanation: Back pressure turbines are usually small with respect to their power output because they have no great volume of exhaust to cope with, the density being high.

6. In terms of cost per MW compared to condensing sets of the same power, the back pressure turbines are?

a) more expensive

b) cheaper

c) costly

d) none of the mentioned

Answer: b

Explanation: Back pressure turbines are usually small with respect to their power output because they have no great volume of exhaust to cope with, the density being high. They are usually single cylinder and hence, usually cheaper in terms of cost per MW.

7. Which of these is not an application of back pressure turbine?

a) desalination of sea water

b) filtration of water

c) process industries

d) petrochemical installations

Answer: b

Explanation: The applications of back pressure turbine are desalination of sea water, process industries, petrochemical installations, district heating and also for driving compressors and feed pumps.

8. Back pressure turbine is placed between ____________

a) Turbine & Pump

b) Boiler & Pump

c) Turbine & Heat Exchanger

d) Boiler & Turbine

Answer: d

Explanation: In a cogeneration plant, the back pressure turbine is placed between the boiler & turbine.

9. Which of the following is a good medium for constant temperature heating?

a) Water

b) Steam

c) Coolant

d) Diesel

Answer: b

Explanation: For constant temperature heating , steam is a very good medium since isothermal condition can be maintained by allowing saturated steam to condense at that temperature and utilising the latent heat released for heating purposes.

10. The cogeneration plant efficiency n CO if W T , Q i , Q H represents turbine work, heat input, heat output respectively is given by?

a) n CO = (W T + Q i ) / Q H

b) n CO = (W T – Q i ) / Q H

c) n CO = (W T + Q H ) / Q i

d) n CO = (W T + Q H ) / Q i

Answer: d

Explanation: The cogeneration plant efficiency n CO if W T , Q i , Q H represents turbine work, heat input, heat output respectively is,

n CO = (W T + Q H ) / Q i .

11. The electricity fraction of total energy output if W 1 and Q 1 represents the turbine work and heat output is given by?

a) W 1 / (W 1 + Q 1 )

b) W 1 / (W 1 – Q 1 )

c) W 1 / (W 1 Q 1 )

d) W 1 / Q 1

Answer: a

Explanation: The electricity fraction of total energy output if W 1 and Q 1 represents the turbine work and heat output is,

W 1 / (W 1 + Q 1 ).

12. If e is the electricity fraction of the total energy output, m is the electric plant efficiency and n is the steam generator efficiency; the heat added per unit total energy output is given by?

a) + / n)

b) + / m)

c) + / n)

d) + / m)

Answer: a

Explanation: If e is the electricity fraction of the total energy output, m is the electric plant efficiency and n is the steam generator efficiency; the heat added per unit total energy output is given by?

+ / n).

13. Pass-out turbines are used in which of these cases?

a) relatively high back pressure

b) small heating requirement

c) only relatively low back pressure

d) both relatively high back pressure and small heating requirement

Answer: d

Explanation: Pass-out turbines are used in cases of relatively high back pressure and small heating requirements. They are used in cases where a certain quantity of steam is continuously extracted from the turbine at an intermediate stage for heating purposes at the desired temperature and pressure.

14. Which of these is not considered economical for cogeneration?

a) a high fraction of electric to total energy

b) a low fraction of electric to total energy

c) a low fraction of total energy to electric energy

d) none of the mentioned

Answer: b

Explanation: A low fraction of electric to total energy is considered as an economical condition for cogeneration. Cogeneration plant is defined as a plant which produces electrical power and processes heat simultaneously.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Flaws of Steam as a Working Fluid and Vapor Cycle Characteristics”.

1. Addition of an infinitesimal amount of heat at the highest temperature is because ___________

a) to initiate reheating

b) to initiate regeneration

c) to initiate superheating

d) none of the mentioned

Answer: c

Explanation: The maximum temperature gained in steam cycles using the best available material is about 600 degree Celsius while the critical temperature of steam is about 375 degree Celsius, which necessitates large superheating and permits addition of an infinitesimal amount of heat at the highest temperature.

2. High moisture content is involved during expansion of steam because ___________

a) to ensure uniform heating

b) to ensure uniform cooling

c) to obtain a higher temperature of heat addition

d) to obtain a lower temperature of heat addition

Answer: c

Explanation: In order to obtain a higher temperature of heat addition, heat moisture content is involved during expansion of steam.

3. What is the relation of the mean temperature of heat addition and cycle efficiency?

a) both are inversely proportional

b) both are directly proportional

c) both are independent of each other

d) none of the mentioned

Answer: b

Explanation: The cycle efficiency is a function of mean temperature of heat addition. Hence, both are directly proportional to each other. The need for high pressure is only forced due to weak characteristics of steam.

4. Temperature of heat rejection in a condenser can be lowered by using?

a) lubricant

b) oil

c) refrigerant

d) diesel

Answer: c

Explanation: A refrigerant in the form of coolant is used to lower the temperature of heat rejection.

5. The use of which of the following becomes necessary during expansion of steam?

a) reheat

b) regeneration

c) refrigeration

d) superheat

Answer: a

Explanation: In order to obtain a higher temperature of heat addition, heat moisture content is involved during expansion of steam. The use of reheat thus becomes necessary.

6. Which is the drawback of the steam as a working substance in a power cycle?

a) in a vapour power cycle, maximum temperature which can be obtained with best available material is more than the critical temperature of water and requires large superheating

b) it allows only small amount of heat addition at the highest temperature

c) it requires reheat and reheater tubes are costly

d) all of the mentioned

Answer: d

Explanation: All the drawbacks mentioned are correct.

7. For maximum efficiency of vapour power cycle, what should be the critical temperature of working fluid?

a) the working fluid should have critical temperature as low as possible

b) the working fluid should have critical temperature as high as possible

c) the critical temperature does not affect the efficiency of the vapour power cycle

d) none of the mentioned

Answer: b

Explanation: More the critical temperature, more efficient will be the working.

8. What is the specific heat of the ideal working fluid used in vapour power cycle?

a) should be constant

b) should be large

c) should be small

d) none of the mentioned

Answer: c

Explanation: The specific heat of a fluid is the amount of energy the fluid takes in heating water for 1 degree Celsius.

9. What is the importance of the freezing point of the working fluid in the vapour power cycle?

a) freezing point of working fluid should be below the room temperature

b) freezing point of working fluid should be above the room temperature

c) freezing point of working fluid should be equal to the room temperature

d) does not have any importance

Answer: a

Explanation: For the efficient working of a working fluid, its freezing point should be below the room temperature.

10. When two vapour cycles are coupled in series and heat rejected by one is absorbed by another, the cycle is called as?

a) Dual vapour cycle

b) Binary vapour cycle

c) Coupled vapour cycle

d) None of the mentioned

Answer: b

Explanation: Binary vapour cycle is a cycle where two vapour cycles are coupled in series and heat rejected by one is absorbed by another.

11. The engines which are operating on gas power cycle are?

a) cyclic

b) non-cyclic

c) either cyclic or non-cyclic

d) none of the mentioned

Answer: c

Explanation: The cyclic nature is totally dependent on power cycle; it can be cyclic as well as non-cyclic depending on the gas power cycle.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Binary Vapour Cycle”.

1. Rankine cycle efficiency of a good steam power plant may be in the range of ___________

a) 15 to 20%

b) 35 to 45%

c) 70 to 80%

d) 90 to 95%

Answer: b

Explanation: The efficiency of a Rankine cycle lies in the range of 35-45 percent mostly.

2. Rankine cycle operating on low pressure limit of p 1 and high pressure limit of p 2 ___________

a) has higher thermal efficiency than the Carnot cycle operating between same pressure limits

b) has lower thermal efficiency than Carnot cycle operating between same pressure limits

c) has same thermal efficiency as Carnot cycle operating between same pressure limits

d) may be more or less depending upon the magnitudes of p 1 and p 2

Answer: a

Explanation: For two pressure limits, the thermal efficiency of a Rankine cycle is more than that of the Carnot cycle operating between the same pressure difference which is evident in the P-V diagrams of both the cycle.

3. Rankine efficiency of a steam power plant ___________

a) improves in summer as compared to that in winter

b) improves in winter as compared to that in summer

c) is unaffected by climatic conditions

d) none of the mentioned

Answer: b

Explanation: Rankine cycle efficiency depends upon condenser temperature.

4. Rankine cycle comprises of ___________

a) two isentropic processes and two constant volume processes

b) two isentropic processes and two constant pressure processes

c) two isothermal processes and two constant pressure processes

d) none of the mentioned

Answer: b

Explanation: A rankine cycle is a thermodynamic cycle which comprises of two isentropic and two isobaric processes which is a major thermodynamic cycle in various applications.

5. In Rankine cycle the work output from the turbine is given by ___________

a) change of internal energy between inlet and outlet

b) change of enthalpy between inlet and outlet

c) change of entropy between inlet and outlet

d) change of temperature between inlet and outlet

Answer: b

Explanation: The power output from the turbine is given by the change of internal energy between inlet and outlet.

6. Regenerative heating i.e., bleeding steam to reheat feed water to boiler ___________

a) decreases thermal efficiency of the cycle

b) increases thermal efficiency of the cycle

c) does not affect thermal efficiency of the cycle

d) may increase or decrease thermal efficiency of the cycle depending upon the point of extraction of steam

Answer: b

Explanation: Bleeding decreases the thermal efficiency of the cycle as it reheats feed water to the boiler.

7. Regenerative cycle thermal efficiency ___________

a) is always greater than simple Rankine thermal efficiency

b) is greater than simple Rankine cycle thermal efficiency only when steam is bled at particular pressure

c) is same as simple Rankine cycle thermal efficiency

d) is always less than simple Rankine cycle thermal efficiency

Answer: a

Explanation: A regeneration is done to increase the efficiency of a reheat cycle so naturally the efficiency of a regenerative cycle is much more than a Rankine cycle.

8. In a regenerative feed heating cycle, the optimum value of the fraction of steam extracted for feed heating ___________

a) decreases with increase in Rankine cycle efficiency

b) increases with increase in Rankine cycle efficiency

c) is unaffected by increase in Rankine cycle efficiency

d) none of the mentioned

Answer: b

9. In a regenerative feed heating cycle, the greatest economy is affected ___________

a) when steam is extracted from only one suitable point of steam turbine

b) when steam is extracted from several places in different stages of steam turbine

c) when steam is extracted only from the last stage of steam turbine

d) when steam is extracted only from the first stage of steam turbine

Answer: b

Explanation: Steam extraction is an important factor in deciding the economy of a regenerative cycle. The greatest economy is affected when steam is extracted from several places in different stages of steam turbine.

10. What is the maximum percentage gain in Regenerative feed heating cycle thermal efficiency?

a) increases with number of feed heaters increasing

b) decreases with number of feed heaters increasing

c) remains same unaffected by number of feed heaters

d) none of the mentioned

Answer: a

Explanation: In case of regenerative feed heating cycle, the optimum value of the fraction of steam extracted for feed heating decreases with increase in Rankine cycle efficiency. As the efficiency of regenerative cycle is more than the Rankine cycle. Naturally, the maximum percentage gain in regenerative feed heating cycle thermal efficiency increases with number of feed heaters increasing.

This set of Power Plant Questions and Answers for Freshers focuses on “Binary Vapour Cycle – II”.

1. How can we differentiate Rankine cycle from Carnot cycle?

a) Heat addition process of Rankine cycle is reversible isothermal whereas heat addition process of Carnot cycle is reversible isobaric

b) Heat addition process of Rankine cycle is reversible isobaric whereas heat addition process of Carnot cycle is reversible isothermal

c) Heat addition process of Rankine cycle is reversible isentropic whereas heat addition process of Carnot cycle is reversible isothermal

d) Both cycles are identical except the working fluid used

Answer: b

Explanation: Heat addition process of Rankine cycle is reversible isobaric whereas heat addition process of Carnot cycle is reversible isothermal. This is one of the major differences in both the cycles.

2. What is the relation between efficiencies of Rankine cycle and Carnot cycle for the same pressure ratio?

a) (η r ) = (η c )

b) (η r ) > (η c )

c) (η r ) < (η c )

d) none of the mentioned

Answer: c

Explanation: The relation between efficiencies of Rankine cycle and Carnot cycle for the same pressure ratio is given by,

(η r ) < (η c ).

3. If T m be the mean temperature of heat addition in Rankine cycle as shown in diagram,

what will the formula for efficiency of Rankine cycle?

power-plant-questions-answers-freshers-q3

a) (η r ) = (T 3 / T m )

b) (η r ) = 1 – (T 3 / T m )

c) (η r ) = 1 – (T 2 / T m )

d) (η r ) = (T 2 / T m )

Answer: b

Explanation:The required formula becomes

(η r ) = 1 – (T 3 / T m ).

4. The maximum efficiency of Rankine cycle (η r ) is the function of ___________

a) the mean temperature of heat addition (T m ) only

b) the mean temperature of heat addition (T m ) and temperature of steam at the exit of the turbine

c) the mean temperature of heat addition (T m ) and temperature of steam at the entry of the turbine

d) the mean temperature of heat addition (T m ) and temperature of steam at exit of the condenser

Answer: a

Explanation: The maximum efficiency of Rankine cycle (η r ) is the function of

the mean temperature of heat addition (T m ) only.

5. What is the effect of superheated steam on efficiency of Rankine cycle?

a) efficiency of Rankine cycle decreases with increase in superheat of the steam

b) efficiency of Rankine cycle increases with increase in superheat of the steam

c) efficiency of Rankine cycle is not affected by change in superheat of the steam

d) none of the mentioned

Answer: b

Explanation: The effect of superheated steam on efficiency of Rankine cycle is that the efficiency of Rankine cycle increases with increase in superheat of the steam.

6. What is the effect of increase in pressure at which heat is added on the pump work in the Rankine cycle?

a) the pump work increases with increase in pressure of heat addition

b) the pump work decreases with increase in pressure of heat addition

c) the pump work does not change with increase in pressure of heat addition

d) the pump work either increases or decreases with increase in pressure of heat addition

Answer: a

Explanation: The effect of increase in pressure at which heat is added on the pump work in the Rankine cycle is that the pump work increases with increase in pressure of heat addition.

7. When the pressure at which heat is added in Rankine cycle increases, the moisture content at the turbine exhaust?

a) increases

b) decreases

c) remains same

d) cannot say

Answer: a

Explanation: With an increase in the pressure at which heat is added in Rankine cycle increases, the moisture content at the turbine exhaust increases.

8. What is the condition for increasing the chances of corrosion of blades of turbine?

a) decrease in the pressure difference between which the Rankine cycle operates

b) increase in the pressure difference between which the Rankine cycle operates

c) increases and decreases in the pressure difference between which the Rankine cycle operates

d) none of the mentioned

Answer: b

Explanation: The condition for increasing the chances of corrosion of blades of turbine is an increase in the pressure difference between which the Rankine cycle operates.

9. What is the maximum content of moisture allowed at the turbine exhaust in the steam power plant?

a) 50 %

b) 60 %

c) 30 %

d) 15 %

Answer: d

Explanation: The maximum content of moisture allowed at the turbine exhaust in the steam power plant is 15 %.

10. Which of these is a binary cycle?

a) Mercury-steam cycle

b) Mercury-water cycle

c) Mercury-Sodium cycle

d) None of the mentioned

Answer: a

Explanation: The binary cycle is mainly a Mercury-Steam cycle.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Coupled Cycles”.

1. The mercury steam cycle represents how many coupled Rankine cycles?

a) 1

b) 2

c) 3

d) 4

Answer: b

Explanation: The mercury steam cycle represents 2 fluid cycles where 2 Rankine cycles have been coupled in series.

2. In the mercury steam cycle, the mercury cycle is called?

a) bottoming cycle

b) middle cycle

c) topping cycle

d) none of the mentioned

Answer: c

Explanation: The mercury steam cycle has the mercury cycle as the topping cycle.

3. In the mercury steam cycle, the steam cycle is called?

a) bottoming cycle

b) middle cycle

c) topping cycle

d) none of the mentioned

Answer: a

Explanation: The mercury steam cycle has the steam cycle as the bottoming cycle.

4. Apart from mercury & steam, which of these is a component of tertiary cycle?

a) nitrogen di-oxide

b) water

c) carbon di-oxide

d) sulphur di-oxide

Answer: d

Explanation: The tertiary cycle is mercury-steam-sulphur dioxide cycle.

5. The addition of sulphur dioxide in a tertiary cycle is at?

a) high temperature

b) low temperature

c) too high temperature

d) none of the mentioned

Answer: b

Explanation: The tertiary cycle is mercury-steam-sulphur dioxide cycle. Here, addition of sulphur dioxide is at low temperature.

6. Which of these can also be used as a topping fluid?

a) Sodium

b) Calcium

c) Boron

d) Titanium

Answer: a

Explanation: Apart from mercury, only Sodium or Potassium are suitable enough to be used as a topping fluid.

7. Which of these can be used as a fluid in the bottoming fluid?

a) Mercury

b) Ammonia

c) Calcium

d) Sodium

Answer: b

Explanation: Apart from Sulphur dioxide, Ammonia is the most suitable bottoming fluid.

8. In case of Sodium-mercury-steam cycle, which is the topping fluid?

a) Mercury

b) Steam

c) Sodium

d) Cannot say

Answer: c

Explanation: Apart from mercury, only Sodium or Potassium are suitable enough to be used as a topping fluid. Here, mercury is not a topping fluid so naturally, sodium becomes the topping fluid.

9. In case of mercury-steam-sulphur dioxide cycle, which is the bottoming fluid?

a) Mercury

b) Steam

c) Sulphur dioxide

d) Cannot say

Answer: c

Explanation: Sulphur dioxide, being the only bottoming fluid in the tertiary cycle is used as a bottoming fluid.

10. The total loss in a tertiary cycle is?

a) sum of losses in the individual cycles

b) product of losses in the individual cycles

c) sum of products of individual losses

d) none of the mentioned

Answer: b

Explanation: The total loss in a tertiary cycle is product of losses in the individual cycles.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Combined Cycle Plants, Nuclear and Thermionic Power Generation”.

1. The maximum steam temperature in a power cycle in degree centigrade is?

a) 600

b) 500

c) 300

d) 100

Answer: a

Explanation: The maximum steam temperature in a power cycle is 600 degree centigrade.

2. The temperature in a dry bottom pulverised coal furnace, in degree Celsius is about?

a) 1200

b) 1300

c) 1400

d) 2000

Answer: b

Explanation: The temperature in a dry bottom pulverised coal furnace, in degree Celsius is about 1300.

3. What happens to the availability in a combined cycle plant?

a) decreases

b) increases

c) remains same

d) cannot say

Answer: a

Explanation: There is a great thermal irreversibility & a decrease of availability because of heat transfer from combustion gases to steam through such a large temperature difference.

4. By superposing a high temperature power plant as a topping unit to the steam plant, the energy conversion efficiency achieved is?

a) higher

b) lower

c) maximum

d) minimum

Answer: a

Explanation: By superposing a high temperature power plant as a topping unit to the steam plant, the energy conversion efficiency achieved is higher from fuel to electricity.

5. Which of the following is not a type of Combined Plant?

a) Sodium- mercury-Potassium plant

b) Gas turbine-Steam turbine plant

c) Thermionic steam plant

d) Thermoelectric steam plant

Answer: a

Explanation: Sodium-mercury-potassium plants have two topping fluids which is impossible for a plant to possess.

6. Which of these is not a component of nuclear reactor?

a) reactor core

b) refractor

c) control rod

d) biological shield

Answer: b

Explanation: A reflector rather than a refractor is a component of nuclear reactor.

7. Which of these is not a merit of nuclear power?

a) amount of fuel required is small

b) plant requires a huge amount of area

c) demand for coal and oil is reduced

d) most economical in large quantities

Answer: b

Explanation: A small amount of area is required.

8. The thermionic generator is essentially which kind of device?

a) low voltage & high current

b) high voltage & high current

c) low voltage & low current

d) high voltage and high current

Answer: a

Explanation: Thermionic generator is essentially a low-voltage & high-current device.

9. What efficiencies of thermionic power generator have been realised?

a) 50-60%

b) 40-50%

c) 10-20%

d) 30-40%

Answer: c

Explanation: Efficiency of 30-40% has been realised in thermionic generators.

10. The maximum electron current per unit area provided by an emitter is given by Misplaced &

a) J = AT expɸ

b) J = AT ɸ

c) J = AT2 expɸ

d) J = expɸ

Answer: c

Explanation: The maximum current density is given by Richardson-Dushman equation.

11. In an electron beam, the average kinetic energy of an electron is given by __________

a) 2KT

b) 3KT

c) 1.5KT

d) 2.5KT

Answer: a

Explanation: The average kinetic energy is equal to 2KT.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Gas Turbine-Steam Power Plant – I”.

1. What is the air standard cycle for a Gas-Turbine called?

a) Reheat cycle

b) Rankine cycle

c) Brayton cycle

d) Diesel cycle

Answer: c

Explanation: Brayton cycle is an ideal air standard cycle for a Gas turbine, which, like the Rankine cycle, also comprises of two reversible adiabatic & two reversible isobars.

2. What is the difference between a Rankine cycle & a Brayton cycle?

a) working fluid in a Brayton cycle undergoes phase change while it doesn’t in Rankine cycle

b) working fluid in a Brayton cycle doesn’t undergo phase change while it does in Rankine cycle

c) both are same

d) none of the mentioned

Answer: b

Explanation: The difference between a Rankine cycle & a Brayton cycle is that the working fluid in a Brayton cycle doesn’t undergo phase change while it does in Rankine cycle.

3. Which of the following is a type of Gas Turbine Plant?

a) Single Acting

b) Double Acting

c) Open

d) None of the mentioned

Answer: c

Explanation: Open & Closed Gas Turbine plants are the two types.

4. Power is produced when the working fluid does some work on the?

a) Shaft

b) Fins

c) Blades

d) None of the mentioned

Answer: c

Explanation: For the production of power, the working fluid does some work on the blades of the turbine, thereby producing Power.

5. A Gas Turbine is which type of combustion plant?

a) external

b) open

c) internal

d) cannot say

Answer: c

Explanation: Since for the production of power, the working fluid does some work on the blades of the turbine, thereby producing Power. Hence, it is called an internal combustion plant.

6. Which among these is the main component of a gas turbine plant?

a) Condenser

b) Compressor

c) Boiler

d) Both Compressor & Boiler

Answer: b

Explanation: The main component of a Gas turbine plant is Compressor.

7. Which type of compressor is used in a gas turbine plant?

a) Reciprocating compressor

b) Screw compressor

c) Multistage axial flow compressor

d) Either Reciprocating compressor & Screw compressor

Answer: c

Explanation: Multistage axial flow compressor is the compressor in practical usage in a gas turbine plant.

8. What part or % of power developed is utilised for driving the compressor?

a) 65 %

b) 70 %

c) 55 %

d) 80 %

Answer: a

Explanation: A total of 65 % of power developed in the gas turbine is used for driving the compressor.

9. The gas turbine power plant mainly uses which among the following fuels?

a) Coal and Peat

b) Kerosene oil and diesel oil and residual oil

c) Gas oil

d) Natural gas and liquid petroleum fuel

Answer: d

Explanation: Natural gas and liquid petroleum fuel are among the two fuels used in a gas turbine.

This set of Power Plant Interview Questions and Answers for freshers focuses on “Gas Turbine-Steam Power Plant – II”.

1. The heating value of gaseous fuels is about _____________

a) 500 kJ/litre

b) 30 kJ/litre

c) 100 kJ/litre

d) 10 kJ/litre

Answer: b

Explanation: 30 kJ/litre is the heating value of gaseous fuels.

2. The compressor has to be started _____________

a) Before starting the gas turbine

b) After starting the gas turbine

c) Simultaneously with starting of gas turbine

d) At any time during the operation

Answer: a

Explanation: Compressor has to be started before starting the gas turbine as the turbine work is used by compressor.

3. Which of these is not a part of a Gas Turbine Plant?

a) Compressor

b) Gas Turbine

c) Combustion chamber

d) Boiler

Answer: d

Explanation: A Gas Turbine Plant has the following parts:

Compressor, Gas Turbine, Combustion chamber.

4. What are the major field of application of gas turbine?

a) Aviation

b) Oil and gas industry

c) Marine propulsion

d) All of the mentioned

Answer: d

Explanation: A Gas Turbine has applications in nearly all fields, the major ones being in the fields of Aviation, Oil & Gas industry, Marine propulsion.

5. Which of the following is the limitation of gas turbines?

a) They are not self-starting

b) Higher rotor speeds

c) Low efficiencies at part loads

d) All of the mentioned

Answer: d

Explanation: The limitations in the functioning of a Gas Turbines are inability of self-starting, excess rotor speeds and inability to adjust to varying loads.

6. The ratio of heat actually released by 1kg of fuel to heat that would be released by complete perfect combustion is called ___________

a) Thermal efficiency

b) Combustion efficiency

c) Engine efficiency

d) Compression efficiency

Answer: b

Explanation: Combustion efficiency is defined as,” The ratio of heat actually released by 1kg of fuel to heat that would be released by complete perfect combustion”.

7. What is the percentage of total energy input appearing as network output of the cycle?

a) Thermal efficiency

b) Combustion efficiency

c) Engine efficiency

d) Compression efficiency

Answer: a

Explanation: Thermal Efficiency is, “The percentage of total energy input appearing as network output of the cycle”.

