Biomedical Instrumentation Pune University MCQs
Biomedical Instrumentation Pune University MCQs
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Origin of Bioelectric Signals”.
1. Source of Bioelectric potential is ____________ in nature.
a) electronic
b) electric
c) ionic
d) mechanical
Answer: c
Explanation: Bioelectric potentials are generated at cellular level and the source of these potentials is ionic in nature. The prominent ions are K + , Na + , and Cl – . Electronic potential is seen in commonly used cells for example the Galvanic cell. Mechanical potential is found nowhere. Electrical potential is found in electricity.
2. Palsied muscles mean _____________
a) paralyzed muscles
b) active muscles
c) voluntary muscles
d) involuntary muscles
Answer: a
Explanation: Palsied is an adjective that means paralyzed. It is used to describe a muscle on which an individual has lost all control . Voluntary muscles are the muscles on which the individual has complete control. Involuntary muscles are the ones on which the individual has no control for example heart wall muscles.
3. The principal ion that is not involved with the phenomena of producing cell potentials is ______________
a) sodium
b) potassium
c) chlorine
d) hydrogen
Answer: d
Explanation: Sodium (Na + ), Potassium (K + ), and Chlorine (Cl – ) are the principal ions involved with the phenomena of producing cell potentials. Na+ is present outside the cell membrane and creates a positively charged environment outside the cell membrane. Cl – is present inside the cell membrane and is responsible for the negative environment inside the cell membrane.
4. What is the relatively static membrane potential of quiescent cells called?
a) half-cell potential
b) action potential
c) resting membrane potential
d) cell potential
Answer: c
Explanation: Resting membrane potential or the resting potential is the relative static membrane potential of quiescent cell. That is if the resting membrane potential of a neuron is about -70 mV it means that the inside of the neuron is 70 mV less than the outside of the neuron. An action potential occurs when the potential of the membrane of a given axonal position increases and decreases rapidly. This depolarization causes depolarization of adjacent positions in a similar way.
5. The variation of the electrical potential associated with the passage of a pulse along the membrane of a muscle cell or a nerve cell is called __________
a) muscle potential
b) action potential
c) resting potential
d) half cell potential
Answer: b
Explanation: An action potential occurs when the potential of the membrane of a given axonal position increases and decreases rapidly. This depolarization causes depolarization of adjacent positions in a similar way. Resting membrane potential or the resting potential is the relative static membrane potential of a quiescent cell.
6. Cells depolarize and action potential in generated as soon as a stimulus is applied.
a) True
b) False
Answer: b
Explanation: This statement is False. This is because unless a stimulus above a certain minimum value is applied, the cell will not be depolarized and no action potential will be generated. This value of potential above which the depolarizes and an action potential is generated is known as the stimulus threshold.
7. After a cell is stimulated, a finite period of time is required for the cell to return to its pre-stimulus state. This period is known as ____________
a) restoration period
b) refactory period
c) regain period
d) regenerative period
Answer: b
Explanation: After a cell is stimulated, a finite period of time is required for the cell to return to its pre-stimulus state. This is because the energy associated with the action potential is developed from metabolic process within the cell which takes time for completion. This time period is called refactory period.
8. Electrooculography is a technique for measuring what?
a) abnormal function of the retina
b) heart rate
c) respiration rate
d) cornea-retinal standing potential
Answer: d
Explanation: Electrooculography is a technique for measuring the potential of the corneal retinal standing potential that exists between the front and back of the human eye. The resulting signal is called electrooculogram. The main applications are in the diagnosis of ophthalmology and the recording of eye movements.
9. EKG stands for _________________
a) Electrocardiography
b) Electroencephalography
c) Electromyography
d) Electrtokinetcography
Answer: a
Explanation: Electrocardiography is the way toward recording the electrical action of the heart over some stretch of time utilizing anodes put on the skin. It could simply be understood as the electrical representation of heart beat. Electroencephalography is the electrical recording of brain.
10. Phonocardiography is listening to __________
a) arm muscle sound
b) lungs sound
c) heart sound
d) respiratory tract sound
Answer: c
Explanation: A phonocardiogram is a record high-constancy recording of sounds and mumble made by the heart with the assistance of the machine called phonocardiography. Consequently, phonocardiography is the chronicle of the considerable number of sounds made by the heart amid a heart cycle. Mostly stethoscope is used phonocardiography.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Recording Electrodes”.