8. Which of the following method can be used to improve the thermal efficiency of open cycle gas turbine plant?

a) Inter-cooling

b) Reheating

c) Regeneration

d) All of the mentioned

Answer: d

Explanation: The various methods to improve the efficiency of open cycles include intercooling the feed water from the compressor to the turbine and then employing regeneration & reheat to just use the power of the reheated water in order to maximize the power output.

9. Which of the following is used as starter for a gas turbine?

a) An Internal combustion engine

b) A steam turbine

c) An auxiliary electric motor

d) All of the mentioned

Answer: d

Explanation: There are various methods by which a Gas Turbine can be started, they are by the use of an Internal Combustion engine, a steam turbine, an auxiliary electric motor, etc.

10. Gas turbine is shut down by ____________

a) Turning off starter

b) Stopping the compressor

c) Fuel is cut off from the combustor

d) All of the mentioned

Answer: c

Explanation: The only way to stop a running Gas turbine is by cutting off the fuel supply so that the various processes in the cycle are stopped.

This set of Power Plant Questions and Answers for Experienced people focuses on “Gas Turbine-Steam Power Plant – III”.

1. In gas turbine, intercooler is placed _____________

a) before low pressure compressor

b) in between low pressure compressor and high pressure compressor

c) in between high pressure compressor and turbine

d) none of the mentioned

Answer: b

2. In gas turbine, what is the function of Re-heater?

a) Heat inlet air

b) Heat exhaust gases

c) Heat air coming out of compressor

d) Heat gases coming out of high pressure turbine

Answer: d

Explanation: In order to make a thermodynamic process of larger efficiency, it is shifted towards isothermal behavior. For this, the output from re-generator, which is at a higher temperature is cooled to the temperature which is mid-way between the two temperature ranges. Then, it is again heated to the final temperature thereby increasing the efficiency of the cycle.

3. The ‘work ratio’ increases with _____________

a) increase in turbine inlet pressure

b) decrease in compressor inlet temperature

c) decrease in pressure ratio of the cycle

d) all of the mentioned

Answer: d

Explanation: The ‘work ratio’ increases when the turbine inlet pressure increases, the compressor inlet temperature decreases, the pressure ratio of the cycle decreases.

4. In the centrifugal compressor, total pressure varies _____________

a) directly as the speed ratio

b) square of speed ratio

c) cube of the speed ratio

d) all of the mentioned

Answer: b

Explanation: The total pressure in a centrifugal compressor is a function of speed ratio. It varies square of the speed ratio.

5. The efficiency of multistage compressor is _____ than a single stage.

a) lower

b) higher

c) equal to

d) all of the mentioned

Answer: a

Explanation: The efficiency of multistage compressor is lower than a single stage.

6. In centrifugal compressor, power input varies as _________

a) directly as the speed ratio

b) the square of speed ratio

c) the cube of the speed ratio

d) all of the mentioned

Answer: c

Explanation: Power output in a centrifugal compressor varies as the cube of the speed ratio.

7. In the ____________ heat transfer takes place between the exhaust gases and cool air.

a) Intercooler

b) Re-heater

c) Regenerator

d) Compressor

Answer: c

Explanation: The process of heat transfer between the exhaust gases and cool air takes place in Regenerator.

8. In centrifugal compressor, the diffuser converts _________

a) Kinetic energy into pressure energy

b) Pressure energy into Kinetic energy

c) Kinetic energy into Mechanical energy

d) Mechanical energy into Kinetic energy

Answer: a

Explanation: The diffuser of a centrifugal compressor converts Kinetic Energy into Pressure energy.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Fuel Oil”.

1. The bulk of hydrocarbon belongs to which group?

a) paraffin

b) isoparaffin

c) cycloparaffin

d) aromatic

Answer: a

Explanation: A bulk of hydrocarbons in fuel oils belongs to paraffin series like methane, ethane.

2. Which of these is not a lighter fraction of fuel oil?

a) gasoline

b) aviation fuel

c) heavy diesel oil

d) boiler fuel

Answer: d

Explanation: Boiler fuel is one of the heavier fraction in the refining process of fuel oil.

3. Which of these properties specifies the minimum temperature at which fuel oil can be ignited?

a) pour point

b) flash point

c) heating value

d) viscosity

Answer: b

Explanation: The flash point is the minimum temperature at which fuel may be ignited.

4. Which of the following type of fuel does not contain ash?

a) coal

b) fuel oil

c) natural gas

d) synthetic fuels

Answer: c

Explanation: Because of its gaseous nature, natural gas is the cleanest of all fuel types as it does contain ash and also produces no smoke on combustion.

5. Which of these gases is the reason for the maintenance of natural gas at cryogenic temperatures?

a) methane

b) ethane

c) propane

d) benzene

Answer: a

Explanation: The major component of natural gas is methane, whose critical temperature is -83C . So cryogenic temperatures are needed to maintain them it in liquid state at moderate pressure.

6. The gas which contributes maximum to heating value of natural gas is?

a) CO

b) CO 2

c) H 2

d) CH 4

Answer: d

Explanation: CH 4 gas contributes maximum to the heating value of natural gas.

7. A coal containing high percentage of durian is called _________

a) splint

b) bright

c) boghead

d) non-banded

Answer: a

Explanation: Coal containing high percentage of durian is called splint.

8. Low temperature carbonisation _________

a) produces less quantity of tar than high temperature carbonisation

b) is mainly producing smokeless domestic coke

c) is meant for production of ‘metallurgical coke’

d) produces higher temperature gas than high temperature carbonisation

Answer: b

Explanation: During this process, the fuel is broken down into solid residue called semicoke, a primary gas and a watery condensate.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Coal-Oil & Coal-Water Mixtures – I”.

1. Which of the following is not considered a type of coal according to ASTM?

a) anthracite

b) bituminous

c) peat

d) lignite

Answer: c

Explanation: Because peat contains 90% of moisture and hence is not suitable as utility fuel.

2. Which of the following is not directly determined in the Proximate Analysis of coal?

a) Volatile Matter

b) Fixed Carbon

c) Moisture

d) Ash

Answer: b

Explanation: Fixed carbon is the difference between 100% and sum of the percentages of volatile matter, moisture and ash.

3. Which of these is not a component of coal in Ultimate Analysis?

a) carbon

b) sulphur

c) ash

d) phosphor

Answer: d

Explanation: This component is not determined in Ultimate Analysis.

4. If M and A represent the percentages of moisture and ash respectively, the dry and ash free analysis in Ultimate Analysis is obtained on dividing other components by the fraction of?

a) {1-}/100

b) {1-}/100

c) {1-}/100

d) 1-{/100}

Answer: d

Explanation: The fraction of ash and moisture is given by /100. So the dry and ash free part is 1-{/100}.

5. The extent of caking in coal is determined using __________

a) swelling index

b) grindability

c) weatherability

d) heating value

Answer: a

Explanation: Swelling index is the quantitative evaluation method devised to determine the extent of calling in coal.

6. Coke devoid of volatile matter is called __________

a) caking coal

b) free-burning coal

c) agglomerate

d) coke

Answer: d

Explanation: Coke is the type of coal devoid of volatile matter.

7. Which of the following property is the inverse of the power required to grind coal to a particular size for burning?

a) heating value

b) weatherabillity

c) grindability

d) sulphur content

Answer: c

Explanation: This property of coal is measured by the standard Grindability Index.

8. The design of steam generator greatly depends on __________

a) spontaneous combustion

b) sulphur content

c) ash softening temperature

d) heating value

Answer: c

Explanation: The ash softening temperature is the temperature at which ash becomes plastic. If the furnace temperature is higher, ash forms molten slag and causes trouble in discharge.

This set of Power Plant Interview Questions and Answers for Experienced people focuses on “Coal-Oil & Coal-Water Mixtures – II”.

1. Presence of ______________ in dry gaseous fuel does not contribute its calorific value.

a) hydrogen

b) sulphur

c) oxygen

d) carbon

Answer: c

Explanation: Oxygen does not contribute to the calorific value of dry gaseous fuels.

2. Improper storage condition results weathering of coal and spontaneous combustion, which increases its?

a) caking index

b) yield of carbonised products

c) calorific value

d) friability and oxygen content

Answer: d

Explanation: Improper storage of coal causes loss of oxygen content, resulting in loss of heat value.

3. Laboratory gas is obtained by cracking of __________

a) fuel oil

b) gasoline

c) kerosene

d) diesel

Answer: c

Explanation: Kerosene on cracking gives laboratory gas.

4. Higher percentage of ash in coal meant for the production of metallurgical grade coke __________

a) causes brittleness in coke

b) increases abrasion resistance of coke

c) decreases hardness of coke

d) causes high toughness

Answer: b

Explanation: A high percentage of ash in coal meant for production of metallurgical grade coke causes an increase in abrasion resistance in coke.

5. Carbon content by weight in air dried wood may be about _____________ %.

a) 25

b) 50

c) 10

d) 80

Answer: b

Explanation: Air dried wood has carbon content of about 50%.

6. Softening temperature of coal is a measure of which tendency of coal?

a) clinkering tendency

b) coking tendency

c) caking tendency

d) size tendency

Answer: a

Explanation: Clinkering tendency is responsible for the softening of coal.

7. Combustion of pulverised coal as compared to lump coal __________

a) can be done with less excess air

b) develops a low temperature flame

c) develops a non-luminous flames

d) provides a lower rate of heat release

Answer: a

Explanation: Pulverisation leads to less use of air.

8. Dry air required to burn 1kg of carbon completely may be around ________________ kg.

a) 11

b) 38

c) 2

d) 20

Answer: a

Explanation: 11kg of dry air is required to burn 1kg of carbon.

9. ‘Fat coal’ means a coal having __________

a) high volatile matter

b) low ash content

c) low calorific value

d) non-smoking tendency

Answer: a

Explanation: Coal having high volatile matter is called ‘fat coal’.

10. A good quality coal should have __________

a) high ash content

b) high sulphur

c) low fusion point of ash

d) none of the mentioned

Answer: d

Explanation: A good quality coal should have high carbon content.

11. Grindability of coal is 100. It implies that __________

a) it can’t be pulverised

b) it is easily pulverised

c) can be pulverised with difficulty

d) power consumption is high in pulverisation

Answer: b

Explanation: High grindability of coal implies easy pulverisation.

12. The difference in total carbon and fixed carbon of coal will be minimum in case of __________

a) lignite

b) bituminous coal

c) high temperature coke

d) anthracite

Answer: c

Explanation: Out of these options, high temperature coke has minimum difference.

13. Fuel gases containing hydrocarbons are not preheated before burning, because __________

a) they crack, thereby choking and fouling heat transfer surface

b) it reduces calorific value tremendously

c) it reduces flame temperature tremendously

d) there are chances of explosion during preheating

Answer: a

Explanation: Hydrocarbons crack easily, hence they are not preheated.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “ASynthetic Fuels, Biomass and Thermodynamic View”.

1. Production of producer gas from coke requires _____________ moles of nitrogen.

a) 3.76

b) 4.51

c) 2.23

d) 3.49

Answer: a

Explanation: None.

2. Which of the following mode is not used to liquefy coal?

a) hydrogenation

b) catalytic conversion

c) hydro pyrolysis

d) coal gasification

Answer: d

Explanation: In coal gasification, coal is gasified in a situ and the gas is conveyed to the surface. The other processes are methods of coal liquefaction.

3. What are the first products in Fischer-Tropsch process?

a) CO+H 2

b) CO 2 +H 2

c) Coke + H 2 O

d) Coke

Answer: a

Explanation: The first products in Fischer-Tropsch process are carbon monoxide and hydrogen.

4. ____________ prohibits the use of alcohols directly in petrol engines.

a) high cost and availability

b) low octane number

c) low flash point

d) low calorific value

Answer: a

Explanation: High cost is the reason for no use of alcohols in petrol engines.

5. Which of these is not a form of bioconversion route?

a) direct combustion

b) fermentation

c) thermochemical conversion

d) biochemical conversion

Answer: b

Explanation: Fermentation is a breakdown of complex molecules in organic compounds. It is a type of biochemical conversion.

6. Which of these is a product of pyrolysis process in dry thermochemical conversion?

a) methane

b) methanol

c) ammonia

d) pyrolytic oils

Answer: d

Explanation: Pyrolytic oils, gas and char are the products of pyrolysis process.

7. Which of these is an important measure of performance in for a power plant?

a) NPHR

b) AP

c) NTO

d) HHV

Answer: a

Explanation: NPHR- net plant heat rate is the most important measure of performance for power plant. AP-auxillary power NTO-net turbine output NTHR-net turbine heat rate.

8. The overall efficiency of a power plant is given by __________

a) 3600/NTO

b) 3600/AP

c) 3600/HHV

d) 3600/NPHR

Answer: d

Explanation: The overall efficiency of a power plant is given by ɳ = 3600/NPHR.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Draught System”.

1. Which of these terms defines the pressure difference in the furnace?

a) draught

b) duct

c) stack

d) chimney

Answer: a

Explanation: The term ‘draught’ is used to define the static pressure in the furnace, in the various ducts and the stack.

2. The draught or pressure difference for a chimney of height of H metres is given by?

a) Δp = gH

b) Δp = gH

c) Δp = gHρg

d) Δp = gH

Answer: a

Explanation: The draught produced is given by Δp = gH.

3. Which of these is not a type of mechanical draft system for a furnace?

a) balanced draft

b) induced draft

c) forced draft

d) actuated draft

Answer: d

Explanation: The three types of mechanical drafts are balanced, induced and forced drafts.

4. Stack heat losses can be minimised by __________

a) using low c.v. fuels

b) controlling the excess air

c) oxygen enrichment of combustion air

d) maintaining proper draft in the furnace

Answer: b

Explanation: Excess amount of air leads to significant losses in energy due to heat loss through flue gases.

5. Which of these accentuates clinkering trouble on furnace grate burning coal?

a) low reactivity of carbonised residue containing high proportions of iron and sulphur

b) low forced draught and low fuel bed temperature

c) thick fire bed and preheated primary air

d) all of the mentioned

Answer: d

Explanation: All these reasons lead to clinkering.

6. Natural draught produced by a chimney depends upon __________

a) density of chimney gases

b) height of chimney

c) both ‘density of chimney gases’ and ‘height of chimney’

d) none of the mentioned

Answer: c

Explanation: Natural draught depends on density of gases in chimney and its height.

7. In a furnace employing forced draught compared to induced draught __________

a) the fan operates hot and hence blades are liable to corrosion and erosion

b) positive pressure exists in the furnace

c) air is sucked in, so air leaks are more and hence furnace efficiency is reduced

d) none of the mentioned

Answer: c

Explanation: A positive pressure exists in the furnace employing forced draught.

8. Which of the following types of the fans has the highest cost?

a) centrifugal fans

b) axial fans

c) primary fans

d) gas recirculation fans

Answer: b

Explanation: Axial fans have the highest cost.

9. Which of these is not a type of drive of variable speed control?

a) variable speed turbine

b) hydraulic coupling

c) multiple speed ac motor

d) electronically adjustable turbine drive

Answer: d

Explanation: Except ‘electronically adjustable turbine drive’, all other are a type of drive in variable speed control.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Heat of Combustion-I”.

1. Internal energy of combustion products is ______________ than that of reactants.

a) less

b) more or less

c) same

d) more

Answer: a

Explanation: The internal energy of combustion is given by uRP=UP-UR which gives a negative value.

2. Higher efficiency in combustion of solid fuel cannot be achieved by ___________

a) keeping flue gas temperature very high

b) proper fuel preparation

c) supplying correct quantity of combustion air

d) adopting efficient fuel-firing technique and equipment

Answer: a

Explanation: Keeping flue gas temperature very high does not result in increased efficiency of solid fuel.

3. Bomb calorimeter is used determine the calorific value of ___________

a) solid fuels

b) liquid fuels

c) both solid and liquid fuels

d) none of the mentioned

Answer: c

Explanation: Bomb calorimeter can be used to determine the calorific value of both solid and liquid fuels.

4. Which of these is not a reason for reduction in maximum flame temperature in actuality?

a) incomplete combustion

b) heat loss to exhaust gases

c) excess air requirements

d) heat loss to surroundings

Answer: b

Explanation: Maximum flame temperature is defined on the temperature of products; hence it cannot be a reason for reduction in flame temperature.

5. Grindability index of a coal is 100. It implies that the __________

a) coal can be easily pulverised

b) coal can be pulverised with great difficulty

c) coal can’t be pulverised

d) power consumption in grinding the coal will be very high

Answer: a

Explanation: Grindability of an object is the ease with which the object can be reduced into powdered form. A measure of the same is the Grindability index of coal.

6. Tar yield in the low temperature and high temperature carbonisation of dry coal may be respectively __________ percent.

a) 10 & 3

b) 3 & 10

c) 15 & 8

d) 10 & 20

Answer: a

Explanation: Tar yield in the low temperature and high temperature carbonisation of dry coal may be respectively 10 & 3 percent.

7. High amount of sulphur and phosphorous in coke causes __________

a) decrease in its calorific value

b) increase in its strength

c) brittleness of steel made by using it

d) none of the mentioned

Answer: d

Explanation: None of the effects are caused by the increased strength of sulphur & phosphorus in coke.

8. The difference between the enthalpy of products & the enthalpy of reactants when complete combustion occurs at specific temperature & pressure is called?

a) Enthalpy of burning

b) Enthalpy of Combustion

c) Enthalpy of complete combustion

d) None of the mentioned

Answer: b

Explanation: Enthalpy of Combustion is defined as, “The difference between the enthalpy of products & the enthalpy of reactants when complete combustion occurs at specific temperature & pressure”.

9. The internal energy of products minus the internal energy of reactants for complete combustion at specific temperature & pressure gives the internal energy of?

a) combustion

b) partial combustion

c) complete combustion

d) none of the mentioned

Answer: a

Explanation: The internal energy of products minus the internal energy of reactants is called the internal energy of combustion.

10. HCV stands for?

a) Higher Combustion Value

b) Higher Convection Value

c) Higher Calorific Value

d) Higher Calorific Value

Answer: d

Explanation: HCV is an acronym for High Calorific Value.

This set of Power Plant test focuses on “Heat of Combustion-II”.

1. The heat transferred when the H 2 O in the products is in the liquid state is called?

a) HCV

b) LCV

c) LHV

d) None of the mentioned

Answer: a

Explanation: The heat transferred when the H 2 O in the products is in the liquid state is called HCV [Higher Calorific Value].

2. The heat transferred when the H 2 O in the products is in the vapour state is called?

a) HCV

b) LCV

c) HHV

d) None of the mentioned

Answer: b

Explanation: The heat transferred when the H 2 O in the products is in the vapour state is called LCV [Lower Calorific Value].

3. The maximum temperature achieved for given reactants is called?

a) Practical Flame Temperature

b) Critical Temperature

c) Theoretical Flame Temperature

d) None of the mentioned

Answer: c

Explanation: Theoretical Flame Temperature is the maximum temperature achieved for given reactants.

4. Maximum Theoretical Flame Temperature corresponds to _____________

a) Partial Combustion

b) Incomplete Combustion

c) Complete combustion

d) None of the mentioned

Answer: c

Explanation: Maximum Theoretical Flame Temperature corresponds to Complete Combustion.

5. In pure oxygen, the maximum flame temperature is _____________

a) higher than the theoretical flame temperature

b) lower than the theoretical flame temperature

c) equal to the theoretical flame temperature

d) none of the mentioned

Answer: a

Explanation: In pure oxygen, the maximum flame temperature is higher than the theoretical flame temperature because of dilution effect of Nitrogen.

6. Maximum permissible temperature in a gas turbine is?

a) Fixed

b) Variable

c) Linearly increasing

d) Linearly decreasing

Answer: a

Explanation: Maximum permissible temperature in a gas turbine is Fixed from metallurgical considerations.

7. Dissociation is directly proportional to temperature.

a) True

b) False

Answer: a

Explanation: Dissociation is directly proportional to temperature as when the temperature increases, the amount of dissociation also increases & vice-versa.

8. Spontaneity of a chemical reaction depends on?

a) Enthalpy of reaction

b) Energy of reaction

c) Gibbs Free Energy

d) None of the mentioned

Answer: c

Explanation: Gibbs free energy is the parameter which determines the spontaneity of the reaction after determining its randomness.

9. For exothermic reactions, free energy change is?

a) positive

b) negative

c) zero

d) none of the mentioned

Answer: b

Explanation: Gibbs free energy is the parameter which determines the spontaneity of the reaction after determining its randomness. For exothermic reactions, this energy difference has to be negative.

This set of Power Plant Quiz focuses on “Heat of Combustion-III”.

1. The free energy of chemical elements at 1 atm & 25H o C is assumed to be?

a) Negative

b) Positive

c) Zero

d) None of the mentioned

Answer: c

Explanation: Initially, for a certain time. the change in the values of free energy change remains same and equal to zero.

2. Effect of dissociation is lower for lean mixtures.

a) True

b) False

Answer: a

Explanation: Effect of dissociation is directly proportional to the amount of oxygen present in the reaction.

3. The maximum turbine flame temperature can be can be controlled by?

a) amount of oxygen extracted

b) amount of air supplied

c) amount of air extracted

d) none of the mentioned

Answer: b

Explanation: Turbine maximum flame temperature is controlled entirely by the amount of air supplied.

4. If the enthalpy change for a reaction is zero, ΔG° is equal to _____________

a) TΔS°

b) -TΔS°

c) -ΔH°

d) lnKeq

Answer: b

Explanation: Gibbs free energy is the parameter which determines the spontaneity of the reaction after determining its randomness.

5. Flue gas discharge velocity through chimney of a big thermal power plant may be around __________ m/sec.

a) 0.5

b) 500

c) 10

d) 50

Answer: c

Explanation: Flue gas discharge velocity through chimney of a big thermal power plant may be around 10 m/sec.

6. Calorific value of coal middling generated in coal washeries during washing of coal may be around __________ Kcal/kg.

a) 1000

b) 4000

c) 6000

d) 8000

Answer: b

Explanation: Calorific value of coal middling generated in coal washeries during washing of coal may be around 4000 Kcal/kg.

7. Combustion of pulverised coal as compared to that of lump coal _____________

a) develops a non-luminous flame

b) can be done with less excess air

c) develops a low temperature flame

d) provides a lower rate of heat release

Answer: b

Explanation: The amount of air required for combustion of pulverised coal is less in comparison to the amount of air in the combustion of Lump Coal.

8. For endothermic reactions, Gibbs free energy change has to be?

a) negative

b) positive

c) zero

d) none of the mentioned

Answer: b

Explanation: Gibbs free energy is the parameter which determines the spontaneity of the reaction after determining its randomness. For endothermic reactions, this energy difference has to be positive.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Chemical & Nuclear Reactions – I”.

1. Heat is generated in a nuclear reactor by __________

a) fusion of atoms of uranium

b) absorption of neutrons in uranium atoms

c) combustion of nuclear fuel

d) fission of U-235 by neutrons

Answer: d

Explanation: In a nuclear reactor, heat is generated by the fission of U-235 by neutrons.

2. Thorium-232 is converted into uranium-233 in a/an __________ nuclear reactor.

a) heavy water moderated

b) fast breeder

c) thermal

d) enriched uranium

Answer: b

Explanation: The conversion of Thorium-232 into Uranium-233 is done in a fast breeder.

3. An electron has a mass that is approximately __________ that of the proton.

a) 1/1836

b) 1

c) 1836

d) none of the mentioned

Answer: a

Explanation: The mass of an electron is approx. 1/1836 times that of the mass of proton.

4. Which of the following may not need a control rod?

a) Candu Reactor

b) Liquid metal cooled reactor

c) Fast breeder reactor

d) None of the mentioned

Answer: d

Explanation: None of the reactors mentioned above require a control rod.

5. The amount of a radioactive material remaining after 400 years will be __________ of its original weight.

a) 0.5

b) 0.25

c) 1/8

d) 1/16

Answer: d

Explanation: The amount of a radioactive material remaining after 400 years will be 1/16 of its original weight [by using radioactive decay formula].

6. The amount of a radioisotope remaining un-decayed after a time equal to four times its half-life will be __________ percent.

a) 3.125

b) 6.25

c) 12.50

d) 25

Answer: b

Explanation: The amount of a radioisotope remaining un-decayed after a time equal to four times its half-life will be 6.25 percent.

7. The time taken for a radioactive element to reduce to 50% of its original weight is __________ years if its half-life period is 12 years.

a) 24

b) 6

c) 18

d) 48

Answer: c

Explanation: As per the radioactive decay rule, the required time will be 18 years.

8. Gas cooling as compared to water cooling of nuclear reactors __________

a) cannot attain a high temperature

b) is more efficient as gas has a higher specific heat

c) can produce only saturated steam for feeding to power turbine

d) none of the mentioned

Answer: d

Explanation: None of the mentioned effects are produced by Gas cooling in comparison to water cooling.

9. What is the decay product of tritium?

a) Hydrogen

b) Deuterium

c) Lithium

d) Helium

Answer: b

Explanation: Tritium decays into a Deuterium & a hydrogen atom.

This set of Power Plant Mcqs focuses on “Chemical & Nuclear Reactions – II”.

1. Which of the following may be used to measure the rate of nuclear disintegration?

a) Geiger-Muller Counter

b) Cold Chamber

c) Cyclotron

d) Van De Graph Generator

Answer: a

Explanation: Geiger-Muller Counter is used to measure the rate of nuclear disintegration.

2. The second underground nuclear test was conducted by India at __________

a) Pokhran

b) Narora

c) Jaisalmer

d) Kalpakkam

Answer: a

Explanation: Pokhran was the place where the second underground nuclear test was conducted by India.

3. Which of the following may not need a moderator?

a) Candu Reactor

b) Fast Breeder Reactor

c) Homogeneous Reactor

d) none of the mentioned

Answer: b

Explanation: Fast Breeder Reactor may not need a moderator.

4. The mass number of an element is not changed, when it emits __________ radiations.

a) α & γ

b) α, β, & γ

c) α & β

d) β & γ

Answer: d

Explanation: The mass number of an element is not changed when it emits β & γ radiations.

5. Which of the following is not a naturally occurring nuclear fuel?

a) Uranium-238

b) Thorium-233

c) Plutonium-239

d) None of the mentioned

Answer: c

Explanation: Plutonium-239 is an artificial nuclear fuel.

6. Which is the most commonly used molten metal for cooling of nuclear reactors?

a) Zinc

b) Sulphur

c) Sodium

d) Manganese

Answer: c

Explanation: Sodium is the most commonly used molten metal for cooling of nuclear reactors.

7. One amu is equivalent to?

a) 931 MeV

b) 93.1 eV

c) 9.31 eV

d) 931 J

Answer: a

Explanation: 91 MeV constitutes one amu.

8. Fast breeder reactors do not __________

a) use molten sodium as coolant

b) use fast neutrons for fission

c) use Th-232 as fissile fuel

d) convert fertile material to fissile material

Answer: c

Explanation: Fast breeder reactors do not use Thorium-232 as fuel.

9. A boiling water reactor is the one, in which the __________

a) pressurised water is pumped into the core.

b) coolant water, after being heated in the reactor core, generates steam in a boiler

c) fuel and the coolant are thoroughly mixed to form a homogeneous solution

d) coolant water is allowed to boil in the core of the reactor

Answer: d

Explanation: A boiling water reactor is the one, in which the coolant water is allowed to boil in the core of the reactor.

10. Commercial power generation from fusion reactor is not yet possible, because __________

a) it is difficult to initiate fusion reaction

b) the fuel required is scarce

c) it is difficult to control fusion reaction

d) quantity of fuel required for initiating fusion reaction is prohibitively high

Answer: c

Explanation: As fission reactions are hard to be controlled, the commercial power generation is not yet possible.

11. Which is a fertile nuclear fuel?

a) U-233

b) U-235

c) Pu-239

d) Th-232

Answer: d

Explanation: Th-232 is the only fertile nuclear fuel amongst all the mentioned nuclear fuel.

12. Thermal shield is used in high powered nuclear reactors to __________

a) absorb the fast neutrons

b) protect the walls of the reactor from radiation damage

c) slow down the secondary neutrons

d) protect the fuel element from coming in contact with the coolant

Answer: b

Explanation: Thermal shield is used in high powered nuclear reactors to protect the walls of the reactor from radiation damage.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Nuclear Fission”.

1. What is the function of moderators in nuclear reactor?

a) absorb the secondary neutrons

b) slow down the secondary neutrons

c) control the chain reaction

d) none of the mentioned

Answer: b

Explanation: The function of moderators in nuclear reactor is to slow down the secondary neutrons.

2. Which of the following is not used as a nuclear fuel cladding material?

a) Cadmium

b) Zircalloy

c) Ceramics

d) Stainless Steel

Answer: a

Explanation: Cadmium is not used as a nuclear fuel cladding material.

3. Nuclear fuel complex, Hyderabad is engaged in the job of __________

a) processing of uranium ore

b) manufacture of nuclear fuel elements/assemblies

c) treatment of spent fuel

d) none of the mentioned

Answer: b

Explanation: The Hyderabad complex is involved in the manufacturing of nuclear fuel elements.

4. Which one is different for the neutral atoms of the isotopes of an element?

a) Number of electrons

b) Atomic weight

c) Atomic number

d) Number of Protons

Answer: b

Explanation: The isotopes are atoms of the same element but with a different atomic weight.

5. Thorium can be converted into U-233 in a __________ reactor.

a) fast breeder

b) liquid metal reactor

c) curtis reactor

d) none of the mentioned

Answer: a

Explanation: Fast breed reactors are used to convert Thorium into U-233.

6. A moderator ______ the neutrons.

a) accelerates

b) slows down

c) blocks

d) stops

Answer: b

Explanation: The function of a moderator is to slow down fast moving neutrons thus controlling the extent of fission reaction.

7. __________ nuclear reactor does not require a heat exchanger to supply steam to power turbine.

a) pressurised water

b) boiling water

c) helium cooled

d) molten sodium cooled

Answer: b

Explanation: Boiling water nuclear reactor does not require a heat exchanger to supply steam to power turbine.

8. If 4 gm of a radioisotope has a half-life period of 10 days, the half-life of 2 gm of the same istotope will be __________ days.

a) 10

b) 5

c) 20

d) 30

Answer: a

Explanation: Applying Radioactive Decay law.

9. Thermal neutrons which are used to cause the fission of U-235 have energy __________ eV.

a) >1

b) <0.025

c) >200

d) 1-25

Answer: b

Explanation: Thermal neutrons which are used to cause the fission of U-235 have energy < 0.025 eV.

10. Pick out the wrong statement.

a) Positron is heavier than a proton

b) A, β-ray particle is identical with an electron

c) The nucleus of a hydrogen atom is identical with a proton

d) Mass of an electron is about 1/1800th of the lightest nucleus

Answer: a

Explanation: Positron is lighter than a proton.

11. Specific gravity of uranium and plutonium is about __________

a) 13

b) 9

c) 19

d) 27

Answer: c

Explanation: Specific gravity of Uranium & Plutonium is about 19.

12. Which of the following types of nuclear reactors is most prone to radioactive hazards?

a) Gas cooled reactor

b) Molten Sodium Reactor

c) Boiling water reactor

d) Pressurised water reactor

Answer: c

Explanation: Boiling water reactor is the most prone to radioactive hazards.

13. The velocity of thermal neutrons triggering nuclear fission reaction is about __________ metres/second.

a) 1100

b) 2200

c) 3300

d) 4400

Answer: b

Explanation: The velocity of thermal neutrons triggering nuclear fission reaction is about 2200 m/sec.

14. Radioactive decay is a ________ change.

a) Physical

b) Chemical

c) Nuclear

d) None of the mentioned

Answer: c

Explanation: Radioactive decay is a nuclear phenomenon.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Chain Reaction and Nuclear Reactors”.

1. The atomic weight and atomic number of an element are A and Z respectively. What is the number of neutrons in the atom of that element?

a) Z

b) A

c) A+Z

d) A-Z

Answer: d

Explanation: Number of neutrons = Atomic weight – Atomic number.

2. The time required for half of the __________ of a radioactive isotope to decay is called its half-life.

a) neutron

b) electron

c) proton

d) nuclei

Answer: d

Explanation: The time required for half of the nuclei of a radioactive isotope to decay is called its half life.

3. Thermal nuclear reactors using enriched uranium as fuel contains a maximum of __________ percent fissile material i.e. U-235.

a) 1

b) 2

c) 3

d) 6

Answer: c

Explanation: Thermal nuclear reactors using enriched uranium as fuel contains a maximum of 6 percent fissile material i.e. U-235.

4. __________ moderator is used in a fast breeder reactor.

a) Heavy water

b) Graphite

c) No

d) Beryllium

Answer: c

Explanation: A fast breeder reactor doesn’t employ any moderator.

5. Nuclides having the same atomic number are termed as?

a) Isobars

b) Isotones

c) Isotopes

d) Isomers

Answer: d

Explanation: Isomers are nuclides having the same atomic number.

6. Main source of __________ is monazite sand.

a) Uranium

b) Polonium

c) Halfnium

d) Thorium

Answer: d

Explanation: Thorium is the main source of Monazite Sand.

7. Emission of β-particles during radioactive decay of a substance is from __________

a) nucleus

b) innermost shell

c) outermost shell

d) none of the mentioned

Answer: a

Explanation: Emission of β-particles during radioactive decay of a substance is from the nucleus as all emissions are nuclear phenomenon.

8. A fertile material is the one, that can be __________

a) converted into fissile material on absorption of neutron

b) fissioned by either slow or fast neutrons

c) fissioned by slow neutrons

d) fissioned by fast neutrons

Answer: a

Explanation: A fertile material is the one, which can be converted into fissile material on absorption of neutron.

9. The half-life period of a radioactive element depends on its __________

a) temperature

b) pressure

c) amount

d) none of the mentioned

Answer: d

Explanation: The half-life is independent of the mentioned factors.

10. Which is radioactive in nature?

a) Helium

b) Deuterium

c) Tritium

d) Heavy Hydrogen

Answer: c

Explanation: Tritium is a radioactive element.

11. Which is the most commonly used nuclear fuel in boiling water reactor?

a) enriched uranium

b) plutonium

c) natural uranium

d) monazite sand

Answer: a

Explanation: Enriched uranium is the most commonly used nuclear fuel in boiling water reactor.

12. Enrichment of uranium is done to increase the concentration of __________ in the natural uranium.

a) U-235

b) U-233

c) U-238

d) PU-239

Answer: a

Explanation: Enrichment of uranium is done to increase the concentration of U-235 in the natural uranium.

13. Fuel for a nuclear reactor is _____________

a) Uranium

b) Plutonium

c) Radium

d) None of the mentioned

Answer: a

Explanation: Uranium is the fuel for a thermal reactor.

14. The first underground nuclear test was conducted by India at _____________

a) Pokhran

b) Kalpakkam

c) Jaisalmer

d) Narora

Answer: a

Explanation: Pokhran had the very first underground nuclear test.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Radioactive Decay & Half Life – I”.

1. Fast breeder nuclear reactors using enriched uranium as fuel may contain upto a maximum of __________ percent of U-235 .

a) 15

b) 45

c) 65

d) 85

Answer: d

Explanation: Fast breeder nuclear reactors using enriched uranium as fuel may contain upto a maximum of 85 percent of U-235 .

2. __________ have the same mass number, but different nuclear charge.

a) Isotones

b) Isobars

c) Isotopes

d) Isoemtropic

Answer: b

Explanation: Isobars have the same mass number, but different nuclear charge.

3. Atoms with same number of neutrons, but different number of nucleons are called __________

a) Isobars

b) Isotones

c) Isotopes

d) Isoters

Answer: b

Explanation: Atoms with same number of neutrons, but different number of nucleons are called Isotones.

4. The half-life period of a radioactive substance is best determined by counting the number of alpha particles emitted per second in a Geiger Muller counter from its known quantity. If the half-life period of a radioactive substance is one month, then?

a) it will completely disintegrate in two months

b) l/8th of it will remain intact at the end of four months

c) 3/4th of it will disintegrate in two months

d) it will completely disintegrate in four months

Answer: a

Explanation: The half-life period of a radioactive substance is best determined by counting the number of alpha particles emitted per second in a Geiger Muller counter from its known quantity. If the half-life period of a radioactive substance is one month, then it will completely disintegrate in two months.

5. Which of the following ores contains maximum percentage of uranium?

a) Rescolite

b) Thorium

c) Pitchblende

d) Carnotite

Answer: c

Explanation: Pitchblende contains the maximum percentage of Uranium.

6. Percentage of U-238 in natural uranium is around __________

a) 29.71

b) 99.29

c) 0.015

d) 0.71

Answer: c

Explanation: Natural Uranium contains around 0.015% of U-238.

7. Uranium ore is currently mined & concentrated at __________

a) Khetri

b) Alwaye

c) Ghatsilla

d) Jadugoda

Answer: d

Explanation: Uranium ore is currently mined & concentrated at Jadugoda.

8. Graphite is used in nuclear reactor as __________

a) lubricant

b) fuel

c) retarder of neutron velocity

d) insulation lining of the reactor

Answer: c

Explanation: Graphite is used in nuclear reactor as retarder of neutron velocity.

9. A fast breeder reactor employs __________

a) U-235 as a fuel

b) water as a coolant

c) graphite as a moderator

d) none of the mentioned

Answer: a

Explanation: U-235 is used as a fuel in a fast breeder reactor.

10. A radioactive isotope undergoes decay with respect to time following __________ law.

a) logarithmic

b) exponential

c) inverse square

d) linear

Answer: b

Explanation: A radioactive isotope undergoes decay with respect to time following exponential law.

11. U-235 content in enriched uranium, that is normally used in power reactors , is about __________ percent.

a) 50

b) 3

c) 85

d) 97

Answer: b

Explanation: U-235 content in enriched uranium, that is normally used in power reactors , is about 3 percent.

12. The half-life period of a radioactive element is 100 days. After 400 days, one gm of the element will be reduced to __________ gm.

a) 1/2

b) 1/4

c) 1/8

d) 1/16

Answer: d

Explanation: The half-life period of a radioactive element is 100 days. After 400 days, one gm of the element will be reduced to1/16 gm.

13. Which of the following is a non-fissile material?

a) Pu-239

b) U-235

c) U-232

d) Th-232

Answer: d

Explanation: Of the mentioned fuels, only Th-232 is the fissile nuclear fuel.

14. Fast breeder reactors are most usable in India, because of our largest __________ deposits.

a) Uranium

b) Plutonium

c) Thorium

d) None of the mentioned

Answer: c

Explanation: Fast breeder reactors are most usable in India, because of our largest Thorium deposits.

15. Which is the main ore of thorium?

a) Magnetite

b) Monazite Sand

c) Pitchblende

d) None of the mentioned

Answer: b

Explanation: Monazite Sand is the main ore of Thorium.

This set of Power Plant Problems focuses on “Radioactive Decay & Half Life – II”.

1. Commercial power generation from fusion reactor is not yet possible, because __________

a) it is hard to control fission

b) it is hard to initiate fission

c) it is a non-periodic process

d) none of the mentioned

Answer: a

Explanation: The inability of controlled fission makes it tough to enable commercial power generation.

2. First experimental observation of nuclear fission was done by __________

a) Rutherford

b) Hahn & Strassman

c) Plane

d) Fermi

Answer: d

Explanation: Fermi made the first experimental observation of nuclear fission.

3. Function of control rod in a nuclear reactor is to control __________

a) pressure

b) temperature

c) fuel consumption

d) absorption of neutrons

Answer: d

Explanation: Control rods control the absorption of neutrons.

4. “Critical mass” is the minimum mass of nuclear fissile material required for the __________

a) sustainment of chain reaction

b) economic power generation

c) power generation on commercial scale

d) none of the mentioned

Answer: a

Explanation: “Critical mass” is the minimum mass of nuclear fissile material required for the sustainment of chain reaction.

5. Which of the following nuclear materials is fissile?

a) U-239

b) U-235

c) U-232

d) Pu-239

Answer: d

Explanation: Pu-239 is a fissile nuclear material.

6. Unit of Radioactivity is?

a) Curie

b) Angstrom

c) Fermi

d) Barn

Answer: a

Explanation: Curie is the unit of Radioactivity.

7. The ratio of neutrons to protons of an element having a mass number and atomic number of 80 and 40 respectively is?

a) 4

b) 3

c) 2

d) 1

Answer: d

Explanation: Number of neutrons = Atomic weight – Atomic number.

8. Critical energy should be __________ the neutron binding energy of the atom in order to initiate a nuclear fission.

a) less than

b) equal to

c) either more or less

d) more than

Answer: d

Explanation: Critical energy should be more than the neutron binding energy of the atom in order to initiate a nuclear fission.

9. Which is the main ore of uranium?

a) cassiterite

b) chalcopyrite

c) pitchblende

d) monazite sand

Answer: c

Explanation: Uranium comes from its main ore Pitchblende.

10. Nucleus of tritium has how many neutrons?

a) 1

b) 2

c) 3

d) 4

Answer: b

Explanation: There are 2 neutrons in tritium.

11. Percentage of natural uranium present in uranium ore found in Jadugoda is?

a) 2

b) 1

c) 0.1

d) 12

Answer: c

Explanation: Percentage of Uranium present in Jadugoda is 0.01%.

12. Coolant present in the primary circuit of a pressurised water reactor is high pressure __________

a) saturated steam

b) superheated steam

c) saturated water

d) sub cooled water

Answer: c

Explanation: Coolant present in the primary circuit of a pressurised water reactor is high pressure saturated water.

13. Candu reactor is a __________ nuclear reactor.

a) natural uranium fuelled heavy water cooled & moderated

b) highly enriched uranium fuelled

c) homogeneous

d) fast breeder

Answer: a

Explanation: Candu reactor is a natural uranium fuelled heavy water cooled & moderated nuclear reactor.

14. Extraction of uranium from its ore is done using __________ methods.

a) chemical

b) pyrometallurgical

c) electrometallurgical

d) physical benefaction

Answer: a

Explanation: Extraction of uranium from its ore is done using chemical methods.

15. Atoms of U-238 and U-235 differ in structure by three __________

a) electrons

b) protons

c) neutrons

d) electrons & three protons

Answer: c

Explanation: The two atoms differ in the structure only in the number of neutrons.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Fission Analysis – I”.

1. The immediate products of fission are called?

a) fission splits

b) fission fragments

c) fission products

d) fission scatters

Answer: b

Explanation: The immediate outputs of a fission reaction are called fission fragments while the same when combined with the various by-products are called fission products.

2. Each neutron produces _________ neutron per fission.

a) 1

b) 2

c) 3

d) 4

Answer: c

Explanation: Per fission of one neutron, there is a release of 3 neutrons & hence, fission reactions are hard to control once started.

3. 1 Curie = _____________

a) 3.615 x 10 10 dis/s

b) 3.615 x 10 0.7 dis.s

c) 3.615 x 10 12 dis

d) 3.615 x 10 dis/s

Answer: a

Explanation: The unit of radioactivity, Curie is given as,

1 Curie = 3.615 x 10 10 dis/s

4. The nuclear activity occurring in the radioisotope H3 is?

a) Alpha emission

b) Gamma Emission

c) Beta emission

d) None of the mentioned

Answer: c

Explanation: The nuclear activity occurring in the radioisotope H3 is Beta Emission.

5. The nuclear activity occurring in the radioisotope Carbon 14 is?

a) Alpha emission

b) Gamma Emission

c) Beta emission

d) None of the mentioned

Answer: c

Explanation: The nuclear activity occurring in the radioisotope Carbon 14 is Beta Emission.

6. The nuclear activity occurring in the radioisotope Krypton 87 is?

a) Alpha emission

b) Gamma Emission

c) Beta emission

d) None of the mentioned

Answer: c

Explanation: The nuclear activity occurring in the radioisotope Krypton 87 is Beta Emission.

7. The nuclear activity occurring in the radioisotope Xenon 135 is?

a) Alpha & Beta emission

b) Gamma & Beta Emission

c) Beta emission

d) None of the mentioned

Answer: b

Explanation: The nuclear activity occurring in the radioisotope Xenon 135 is Gamma & Beta Emission.

8. The nuclear activity occurring in the radioisotope Strontium 90 is?

a) Alpha emission

b) Gamma Emission

c) Beta emission

d) None of the mentioned

Answer: c

Explanation: The nuclear activity occurring in the radioisotope Strontium 90 is Beta Emission.

9. The nuclear activity occurring in the radioisotope Barium 139 is?

a) Alpha & Beta emission

b) Gamma & Beta Emission

c) Beta emission

d) None of the mentioned

Answer: b

Explanation: The nuclear activity occurring in the radioisotope Barium 139 is Gamma & Beta Emission.

10. The nuclear activity occurring in the radioisotope Radium 223 is?

a) Alpha & Gamma emission

b) Gamma & Beta Emission

c) Beta emission

d) None of the mentioned

Answer: a

Explanation: The nuclear activity occurring in the radioisotope Radium 223 is Alpha & Gamma Emission.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Fission Analysis – II”.

1. The half-life of H3 radioisotope is?

a) 12.26 yr

b) 5730 yr

c) 76 min

d) 28.1 yr

Answer: a

Explanation: The Half-life of tritium radioisotope is 12.26 years.

2. Readily fissile isotopes have ___________ half-lives.

a) short

b) long

c) short & long

d) none of the mentioned

Answer: b

Explanation: As the isotopes are fissile, naturally they will have more half-life.

3. The unit superseding Curie as the unit of Radioactivity is?

a) Decibel

b) Hectare

c) Becquerel

d) None of the mentioned

Answer: c

Explanation: Becquerel signifies number of disintegrations per second, much similar to the unit Curie.

4. A series of radioactive fissions is called a _____________

a) Fission Row

b) Fission Chain

c) Fission Column

d) None of the mentioned

Answer: b

Explanation: A series of radioactive fission reactions is called a Fission Chain.

5. Beta decay is usually accompanied by?

a) alpha decay

b) beta decay

c) gamma decay

d) gamma radiation

Answer: d

Explanation: The entire beta decay process involves the release of gamma radiation apart from various factors.

6. The amount of energy in MW-days produced of each metric tonne of fuel is?

a) fuel ignition

b) fuel burnup

c) fuel Chain

d) fuel Column

Answer: b

Explanation: Fuel burnup is the amount of energy in MW-days produced of each metric tonne of fuel.

7. The number of newly born neutrons in an uncontrolled fission reaction is?

a) 2

b) 2.5

c) 2.47

d) 2.38

Answer: c

Explanation: The number of newly born neutrons in an uncontrolled fission reaction is 2.47.

8. The process of losing speed of newly born neutrons on collision with other freshly produced neutrons & other obstacles in the way is called?

a) Dispersion

b) Diversion

c) Deviation

d) Scattering

Answer: d

Explanation: The process of losing speed of newly born neutrons on collision with other freshly produced neutrons & other obstacles in the way is called Scattering.

9. In terms of speed, the newly produced neutrons are classed into how many types?

a) 2

b) 3

c) 4

d) 5

Answer: b

Explanation: In terms of speed, the newly produced neutrons are classed in many types which are Fast, Slow & Intermediate moving neutrons.

10. The velocity of a fast moving neutron is?

a) 2 m/s

b) 2.4 x 10 10 m/s

c) 4.4 x 10 10 m/s

d) 4.4 x 10 6 m/s

Answer: d

Explanation: The velocity of the newly produced fast moving neutron is 4.4 x 10 6 m/s.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Pelton Wheel Turbine”.

1. For centrifugal pump impeller, what is the maximum value of the vane exit angle?

a) 100 to 150

b) 150 to 200

c) 200 to 250

d) 250 to 300

Answer: c

Explanation: The maximum value of the vane exit angle is 200 to 250.

2. In which turbine the pressure energy of water is first converted into kinetic energy by means of nozzle kept close to the runner?

a) Impulse turbine

b) Reaction turbine

c) Both Impulse and Reaction turbine

d) None of the mentioned

Answer: a

Explanation: Impulse Turbine is the one in which pressure energy of water is first converted into kinetic energy by means of nozzle kept close to the runner.

3. The pressure of water is atmospheric and remains constant while passing over the runner in __________

a) Impulse turbine

b) Reaction turbine

c) Both Impulse and Reaction turbine

d) None of the mentioned

Answer: a

Explanation: The pressure of water is atmospheric and remains constant while passing over the runner in Impulse Turbine.

4. The energy of water entering the reaction turbine is _______

a) fully the kinetic energy

b) fully the pressure energy

c) partly the pressure energy and partly the kinetic energy

d) unpredictable

Answer: c

Explanation: The energy of water entering the reaction turbine is partly the pressure energy and partly the kinetic energy.

5. Which of the following is an example of impulse turbine?

a) Propeller turbine

b) Francis turbine

c) Kaplan turbine

d) Pelton wheel

Answer: d

Explanation: Pelton Wheel Turbine is an example of impulse Turbine.

6. The runner of __________ turbine always be under pressure of above atmospheric pressure.

a) Turgo

b) Girand

c) Kaplan

d) None of the mentioned

Answer: c

Explanation: The runner of Kaplan turbine always be under pressure of above atmospheric pressure.

7. What is the head of water available at turbine inlet in hydro-electric power plant called?

a) head race

b) tail race

c) gross head

d) net head

Answer: d

Explanation: the head of water available at turbine inlet in hydro-electric power plant called Net Head.

8. Gross head is the difference between __________

a) head race and tail race

b) head race and net head

c) head race and friction losses

d) net head and friction losses

Answer: a

Explanation: Gross head is the difference between head race and tail race.

9. Which of the following hydraulic turbines has a construction given in diagram below?

power-plant-questions-answers-pelton-wheel-turbine-q9

a) Kaplan turbine

b) Francis turbine

c) Pelton turbine

d) Propeller turbine

Answer: c

Explanation: From the diagram above, it is clear that the turbine shown is a Pelton Wheel Turbine.

10. What is runaway speed of the runner of Pelton wheel?

a) maximum unsafe speed of the runner due to sudden increase in load on turbine

b) minimum safe speed of the runner due to sudden increase in load on turbine

c) maximum unsafe speed of the runner due to sudden decrease in load on turbine

d) minimum safe speed of the runner due to sudden decrease in load on turbine

Answer: c

Explanation: The maximum unsafe speed of the runner due to sudden decrease in load on turbine is called runaway speed of the runner of Pelton wheel.

11. What is the formula for the velocity of water jet at the inlet of turbine?

Where,

H = Net head acting on Pelton wheel

Cv = coefficient of velocity of jet

a) V = Cv )

b) V = 2Cv )

c) V = Cv )

d) V = 2Cv )

Answer: c

Explanation: The relation between the various quantities mentioned above is given by,

V = Cv ).

12. Power required to drive a centrifugal pump is directly proportional to __________ of its impeller.

a) cube of diameter

b) fourth power of diameter

c) diameter

d) square of diameter

Answer: b

Explanation: Power required to drive a centrifugal pump is directly proportional to fourth power of its impeller.