1. Electrodes make a transfer from the __________ in the tissue to the electronic conduction which is necessary to make measurements.
a) electronic conduction
b) ionic conduction
c) electric conduction
d) impulsive conduction
Answer: b
Explanation: Electrodes make an exchange from the ionic conduction in the tissue to the electronic conduction which is important to make measurements. An electrolytic paste is applied between the electrodes and the skin to reduce skin contact impedance. The electrolyte also facilitates ionic conduction from the skin to the electrodes.
2. Surface electrodes damage the living tissues.
a) True
b) False
Answer: b
Explanation: The surface electrodes pick up the potential difference from the tissue surface when placed over it without damaging the living tissues. They are placed above the skin and cause no harm to the living tissues. They capture the electrical activities of bunch of tissues together.
3. Deep-seated electrodes indicates the electric potential difference arising ________ the living tissues or cells.
a) inside
b) outside
c) around
d) adjacent
Answer: a
Explanation: Deep-seated electrodes indicate the electric potential difference arising inside the living tissues or cells. Surface electrodes indicates the electric potentials arising outside the living tissues that is on the surface of the skin. Needle electrodes are example of deep seated electrodes.
4. Impedance pneumography is a commonly-used technique to monitor a person’s _______
a) respiration rate
b) heart rate
c) pulse rate
d) skin impedance
Answer: a
Explanation: Impedance pneumography is a commonly-used technique to monitor a person’s respiration rate, or breathing rate. It is implemented by using two electrodes or four electrodes. Skin impedance is the resistance between the skin and the electrode. Heart rate measurement is called ECG.
5. Electrode paste ____________
a) increases contact impedance
b) equates contact impedance
c) reduces contact impedance
d) absorbs contact impedance
Answer: c
Explanation: In order to obtain a clearly established contact an electrolyte or electrode paste is usually employed as an interface between the electrode and the surface of the source of the event. It is placed between the skin and the electrode. It helps to get better signal acquisition.
6. All electrode potentials are measured with respect to which reference electrode?
a) hydrogen electrode
b) platinum electrode
c) calomel electrode
d) hydrogen absorbed on platinum electrode
Answer: d
Explanation: All electrode potentials are measured with respect to a reference electrode, usually that of hydrogen absorbed on platinum black. Thus, considering potential of hydrogen absorbed on platinum electrode to be zero, other all have positive of negative potentials.
7. What is the frequency range of ECG?
a) 70-120 Hz
b) 0.05-120 Hz
c) 5-120 Hz
d) 12-120 Hz
Answer: b
Explanation: Primary signal characteristics of ECG are:
Frequency range: 0.05-120 Hz.
Signal amplitude: 0.1-5 mV.
Typical signal: 1mV.
8. What is the signal amplitude of EEG?
a) 2-200 µV
b) 2-200mV
c) 2-2000 µV
d) 2-2000mV
Answer: a
Explanation: The signal amplitude of EEG is between 2-200 µV. It is very small and requires special type of electrodes namely scalp electrodes. EEGs are difficult to capture because its signal range in very small and motion artifacts are much greater.
9. Needle electrode is used to measure ____________
a) EKG
b) EEG
c) EOG
d) EMG
Answer: d
Explanation: EMG stands of Electromyogram. For recording action potential for individual motor units of muscle fiber, needle electrodes are used for better diagnostic information. These electrodes fall in the category of deep seated electrodes.
10. From equipment point of view, the respiratory system in the human body is a _________ system.
a) hydraulic
b) pneumatic
c) mechanical
d) electrical
Answer: b
Explanation: Respiratory system is a pneumatic system in which an air pump alternately creates negative and positive pressures in a sealed chamber and causes air to be sucked into and forced out of a pair of elastic bags . Blood circulatory system is related to hydraulic system.
11. Off-set potential is _____________
a) difference in half-cell potentials between two electrodes
b) sum of half-cell potentials between two electrodes
c) average of half-cell potentials between two electrodes
d) complement of half-cell potentials between two electrodes
Answer: a
Explanation: The difference in half cell potential that exists between two electrodes is called off-set potential. The differential amplifies used to measure potentials between two electrodes are generally designed to cancel the electrode offset potential so that only the signals of interest are recorded.