13. In a reaction turbine, the draft tube is used __________

a) to increase the head of water by an amount equal to the height of the runner outlet above the tail race

b) to transport water to downstream

c) to run the turbine full

d) to prevent air to enter the turbine

Answer: a

Explanation: In a reaction turbine, the draft tube is used to increase the head of water by an amount equal to the height of the runner outlet above the tail race.

14. The specific speed from 160 to 500 r.p.m. of a centrifugal pump indicates that the pump is __________

a) high speed with radial flow at outlet

b) slow speed with radial flow at outlet

c) medium speed with radial flow at outlet

d) high speed with axial flow at outlet

Answer: d

Explanation: The specific speed from 160 to 500 r.p.m. of a centrifugal pump indicates that the pump is high speed with axial flow at outlet.

15. Which of the following pump is preferred for flood control and irrigation applications?

a) Reciprocating pump

b) Axial flow pump

c) Mixed flow pump

d) Centrifugal pump

Answer: b

Explanation: Axial flow pump is preferred for flood control and irrigation applications.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Kaplan, Francis and Deriaz Turbines – I”.

1. Kinematic similarity is said to exist between the model and the prototype, if both of them __________

a) are equal in size and shape

b) have identical velocities

c) are identical in shape, but differ only in size

d) have identical forces

Answer: b

Explanation: Kinematic similarity is said to exist between the model and the prototype, if both of them have identical velocities.

2. The impeller of a centrifugal pump may have __________

a) vortex casing

b) volute casing

c) volute casing with guide blades

d) any of the mentioned

Answer: d

Explanation: The impeller of a centrifugal pump may have vortex casing, volute casing & volute casing with guide blades.

3. In a Francis turbine runner, the number of blades are generally between __________

a) 2 to 4

b) 8 to 16

c) 4 to 8

d) 16 to 24

Answer: d

Explanation: In a Francis turbine runner, the number of blades are generally between 16 to 24.

4. The hydraulic efficiency of a reaction turbine is the ratio of __________

a) actual work available at the turbine to energy imparted to the wheel

b) power produced by the turbine to the energy actually supplied by the turbine

c) work done on the wheel to the energy actually supplied to the turbine

d) none of the mentioned

Answer: c

Explanation: The hydraulic efficiency of a reaction turbine, is the ratio of work done on the wheel to the energy supplied to the turbine.

5. If the ratios of the corresponding forces acting at corresponding points are equal, then the model and the prototype are said to have __________

a) kinematic similarity

b) geometric similarity

c) dynamic similarity

d) none of the mentioned

Answer: c

Explanation: If the ratios of the corresponding forces acting at corresponding points are equal, then the model and the prototype are said to have dynamic similarly.

6. In a reciprocating pump, air vessels are used to __________

a) increase delivery head

b) reduce suction head

c) smoothen the flow

d) reduce acceleration head

Answer: d

Explanation: In a reciprocating pump, air vessels are used to reduce acceleration head.

7. The ratio of quantity of liquid discharged per second from the pump to the quantity of liquid passing per second through the impeller is known as?

a) overall efficiency

b) volumetric efficiency

c) manometric efficiency

d) mechanical efficiency

Answer: b

Explanation: The ratio of quantity of liquid discharged per second from the pump to the quantity of liquid passing per second through the impeller is known as volumetric efficiency.

8. The working of which of the following hydraulic units is based on Pascal’s law?

a) Hydraulic coupling

b) Air lift pump

c) Jet pump

d) Hydraulic press

Answer: d

Explanation: The working of which of the following hydraulic units is based on Pascal’s law Hydraulic press.

9. Which of the following pump is generally used to pump highly viscous fluid?

a) Air lift pump

b) Centrifugal pump

c) Screw pump

d) Reciprocating pump

Answer: a

Explanation: Air lift pump is used to pump highly viscous fluids up the height.

10. The maximum efficiency of jet propulsion of a ship with inlet orifices at right angles to the direction of motion of ship, will be?

a) 40%

b) 50%

c) 60%

d) 80%

Answer: b

Explanation: maximum efficiency of jet propulsion of a ship with inlet orifices at right angles to the direction of motion of ship is 50%.

11. By fitting an air vessel to the reciprocating pump, there is always a saving of work done and subsequently saving of power. This saving in case of a single acting reciprocating pump is?

a) 84.8%

b) 74.8%

c) 64.8%

d) 54.8%

Answer: a

Explanation: Required percentage saving is 84.8%.

12. A Pelton wheel working under a constant head and discharge, has maximum efficiency when the speed ratio is?

a) 0.26

b) 0.36

c) 0.46

d) 0.56

Answer: d

Explanation: The maximum speed ratio of a Pelton wheel turbine is 0.56.

13. The cups at the periphery of the Pelton wheel are __________

a) equiangular

b) equidistant

c) equimolar

d) none of the mentioned

Answer: b

Explanation: The buckets in a Pelton Turbine are equidistant.

This set of Power Plant Multiple Choice Questions & Answers focuses on “Kaplan, Francis and Deriaz Turbines – II”.

1. The maximum number of jets, generally, employed in an impulse turbine without jet interference are __________

a) 2

b) 6

c) 7

d) 5

Answer: a

Explanation: The maximum number of jets, generally, employed in an impulse turbine without jet interference are 2.

2. A Francis turbine is used when the available head of water is?

a) 0 to 25 m

b) 25 to 250 m

c) > 250 m

d) none of the mentioned

Answer: b

Explanation: Francis Turbine is used for high heads of water.

3. The overall efficiency of a reaction turbine is the ratio of __________

a) actual work available at the turbine to the energy imparted to the wheel

b) power produced by the turbine to the energy actually supplied by the turbine

c) workdone on the wheel to the energy actually supplied to the turbine

d) none of the mentioned

Answer: b

Explanation: The overall efficiency of a reaction turbine is the ratio of power produced by the turbine to the energy actually supplied by the turbine.

4. Manometric head, in case of a centrifugal pump, is equal to __________

a) Suction lift + Loss of head in suction pipe due to friction + Delivery lift + Loss of head in delivery pipe due to friction + Velocity head in the delivery pipe

b) Energy per kN at outlet of impeller – Energy per kN at inlet of impeller

c) Workdone per kN of water – Losses within the impeller

d) All of the mentioned

Answer: d

Explanation: Manometric head, in case of a centrifugal pump = Suction lift + Loss of head in suction pipe due to friction + Delivery lift + Loss of head in delivery pipe due to friction + Velocity head in the delivery pipe = Energy per kN at outlet of impeller – Energy per kN at inlet of impeller = Workdone per kN of water – Losses within the impeller.

5. What is the mechanical efficiency of an impulse turbine?

a) ratio of the actual power produced by the turbine to the energy actually supplied by the turbine

b) ratio of the actual work available at the turbine to the energy imparted to the wheel

c) ratio of the Work done on the wheel to the energy of the jet

d) none of the mentioned

Answer: b

Explanation: The mechanical efficiency of an impulse turbine is ratio of the actual work available at the turbine to the energy imparted to the wheel.

6. The speed of an imaginary turbine, identical with the given turbine, which will develop a unit power under a unit head, is known as?

a) unit speed

b) terrific speed

c) specific velocity

d) specific speed

Answer: d

Explanation: The speed of an imaginary turbine, identical with the given turbine, which will develop a unit power under a unit head, is known as Specific Speed.

7. Geometric similarity is said to exist between the model and the prototype if both of them __________

a) are equal in size and shape

b) have identical velocities

c) have identical forces

d) are identical in shape, but differ only in size

Answer: d

Explanation: Geometric similarity is said to exist between the model and the prototype, if both of them are identical in shape, but differ only in size.

8. A centrifugal pump will start delivering liquid only when the pressure rise in the impeller is equal to the __________

a) manometric head

b) velocity head

c) kinetic head

d) static head

Answer: a

Explanation: A centrifugal pump will start delivering liquid only when the pressure rise in the impeller is equal to the manometric head.

9. Slip of a reciprocating pump is defined as the __________

a) sum of actual discharge and the theoretical discharge

b) ratio of actual discharge to the theoretical discharge

c) difference of theoretical discharge and the actual discharge

d) product of theoretical discharge and the actual discharge

Answer: c

Explanation: Slip of a reciprocating pump is defined as the difference of theoretical discharge and the actual discharge.

10. Multi-stage centrifugal pumps are used to __________

a) produce high heads

b) give high discharge

c) pump viscous fluids

d) all of the mentioned

Answer: a

Explanation: Multi-stage centrifugal pumps are used to produce high heads.

11. A hydraulic coupling belongs to the category of __________

a) power absorbing machines

b) energy transfer machines

c) power developing machines

d) energy generating machines

Answer: b

Explanation: A hydraulic coupling belongs to the category of energy transfer machines.

12. Discharge of a centrifugal pump is __________

a) inversely proportional to 2 of its impeller

b) inversely proportional to diameter of its impeller

c) directly proportional to 2 of its impeller

d) directly proportional to diameter of its impeller

Answer: a

Explanation: Discharge of a centrifugal pump is inversely proportional to 2 of its impeller.

13. Which of the following turbine is preferred for 0 to 25 m head of water?

a) Kaplan Turbine

b) Pelton Turbine

c) Francis Turbine

d) None of the mentioned

Answer: a

Explanation: Kaplan turbine is preferred for low heads of water.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Diesel Engine Basics”.

1. If the temperature of intake air in internal combustion engine increases, then its efficiency will __________

a) remain same

b) increase

c) decrease

d) none of the mentioned

Answer: c

Explanation: The efficiency of an IC Engine is inversely proportional to the temperature of intake air.

2. The operation of forcing additional air under pressure in the engine cylinder is known as __________

a) Supercharging

b) Scavenging

c) Turbulence

d) Pre-ignition

Answer: a

Explanation: Supercharging is the operation of forcing additional air under pressure in the engine cylinder.

3. The ignition quality of petrol is expressed by __________

a) Cetane number

b) Octane number

c) Calorific Value

d) None of the mentioned

Answer: b

Explanation: Octane number estimates the quality of petrol.

4. The mean effective pressure obtained from engine indicator indicates the __________

a) maximum pressure developed

b) minimum pressure developed

c) instantaneous pressure at any point

d) average pressure

Answer: d

Explanation: The mean effective pressure indicates the average pressure on the engine.

5. The probability of knocking in diesel engines is increased by __________

a) high self-ignition temperature

b) low volatility

c) high viscosity

d) all of the mentioned

Answer: d

Explanation: The probability of knocking in diesel engines is increased by keeping high self-ignition temperature, low volatility, high viscosity, etc.

6. Reactors for propulsion applications are designed for__________

a) any form of uranium

b) natural uranium

c) enriched uranium

d) thorium

Answer: c

Explanation: Enriched uranium is the material that is used for making reactors for propulsion application.

7. What is the pour point of fuel oil?

a) Minimum temperature to which oil is heated in order to give off inflammable vapours in sufficient quantity to ignite momentarily when brought in contact with a flame

b) Temperature at which it solidifies or congeals

c) It catches fire without external aid

d) Indicated by 90% distillation temperature i.e., when 90% of sample oil has distilled off

Answer: b

Explanation: The temperature at which fuel oil solidifies or congeals is called pour point of fuel oil.

8. What is the maximum temperature in the I.C. engine cylinder is of the order of?

a) 500-1000

b) 1000-1500

c) 1500-2000

d) 2000-2500

Answer: d

Explanation: The maximum temperature in the I.C. engine cylinder is of the order of is 2000-25000 degree Celsius.

9. In compression ignition engines, swirl denotes a __________

a) Haphazard motion of the gases in the chamber

b) Rotary motion of the gases in the chamber

c) Radial motion of the gases in the chamber

d) None of the mentioned

Answer: b

Explanation: Swirl in a compression ignition engine denotes rotary motion of the gases in the chamber.

10. Supercharging is the process of __________

a) Supplying the intake of an engine with air at a density greater than the density of the surrounding atmosphere

b) Supplying compressed air to remove combustion products fully

c) Providing excess temperature to the sucked in gases

d) None of the mentioned

Answer: a

Explanation: Supercharging is the process of supplying the intake of an engine with air at a density greater than the density of the surrounding atmosphere.

11. The object of supercharging the engine is __________

a) to increase the power output of an engine when greater power is required

b) to reduce mass of the engine per brake power

c) to reduce space occupied by the engine

d) all of the mentioned

Answer: d

Explanation: Supercharging is done to increase the power output of an engine, to reduce mass of the engine per brake power & to reduce space occupied by the engine.

12. The compensating jet in a carburettor supplies almost constant amount of petrol at all speeds because the __________

a) jet area is automatically varied depending on the suction

b) the flow from the main jet is diverted to the compensating jet with increase in speed

c) flow is produced due to the static head in the float chamber

d) the diameter of the jet is constant and the discharge coefficient is invariant

Answer: c

Explanation: The compensating jet in a carburettor supplies almost constant amount of petrol at all speeds because the flow is produced due to the static head in the float chamber.

13. The ratio of the volume of charge admitted at N.T.P. to the swept volume of the piston is called?

a) overall efficiency

b) mechanical efficiency

c) relative efficiency

d) volumetric efficiency

Answer: d

Explanation: Volumetric Efficiency is the ratio of the volume of charge admitted at N.T.P. to the swept volume of the piston.

14. A moderator generally used in nuclear power plants is?

a) heavy water

b) concrete

c) graphite & concrete

d) graphite

Answer: c

Explanation: A moderator generally used in nuclear power plants is made up of graphite & concrete.

15. In a diesel engine, the duration between the time of injection and ignition is known as?

a) delay period

b) period of ignition

c) burning period

d) pre-ignition period

Answer: a

Explanation: In a diesel engine, the duration between the time of injection and ignition, is known as the delay period.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Diesel Engine Types and their Applications – I”.

1. Nuclear Reactors are used __________

a) to produce heat for thermoelectric power

b) to propel ships, submarines, aircrafts

c) to produce fissionable material

d) all of the mentioned

Answer: d

Explanation: Nuclear reactors have wide range of usage which include producing heat for thermoelectric power, ship propulsion, production of fissionable materials, etc.

2. Where reactor operation is designed with fast neutrons such as in reactors using highly enriched fuel, the moderator used is?

a) Carbon dioxide

b) Heavy Water

c) Graphite

d) No moderator is needed

Answer: d

Explanation: Where reactor operation is designed with fast neutrons such as in reactors using highly enriched fuel, no moderator is required.

3. The expansion of fuel in a four stroke cycle diesel engine __________

a) starts at 15° after top dead centre and ends at 30° before bottom dead centre

b) starts at top dead centre and ends at 30° after top dead centre

c) may start and end anywhere

d) starts at 15° before top dead centre and ends at 30° after top dead centre

Answer: a

Explanation: The expansion of fuel in a four stroke cycle diesel engine starts at 15° after top dead centre and ends at 30° before bottom dead centre.

4. A moderator, in nuclear power plants, is a medium introduced into the fuel mass in order to __________

a) slow down the speed of fast moving neutrons

b) control the reaction

c) reduce the temperature

d) extract heat from nuclear reaction

Answer: a

Explanation: A moderator, in nuclear power plants, is a medium introduced into the fuel mass in order to slow down the speed of fast moving neutrons.

5. The thermal efficiency of diesel engines is about __________

a) 30%

b) 15%

c) 50%

d) 70%

Answer: d

Explanation: The thermal efficiency of diesel engines is about 70%.

6. In a four stroke cycle petrol engine, the charge is ignited at __________

a) 30° after bottom dead centre

b) 30° before bottom dead centre

c) 30° after top dead centre

d) 30° before top dead centre

Answer: d

Explanation: In a four stroke cycle petrol engine, the charge is ignited at 30° before top dead centre.

7. The exhaust valve in a four stroke cycle petrol engine __________

a) opens at 50° after bottom dead centre and closes at 15° before top dead centre

b) opens at 50° before bottom dead centre and closes at 15° after top dead centre

c) opens at bottom dead centre and closes at top dead centre

d) may open and close anywhere

Answer: b

Explanation: The exhaust valve in a four stroke cycle petrol engine opens at 50° before bottom dead centre and closes at 15° after top dead centre.

8. The brake power of a diesel engine, keeping other parameters constant, can be increased by __________

a) increasing the pressure of intake air

b) decreasing the density of intake air

c) decreasing the pressure of intake air

d) increasing the temperature of intake air

Answer: a

Explanation: The brake power of a diesel engine, keeping other parameters constant, can be increased by increasing the pressure of intake air.

9. In a four stroke cycle, the minimum temperature inside the engine cylinder occurs at the __________

a) end of suction stroke

b) beginning of exhaust stroke

c) beginning of suction stroke

d) end of exhaust stroke

Answer: c

Explanation: In a four stroke cycle, the minimum temperature inside the engine cylinder occurs at the beginning of exhaust stroke.

10. The effective inhibitor of pre-ignition is __________

a) alcohol

b) lead

c) water

d) none of the mentioned

Answer: c

Explanation: Water is the most effective inhibitor of pre-ignition.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Diesel Engine Types and their Applications – II”.

1. The reference fuels for knock rating of spark ignition engines would include __________

a) normal octane and aniline

b) iso-octane and normal hexane

c) iso-octane and alpha-methyl naphthalene

d) normal heptane and iso-octane

Answer: d

Explanation: The reference fuels for knock rating of spark ignition engines would include normal heptane and iso-octane.

2. What is the purpose of testing an internal combustion engine?

a) to conform the data used in design, the validity of which may be doubtful

b) to satisfy the customer regarding the performance of the engine

c) to determine the information, which cannot be obtained by calculations

d) all of the mentioned

Answer: d

Explanation: The purpose of testing an internal combustion engine is to conform the data used in design, the validity of which may be doubtful; to satisfy the customer regarding the performance of the engine & to determine the information, which cannot be obtained by calculations.

3. Pre-ignition is caused by the spontaneous combustion of the mixture before the end of the compression stroke, and is due to __________

a) overheated spark plug points

b) red hot carbon deposits on cylinder walls

c) cylinder walls being too hot

d) any of the mentioned

Answer: d

Explanation: Pre-ignition is caused by the spontaneous combustion of the mixture before the end of the compression stroke, and is due to either overheated spark plug points, red hot carbon deposits on cylinder walls, & cylinder walls being too hot.

4. The thermal efficiency of a standard Otto cycle for a compression ratio of 5.5 will be __________

a) 20%

b) 25%

c) 50%

d) 55%

Answer: c

Explanation: The Thermal efficiency of a standard Otto cycle for a compression ratio r is given by,

N = 1 – .

5. The fuels in order of decreasing knock tendency for spark ignition engines are __________

a) Paraffin, aromatic, napthene

b) Paraffin, napthene, aromatic

c) Napthene, aromatics, paraffin

d) Napthene, paraffin, aromatic

Answer: b

Explanation: The fuels in order of decreasing knock tendency for spark ignition engines are Paraffin, napthene, aromatic.

6. In a four stroke cycle petrol engine, the pressure inside the engine cylinder during the suction stroke is __________ the atmospheric pressure.

a) equal to

b) below

c) above

d) middle

Answer: b

Explanation: In a four stroke cycle petrol engine, the pressure inside the engine cylinder during the suction stroke is below the atmospheric pressure.

7. Solid fuel fabricated into various small shapes, which are assembled to form fuel elements, is in the form of __________

a) pallets

b) plates

c) pins

d) all of the mentioned

Answer: d

Explanation: Solid fuel fabricated into various small shapes are of the form of pallets, plates, pins, etc.

8. A diesel engine is __________ as compared to petrol engine, both running at rated load.

a) equally efficient

b) more efficient

c) less efficient

d) all of the mentioned

Answer: b

Explanation: A diesel engine is more efficient as compared to petrol engine, both running at rated load.

9. A higher compression ratio causes __________

a) increase in detonation

b) pre-ignition

c) an acceleration in the rate of combustion

d) any one of the mentioned

Answer: d

Explanation: A higher compression ratio causes increased detonation, increased rate of combustion & pre-ignition.

10. Which one of the following event would reduce volumetric efficiency of a vertical compression ignition engine?

a) inlet valve closing before bottom dead centre

b) inlet valve closing after bottom dead centre

c) inlet valve opening before top dead centre

d) exhaust valve closing after top dead centre

Answer: a

Explanation: Inlet valve closing before bottom dead centre would reduce the volumetric efficiency of a vertical compression ignition engine.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Diesel Engine Analysis”.

1. A fuel of cetane number 40 has the same ignition quality as a mixture of __________

a) 40% alpha methyl napthalene and 60% cetane

b) 40% cetane and 60% alpha methyl napthalene

c) 40% petrol and 60% diesel

d) 40% diesel and 60% petrol

Answer: b

Explanation: A fuel of cetane number 40 has the same ignition quality as a mixture of 40% cetane and 60% alpha methyl naphthalene.

2. The control rods in the control system of nuclear reactors are used to __________

a) control fuel consumption

b) absorb excess neutrons

c) control temperature

d) all of the mentioned

Answer: b

Explanation: The function of control rods is to absorb the excess neutrons released during fission.

3. The pressure at the end of compression, in petrol engines, is approximately __________

a) 10 bar

b) 20 bar

c) 25 bar

d) 35 bar

Answer: a

Explanation: The pressure at the end of compression, in petrol engines, is approximately 10 bar.

4. If the speed of the engine is increased, the indicated power will __________

a) increase

b) decrease

c) remain same

d) none of the mentioned

Answer: a

Explanation: The speed of the engine & indicated power are inter related as they are directly proportional to each other, so if one increases, the other also increases & vice-versa.

5. Number of working strokes per min. for a two stroke cycle engine are __________ the speed of the engine in r.p.m.

a) equal to

b) one-half

c) four-times

d) twice

Answer: a

Explanation: Number of working strokes per min. for a two stroke cycle engine are equal to the speed of the engine in rpm.

6. Reflector in nuclear power plants __________ neutron leakage.

a) increases

b) decreases

c) has no effect

d) all of the mentioned

Answer: b

Explanation: Reflector in nuclear power plants decreases neutron leakage.

7. In order to eliminate knocking in compression ignition engines, there should be __________

a) high self-ignition temperature of fuel

b) late auto-ignition

c) short delay period

d) low compression ratio

Answer: c

Explanation: In order to eliminate knocking in compression ignition engines, there should be a shorter delay period.

8. Which of the following statement is correct?

a) Compression ratio for petrol engines varies from 6 to 10

b) Petrol engines work on Otto cycle

c) Higher compression ratio in diesel engines results in higher pressures

d) All of the mentioned

Answer: d

Explanation: All the mentioned statements are correct.

9. The injector nozzle of a compression ignition engine is required to inject fuel at a sufficiently high pressure in order to __________

a) inject fuel at a high velocity to facilitate atomisation

b) inject fuel in a chamber of high pressure at the end of compression stroke

c) ensure that penetration is not high

d) all of the mentioned

Answer: d

Explanation: The fuel injection is at a sufficiently higher pressure in order to inject fuel at a high velocity to facilitate atomisation, to inject fuel in a chamber of high pressure at the end of compression stroke & to ensure that penetration is not high.

10. The two reference fuels used for cetane rating are __________

a) cetane & iso-octane

b) cetane & normal heptane

c) cetane & alpha methyl naphthalene

d) cetane & tetra ethyl lead

Answer: c

Explanation: Cetane & alpha methyl naphthalene are the two reference fuels used for cetane rating.

11. In petrol engines, the delay period is of the order of __________

a) 0.001 sec

b) 0.002 sec

c) 0.003 sec

d) 0.004 sec

Answer: b

Explanation: The delay period in petrol engines is of the order of 0.002 sec.

12. How much voltage required to produce a spark across the gap, between the sparking points?

a) 2000-4000 volts

b) 4000-6000 volts

c) 6000-10000 volts

d) 10000-12000 volts

Answer: c

Explanation: The voltage required to produce a spark across the gap, between the sparking points is 6000-10000 Volts.

13. The scavenging efficiency of a tour stroke cycle diesel engine is __________

a) between 50-85%

b) between 95-100%

c) below 50%

d) between 85-95%

Answer: b

Explanation: The scavenging efficiency of a tour stroke cycle diesel engine is between 95-100%.

14. The specific fuel consumption per B.P. hour for a petrol engine is about __________

a) 0.2 kg

b) 0.25 kg

c) 0.3 kg

d) 0.35 kg

Answer: b

Explanation: The brake specific fuel consumption for a petrol engine is about 0.25 kg.

15. Which material is most commonly used for shielding?

a) Carbon

b) Concrete

c) Lead

d) All of the mentioned

Answer: c

Explanation: Lead is the material that is most commonly used for Shielding.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Pulverisation and Gasifiers”.

1. Temperature of preheated air used for the transportation of pulverised coal through pipes to the burner of a boiler furnace is restricted to a maximum limit of about 300° C to avoid the __________

a) requirement of large volume of combustion chamber

b) incomplete combustion of coal

c) risk of explosion

d) chances of clinker formation

Answer: c

Explanation: Temperature of preheated air used for the transportation of pulverised coal through pipes to the burner of a boiler furnace is restricted to a maximum limit of about 300° C to avoid the risk of explosion owing to the reacting mixture.

2. The temperature at which plastic layer formation takes place during carbonisation of coal varies from __________ °C.

a) 100-150

b) 350-450

c) 700-850

d) 550-650

Answer: b

Explanation: The temperature at which plastic layer formation takes place during carbonisation of coal varies from 350 to 450 °C.

3. Which of the following is not a by-product recovered in a high temperature coal carbonisation plant?

a) Benzol

b) Ethylene

c) Pitch-cresosote mixture

d) Naphthalene

Answer: b

Explanation: Apart from Ethylene all the others are by-products obtained in high temperature coal carbonisation plant.