12. Which of the following is not preferred for electrode making?
a) Ag-AgCl
b) Copper
c) Stainless-steel
d) Gold
Answer: c
Explanation: Stainless steel in contact with a saline electrolyte produce a potential difference of 10 mV between the electrodes which is much more than the limit . Ad-AgCl electrodes give almost noise free characteristics. They are also found to be acceptable from the point of view of long term drift.
13. Which of the following statement is false about polarizable electrodes?
a) they are made using stainless steel
b) used for recording resting ECG
c) retain a residual charge when exposed to large pulse of energy
d) can transmit small bioelectric signals even after getting exposed to large pulse of energy
Answer: d
Explanation: Polarizable electrodes usually employ stainless steel and are used for resting ECG or other situations where there is small likelihood that the electrode would be exposed to a large pulse of energy in which case they would retain a residual charge, become polarized, and will no longer transmit the relatively small bioelectric signals, thus become useless.
14. Which electrodes can work even after being induced to large electric discharge such as defibrillation?
a) polarizing electrodes
b) magnetic electrodes
c) non-polarizing electrodes
d) electrolytic electrodes
Answer: c
Explanation: Non-polarizing electrodes are designed to rapidly dissipate any charge imbalance induced by powerful electric discharges such as a defibrillation procedure. Rapid depolarization enables the immediate reappearance of bioelectric signals on the monitor after defibrillation. For this reason, non-polarizing electrodes have become the electrodes of choice for monitoring in the intensive care units and stress testing procedures.
This set of Biomedical Instrumentation Interview Questions and Answers focuses on “Silver-Silver Chloride Electrodes”.
1. On increasing the chloride deposit the Ag-AgCl electrode ______________
a) increases the impedance
b) reduces impedance
c) has no effect on impedance
d) cannot be determined
Answer: a
Explanation: Studies have shown that the impedance of the electrode was different layers of chloride. There is an optimum chloriding, which gives the lowest impedance. Above and below that value the impedance is high.
2. Ag-AgCl electrodes are ___________
a) polarized
b) non-polarized
c) partially polarized
d) cannot be said
Answer: b
Explanation: The most important and desirable property of the electrodes designed to pick up signals from biological objects is that they should not polarize. This means that the electrodes potential must not vary considerably even when current passes through it. Electrodes made of Ag-AgCl yield acceptable standards of performance.
3. Silver -Silver Chloride electrodes are prepared by the process of ____________
a) centrifugation
b) etching
c) manually
d) electrolysis
Answer: d
Explanation: Silver-Silver Chloride electrodes are normally prepared by electrolysis. Two silver discs are suspended in a saline solution. The positive pole of dc supply is connected to the disc to be chloride and the negative pole goes to the other disc.
4. Electrocardiography was invented by ___________
a) Willem Einthoven
b) Robert Koch
c) Werner Forssmann
d) Gertrude B.Elion
Answer: a
Explanation: Willem Einthoven a Dutch physician and physiologist. He invented the first Electrocardiogram in 1903. He received the Nobel Prize for Medicine in 1924 for it.
5. MRI stands for ____________
a) Mechanical Resonance Imaging
b) Magnetic Resonance Imaging
c) Mutually Related Imaging
d) Magnetic Resultant Imaging
Answer: b
Explanation: MRI stands for Magnetic Resonance Imaging. The MRI is a diagnostic technique that uses magnetic fields and radio waves to produce a detailed picture of soft tissues and body bones. An MR mirrors the spine using a magnet crossing the body to excite hydrogen atoms.
6. The interior of the neuron is at a potential of about _____ mV relative to the exterior.
a) -70
b) +70
c) -170
d) +170
Answer: a
Explanation: The neurons, like the other cells of the body, are electrically polarized at rest. The interior of the neuron is at a potential of about -70 mV relative to the exterior. When a neuron is exposed to a stimulus above a certain threshold, a nerve impulse, seen as a change in membrane potential, is generated which spreads in the cell resulting in the depolarization of the cell.
7. Tricuspid valve is also called _______________
a) Left Atrio-ventricular valve
b) Right Atrio-ventricular valve
c) Pulmonary valve
d) Cardiac valve
Answer: b
Explanation: It’s placed between right atrium and ventricle. It consists of three flaps or cusps. It prevents backward flow of blood from right ventricle to the right atrium.