4. Pick out the wrong statement.

a) Regulation of furnace temperature and atmosphere is easily possible with pulverised fuel firing

b) Low grade coal can be used, but generally high volatile matter coals are more suitable for making pulverised fuel

c) Pulverised fuel can be completely burnt with less percentage of excess air compared to lump coal

d) None of the mentioned

Answer: d

Explanation: All the mentioned statements are correct.

5. Flue gas discharge velocity through chimney of a big thermal power plant may be around __________ m/sec.

a) 0.5

b) 500

c) 10

d) 50

Answer: c

Explanation: Flue gas discharge velocity through chimney of a big thermal power plant may be around 10 m/sec.

6. Calorific value of coal middling generated in coal washeries during washing of coal may be around __________ Kcal/kg.

a) 1000

b) 4000

c) 6000

d) 8000

Answer: b

Explanation: Calorific value of coal middling generated in coal washeries during washing of coal may be around 4000 Kcal/kg.

7. Combustion of pulverised coal as compared to that of lump coal __________

a) develops a non-luminous flame

b) can be done with less excess air

c) develops a low temperature flame

d) provides a lower rate of heat release

Answer: b

Explanation: Combustion of pulverised coal as compared to that of lump coal can be done with less excess air.

8. The decrease in the atomic number is not observed in case of __________

a) alpha emission

b) beta emission

c) gamma emission

d) none of the mentioned

Answer: b

Explanation: There is no change in the atomic number as the number of electrons remains the same.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Kinetic and Diffusion Control – I”.

1. Which of these is the outer most coating in the burning of a coke particle?

a) Oxygen

b) Carbon monoxide

c) Carbon dioxide

d) Ash Layer

Answer: a

Explanation: Oxygen, being a supporter of combustion helps in combustion of coke particle and so forms a layer on the periphery of the coke particle.

2. Which law deals with the rate of diffusion of Oxygen per unit surface area of the particle?

a) Kirchhoff’s Law

b) Plank’s Law

c) Fourier’s Law

d) Fick’s Law

Answer: d

Explanation: Fick’s Law deals with the rate of diffusion of Oxygen per unit surface area of the particle.

3. If d is the diffusion coefficient and t is the boundary layer thickness. Then the mass transfer coefficient k is given by?

a) k = d x t

b) k = d / t

c) k = d + t

d) k = d – t

Answer: b

Explanation: If d is the diffusion coefficient and t is the boundary layer thickness. Then the mass transfer coefficient k is given by,

k = d / t.

4. Gobar gas is produced by the __________ of ‘gobar’ .

a) Fermentation

b) Condensation

c) Combustion

d) Distillation

Answer: a

Explanation: Fermentation is the process which converts cow’s dung into ‘Gobar Gas’.

5. Coking time in beehive coke oven is about __________

a) one week

b) 12 hours

c) 2-3 days

d) 2 weeks

Answer: c

Explanation: The total time of coking in a beehive oven is about 2-3 days.

6. __________ present in coal is not determined in its ultimate analysis.

a) Fixed Carbon

b) Total Carbon

c) Nitrogen

d) Hydrogen

Answer: a

Explanation: Fixed Carbon present in coal is not determined in its ultimate analysis. It is determined by Proximate analysis of Coal.

7. The maximum adiabatic flame temperature is attained when the fuel is burnt with __________

a) theoretically required amount of air

b) less than theoretically required amount of air

c) more than theoretically required amount of air

d) theoretically required amount of oxygen

Answer: d

Explanation: The maximum adiabatic flame temperature is attained when the fuel is burnt with theoretically required amount of Oxygen.

8. Height of coke oven is limited mainly by the __________

a) problem of uniform heating along its height.

b) structural strength of silica bricks

c) problem in door cleaning

d) buckling of ram of pusher car at the time of coke pushing

Answer: a

Explanation: Height of coke oven is limited mainly by the problem of Uniform heating as the heat is distributed along the height.

9. Which of the following has the highest calorific value?

a) Sub-bituminous

b) Anthracite

c) Lignite

d) Peat

Answer: b

Explanation: Among the given varieties of coal, the highest calorific value is possessed by the one which has the maximum carbon content. Here, Anthracite has the maximum Calorific Value.

This set of Power Plant online quiz focuses on “Kinetic and Diffusion Control – II”.

1. Higher fuel combustion efficiency cannot be achieved by __________

a) preheating of fuel gases & combustion air

b) supplying correct amount of combustion air

c) reducing sulphur content in the fuel

d) adopting proper fuel firing technique & fuel preparation

Answer: c

Explanation: Higher fuel combustion efficiency cannot be achieved by reducing the sulphur content in the fuel as sulphur content has nothing much to do with the combustion efficiency.

2. Particular coal is said to be free burning when it __________

a) gives smokeless burning

b) shows little or no fusing action

c) burns completely

d) none of the mentioned

Answer: b

Explanation: When a coal shows little or no fusing action, it is said to be free burning.

3. Bunsen burner is an example of a/an __________ burner.

a) inside mixing/premix type

b) submerged combustion

c) rotary cup

d) outside mixing/diffusion flame/nozzle mix type

Answer: a

Explanation: Bunsen burner is an example of a/an inside mixing/premix type burner.

4. The cooling medium used in dry quenching of coke is __________

a) nitrogen

b) air

c) phenolic water

d) carbon dioxide

Answer: a

Explanation: The cooling medium used in dry quenching of coke is nitrogen.

5. High amount of sulphur and phosphorous in coke causes __________

a) increase in its strength

b) decrease in its calorific value

c) brittleness of steel made by using it

d) none of the mentioned

Answer: c

Explanation: Steel is made brittle by the presence of high amount of sulphur and phosphorus in coke.

6. Cannel coal and boghead coal are the examples of __________

a) liptobiolites

b) humic coals

c) sapropelic coals

d) none of the mentioned

Answer: c

Explanation: Cannel coal and boghead coal are the examples of Sapropelic Coals. Sapropelic Coals are rich in microscopic organic matter derived from waxy or resinous plant parts and have high yields of volatile matter.

7. The difference between total carbon and fixed carbon of coal will be minimum in case of __________

a) anthracite

b) lignite

c) bituminous

d) high temperature coke

Answer: d

Explanation: The difference between total carbon and fixed carbon of coal will be minimum in case of high temperature coke. The high temperature coke has low volatile matter that is the erason for the same.

8. Out of the following fuels, the difference between the net and gross calorific value is maximum in case of __________

a) fuel oil

b) blast furnace gas

c) bituminous coal

d) pitch

Answer: a

Explanation: The difference between the net and gross calorific value is maximum in case of

Fuel Oil.

9. Which of the following is the maximum coal producing state in India?

a) Orissa

b) West Bengal

c) Jharkhand

d) Assam

Answer: c

Explanation: Jamshedpur has the highest production of coal in India.

10. A good quality coal should have __________

a) low fusion point of ash

b) high sulphur

c) high ash content

d) none of the mentioned

Answer: d

Explanation: A good quality coal should have high concentration of carbon, low moisture content, etc.

11. __________ prohibits the use of alcohols directly in petrol engines.

a) High cost & difficult availability

b) Low octane number

c) Low flash point

d) Low calorific value

Answer: a

Explanation: High cost & difficult availability prohibits the use of alcohols directly in petrol engines.

12. The hottest part of the flame lies in its ___________ zone.

a) non-luminous

b) luminous

c) yellow

d) unburnt gases

Answer: a

Explanation: The hottest part of the flame lies in its non-luminous zone.

13. Percentage of methane in coke oven gas may be around __________

a) 5

b) 15

c) 25

d) 35

Answer: c

Explanation: Percentage of methane in coke oven gas may be around 25%.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Coal Firing Systems – I”.

1. __________ of the coal is the basis for Seylor’s coal classification.

a) Proximate analysis

b) Calorific value

c) Ultimate analysis

d) Caking index

Answer: c

Explanation: Ultimate Analysis of the coal is the basis for Seylor’s coal classification.

2. Yield of pitch from distillation of high temperature tar is around __________ percent.

a) 10

b) 25

c) 65

d) 100

Answer: c

Explanation: Yield of pitch from distillation of high temperature tar is around 65 percent.

3. Caking index of the coal blend used for the manufacture of metallurgical coke should be around __________

a) 5

b) 40

c) 21

d) 48

Answer: c

Explanation: Caking index is the ability of coal to be formed into cakes. Caking index of the coal blend used for the manufacture of metallurgical coke should be around 21.

4. High excess air in combustion of fuels results in __________

a) smoky flame

b) increased fuel consumption

c) incomplete combustion

d) none of the mentioned

Answer: b

Explanation: High excess air in combustion of fuels results in increased fuel consumption. More the quantity of air in the fuel, more lean a mixture becomes.

5. The heat of combustion of a fuel __________

a) is equal to the heat of formation

b) is always negative

c) can’t be known without calculating it

d) is always positive

Answer: b

Explanation: The heat of combustion of a fuel is always negative as always some heat has to be given to the fuel for burning it.

6. _________ has the widest inflammability limit of all the gases.

a) Carbon monoxide

b) Methane

c) Hydrogen

d) Acetylene

Answer: d

Explanation: Acetylene has the widest inflammability limit of all the gases. That is another factor due to which the gas is used in Gas welding.

7. What are the main constituents of benzol?

a) benzene, toluene & xylene

b) tar & creosote

c) ammonia & phenol

d) anthracene & phenol

Answer: a

Explanation: Benzol comprises of benzene, toluene and xylene.

8. With increase in moisture content of coal, its __________

a) calorific value increases sometimes

b) bulk density always decreases

c) clinkering tendency during combustion increases

d) none of the mentioned

Answer: d

Explanation: None of the mentioned factors behave in the manner when the moisture content increases.

9. Oxygen percentage in atmospheric air is?

a) 22

b) 20

c) 19

d) 21

Answer: d

Explanation: 21 % of the atmospheric air is Oxygen.

10. In flue gas analysis by Orsat’s apparatus, carbon dioxide is absorbed by __________

a) cuporus chloride

b) dilute potassium carbonate

c) potassium hydroxide

d) alkaline pyragllol solution

Answer: c

Explanation: In flue gas analysis by Orsat’s apparatus, carbon dioxide is absorbed by potassium hydroxide.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Coal Firing Systems – II”.

1. Presence of free moisture in coal is most disadvantageous during __________

a) combustion of fire slacks on the grates

b) its pulverisation

c) handling

d) none of the mentioned

Answer: b

Explanation: As pulverisation of coal is a power consuming process, the presence of free moisture in coal is most disadvantageous.

2. Abrasion index of blast furnace coke should be around __________ percent.

a) 20

b) 35

c) 80

d) 55

Answer: c

Explanation: Abrasion index of blast furnace coke should be around 80 percent. More this abrasion index, which is an indicator of Abrasion; more is the combustibility.

3. Which of the following petrographic constituents of coal is non-coking?

a) Durain

b) Vitrain

c) Clarain

d) Fussain

Answer: d

Explanation: Among the mentioned petrographic constituents, Fussain is non-coking.

4. ‘Fat’ coal means a coal having __________

a) low ash content

b) non-smoking tendency

c) high volatile matter

d) low calorific value

Answer: c

Explanation: ‘Fat’ coal means a coal having high volatile matter.

5. Initial pressure of oxygen introduced into the ‘bomb’ of the bomb calorimeter for determination of calorific value of coal/fuel oil may be around __________ atm.

a) 20-30

b) 60-65

c) 95-100

d) 3-5

Answer: a

Explanation: Initial pressure of oxygen introduced into the ‘bomb’ of the bomb calorimeter for determination of calorific value of coal/fuel oil may be around 20-30 atm.

6. Proximate analysis of coal determines its __________ content.

a) moisture, ash, sulphur & volatile matter

b) moisture, volatile matter, ash & fixed carbon

c) moisture, sulphur, nitrogen & fixed carbon

d) none of the mentioned

Answer: b

Explanation: Proximate analysis of coal determines its moisture, volatile matter, ash & fixed carbon content.

7. If the specific heat of gaseous products of combustion of a fuel is high, the abiabatic flame temperature will be?

a) very high, if the fuel is of low calorific value

b) low

c) high

d) none of the mentioned

Answer: b

Explanation: If the specific heat of gaseous products of combustion of a fuel is high, the abiabatic flame temperature will below.

8. “Overfire burning” in a furnace is a phenomenon characterised by the __________

a) burning of carbon monoxide and other incombustibles in upper zone of furnace by supplying more air

b) supply of excess fuel

c) supply of excess air

d) none of the mentioned

Answer: a

Explanation: “Overfire burning” in a furnace is a phenomenon characterised by the burning of carbon monoxide and other incombustibles in upper zone of furnace by supplying more air.

9. Atomising steam to fuel oil ratio in a burner should be around __________

a) 0.5

b) 1.5

c) 2.5

d) 3.5

Answer: a

Explanation: A low atomising fuel oil ratio is favourable enough to ensure good combustion.

10. Presence of free moisture in coal during its high temperature carbonisation __________

a) increases the loss of fine coal dust from the ovens when charging

b) protects the volatile products from pyrolysis in the presence of hot coke and hot oven walls

c) reduces the coking time

d) none of the mentioned

Answer: b

Explanation: The presence of free moisture in coal during its high temperature carbonisation protects the volatile products from pyrolysis in the presence of hot coke and hot oven walls.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Energy Analysis of Combined Cycles and Choice of a Gas Turbine”.

1. The maximum work attainable as the system comes in equilibrium with surrounding is called?

a) Energy

b) Availability

c) Exergy

d) Entropy

Answer: c

Explanation: Exergy is defined as, “The maximum work attainable as the system comes in equilibrium with surrounding”.

2. More the exergy ___________ is the work obtained from the system.

a) more

b) less

c) equal

d) very less

Answer: a

Explanation: Exergy is defined as, “The maximum work attainable as the system comes in equilibrium with surrounding”. Naturally, more the exergy, more is the work obtained from the system.

3. Which of these is a measure of energy quality?

a) Entropy

b) Enthalpy

c) Exergy

d) none of the mentioned

Answer: c

Explanation: Exergy is also a measure of the quality of energy apart from the work obtained from the system.

4. Exergic __________ is a measure of the perfectness of a thermal system.

a) enthalpy

b) efficiency

c) strength

d) degree

Answer: b

Explanation: Exergy is also a measure of the quality of energy apart from the work obtained from the system. For this, exergic efficiency is a measure of the perfectness of a thermal system.

5. The values of dry solid fuel ratio are highest in?

a) Coke

b) Coal

c) Wood

d) Natural Gas

Answer: c

Explanation: The values of the ratio are 1.05 for coke, 1.05-1.10 for coal, 1.15-1.30 for wood & 1.04 for Natural Gas.

6. Choice of a gas turbine depends most on which of these factors?

a) Compression ratio

b) Cut-off ratio

c) Pressure ratio

d) none of the mentioned

Answer: c

Explanation: The working a Brayton cycle can be estimated most effectively by pressure ratio, so it becomes the most important factor.

7. Gas turbines with intercooling, regeneration & reheat are more suitable for combined cycles.

a) True

b) False

Answer: b

Explanation: Increasing the stages in a gas turbine with combined cycles will decrease its efficiency.

8. What is the optimum pressure ratio range for a gas turbine to obtain optimum efficiency?

a) 7-8.5

b) 10.5-12

c) 9.5-10

d) 10-20

Answer: b

Explanation: The optimum pressure ratio range for a gas turbine to obtain optimum efficiency is 10.5-12.

9. What is that temperature called to which the exhaust gases of a gas turbine are cooled?

a) Oxygen Dewpoint

b) Carbon dioxide Dewpoint

c) Nitrogen Dewpoint

d) Sulphuric Acid Dewpoint

Answer: d

Explanation: As the maximum temperature of cooling that can be reached has to be the dewpoint of one of these gases, so the dewpoint of Sulphuric Acid [Sulphur dioxide discharge] is chosen.

10. With an increase in the combined cycle pressure ratio, the efficiency of the bottoming cycle?

a) increases

b) decreases

c) remains same

d) none of the mentioned

Answer: b

Explanation: The efficiency of the bottoming cycle is inversely proportional to the combined cycle pressure ratio, so this relation.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Thermodynamics of Brayton-Rankine Combined Plant – I”.

1. If p and q are the efficiencies of a Brayton & Rankine cycles respectively in a Brayton-Rankine combined plant, the efficiency n of a combined plant is?

a) n = p/q

b) n = p+q-pq

c) n = pq

d) n =

Answer: b

Explanation: The efficiency of a Brayton-Rankine combined plant when p and q are the efficiencies of a Brayton & Rankine cycles respectively is given as,

n = p + q – pq.

2. Which of these is a working fluid in the topping plant of a Brayton-Rankine combined plant?

a) Hydrogen

b) Helium

c) Nitrogen

d) All of the mentioned

Answer: b

Explanation: The low molecular mass of Helium makes it the most suitable working fluid in the topping plant.

3. Which of these is a working fluid in the bottoming plant of a Brayton-Rankine combined plant?

a) Mercury

b) Steam

c) Water

d) Air

Answer: c

Explanation: Water is the bottoming fluid due to its high specific heat capacity.

4. What would be the temperature of the gas in the combustion chamber?

a) 500 °C

b) 1600 °C

c) 1200 °C

d) 650 °C

Answer: b

Explanation: The gas in the combustion chamber is at a temperature of 1600 °C.

5. The efficiency of the open cycle gas plant is quite low. Why?

a) Gas gets cooled before reaching the turbine wheels

b) A lot of mechanical energy is used up by the compressor

c) Due to the presence of regenerator and absence of air pre heater

d) Both Gas gets cooled before reaching the turbine wheels and a lot of mechanical energy is used up by the compressor

Answer: d

Explanation: The efficiency of the open cycle gas plant is quite low. This is because of mainly two reasons,

Gas gets cooled before reaching the turbine wheels and a lot of mechanical energy is used up by the turbine wheels.

6. To improve the efficiency of the gas turbines, which among these are used?

a) Regenerator

b) Inter cooling

c) Reheating

d) All of the mentioned

Answer: d

Explanation: All of the methods- Reheating, Regeneration and Intercooling are used to improve the efficiency of gas turbines.

7. What is regeneration?

a) Removal of heat from compressed air between stages of compression

b) Transfer of heat energy from exhaust gases to the compressed air flowing between compressor and the combustion chamber

c) To increase the temperature of partially expanded gases by burning more fuel

d) Transfer of heat energy from exhaust gases to the compressed air flowing between compressor and the combustion chamber and increases the temperature of partially expanded gases by burning more fuel

Answer: b

Explanation: Transfer of heat energy from exhaust gases to the compressed air flowing between compressor and the combustion chamber is called the process of Regeneration.

8. What is meant by inter cooling?

a) Removal of heat from compressed air between stages of compression

b) Transfer of heat energy from exhaust gases to the compressed air flowing between compressor and the combustion chamber

c) To increase the temperature of partially expanded gases by burning more fuel

d) None of the mentioned

Answer: a

Explanation: Removal of heat from compressed air between various stages of compression is called Inter cooling.

9. Which material is used for the manufacture of the turbine blades?

a) Stainless steel

b) Carbon steel

c) High nickel alloy

d) High alloy steel

Answer: c

Explanation: High nickel alloy is the most sufficient material for the manufacture of Turbine Blades.

This set of Power Plant Question Bank focuses on “Thermodynamics of Brayton-Rankine Combined Plant – II”.

1. In the Brayton Rankine combined plant in series, the efficiency of the bottoming plant is?

a) a product of two efficiencies

b) a sum of two efficiencies

c) difference of two efficiencies

d) none of the mentioned

Answer: a

Explanation: In the Brayton Rankine combined plant in series, the efficiency of the bottoming plant is,

(n o ) = n b x n 2 .

2. What does HRSG stand for?

a) Heat Recovery Stem Generator

b) Heat Recovery Steam Generator

c) Heat Recuperating Steam Generator

d) Heat Regenerative Steam Generator

Answer: b

Explanation: HRSG stands for,

Heat Recovery Steam Generator.

3. Fuel is burnt partially in the Combustion Chamber & partially in the __________

a) HRCG

b) HRSC

c) HRSG

d) Compressor

Answer: c

Explanation: Fuel is burnt partially in the Combustion Chamber & partially in the Heat Recovery Steam Generator.

4. Supplementary firing in a Brayton-Rankine combined cycle is?

a) Good

b) Less effective

c) Very effective

d) None of the mentioned

Answer: b

Explanation: Supplementary firing in a Brayton-Rankine combined cycle is less effective as there is no appreciable increase in overall efficiency due to this combined cycle.

5. What is the effect of Supplementary Firing on exhaust gas temperature?

a) exhaust gas temperature increases

b) exhaust gas temperature decreases

c) exhaust gas temperature remains steady

d) none of the mentioned

Answer: a

Explanation: the effect of Supplementary Firing on exhaust gas temperature is that the exhaust gas temperature increases from 800 Degree Celsius – 900 Degree Celsius.

6. Maximum supplementary firing refers to __________

a) The maximum fuel that can be fired with the oxygen available in the gas turbine inlet

b) The maximum fuel that can be fired with the oxygen available in the gas turbine exhaust

c) The maximum fuel that cannot be fired with the oxygen available in the gas turbine inlet

d) None of the mentioned

Answer: b

Explanation: Maximum supplementary firing refers to the maximum fuel that can be fired with the oxygen available in the gas turbine exhaust.

7. It is advantageous to use a Combustion chamber plant with maximum supplementary firing than Combustion Chamber installations.

a) True

b) False

Answer: b

Explanation: As maximum supplementary firing is of no use when it comes to Combustion chamber installations hence, the above statement is false.

8. Which among these plants are most efficient?

a) Open cycle

b) Combined cycle

c) Closed cycle

d) Either Open or Closed cycle

Answer: b

Explanation: Combined cycle plants have most efficiency as the include two independent cycles working in relation to each other.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Advantages of Combined Cycle Power Generation”.

1. The overall plant efficiencies in case of a combined cycle power generation is?

a) Low

b) High

c) Very low

d) Very high

Answer: b

Explanation: It is practically possible to attain efficiencies near to 50% in case of a combined cycle power generation.

2. The investment cost related to the combined power generation is?

a) high

b) low

c) very high

d) none of the mentioned

Answer: b

Explanation: The investment cost related to the combined power generation is. This is because only 2/3 of the total output is produced in the gas turbine.

3. What % is the investment cost in Conventional steam power plant more than those in the combined cycle plants?

a) 10

b) 20

c) 30

d) 40

Answer: c

Explanation: The investment cost in Conventional steam power plant is 30% more than those in the combined cycle plants.

4. The amount of water required as coolant for a combined cycle plant is?

a) very high

b) less

c) medium

d) none of the mentioned

Answer: b

Explanation: The amount of cooling water required is only 40-50% of the steam power plant requirement.

5. Combined cycle plants have _____________ operation flexibility.

a) high

b) low

c) equal

d) very low

Answer: a

Explanation: The ease of operation, i.e, the ease with which the plant can be started and stopped is the operation flexibility.

6. Installations in stages is possible in Combined Cycle Plants.

a) true

b) false

Answer: a

Explanation: Because the gas turbines go into operation much sooner than the steam plants, installations in stages is possible in Combined Cycle plants.

7. Which of these has the most simple operation?

a) combined cycle plant

b) steam plant

c) combined cycle & steam plant

d) none of the mentioned

Answer: a

Explanation: Combined cycle plant is more flexible than the steam plant and so it has the simplest operation.

8. Combustion in a Combined cycle plant has ______ environmental impact.

a) serious

b) little/no

c) toxic

d) none of the mentioned

Answer: b

Explanation: As most of the processes of a combined cycle plant are degradable, so combustion in a combined cycle plant has no impact on the environment.

9. Cogeneration of heat & electricity is possible in a Combined cycle plants.

a) True

b) False

Answer: a

Explanation: One of the major advantages of a combined cycle plants is the cogeneration of heat & electricity.

10. Efficiency of Natural gas fired Combined cycle plants is more than that of coal-fired plants.

a) true

b) false

Answer: a

Explanation: As the efficiency of a combined cycle plant is high in comparison to that of steam power plant, naturally, the statement mentioned becomes true.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Steam Turbines Basics – I”.

1. A steam turbine converts the output from a steam generator into ____________

a) Shaft work

b) Turbine work

c) Mechanical work

d) None of the mentioned

Answer: a

Explanation: A steam turbine is a device that converts the energy of high-pressure, high-temperature steam supplied by a steam generator into shaft work.

2. The energy conversion occurring in a steam turbine is a ______ step process.

a) 1

b) 2

c) 3

d) 4

Answer: b

Explanation: The high pressure steam first expands in a nozzle, gains velocity & then loses this velocity when it impinges on the blades.

3. A steam turbine is basically an assemblage of ____________

a) nozzle & condenser

b) blades & condenser

c) nozzle & blades

d) nozzle & fans

Answer: c

Explanation: A steam turbine is a device that converts the energy of high-pressure, high-temperature steam supplied by a steam generator into shaft work. The high pressure steam first expands in a nozzle, gains velocity & then loses this velocity when it impinges on the blades.

4. Depending on whether the back pressure is below or equal to the atmospheric pressure, how many types of turbines do exist?

a) 1

b) 2

c) 3

d) 4

Answer: b

Explanation: Depending on whether the back pressure is below or equal to the atmospheric pressure, there are two types of turbines that exist- condensing & non-condensing turbines.

5. The overall steam turbine generator arrangement of a power plant is designated as ________ compound on the basis of shaft orientation.

a) tandem

b) cross

c) tandem & cross

d) none of the mentioned

Answer: c

Explanation: The overall steam turbine generator arrangement of a power plant is designated as tandem or cross-compound on the basis of shaft orientation.

6. A ______ is a duct through which velocity of a fluid increases at the expense of pressure.

a) orifice

b) nozzle

c) jet

d) diffuser

Answer: b

Explanation: A nozzle is a duct through which the velocity of a fluid increases at the expense of pressure.

7. A duct which decreases the velocity of fluid & causes a corresponding increase in pressure is called?

a) nozzle

b) diffuser

c) jet

d) orifice

Answer: b

Explanation: A duct which decreases the velocity of fluid & causes a corresponding increase in pressure is called a diffuser.

8. A regenerative steam cycle renders ____________

a) decreased work output per unit mass of steam

b) increased thermal efficiency

c) increased work output per unit mass of steam

d) decreased work output per unit mass of steam as well as increased thermal efficiency

Answer: d

Explanation: The decreased work output per unit mass of steam as well as increased thermal efficiency.

9. The reheat factor is the ratio of the ____________

a) total useful heat drop to the total isentropic heat drop

b) cumulative heat drop to the isentropic heat drop

c) isentropic heat drop to the heat supplied

d) none of the mentioned

Answer: b

Explanation: The ratio of cumulative heat drop to the isentropic heat drop is called the reheat factor.

10. Thermal equilibrium means that the flow of steam is ____________

a) hyperbolic

b) isothermal

c) isentropic

d) polytropic

Answer: c

Explanation: When the steam flow is isentropic it is thermal equilibrium condition.

This set of Power Plant Questions and Answers for Entrance exams focuses on “Steam Turbines Basics – II”.

1. The ratio of the work done on the blades to the energy supplied to the blades is called ____________

a) gross or stage efficiency

b) blading efficiency

c) nozzle efficiency

d) mechanical efficiency

Answer: b

Explanation: Blading Efficiency is the ratio of work done on the blades to the energy supplied to the blades of a turbine.

2. A nozzle is said to be a convergent nozzle when?

a) the cross-section of the nozzle increases continuously from entrance to exit

b) the cross-section of the nozzle decreases continuously from entrance to exit

c) the cross-section of the nozzle first decreases from entrance to throat and then increases from its throat to exit

d) none of the mentioned

Answer: b

Explanation: In case of a convergent nozzle, the cross-section of the nozzle decreases continuously from entrance to exit.

3. Multi-stage steam turbines are of the ___________

a) reaction type

b) velocity compounded type

c) pressure compounded type

d) all of the mentioned

Answer: d

Explanation: There are various types of multi-stage steam turbines which are, reaction; velocity compounded; & pressure compounded, respectively.

4. The impulse reaction turbine has its driving force ___________

a) partly as an impulsive force and partly as a reaction force

b) as an impulsive force

c) as a reaction force

d) none of the mentioned

Answer: a

Explanation: The impulse reaction turbine has its driving force partly as an impulsive force & partly as a reaction force as the components add to the resultant.

5. In a nozzle, whole frictional loss is assumed to occur between ___________

a) inlet and throat

b) throat and exit

c) inlet and outlet

d) none of the mentioned

Answer: b

Explanation: In a nozzle, whole frictional loss is assumed to occur between the throat & exit of the nozzle.

6. The ratio of total useful heat drop to the total isentropic heat drop is called?

a) Rankine efficiency

b) Stage efficiency

c) Internal efficiency

d) None of the mentioned

Answer: c

Explanation: The ratio of total useful heat drop to the total isentropic heat drop is called internal efficiency.

7. What is the action of steam in a steam turbine?

a) neither static nor dynamic

b) dynamic

c) static

d) both dynamic & static

Answer: b

Explanation: Steam action in a steam turbine is Dynamic.

8. The critical pressure gives the velocity of steam at the throat ___________

a) equal to the velocity of sound

b) more than velocity of sound

c) less than the velocity of light

d) none of the mentioned

Answer: a

Explanation: The critical pressure gives the velocity of steam at the throat which is equal to the velocity of sound.

9. The isentropic enthalpy drop in moving blade is two-third of the isentropic enthalpy drop in fixed blades of a turbine. The degree of reaction will be ___________

a) 0.67

b) 0.4

c) 0.5

d) 0.56

Answer: a

Explanation: The required degree of reaction will be 0.67.

10. The flow through a nozzle is regarded as ___________

a) isothermal flow

b) isobaric flow

c) isochoric flow

d) isentropic flow

Answer: d

Explanation: The flow through a nozzle is regarded as isentropic flow.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Turbine Efficiency and Flow Through Nozzles – I”.

1. The steam leaves the nozzle at a ____________

a) low pressure and a high velocity

b) high pressure and a high velocity

c) high pressure and a low velocity

d) low pressure and a low velocity

Answer: a

Explanation: The steam leaves the nozzle at low pressure & a high velocity as the action of steam is best suited for turbine operations under these conditions.

2. When the back pressure of a nozzle is below the designed value of pressure at exit of nozzle, the nozzle is said to be ____________

a) overdamping

b) underdamping

c) chocked

d) none of the mentioned

Answer: b

Explanation: When the back pressure of a nozzle is below the designed value of pressure at exit of nozzle, the nozzle is said to be underdamping.

3. De-Laval turbine is a ____________

a) multi rotor impulse turbine

b) impulse reaction turbine

c) single rotor impulse turbine

d) none of the mentioned

Answer: c

Explanation: A De-Laval turbine is a single rotor impulse turbine.

4. The supersaturated flow of steam through a nozzle as compared to a stable flow, the available heat drop ____________

a) increases

b) decreases

c) is unpredictable

d) remains same

Answer: b

Explanation: The supersaturated flow of steam through a nozzle as compared to a stable flow, the available heat drop decreases.

5. A turbine is said to have an axial discharge when the steam leaves the blade tip at __________ to the direction of the blade motion.

a) 90°

b) 60°

c) 270°

d) 180°

Answer: b

Explanation: A turbine is said to have an axial discharge when the steam leaves the blade tip at 60°

to the direction of the blade motion.

6. The Parsons’ reaction turbine has ____________

a) only moving blades

b) only fixed blades

c) fixed and moving blades of different shape

d) identical fixed and moving blades

Answer: d

Explanation: The Parsons’ reaction turbine has identical fixed & moving blades.

7. What is the critical pressure ratio for initially wet steam?

a) 0.582

b) 0.546

c) 0.577

d) 0.601

Answer: a

Explanation: The critical pressure ratio for initially wet steam is 0.582.

8. The ratio of the useful heat drop to the isentropic heat drop is called ____________

a) condenser efficiency

b) nozzle efficiency

c) vacuum efficiency

d) boiler efficiency

Answer: b

Explanation: The ratio of the useful heat drop to the isentropic heat drop is called nozzle efficiency.

9. Rateau turbine is ____________

a) pressure-velocity compounded turbine

b) simple reaction turbine

c) velocity compounded turbine

d) pressure compounded turbine

Answer: d

Explanation: A Rateau turbine is a pressure compounded turbine.

10. When the cross-section of a nozzle increases continuously from entrance to exit, it is called a ____________

a) convergent-divergent nozzle

b) divergent nozzle

c) convergent nozzle

d) none of the mentioned

Answer: b

Explanation: When the cross-section of a nozzle increases continuously from entrance to exit, it is called a divergent nozzle.

This set of Power Plant Questions and Answers for Campus interviews focuses on “Turbine Efficiency and Flow Through Nozzles – II”.

1. The value of the reheat factor varies from ____________

a) 1.08 to 1.10

b) 1.2 to 1.6

c) 1.6 to 2

d) 1.02 to 1.06

Answer: d

Explanation: The value of the reheat factor varies from 1.02 to 1.06.

2. The difference in supersaturated temperature and saturation temperature at that pressure is called ____________

a) degree of super saturation

b) degree of superheat

c) degree of undercooling

d) none of the mentioned

Answer: c

Explanation: The difference of supersaturated temperature and saturation temperature at that pressure is called degree of undercooling.

3. Parson’s turbine is a ____________

a) simple impulse turbine

b) impulse-reaction turbine

c) simple reaction turbine

d) none of the mentioned

Answer: c

Explanation: Parson’s turbine is a simple reaction turbine.

4. In reaction turbines, the axial thrust is due to ____________

a) pressure drop across the rotor

b) change in axial velocity

c) both pressure drop across the rotor and change in axial velocity

d) none of the mentioned

Answer: c

Explanation: In reaction turbines, the axial thrust is due to the pressure drop across the rotor & change in axial velocity.

5. The flow of steam is super-sonic ____________

a) in the convergent portion of the nozzle

b) at the entrance to the nozzle

c) at the throat of the nozzle

d) in the divergent portion of the nozzle

Answer: d

Explanation: The flow of steam is super-sonic in the divergent portion of the nozzle.

6. The variation of steam pressure in the nozzle depends upon ____________

a) dryness fraction of steam

b) specific volume of steam

c) velocity of steam

d) all of the mentioned

Answer: d

Explanation: The variation of steam pressure in the nozzle depends upon dryness fraction of steam, specifically volume of steam & velocity of steam.

7. A binary vapour plant consists of ____________

a) mercury boiler

b) steam turbine

c) steam condenser

d) all of the mentioned

Answer: d

Explanation: A binary vapour plant consists of mercury boiler, steam turbine, steam condenser, etc.

8. The steam enters the nozzle at a ____________

a) low pressure and a low velocity

b) high pressure and a low velocity

c) low pressure and a high velocity

d) high pressure and a high velocity

Answer: d

Explanation: The steam enters the nozzle at a high pressure & a high velocity to force the maximum volume into the nozzle.

9. In a reaction turbine, when steam flows through the fixed blades ____________

a) pressure decreases while velocity increases

b) pressure increases while velocity decreases

c) pressure and velocity both increases

d) pressure and velocity both decreases

Answer: a

Explanation: In a reaction turbine, when steam flows through the fixed blades, the pressure decreases while velocity increases.

10. The impulse turbine rotor efficiency will have a maximum value of 0.5 cos2 α, where α is the nozzle exit flow angle, if the ____________

a) blades are equiangular

b) blade velocity coefficient is unity

c) blade solidity is 0.65

d) blades are equiangular and frictionless

Answer: d

Explanation: The impulse turbine rotor efficiency will have a maximum value of 0.5 cos2 α, where α is the nozzle exit flow angle, if the blades are equiangular & frictionless.

11. Steam turbines are used for ____________

a) electric power generation

b) large marine propulsion

c) direct drive of fans, compressors, pumps

d) all of the mentioned

Answer: d

Explanation: Steam turbines are used for various applications which include, electric power generation, large marine propulsion, direct drive of fans, compressors, pumps, etc.

12. Curtis turbine is a ____________

a) pressure compounded turbine

b) velocity compounded turbine

c) simple reaction turbine

d) pressure-velocity compounded turbine

Answer: d

Explanation: A type of the pressure-velocity compounded turbine is a Curtis Turbine.

13. Which of the following statement is correct?

a) The expansion of steam in a nozzle follows Rankine cycle

b) The friction in the nozzle increases the dryness fraction of steam

c) The pressure of steam at throat is called critical pressure

d) All of the mentioned

Answer: d

Explanation: All the mentioned statements are correct.

14. Parson’s reaction turbine is a __________ reaction turbine.

a) 40%

b) 50%

c) 60%

d) 70%

Answer: b

Explanation: Parson’s reaction turbine is a 50% reaction turbine.

15. The diagram efficiency is the ratio of ____________

a) work done on the blades to the energy supplied to the blades

b) energy supplied to the blades per kg of steam to the total energy supplied per stage per kg of steam

c) work done on the blades per kg of steam to the total energy supplied per stage per kg of steam

d) none of the mentioned

Answer: a

Explanation: The diagram efficiency is the ratio of work done on the blades to the energy supplied to the blades.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Turbine and Nozzles Types”.

1. What is the purpose of governing in steam turbines?

a) reheat the steam and improve its quality

b) maintain the speed of the turbine

c) reduce the effective heat drop

d) completely balance against end thrust

Answer: b

Explanation: The purpose of governing in steam turbines is to maintain the speed of the turbine.

2. The ratio of the work done on the blades per kg of steam to the total energy supplied per stage per kg of steam is called?

a) nozzle efficiency

b) stage efficiency

c) mechanical efficiency

d) blading efficiency

Answer: b

Explanation: The ratio of the work done on the blades per kg of steam to the total energy supplied per stage per kg of steam is called Stage Efficiency.

3. A nozzle is said to be a divergent nozzle ____________

a) when the cross-section of the nozzle increases continuously from entrance to exit

b) when the cross-section of the nozzle decreases continuously from entrance to exit

c) when the cross-section of the nozzle first decreases from entrance to throat and then increases from its throat to exit

d) none of the mentioned

Answer: a

Explanation: A nozzle is said to be a divergent nozzle when the cross-section of the nozzle increases continuously from entrance to exit.

4. The ratio of the isentropic heat drop to the heat supplied is called ____________

a) stage efficiency

b) reheat factor

c) internal efficiency

d) rankine efficiency

Answer: d

Explanation: The ratio of the isentropic heat drop to the heat supplied is called Rankine efficiency.

5. The reheat factor depends upon ____________

a) exit pressure

b) turbine stage efficiency

c) initial pressure and superheat

d) all of the mentioned

Answer: d

Explanation: The factors on which the reheat factor depends are exit pressure, turbine stage efficiency, initial pressure & superheat.

6. What is the critical pressure ratio for initially dry saturated steam?

a) 0.546

b) 0.577

c) 0.586

d) 0.578

Answer: b

Explanation: The critical pressure ratio for initially dry saturated steam is 0.577.

7. In order to reduce the rotor speed of an impulse turbine, the method employed is ____________

a) pressure compounding

b) velocity compounding

c) pressure-velocity compounding

d) all of the mentioned

Answer: d

Explanation: In order to reduce the rotor speed of an impulse turbine, the methods employed are

Pressure compounding, Velocity compounding, Pressure-Velocity compounding, etc.

8. Which of the following statement is wrong?

a) The flowing the convergent portion of the nozzle is sub-sonic

b) The critical pressure gives the velocity of steam at the throat equal to the velocity of sound

c) The flow in the divergent portion of the nozzle is super-sonic

d) To increase the velocity of steam above sonic velocity by expanding steam below the critical pressure, the divergent portion for the nozzle is not necessary

Answer: d

Explanation: In order to increase the velocity of steam above sonic velocity by expanding steam below the critical pressure, the divergent portion for the nozzle is necessary.

9. In an impulse turbine, steam expands ____________

a) wholly in nozzle

b) partly in the nozzle and partly in blades

c) wholly in blades

d) none of the mentioned

Answer: a

Explanation: In an impulse turbine, steam expands wholly in nozzle.

10. A steam nozzle converts ____________

a) heat energy of steam into potential energy

b) potential energy into heat energy of steam

c) heat energy of steam into kinetic energy

d) kinetic energy into heat energy of steam

Answer: c

Explanation: A steam nozzle converts heat energy of steam into kinetic energy.

11. The process of draining steam from the turbine, at certain points during its expansion and using this steam for heating the feed water in feed water heaters and then supplying it to the boiler is known as?

a) regenerative heating

b) reheating of steam

c) bleeding

d) none of the mentioned

Answer: c

Explanation: The process of draining steam from the turbine, at certain points during its expansion and using this steam for heating the feed water in feed water heaters and then supplying it to the boiler is known as Bleeding.

12. If the critical pressure ratio for steam is 0.546, then the steam is initially ____________

a) wet

b) dry saturated

c) superheated

d) none of the mentioned

Answer: c

Explanation: Generally, when the critical pressure ratio for steam is 0.546, then the steam is said to be superheated.

13. A steam turbine, in which a part of the steam after partial expansion, is used for process heating and the remaining steam is further expanded for power generation, is known as?

a) pass out turbine

b) impulse turbine

c) low pressure turbine

d) high pressure turbine

Answer: a

Explanation: A steam turbine, in which a part of the steam after partial expansion, is used for process heating and the remaining steam is further expanded for power generation, is known as Pass out Turbine.

14. A stage, in reaction turbine, is represented by ____________

a) each row of blades

b) number of entries of steam

c) number of exits of steam

d) none of the mentioned

Answer: a

Explanation: Each row of blades represents each stage in a reaction turbine.

15. Which of the following statement is correct?

a) The pressure of steam, in reaction turbines, is increased in fixed blades as well as in moving blades

b) The efficiency of steam turbine is greater than the steam engines

c) A flywheel is a must for steam turbine

d) The turbine blades do not change the direction of steam issuing from the nozzle

Answer: b

Explanation: The efficiency of steam turbines is greater than that of a steam engine.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Turbine Blading – I”.

1. In turbines, the fluid undergoes a continuous steady flow process and the speed of flow is ____________

a) very high

b) high

c) low

d) very low

Answer: a

Explanation: In turbines, the fluid undergoes a continuous steady flow process and the speed of flow is very high.

2. Steam turbines may be classified according to ____________

a) number of stages

b) direction of steam flow

c) mode of steam action

d) all of the mentioned

Answer: d

Explanation: The steam turbines are classed under various types based on number of stages, direction of steam flow, mode of steam action, etc.

3. A steam nozzle converts ____________

a) heat energy of steam into kinetic energy

b) kinetic energy of steam into heat energy

c) potential energy into heat energy

d) none of the mentioned

Answer: a

Explanation: A steam nozzle converts heat energy of steam into kinetic energy.

4. In a velocity compounded impulse turbine, when steam flows through the second row of moving blades ____________

a) velocity decreases

b) velocity increases

c) pressure decreases

d) pressure increases

Answer: a

Explanation: In a velocity compounded impulse turbine, when steam flows through the second row of moving blades, the velocity decreases.

5. In a reaction turbine when the degree of reaction is zero, then there is ____________

a) no heat drop in moving blades

b) maximum heat drop in fixed blades

c) no heat drop in fixed blades

d) maximum heat drop in moving blades

Answer: a

Explanation: In a reaction turbine when the degree of reaction is zero, then there isn’t any heat drop in moving blades.

6. The process of draining steam from the turbine, at certain points during its expansion and using this steam for heating the feed water in feed water heaters and then supplying it to the boiler is known as?

a) regenerative heating

b) reheating of steam

c) bleeding

d) none of the mentioned

Answer: c

7. Turbo alternators run at speeds ____________

a) constant speed of 3000 rpm

b) constant speed of 1000 rpm

c) variable speed of 1000 rpm

d) none of the mentioned

Answer: c

Explanation: The turbo alternators run at speeds varying in 1000 rpm.

8. In an impulse reaction turbine, the pressure drops gradually and continuously over ____________

a) moving blades

b) fixed blades

c) both moving & fixed blades

d) none of the mentioned

Answer: c

Explanation: The pressure drops gradually & continuously over both moving & fixed blades in an impulse turbine.

9. A steam turbine with no nozzle is?

a) Reaction Turbine

b) Impulse Turbine

c) Reaction & Impulse Turbines

d) None of the mentioned

Answer: a

Explanation: Reaction turbine is basically a steam turbine without any nozzle.

10. The pipes carrying steam are made up of?

a) Steel

b) Copper

c) Aluminium

d) Iron

Answer: a

Explanation: The pipes carrying steam in a steam turbine are made up of Steel.

This set of Power Plant Questions and Answers for Aptitude test focuses on “Turbine Blading – II”.

1. Governing principle of steam turbine is?

a) Nozzle control governing

b) Throttle governing

c) Bypass governing

d) All of the mentioned

Answer: d

Explanation: The various principles of Steam turbine governance are Nozzle control governing, bypass governing, throttle governing, etc.

2. Air-Preheater in a steam power plant _____________

a) Recovers the heat from the flue gases leaving the economiser

b) Improves combustion rate

c) Raises the temperature of the furnace gases

d) All of the mentioned

Answer: d

Explanation: Air- preheater in a steam power plant recovers the heat from the flue gases leaving the economiser, improves combustion rate, raises temperature of the furnace gases, etc.

3. What is the definition of the draught system?

a) A device used to pull in air

b) The difference between absolute gas pressure at any point in a gas flow and the ambient atmospheric pressure

c) The sum of the absolute gas pressure at any point in a gas flow and the ambient atmospheric pressure

d) A device used to pull out air

Answer: d

Explanation: The difference between absolute gas pressure at any point in a gas flow and the ambient atmospheric pressure is called Draught.

4. A condenser condenses the steam coming out from?

a) Boiler

b) Turbine

c) Economiser

d) Super heater

Answer: b

Explanation: The condensing action of a condenser begins when the steam comes out from the Turbine.

5. Water used in the steam plant is used for cooling in _______________

a) Condenser

b) Turbine only

c) Boiler tube

d) Boiler tubes and turbines

Answer: a

Explanation: The only condensing process in a steam power plant occurs in the condenser so the water used in the steam plant is used for cooling in Condenser.

6. What is use of the air pumps in the condenser?

a) Remove water

b) Air leaking in the condenser and to maintain the vacuum

c) Maintain atmospheric pressure and the condenser

d) Remove water & Air leaking in the condenser and to maintain the vacuum

Answer: b

Explanation: Air pumps used in the condenser are used to maintain the vacuum by letting air outside.

7. Spray ponds are used to cool the warm water coming from the condenser in ________

a) Large power plants

b) Small power plants

c) Medium power plants

d) Both medium and large power plants

Answer: b

Explanation: Spray ponds are used to cool the warm water coming from the condenser in small power plants.

8. Evaporative type of condenser has ________

a) Water in pipes surrounded by steam outside

b) Steam and cooling water mixed to give the condensate

c) Steam in pipes surrounded by water

d) None of the mentioned

Answer: c

Explanation: Steam in pipes surrounded by water is the evaporative type condenser.

9. Due to friction between the fluid & walls of the nozzle, the expansion process is?

a) reversible

b) irreversible

c) reversible adiabatic

d) irreversible adiabatic

Answer: d

Explanation: The friction between the walls of fluid & walls of the nozzle is irreversible & the entire process remains adiabatic.

10. The ratio of actual mass flow through the nozzle to the mass flow if the flow were isentropic is?

a) Coefficient of viscosity

b) Coefficient of velocity

c) Coefficient of discharge

d) None of the mentioned

Answer: c

Explanation: Coefficient of discharge is defined as the ratio of actual mass flow through the nozzle to the mass flow if the flow were isentropic.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Electricity Generation – I”.

1. Convergent part of the nozzle is usually sharp while the divergent one is?

a) slopy

b) gradual

c) slopy & gradual

d) none of the mentioned

Answer: b

Explanation: The divergent part of the nozzle is gradual in comparison to the convergent part.

2. What is another name of converging nozzle?

a) diverging nozzle

b) subsonic nozzle

c) supersonic nozzle

d) none of the mentioned

Answer: b

Explanation: Another name of converging nozzle is Subsonic Nozzle.

3. Based on the type of applications, the nozzles are divided into?

a) 3 types

b) 4 types

c) 2 types

d) 5 types

Answer: c

Explanation: There are 2 types of nozzles based on their applications, namely Reamed & Foil nozzles.

4. Which of the following is used in high pressure impulses stages of steam turbine?

a) Reamed Nozzles

b) Foil Nozzles

c) Reamed & Foil Nozzles

d) None of the mentioned

Answer: a

Explanation: Reamed nozzle is used in high pressure impulses stages of steam turbine.

5. Angle of divergence in reamed nozzles is?

a) 10 deg

b) 12 deg

c) 14 deg

d) 16 deg

Answer: b

Explanation: The angle of divergence in reamed nozzles is approx. 12 degrees.

6. The nozzle formed by curved airfoil sections is called?

a) Curved nozzle

b) Airfoil Nozzle

c) Foil nozzle

d) Reamed nozzle

Answer: c

Explanation: Foil nozzle is the nozzle formed by curved air foil sections.

7. There are mainly _______ types of turbines.

a) 2

b) 3

c) 4

d) 5

Answer: a

Explanation: There are mainly two types of Turbines- Impulse & Reaction Turbine.

8. Moving blades are placed next to ___________

a) Fixed blades

b) Nozzle

c) Nozzle vanes

d) None of the mentioned

Answer: c

Explanation: Moving blades are positioned next to the nozzle vanes to allow sufficient flow.

9. The incoming steam inside the turbine goes into ___________

a) Steam vanes

b) Steam chest

c) Nozzle vanes

d) Moving blades

Answer: b

Explanation: The incoming steam is housed into the steam chest situated just below the steam inlet.

10. One row of nozzles followed by one row of blades is called?

a) a group of turbine

b) a step of turbine

c) a process of turbine

d) a stage of turbine

Answer: d

Explanation: One row of nozzles followed by one row of blades is called a stage of Turbine.

This set of Power Plant Assessment Questions and Answers focuses on “Electricity Generation – II”.

1. Single stage impulse turbines are also called as?

a) Laval Turbines

b) Lancashire Turbines

c) Cochran Turbines

d) La Del turbines

Answer: a

Explanation: Laval Turbines are single-stage impulse turbines.

2. There are basically ______ Ways of compounding steam turbines.

a) 2

b) 3

c) 4

d) 5

Answer: a

Explanation: There are basically 2 ways of compounding steam turbines namely, Rateau staging & Curtis staging.

3. Rateau staging is another name for?

a) Pressure compounding

b) Velocity compounding

c) Pressure & Velocity compounding

d) None of the mentioned

Answer: a

Explanation: Pressure compounding is also called as Rateau staging.

4. The another name for Velocity compounding is?

a) Rateau Staging

b) Curtis staging

c) Rateau & Curtis staging

d) None of the mentioned

Answer: b

Explanation: The another name for Velocity compounding is Curtis Staging.

5. The Guide vanes remain stationary in?

a) Curtis staging

b) Rateau staging

c) Rateau & Curtis staging

d) None of the mentioned

Answer: a

Explanation: The guide vanes remain stationary in velocity compounding to ensure better operating efficiency.

6. The pressure drop in reaction turbines occurs in?

a) fixed blades

b) movable blades

c) both in nozzles & fixed blades

d) nozzles

Answer: c

Explanation: The pressure drop in reaction turbines occurs in both, the nozzle & in fixed blades.

7. The loss in efficiency from one stage to another is called?

a) Lost efficiency

b) Carry below efficiency

c) Carry-over efficiency

d) None of the mentioned

Answer: c

Explanation: Carry-over efficiency is defined as the loss in efficiency from one stage to another.

8. For straight blades, the minimum blade height is __________ of the mean blade ring diameter.

a) 20%

b) 30%

c) 40%

d) 50%

Answer: a

Explanation: For straight blades, the minimum blade height is 20% of the mean blade ring diameter.

9. Number of parallel exhausts required for a given steam flow rate of x is?

a) x/63.5

b) x/36.5

c) x/68.5

d) x/56.5

Answer: a

Explanation: Number of parallel exhausts required for a given steam flow rate of x is, x/63.5.

10. External loses occur ___________ turbine casing.

a) inside

b) outside

c) inside & outside

d) none of the mentioned

Answer: b

Explanation: External loses are those which occur outside the turbine casing.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Steam generators”.

1. How can we classify steam generators on the basis of application?

a) utility steam generators

b) industrial steam generator

c) marine steam generator

d) all of the mentioned

Answer: d

Explanation: Steam generators can be classified in a number of ways, on the basis of application these three generators are known.

2. What is the critical pressure of steam?

a) 221.2 bar

b) 220 bar

c) 120 bar

d) 300 bar

Answer: a

Explanation: Below 221.2 its sub critical and above 221.2 its super critical.

3. An air preheater is installed _____________

a) between the economiser and chimney

b) before the superheater

c) before the economiser

d) none of the mentioned

Answer: a

Explanation: Preheater is used to increase the temperature of steam.

4. What is the length of shell of a Locomotive boiler?

a) 5m

b) 4m

c) 3m

d) 2m

Answer: b

Explanation: It is fixed due to mechanical constraints.

5. Which of the following statement is correct?

a) A simple vertical boiler has one fire tube

b) A fire tube boiler occupies less space than a water tube boiler, for a given power

c) Steam at a high pressure and in large quantities can be produced with a simple vertical boiler

d) all of the mentioned

Answer: a

Explanation: A typical vertical boiler can have only one fire tube for the flow of fire or heat.

6. The object of producing draught in a boiler is _________

a) to discharge the gases of combustion to the atmosphere through the chimney

b) all of the mentioned

c) to exhaust the gases of combustion from the combustion chamber

d) to provide an adequate supply of air for the fuel combustion

Answer: b

Explanation: None.

7. The natural draught is produced by _________

a) team jet

b) chimney

c) centrifugal fan

d) none of the mentioned

Answer: b

Explanation: When air or flue gases flow due to the difference in density of the hot flue gases and cooler ambient gases.

8. Which of the following statement is wrong?

a) Water tube boilers are internally fired

b) Locomotive boiler is a water tube boiler

c) La-mont boiler is a low pressure water tube boiler

d) All of the mentioned

Answer: d

Explanation: Water tube boilers are externally fired where as fire tube boilers are internally fired.

9. Which of the following boiler is best suited to meet the fluctuating demand of steam?

a) Locomotive boiler

b) Lancashire boiler

c) Babcock and Wilcox boiler

d) Cornish boiler

Answer: a

Explanation: Because forced draught is provided in the locomotive boiler by injecting exhausted steam back into the exhaust via a blast pipe in the smokebox.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Steam Generator Types – I”.

1. Which of the following auxiliaries are not used in steam Generators?

a) economiser

b) burner

c) fan

d) stoker

Answer: a

Explanation: Burner, fan, stoker, pulverisers, etc. are the various auxiliaries that are used in steam generators.

An economiser is a part of the steam generation plant.

2. The formation of scale boiler leads to _________

a) decrease in efficiency of boiler

b) increase in efficiency of boiler

c) increase in heat transfer

d) decrease in maintenance of boiler

Answer: a

Explanation: Efficiency of boiler is inversely proportional to the scale formation.

3. What is the pH value of water permissible for boiler?

a) 0

b) 7

c) slightly less than 7

d) slightly more than 7

Answer: c

Explanation: The pH value of water used in the boiler is slightly greater than 7 for most of the commonly used boiler.

4. Which device used to separate condensate from the steam without letting steam escape?

a) condenser

b) steam valve

c) steam trap

d) none of the mentioned

Answer: c

Explanation: The steam trap is a device that is used to separate condensate from the steam without letting steam escape.

5. What is the disadvantage of natural draught?

a) it has less life

b) it has more maintenance cost of cleaning and more capital cost to build the chimney

c) the available draught decreases with increasing outside air temperature

d) all of the mentioned

Answer: c

Explanation: The only disadvantage of natural draught is that the available draught decreases with increasing the outside temperature.

6. The natural draught in the steam generator depends upon _________

a) the air condition outside the chimney

b) the temperature of exhaust gases

c) the air condition outside the chimney & the temperature of exhaust gases

d) none of the mentioned

Answer: c

Explanation: The natural draught in the steam generator depends upon the air condition outside chimney & the temperature of the exhaust gases.

7. What is the purpose of super heater in a boiler?

a) to increase the temperature of saturated steam with increase in its pressure

b) to increase the temperature of saturated steam without increase in its pressure

c) to increase the temperature of feedwater for better efficiency

d) none of the mentioned

Answer: b

Explanation: Superheater in a boiler has the function of increasing the temperature of saturated steam without increase in its pressure.

8. How is the natural draught produced for exhaust gases?

a) by using fan

b) by using chimney

c) by using gravity

d) none of the mentioned

Answer: b

Explanation: The natural draught is produced for exhaust gases by using chimney.

9. What is the purpose of using economizer in the boiler?

a) to heat feed water by utilizing heat from exhaust gases

b) to heat feed water by utilizing some heat from superheated steam

c) to superheat steam

d) none of the mentioned

Answer: a

Explanation: The use of Economiser in a boiler is to heat the feed water by utilizing heat from exhaust gases.

10. Comparing fire tube and water tube boilers, which boiler can produce comparatively higher pressure steam than another for the same capacity?

a) fire tube boiler

b) water tube boiler

c) both can produce steam at same pressure for the same capacity

d) none of the mentioned

Answer: b

Explanation: A water tube boiler can produce comparatively higher pressure steam than another for the same capacity.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Steam Generator Types – II”.

1. The boiler in which the tubes are surrounded by hot gases is called ___________

a) fire tube boiler

b) water tube boiler

c) both fire and water tube boiler

d) none of the mentioned

Answer: b

Explanation: A water tube boiler is a boiler in which the cool water containing water tubes are surrounded by hot gases.

2. Which of these is not a type of steam generator depending upon the kind of applications?

a) utility steam generators

b) marine steam generators

c) agricultural steam generators

d) industrial steam generators

Answer: c

Explanation: There are three types of steam generators depending upon the type of application which are utility, industrial & marine steam engines.

3. What is the critical pressure of steam in a utility steam generator?

a) 220.2 bar

b) 221.2 bar

c) 222.2 bar

d) 225.2 bar

Answer: b

Explanation: The critical pressure of steam in a utility steam generator is 221.2 bar.

4. Which of the following are drumless once-through steam generators?

a) Subcritical steam generator

b) Supercritical steam generators

c) Utility steam generators

d) Marine steam generators

Answer: b

Explanation: Supercritical steam generators are drumless once-through steam generators while the subcritical steam generators are the water-tube drum type ones.

5. The subcritical steam generators operate between a pressure ranges of ___________

a) 120-160 bar

b) 100-110 bar

c) 130-180 bar

d) 140- 200 bar

Answer: c

Explanation: The subcritical steam generators operate between a pressure range of 130-180 bar.

6. The supercritical steam generators operate at a pressure range of ___________

a) 200-240 bar

b) 200-220 bar

c) 220- 240 bar

d) >240 bar

Answer: d

Explanation: The supercritical steam generators operate at a pressure range of more than 240 bar.

7. Industrial steam generators operate in a pressure range of ___________

a) 5-105 bar

b) 6-106 bar

c) <5 bar

d) >105 bar

Answer: a

Explanation: Industrial steam generators operate in a pressure range of 5-105 bar.

8. Industrial steam generators operate at a steam capacity of ___________

a) 1300 kg/s

b) 1000 kg/s

c) 500 kg/s

d) 125 kg/s

Answer: d

Explanation: Industrial steam generators operate at a steam capacity of about 125 kg/s which is lesser than that of utility steam generators.

9. Marine steam generators are ___________ fired.

a) water

b) oil

c) phenol

d) none of the mentioned

Answer: b

Explanation: Marine steam generators are oil-fired.

10. What is the pressure range between which a marine steam generator works?

a) 100-200 bar

b) 60-65 bar

c) 80-100 bar

d) 70-85 bar

Answer: b

Explanation: The pressure range between which a marine steam generator works is 60-65 bar.

11. In a fire-tube boiler, the water is in ___________

a) tube

b) shell

c) drum

d) all of the mentioned

Answer: b

Explanation: A fire-tube boiler is one in which the hot flue gases flow through the tubes surrounded by water in a shell.

12. In a water-tube boiler, water flows through?

a) drum

b) shell

c) tube

d) none of the mentioned

Answer: a

Explanation: In a water-tube boiler, water from a drum flows through the tubes & hot gases flow over them.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Fire Tube Boilers – I”.

1. Fire-tube boilers are used in?

a) industrial steam generators

b) utility steam generators

c) marine steam generators

d) none of the mentioned

Answer: a

Explanation: Industrial steam generators use fire-tube boilers as they suit the most for the quantity of steam in the industrial steam generators.

2. Which of the following is not an advantage of a fire-tube boiler?

a) low first cost

b) reliability in operation

c) more draught required

d) quick response to load changes

Answer: c

Explanation: The advantages of using a fire tube boiler are low first cost, reliability in operation, less draught required, quick response to load changes, etc.

3. Which of these is a type of fire-tube boiler?

a) Externally fired

b) Internally fired

c) Internally & Externally fired

d) None of the mentioned

Answer: c

Explanation: There are two types of a fire-tube boiler which are Internally & Externally fired boilers.

4. Which of these is an externally fired boiler?

a) Package boiler

b) Scotch-marine boiler

c) Lancashire boiler

d) None of the mentioned

Answer: c

Explanation: The various types of externally fired boiler include Lancashire boilers, Locomotive type boilers, HRT boiler, etc.

5. Which of the following is a type of internally fired boiler?

a) Package boiler

b) HRT boiler

c) Lancashire boiler

d) Locomotive type boiler

Answer: a

Explanation: The various types of an internally fired boiler include Scotch-marine boiler, Package boiler, etc.

6. What is the function of the fusible plug installed in a furnace?

a) to detect excess current

b) to detect excess heat

c) to detect water level in the tube

d) to detect water level in the shell

Answer: d

Explanation: Water level in the shell is detected by the fusible plug installed in the crown of the furnace.

7. Which of the following gaseous fuels has the lowest calorific value?

a) Refinery Gas

b) Gobar Gas

c) Converter Gas

d) Blast Furnace Gas

Answer: d

Explanation: The lowest calorific value fuel means a fuel which burns most readily. Among all the given options, the most combustible gas is the blast furnace gas.

8. Fuel gases containing hydrocarbons are not preheated before burning, mainly because ____________

a) there are chances of explosion during preheating

b) it reduces its calorific value tremendously

c) the hydrocarbons crack thereby choking and fouling the heat transfer surface by carbon soot

d) it reduces its flame temperature tremendously

Answer: c

Explanation: Fuel gases containing hydrocarbons are not preheated before burning, mainly because the hydrocarbons crack thereby choking and fouling the heat transfer surface by carbon soot.

9. Flue gas discharge velocity through chimney of a big thermal power plant may be around __________ m/sec.

a) 500

b) 0.5

c) 10

d) 50

Answer: c

Explanation: The velocity of discharge of flue gases through the chimney of a big thermal power plant is around 10 m/sec.

10. In water tube boilers ___________

a) forced circulation takes place

b) water passes through the tubes which are surrounded by flames and hot gases

c) the flames and hot gases pass through the tubes which are surrounded by water

d) none of the mentioned

Answer: c

Explanation: In water tube boilers the flames and hot gases pass through the tubes which are surrounded by water.

This set of Power Plant online test focuses on ” Fire Tube Boilers – II”.

1. The object of producing draught in a boiler is ___________

a) to provide an adequate supply of air for the fuel combustion

b) to exhaust the gases of combustion from the combustion chamber

c) to discharge the gases of combustion to the atmosphere through the chimney

d) all of the mentioned

Answer: d

Explanation: The objectives of producing draught in a boiler are providing an adequate supply of air for the fuel combustion, to vent the exhaust gases of combustion from combustion chamber to the atmosphere via chimney.

2. What is the function of a piston rod?

a) to transfer motion from the piston to the cross head

b) to convert heat energy of the steam into mechanical work

c) to guide motion of the piston rod and to prevent it from bending

d) to exhaust steam from the cylinder at proper moment

Answer: a

Explanation: Piston rod transfers motion from the piston to the cross head.

3. The cylinder dimensions of a compound engine may be designed on the basis of ___________

a) equal initial piston loads on all pistons for obtaining same size of piston rod, connecting rod etc. for all cylinders

b) equal power developed in each cylinder for uniform turning moment

c) equal temperature drop in each cylinder for economy of steam

d) all of the mentioned

Answer: d

Explanation: The cylinder dimensions of a compound engine may be designed on the basis of equal temperature drop in each cylinder for economy of steam, equal power developed per cylinder for uniform turning moment, equal initial positions for all pistons.

4. The function of a crosshead is to guide motion of the __________ and to prevent it from bending.

a) valve rod

b) eccentric rod

c) connecting rod

d) piston rod

Answer: d

Explanation: The function of a crosshead is to guide motion of the piston rod and to prevent it from bending.

5. Which of the following statement is wrong?

a) The amount of water evaporated in kg per kg of fuel burnt is called equivalent evaporation from and at 100° C

b) The ratio of heat actually used in producing the steam to the heat liberated in the furnace is called boiler efficiency

c) The factor of evaporation for all boilers is always greater than unity

d) None of the mentioned

Answer: d

Explanation: All the given statements are true.

6. A device used to increase the temperature of saturated steam without raising its pressure is called?

a) fusible plug

b) blow off cork

c) super heater

d) stop valve

Answer: c

Explanation: Super heater is the device used to increase the temperature of saturated steam without raising its pressure.

7. A safety valve usually employed with stationary boilers is ___________

a) high steam and low water safety valve

b) dead weight safety valve

c) lever safety valve

d) all of the mentioned

Answer: d

Explanation: The safety valve can also be called as high/low steam safety valve, dead weight safety valve, lever safety valve.

8. Fire tube boilers are ___________

a) internally fired

b) externally fired

c) both internally as well as externally fired

d) none of the mentioned

Answer: a

Explanation: fire-tube boiler is an internally fired boiler.

9. The diameter of flue tube in a Cornish boiler is __________ that of the shell.

a) 3/5

b) 2/5

c) 1/3

d) 1/4

Answer: a

Explanation: The diameter of flue tube in a Cornish boiler is 3/5 of that of the shell.

10. Which of the following statement is correct?

a) A simple vertical boiler has one fire tube

b) Steam at a high pressure and in large quantities can be produced with a simple vertical boiler

c) A fire tube boiler occupies less space than a water tube boiler, for a given power

d) All of the mentioned

Answer: a

Explanation: “A simple vertical boiler has one fire tube” is the wrong statement.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Water Tube Boilers”.

1. In a glass rube type water indicator for a boiler, one end of the tube is connected to water space and the other end is connected to ________________

a) chimney

b) water space

c) steam space

d) super heater

Answer: c

Explanation: In a glass rube type water indicator for a boiler, one end of the tube is connected to water space and the other end is connected to the steam space.

2. The draught produced by a steam jet issuing from a nozzle placed in the ashpit under the fire grate of the furnace is called ___________

a) chimney draught

b) induced steam jet draught

c) forced steam jet draught

d) none of the mentioned

Answer: b

Explanation: The draught produced by a steam jet issuing from a nozzle placed in the ashpit under the fire grate of the furnace is called induced steam jet draught.

3. Willian’s line for the steam engine is a straight line relationship between the steam consumption per hour and ___________

a) brake power

b) indicated power

c) pressure of steam

d) efficiency

Answer: b

Explanation: Willian’s line for the steam engine is a straight line relationship between the steam consumption per hour and indicated power.

4. The natural draught is produced by ___________

a) chimney

b) centrifugal fan

c) steam jet

d) none of the mentioned

Answer: a

Explanation: The natural draught is produced by chimney.

5. Which of the following statement is wrong?

a) Water tube boilers are internally fired

b) Locomotive boiler is a water tube boiler

c) La-mont boiler is a low pressure water tube boiler

d) All of the mentioned

Answer: d

Explanation: All the mentioned statement are wrong as water-tube boilers are externally fired, locomotive boiler isn’t a water-tube boiler & La-mont boiler is a high pressure boiler.

6. An air preheater is installed ___________

a) between the economiser and chimney

b) before the superheater

c) before the economiser

d) none of the mentioned

Answer: a

Explanation: The installation of an air pre-heater is between the economiser & the chimney.

7. Which of the following statement is correct for a compound steam engine?

a) The forces in the working parts are increased as the forces are distributed over more parts

b) The cost of the engine, for the same power and economy, is more than that of a simple steam engine

c) The temperature range per cylinder is increased, with corresponding increase in condensation

d) The ratio of expansion is reduced, thus reducing the length of stroke

Answer: d

Explanation: When the ratio of expansion is reduced, the length of stroke is reduced in a compound steam engine.

8. What is the length of shell of a Locomotive boiler?

a) 2m

b) 3m

c) 4m

d) 6m

Answer: c

Explanation: The shell of a locomotive boiler has a length of 4m.

9. What is the function of a flywheel?

a) to convert reciprocating motion of the piston into rotary motion

b) to prevent fluctuation of speed

c) to keep the engine speed uniform at all load conditions

d) to convert rotary motion of the crankshaft into to and fro motion of the valve rod

Answer: b

Explanation: Flywheel is employed to prevent fluctuation of speed.

10. The shell diameter of a Locomotive boiler is?

a) 1.5m

b) 1m

c) 2m

d) 2.5m

Answer: a

Explanation: The shell diameter of a Locomotive boiler is 1.5 m.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Superheaters, Reheaters and Steam Generator Control”.

1. Which of the following is a water tube boiler?

a) Lancashire boiler

b) Cochran boiler

c) Babcock & Wilcox boiler

d) Locomotive boiler

Answer: c

Explanation: The Cochran Boiler is a type of water tube boiler.

2. The number of fire tubes in a Cochran boiler are ___________

a) 75

b) 165

c) 225

d) 175

Answer: b

Explanation: The number of fire tubes in a Cochran boiler is 165.

3. The chimney draught varies with?

a) climatic conditions

b) temperature of furnace gases

c) height of chimney

d) all of the mentioned

Answer: d

Explanation: The chimney draught varies with climatic conditions, temperature of furnace gases, height of chimney, etc.

4. The diagram factor is the ratio of ___________

a) area of actual indicator diagram to the area of theoretical indicator diagram

b) actual work done per stroke to the theoretical work done per stroke

c) actual mean effective pressure to the theoretical mean effective pressure

d) any of the above mentioned

Answer: d

Explanation: The ratio of any of the mentioned factors is called the Diagram factor.

5. The diameter of a cylindrical shell of a Scotch marine boiler varies from ___________

a) 3.5 to 4.5m

b) 1.5 to 2m

c) 2.5 to 3.5m

d) none of the mentioned

Answer: c

Explanation: The diameter of a cylindrical shell of a Scotch marine boiler varies from 2.5 to 3.5m.

6. A closed vessel made of steel & used for the generation of steam is called a ___________

a) steam condenser

b) steam boiler

c) steam injector

d) steam turbine

Answer: b

Explanation: A closed vessel made of steel & used for the generation of steam is called a steam boiler.

7. Lancashire boiler has _____ internal flue tubes.

a) 1

b) 3

c) 2

d) 4

Answer: c

Explanation: Lancashire boiler has 2 internal flue tubes.

8. Locomotive boiler is a ___________

a) single tube, vertical, externally fired & stationary boiler

b) single tube, horizontal, internally fired& stationary boiler

c) multitubular, horizontal, externally fired & stationary boiler

d) multitubular, horizontal, internally fired & mobile boiler

Answer: d

Explanation: Locomotive boiler is a multitubular, horizontal, internally fired & mobile boiler.

9. Cut-off ratio is the ratio of?

a) cut-off volume to clearance volume

b) clearance volume to cut-off volume

c) volume at cut-off to swept volume

d) swept volume to volume at cut-off

Answer: c

Explanation: Cut-off ratio is the ratio of volume at cut-off to swept volume.

10. The equivalent evaporation is defined as?

a) the ratio of heat actually used in producing the steam to the heat liberated in the furnace

b) the amount of water evaporated or steam produced in kg of fuel burnt

c) the amount of water evaporated from and at 100 degree C into dry & saturated steam

d) none of the mentioned

Answer: c

Explanation: The equivalent evaporation is defined as the amount of water evaporated from and at 100 degree C into dry & saturated steam.

11. The theoretical indicator diagram of a simple steam engine is based upon the assumption that ___________

a) there is no pressure drop due to condensation

b) steam is admitted at boiler pressure & exhausted at condenser pressure

c) the expansion of the steam is hyperbolic

d) all of the mentioned

Answer: d

Explanation: The theoretical indicator diagram of a simple steam engine is based upon the assumption that there is no pressure drop due to condensation, the steam is admitted at boiler pressure & exhausted at condenser pressure, the expansion of the steam is hyperbolic.

12. The actual power supplied by the engine crankshaft is called?

a) indicated power

b) frictional power

c) brake power

d) none of the mentioned

Answer: c

Explanation: The actual power supplied by the engine crankshaft is called Brake Power.

13. When steam after doing work in the cylinder passes into a condenser, the engine is said to be a ___________

a) slow speed engine

b) vertical steam engine

c) condensing steam engine

d) no-condensing steam engine

Answer: c

Explanation: When steam after doing work in the cylinder passes into a condenser, the engine is said to be a condensing steam engine.

14. The missing quantity per stroke is equal to?

a) cylinder feed + indicated mass of steam

b) cylinder feed + indicated mass of steam

c) mass of cushion steam + indicated mass of steam

d) mass of cushion steam + cylinder feed

Answer: b

Explanation: The missing quantity per stroke is equal to cylinder feed + indicated mass of steam.

15. An economiser is installed in a boiler primarily to ___________

a) increase steam pressure

b) reduce fuel consumption

c) superheat the steam

d) all of the mentioned

Answer: b

Explanation: An economiser is installed in a boiler primarily to reduce fuel consumption.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Air Preheaters, ESP and Deareration”.

1. The relative efficiency is defined as?

a) ratio of thermal efficiency to rankine efficiency

b) ratio of brake power to the indicated power

c) ratio of heat equivalent to indicated power to the energy supplied in steam

d) product of thermal efficiency & Rankine efficiency

Answer: a

Explanation: The ratio of thermal efficiency to rankine efficiency is called Relative efficiency.

2. Lancashire boiler is ___________

a) stationary fire tube boiler

b) horizontal boiler

c) internally fired boiler

d) all of the mentioned

Answer: d

Explanation: Lancashire boiler is a stationary fire tube, horizontal & internally fired boiler.

3. The heat balance sheet for the boiler shows the ___________

a) steam formed by combustion of hydrogen per kg of fuel

b) moisture present in the fuel

c) complete account of heat supplied by 1 kg of dry fuel & the heat consumed

d) all of the mentioned

Answer: c

Explanation: The heat balance sheet for the boiler shows the complete account of heat supplied by 1 kg of dry fuel & the heat consumed.

4. A compound steam engine in which piston rods of high pressure & low pressure cylinders are attached to two different crank sets at 1800 to each other, is called ___________

a) Tandem type compound engine

b) Receiver type compound engine

c) Woolf type compound engine

d) none of the mentioned

Answer: c

Explanation: A compound steam engine in which piston rods of high pressure & low pressure cylinders are attached to two different crank sets at 1800 to each other, is called Woolf type compound engine.

5. The actual vacuum in a condenser is equal to ___________

a) barometric pressure – actual pressure

b) barometric pressure + actual pressure

c) gauge pressure – atmospheric pressure

d) gauge pressure + atmospheric pressure

Answer: a

Explanation: The actual vacuum in a condenser is equal to barometric pressure – actual pressure.

6. The high steam and low water safety valve is used to blow off steam when the ___________

a) steam pressure exceeds the working pressure

b) water level in the boiler becomes too low

c) none of the mentioned

d) steam pressure exceeds the working pressure & water level in the boiler becomes too low

Answer: d

Explanation: The high steam and low water safety valve is used to blow off steam when the steam pressure exceeds the working pressure & water level in the boiler becomes too low.

7. The performance of a boiler is measured by the ___________

a) dry flue gases

b) steam formation

c) moisture in fuel

d) unburnt carbon

Answer: a

Explanation: The performance of a boiler is measured by the amount of dry flue gases exhausted.

8. Benson boiler requires ___________

a) 2 drums

b) 3 drums

c) 0 drums

d) 1 drum

Answer: c

Explanation: Benson boiler requires no drums. It is a drum-less boiler.

9. The cylinder condensation or missing quantity may be reduced by ___________

a) keeping the expansion ratio small in each cylinder

b) superheating the steam supplied to the engine cylinder

c) the efficient steam jacketing of the cylinder walls

d) all of the mentioned

Answer: d

Explanation: The cylinder condensation or missing quantity may be reduced by keeping the expansion ratio small, superheating the steam supplied to the engine cylinder, the efficient steam jacketing of the cylinder walls, etc.

10. In a Tandem type compound engine, the high pressure and low pressure cylinders ___________

a) have common piston rods

b) have separate piston rods

c) are set at 90 degrees

d) are set in V-arrangement

Answer: a

Explanation: In a Tandem type compound engine, the high pressure and low pressure cylinders have common piston rods.

11. A device used in a boiler to control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required, is known as?

a) fusible plug

b) superheater

c) stop valve

d) blow off cork

Answer: c

Explanation: A device used in a boiler to control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required, is known as Stop Valve.

12. The performance of a boiler is measured by the ___________

a) steam produced in kg/h

b) steam produced in kg/kg of fuel burnt

c) amount of water evaporated per hour

d) all of the mentioned

Answer: d

Explanation: The performance of a boiler is measured by the rate of steam produced in kg/h, kg/kg & the amount of water evaporated per hour.

13. The high pressure and low pressure cylinders in a receiver type compound engine are regarded as having cranks at ___________

a) 180° to each other

b) 90° to each other

c) 0° to each other

d) none of the mentioned

Answer: b

Explanation: The high pressure and low pressure cylinders in a receiver type compound engine are regarded as having cranks at 90° to each other.

14. Throttle governing of steam engines is a method of controlling the engine output by varying ___________

a) volume of intake steam

b) pressure of intake system

c) temperature of intake system

d) none of the mentioned

Answer: b

Explanation: Throttle governing of steam engines is a method of controlling the engine output by varying pressure of intake system.

15. What is the aim of a compound steam engine?

a) to reduce the ratio of expansion in each cylinder

b) to reduce the temperature range in each cylinder

c) to reduce the length of stroke

d) all of the mentioned

Answer: a

Explanation: The aim of a compound steam engine is to reduce the ratio of expansion in each cylinder.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Evaporation, Boiler Blowdown and Steam Purity”.

1. When the circulation of water, in a boiler, is by a centrifugal pump, then the boiler is known as _____________

a) forced circulation boiler

b) externally fired boiler

c) naturally circulation boiler

d) internally fired boiler

Answer: a

Explanation: When the circulation of water, in a boiler, is by a centrifugal pump, then the boiler is known as forced circulation boiler.

2. A single acting steam engine produces __________ power than that of double acting steam engine.

a) equal

b) double

c) half

d) 4 times

Answer: c

Explanation: A single acting steam engine produces half power than that of double acting steam engine.

3. Cut-off governing of steam engines is a method of controlling the engine output by varying __________

a) volume of intake steam

b) pressure of intake steam

c) temperature of intake steam

d) all of the mentioned

Answer: a

Explanation: Cut-off governing of steam engines is a method of controlling the engine output by varying volume of intake steam.

4. A device in which some portion of waste heat of flue gases is recovered to heat the air before it passes to the furnace for combustion purpose is known as __________

a) air preheater

b) superheater

c) injector

d) none of the mentioned

Answer: a

Explanation: A device in which some portion of waste heat of flue gases is recovered to heat the air before it passes to the furnace for combustion purpose, is knwon as air-preheater.

5. Which of the following statement is correct?

a) Fire tube boilers are internally fired

b) Lancashire boiler is a fire tube boiler

c) Babcock and Wilcox boiler is a water tube boiler

d) All of the mentioned

Answer: d

Explanation: All the mentioned statements are correct.

6. In a uniflow engine __________

a) steam enters and exhausts through the same port

b) steam enters at one end and exhausts at the centre

c) steam enters at the centre and exhausts at the other end

d) none of the mentioned

Answer: b

Explanation: Steam enters at one end and exhausts at the centre in a Uniflow engine.

7. A safety valve mainly used with locomotive and marine boilers is __________

a) lever safety valve

b) dead weight safety valve

c) spring loaded safety valve

d) high steam and low water safety valve

Answer: c

Explanation: A safety valve mainly used with locomotive and marine boilers is spring loaded safety valve.

8. The power of a boiler may be defined as __________

a) the amount of water evaporated or steam produced in kg per kg of fuel burnt

b) the ratio of heat actually used in producing the steam to the heat liberated in the furnace

c) the evaporation of 15.653 kg of water per hour from and at 100° C

d) the amount of water evaporated from and at 100° C into dry and saturated steam

Answer: a

Explanation: The power of a boiler may be defined as the amount of water evaporated or steam produced in kg per kg of fuel burnt.

9. Which of the following boiler is best suited to meet the fluctuating demand of steam?

a) Cornish boiler

b) Lancashire boiler

c) Locomotive boiler

d) Babcock & Wilcox boiler

Answer: c

Explanation: Locomotive Boiler is the best suited to meet the fluctuating demand of steam.

10. The diameter of Cornish boiler varies from __________

a) 1 to 2m

b) 0.5 to 1m

c) 1.25 to 2.5m

d) 2 to 3m

Answer: a

Explanation: The diameter of Cornish Boiler varies from 1-2 m.

11. Besides mean effective pressure, the data required to determine the indicated power of an engine include __________

a) piston diameter, length of stroke and calorific value of fuel

b) piston diameter, specific fuel consumption and Calorific value of fuel

c) piston diameter, length of stroke and speed of rotation

d) specific fuel consumption, speed of rotation and torque

Answer: c

Explanation: Besides mean effective pressure, the data required to determine the indicated power of an engine include piston diameter, length of stroke and speed of rotation.

12. A compound steam engine in which the high pressure and low pressure cylinders have common piston rod is called __________

a) Tandem type compound engine

b) Woolf type compound engine

c) Receiver type compound engine

d) None of the mentioned

Answer: a

Explanation: A compound steam engine in which the high pressure and low pressure cylinders have common piston rod, is called Tandem type compound engine.

13. What is the average operating pressure of Benson boiler?

a) 200 bar

b) 150 bar

c) 250 bar

d) 100 bar

Answer: b

Explanation: The average operating pressure of Benson boiler is 150 bar.

14. What is the function of a safety valve?

a) to indicate the water level inside the boiler to an observer

b) to measure pressure of steam inside the steam boiler

c) to blow off steam when the pressure of steam inside the boiler exceeds the working pressure

d) none of the mentioned

Answer: c

Explanation: The function of a safety valve is to blow off steam when the pressure of steam inside the boiler exceeds the working pressure.

15. What is the rate of steam produced in Benson boiler?

a) 250 tonnes/h

b) 175 tonnes/h

c) 100 tonnes/h

d) 135 tonnes/h

Answer: d

Explanation: The rate of steam produced in Benson boiler is 135 tonnes/h.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Magneto hydrodynamic Plant Basics”.

1. Which of these is not a major direct energy conversion device?

a) magnetohydrodynamic

b) thermionic

c) geothermal

d) fuel cell

Answer: c

Explanation: Geothermal energy is not available everywhere.

2. Which of these is the most promising power generation system?

a) magnetohydrodynamic

b) thermoelectric

c) hydrogen

d) fuel cell

Answer: a

Explanation: Since it is capable of tapping vast potential of modern furnaces.

3. Which of these is not a limitation of conventional energy sources?

a) Resources are limited some are seasonal

b) Most of them emit harmful gases contributing to global warming

c) Situated in remote areas and higher T and D losses

d) requires small areas

Answer: d

Explanation: Conventional energy resources require large areas.

4. Which of these is a conventional source of energy?

a) sun

b) wind

c) fossil fuels

d) fuel cells

Answer: c

Explanation: Fossil fuels are conventional sources of energy.

5. Which of these is a non-conventional type of power generation without prime movers?

a) hydro power

b) thermal

c) nuclear

d) thermoelectric

Answer: d

Explanation: Thermoelectric power generation of a non conventional type.

6. Which of these is not a type of collector in solar power generation?

a) flat plate

b) focusing or concentrating collectors

c) cylindrical parabolic concentrator

d) hyperbolic concentrator

Answer: d

Explanation: The shape is not hyperbolic but parabolic.

7. Which of these is not a merit of tidal power generation?

a) free from problems of ecology balance

b) everlasting

c) no extra submerging of land is required

d) uneven operation

Answer: d

Explanation: The uneven operation is a demerit of tidal power.

8. Which of these is not an effect of distributed generation system on power generation?

a) affects over power generation setting

b) effect in auto reclosing

c) creation of ferro resonance

d) protection from insulation failure

Answer: d

Explanation: Distributed generation system actually causes insulation failure.

9. Which of these is not a component of natural gas?

a) methanol

b) methane

c) ethane

d) propane

Answer: a

Explanation: Methanol is not a component of natural gas.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Magnetohydrodynamic Power Generation – I”.

1. In an open cycle MHD-steam power plant, the temperature at the entrance of MHD duct is ?

a) 2500-3000

b) 2000-2500

c) 1500-2000

d) 2250

Answer: a

Explanation: The temperature is kept in between 2500-3000K.

2. The air at the entrance of MHD duct is seeded with potasium upto ____________

a) 7%

b) 5%

c) 3%

d) 1%

Answer: d

Explanation: The air is seeded upto 1%/.

3. Air pollution in an MHD-steam power plant is caused due to the formation of which of the following compounds?

a) oxides and hydroxides

b) chlorides and hydroxides

c) oxides and carbonates

d) carbonates and bicarbonates

Answer: a

Explanation: Oxides and hydroxides of seeding element formed cause air pollution.

4. Which of the following device helps in recovery of seeding element?

a) ion precipitator

b) condenser

c) electrostatic precipitator

d) orsat’s apparatus

Answer: c

Explanation: Electrostatic precipitator helps in recovery of the seed.

5. In closed cycle MHD-steam power plant, which of the following gas is seeded in the MHD duct?

a) helium

b) xenon

c) sodium vapour

d) chlorine

Answer: a

Explanation: Helium is seeded in the air.

6. Where is the input of the MHD duct heated in a closed cycle MHD-steam power plant?

a) blast furnace

b) nuclear reactor

c) reverabatory furnace

d) combustion chamber

Answer: b

Explanation: The seed is heated in the nuclear reactor.

7. Which of these materials are not used for MHD duct walls?

a) magnesium oxide

b) strontium zirconate

c) hafnia

d) manganese zirconate

Answer: a

Explanation: The other three materials are used for MHD duct walls.

8. To reduce the power consumption of electromagnets, which type of coils have been suggested?

a) aluminium

b) high temperature resistant

c) cryogenic & superconducting

d) none of the mentioned

Answer: c

Explanation: Cryogenic or superconductiong coils have been suggested for reducing power consumption of electromagnets.

9. Which is the only fuel better than coal for use?

a) natural gas

b) char

c) kerosene

d) benzene

Answer: b

Explanation: Char is a better fuel than coal since it has less hydrogen and increases performance by 25%.

10. Which of these is not a property of MHD power generation?

a) has no moving part, so is reliable

b) overall generation cost is less

c) closed cycle has almost no pollution

d) conversion is about 80-90%

Answer: d

Explanation: The overall efficiency of MHD generation is 50-60%.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Fuel Cell”.

1. Fuel cell converts chemical energy to electrical energy using a reaction that __________

a) eliminates combustion of fuel

b) requires combustion of fuel

c) requires no ignition of fuel

d) fuel is not required

Answer: a

Explanation: Combustion of fuel is eliminated in fuel cells.

2. Fuel cell performance is not limited by __________

a) First law of Thermodynamics

b) Second law of Thermodynamics

c) Third law of Thermodynamics

d) All three laws are applicable

Answer: b

Explanation: The performance of fuel cell is not limited by the Second law of Thermodynamics.

3. For which of these devices does negative charge carriers flow from anode to cathode in the external circuit?

a) MHD generator

b) Thermionic generator

c) Thermoelectric generator

d) Fuel cell

Answer: d

Explanation: The sign convention of anode and cathode is same for fuel cell and batteries.

4. The fuel cell is considered a battery in which ___________ is continuously replaced.

a) fuel only

b) oxidizer

c) both fuel and oxidizer

d) none of the mentioned

Answer: c

Explanation: Both fuel and oxidizer are replaced in fuel cell.

5. The type of reactions in a fuel cell is not determined by __________

a) fuel and oxidizer combination

b) composition of electrolyte

c) materials of anode and cathode

d) catalytic effects of reaction container

Answer: d

Explanation: The catalytic effects of electrodes rather than that of reaction container effects the fuel cell reactions.

6. What is the voltage output of hydrogen-oxygen fuel cell?

a) -1.23

b) -1.45

c) -1.01

d) -.93

Answer: a

Explanation: The voltage output of hydrogen-oxygen fuel cell is -1.23V.

7. What is the voltage output of carbon-oxygen fuel cell?

a) -.91

b) -1.24

c) -1.02

d) -1.17

Answer: c

Explanation: The voltage output of carbon-oxygen fuel cell is -1.02V.

8. What is the voltage output of methane-oxygen fuel cell?

a) -1.16

b) -1.06

c) -1.26

d) -0.96

Answer: b

Explanation: The voltage output of methane-oxygen fuel cell is -1.06V.

9. Which of these gases or liquids are not used as source of hydrogen in fuel cells?

a) C 2 H 6

b) C 2 H 2

c) C 6 H 6

d) C 2 H 5 OH

Answer: d

Explanation: The only liquid from alcohol series used as a source of hydrogen in fuel cells is methanol CH3OH.

10. The hydrocarbons cracked with steam in fuel cells do not give rise to __________

a) CO

b) CO 2

c) H 2

d) H 2 O

Answer: d

Explanation: The cracking of fuel in fuel cells foes not give rise to H 2 O.

11. Which of these should not be a properties of fuel cell electrodes?

a) good electrical conductors

b) highly resistant to corrosive environment

c) should perform charge seperation

d) take part in chemical reactions

Answer: d

Explanation: The fuel cell electrode should not take part in fuel cell electrode.

12. Which of these fuel cell operates at temperature below 100.C?

a) phosphoric fuel cell

b) solid polymer electrolyte fuel cell

c) molten carbon fuel cell

d) hydrogen-oxygen fuel cell

Answer: c

Explanation: The Solid Polymer Electrolyte Fuel Cell operates at temperatures less than 100.C.

13. Which of these fuel cells operates at high temperatures and pressures?

a) high temperature solid oxide fuel cell

b) alkaline fuel cell

c) molten carbon fuel cell

d) phosphoric acid fuel cell

Answer: c

Explanation: The Molten Carbon Fuel Cell operates at high temperatures and pressures.

This set of Power Plant Interview Questions and Answers focuses on “Sources of Energy – 1”.

1. Which of the following is a non-renewable resource?

a) Coal

b) Forests

c) Water

d) Wildlife

Answer: a

Explanation: Amongst all the resources mentioned, Coal is a non-renewable resource.

2. Which among the following is not a renewable source of energy?

a) Solar energy

b) Biomass energy

c) Hydro-power

d) Geothermal energy

Answer: b

Explanation: Biomass corresponds to the exhaustible wastes, so this isn’t a renewable source of energy.

3. Identify the non-renewable energy resource from the following.

a) Coal

b) Fuel cells

c) Wind power

d) Wave power

Answer: a

Explanation: Coal is an exhaustible source of energy.

4. Which of the following is a disadvantage of most of the renewable energy sources?

a) Highly polluting

b) High waste disposal cost

c) Unreliable supply

d) High running cost

Answer: c

Explanation: Unreliable supply is a disadvantage of most of the renewable energy sources.

5. Photovoltaic energy is the conversion of sunlight into ___________

a) Chemical energy

b) Biogas

c) Electricity

d) Geothermal energy

Answer: a

Explanation: Photovoltaic energy is the conversion of sunlight into Chemical Energy.

6. Horizontal axis and vertical axis are the types of ___________

a) Nuclear reactor

b) Wind mills

c) Biogas reactor

d) Solar cell

Answer: b

Explanation: Horizontal axis and vertical axis are the types of wind mills.

7. Which among the following is not an adverse environmental impact of tidal power generation?

a) Interference with spewing and migration of fish

b) Pollution and health hazard in the estuary due to blockage of flow of polluted water into the sea

c) Navigational hazard

d) None of the mentioned

Answer: d

Explanation: None of the mentioned impacts are adverse impacts of tidal power generation.

8. Steam reforming is currently the least expensive method of producing ___________

a) Coal

b) Biogas

c) Hydrogen

d) Natural gas

Answer: c

Explanation: Steam reforming is currently the least expensive method of producing Hydrogen.

9. A fuel cell, in order to produce electricity, burns ___________

a) Helium

b) Nitrogen

c) Hydrogen

d) None of the mentioned

Answer: c

Explanation: A fuel cell, in order to produce electricity, burns Hydrogen.

10. Fuel cells are ___________

a) Carbon cell

b) Hydrogen battery

c) Nuclear cell

d) Chromium cell

Answer: b

Explanation: Hydrogen battery cells are called fuel cells.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Miscellaneous”.

1. Greenhouse effect is not caused by?

a) CFC’s

b) Sulphur dioxide

c) Carbon dioxide

d) None of the mentioned

Answer: a

Explanation: CFC’s aren’t responsible for the greenhouse effect.

2. In a four stroke cycle petrol engine, the inlet valve ___________

a) opens at top dead centre and closes at bottom dead centre

b) opens at 20° before top dead centre and closes at 40° after bottom dead centre

c) opens at 20° after top dead centre and closes at 20° before bottom dead centre id may open or close anywhere

d) none of the mentioned

Answer: b

Explanation: In a four stroke cycle petrol engine, the inlet valve opens at 20° before top dead centre and closes at 40° after bottom dead centre.

3. Which of the following does not relate to a compression ignition engine?

a) Fuel injector

b) Fuel pump

c) Governor

d) Carburettor

Answer: d

Explanation: Carburettor isn’t used in a compression ignition engine, instead it is used in spark ignition engine.

4. The theoretically correct mixture of air and petrol is?

a) 20:1

b) 15:1

c) 40:1

d) 50:1

Answer: a

Explanation: The theoretically correct mixture of air & petrol is 20:1.

5. The injection pressure in a diesel engine is about ___________

a) 10 bar

b) 100 bar

c) 150 bar

d) 300 bar

Answer: b

Explanation: The injection pressure in a diesel engine is about 100 bar.

6. The pressure at the end of compression, in diesel engines, is approximately ___________

a) 10 bar

b) 15 bar

c) 20 bar

d) 35 bar

Answer: d

Explanation: The pressure at the end of compression, in diesel engines, is approximately 35 bar.

7. The function of a distributor in a coil ignition system of I.C. engines is ___________

a) to distribute spark

b) to distribute power

c) to time the spark

d) to distribute current

Answer: c

Explanation: Distributor in a coil ignition system of an IC Engine times the spark produced.

8. Brayton cycle corresponds to ___________

a) IC Engines

b) Gas Turbines

c) IC Engines & Gas Turbines

d) None of the above mentioned

Answer: b

Explanation: Gas Turbines are based on Brayton cycle.

9. Intercooling is done in ___________

a) CI Engines

b) SI Engines

c) Gas Turbines

d) None of the mentioned

Answer: c

Explanation: Intercooling is done in Gas Turbines.

10. A Gas Turbine is also known as?

a) Compression Turbine

b) Compensation Turbine

c) Combustion Turbine

d) None of the mentioned

Answer: c

Explanation: Combustion Turbine is yet another name of Gas Turbines.

This set of Power Plant Engineering Multiple Choice Questions & Answers focuses on “Environmental Degradation & Use of Renewable Energy – I”.

1. What is the harm from the depletion of Earth’s ozone layer?

a) The average temperature of earth’s surface will increase gradually

b) The oxygen content of the atmosphere will decrease

c) Increased amount of Ultra violet radiation will reach earth’s surface

d) Sea levels will rise as the polar ice caps will gradually melt

Answer: c

Explanation: The decrease in the oxygen content of the atmosphere is the only harm from the depletion of Earth’s Ozone Layer.

2. Acid rain is formed due to contribution from the following pair of gases?

a) Methane and ozone

b) Oxygen and nitrous oxide

c) Methane and sulphur dioxide

d) Carbon dioxide and sulphur dioxide

Answer: b

Explanation: Acid rain is formed due to contribution of Methane & Sulphur dioxide.

3. Which of the following is a prime health risks associated with greater UV radiation through the atmosphere due to depletion of stratospheric ozone?

a) Damage to digestive system

b) Increased liver cancer

c) Neurological disorder

d) Increased skin cancer

Answer: d

Explanation: Increased risk of Skin Cancer is the prime health risks associated with greater UV radiation through the atmosphere due to depletion of stratospheric ozone.

4. Which is the most serious environmental effect posed by hazardous wastes?

a) air pollution

b) contamination of groundwater

c) increased use of land for landfills

d) destruction of habitat

Answer: b

Explanation: The most serious environmental effect posed by hazardous wastes is contamination of groundwater.

5. The concentration of which gas is highest in our environment?

a) Oxygen

b) Hydrogen

c) Nitrogen

d) Carbon dioxide

Answer: c

Explanation: Nitrogen has the highest concentration in the environment constituting about 71% of the environmental gases.

6. Which of the following is not as a consequence of global warming?

a) rising sea level

b) increased agricultural productivity worldwide

c) worsening health effects

d) increased storm frequency and intensity

Answer: b

Explanation: Increased agricultural productivity is not a consequence of global warming.

7. Which of the following is not a primary contributor to the greenhouse effect?

a) carbon dioxide

b) carbon monoxide

c) chlorofluorocarbons

d) methane gas

Answer: c

Explanation: CFC’s aren’t a primary contributor to the greenhouse effect.

8. The increase in the concentration of CO 2 in our environment in last fifty years; since 1960 is about _________

a) 20%

b) 10%

c) 14%

d) 6%

Answer: c

Explanation: The increase in the concentration of CO 2 in our environment in last fifty years; since 1960 is about 14%.

9. The depletion in the Ozone layer is caused by _________

a) nitrous oxide

b) carbon dioxide

c) chlorofluorocarbons

d) methane

Answer: c

Explanation: The depletion in the Ozone layer is caused by Chlorofluorocarbons.

10. A major in-stream use of water is for _________

a) producing hydroelectric power

b) dissolving industrial wastes

c) agricultural irrigation

d) domestic use

Answer: a

Explanation: Production of hydroelectric power is a major in-stream use of water.

This set of Basic Power Plant Questions and Answers focuses on “Environmental Degradation & Use of Renewable Energy – II”.

1. Which of the following are the example of Municipal and industrial discharge pipes?

a) nonpoint sources of pollution

b) violations of the Clean Water Act

c) point sources of pollution

d) irrigation

Answer: c

Explanation: Point sources of pollution are the examples of Municipal & industrial discharge pipes.

2. The presence of high coliform counts in water indicate _________

a) contamination by human wastes

b) phosphorus contamination

c) decreased biological oxygen demand

d) hydrocarbon contamination

Answer: a

Explanation: The presence of high coli-form counts in water indicate contamination by human wastes.

3. How the biological oxygen demand gets affected with the increased presence of organic matter in water?

a) the oxygen demand increases

b) the oxygen demand decreases

c) the oxygen demand remains unchanged

d) none of the mentioned

Answer: a

Explanation: With the increased presence of organic matter in water, the oxygen demand increases.

4. Which of the following is a major source of groundwater contamination?

a) agricultural products

b) landfills

c) septic tanks

d) all of the mentioned

Answer: d

Explanation: All of the mentioned options are major sources of groundwater contamination.

5. Which of the following is considered as part of water use planning?

a) waste water treatment

b) water diversion projects

c) storm sewer drainage

d) all of the mentioned

Answer: d

Explanation: All the mentioned issues come under water use planning.

6. The stage in which the biological processes are used to purify water in a wastewater treatment plants is called?

a) secondary sewage treatment

b) primary sewage treatment

c) wastewater reduction

d) biochemical reduction

Answer: a

Explanation: The stage in which the biological processes are used to purify water in a wastewater treatment plants is called Secondary Sewage Treatment.

7. Groundwater mining in coastal areas can result into _________

a) increase in the salinity of groundwater

b) decrease in the toxicity of groundwater

c) decrease in the salinity of groundwater

d) increase in the water table

Answer: a

Explanation: Groundwater mining in coastal areas can result into an increase in the salinity of groundwater.

8. Which of the following is not an important characteristic of the Green Revolution?

a) mechanized agriculture

b) hybrid seeds

c) slash and burn

d) monoculture

Answer: c

Explanation: Slash & Burn isn’t an important characteristic of the Green Revolution.

9. The three primary soil macronutrients are _________

a) carbon, oxygen and water

b) copper, cadmium and carbon

c) potassium, phosphorus and nitrogen

d) boron, zinc and manganese

Answer: c

Explanation: Potassium, phosphorus, and nitrogen are the three primary soil macronutrients.

10. Which of the following are negative effects on the soil and water due to conventional, mechanized farming practices?

a) soil compaction

b) reduction in soil organic matter

c) soil erosion

d) all of the mentioned

Answer: d

Explanation: All the mentioned impacts are the negative effects on the soil & water due to conventional, mechanized farming practices.