8. From instruments point of view, heart is a ______ system.
a) pneumatic
b) electric
c) electronic
d) hydraulic
Answer: d
Explanation: Heart pumps blood. It is analogous to water. Thus heart can be considered as a hydraulic system.
9. The basic functional unit of nervous system is ____________
a) nerves
b) axon
c) neuron
d) dendrite
Answer: c
Explanation: The basic functional unit of the nervous system is a neuron. A typical neuron consists of a nucleated cell body and has several processes and branches. The dendrites normally conduct impulses towards the cell body and the axon conducts away from it.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Electrodes for ECG”.
1. The material used in limb surface electrode is ___________
a) German silver
b) Copper
c) Gold
d) Platinum
Answer: a
Explanation: The most common type of electrode most routinely used for recording ECG are rectangular or circular surface limb electrodes. The material used in them is German silver, nickel silver or nickel plated steel. They are applied to the surface of the body with electrode jelly.
2. Welsh cup electrodes have __________
a) low contact impedance
b) negligible contact impedance
c) high contact impedance
d) zero contact impedance
Answer: c
Explanation: Welsh cup electrodes or suction electrodes is a metallic cup shaped electrode which is used for recording ECG from various positions from the chest. It has a high contact impedance as only the rim of the electrode is in contact with the skin. It is commonly used to record the unipolar chest leads.
3. In floating electrodes metal electrode does not make direct contact with the skin.
a) True
b) False
Answer: a
Explanation: In floating electrode the metal electrode does not make direct contact with the skin. The electrode consists of a light weighted metalled screen or plate held away from the subject by a flat washer which is connected to the skin. Floating electrodes can be recharged, i.e. the jelly in the electrodes can be replenished if desired.
4. The main design feature of pregelled disposable electrodes which helps to reduce the possibility of artefacts, drift and baseline wandering is _____________
a) low absorbency buffer layer with isotonic electrolyte
b) high absorbency buffer layer with isotonic electrolyte
c) high absorbency buffer layer without isotonic electrolyte
d) low absorbency buffer layer without isotonic electrolyte
Answer: b
Explanation: The main design feature of pregelled disposable electrode that helps in reducing the possibility of artefacts, drift and baseline wandering is the provision of high absorbency buffer layers with isotonic electrolyte. This layer absorbs the effects of movement of the electrode in relationship to the skin and attempts to maintain the polarization associated with the half-cell potential constant.
5. Recording electrical activities associated with heart is known as ____________
a) EEG
b) EOG
c) EMG
d) ECG
Answer: d
Explanation: The recording of the electrical activities associated with the functioning of the heart is known as electrocardiogram. ECG is a quasi-periodical, rhythmically repeating signals synchronized by the function of the heart, which acts as a generator of bioelectric events. This generated signals can be described by the means of a simple electric dipole.
6. Which of the following is considered to be the primary pacemaker of the heart?
a) sino-atrial node
b) atrio-ventricular node
c) purkinje fibres
d) bundle of his
Answer: a
Explanation: Located in the top right atrium near the entry of the vena cava, are a group of cells known as the sino-atrial node that initiates the heart activity. Because this is also considered as the primary pacemaker of the heart. The SA node is 25 to 30 mm in length and 2 to 5 mm in thickness.
7. Atrio ventricular node is located at __________
a) upper part of the heart wall between the two atrial
b) lower part of the heart wall above the two atrial
c) lower part of the heart wall between the two atrial
d) upper part of the heart wall above the two atrial
Answer: c
Explanation: The AV node is located in the lower part of the wall between the two atria. The AV node delays the spread of excitation for about 0.12s, due to the presence of a fibrous barrier of non-excitable cells that effectively prevent its propagation from continuing beyond the limits of stria.
8. Buffer amplifier converts ____________
a) low impedance signals to high impedance signals
b) high impedance signals to low impedance signals
c) ac impedance signals to dc impedance signals
d) dc impedance signals to ac impedance signals
Answer: b
Explanation: Noise is typically generated from motion artefacts and power line interference. A common solution used to suppress noise in dry electrode signals is a buffer amplifier. A buffer amplifies is essentially an impedance converter, that converts high impedance signals to low impedance signals.
9. Which of the following is a wireless ECG acquiring system?
a) pregelled disposable electrodes
b) limb electrodes
c) pasteless electrodes
d) smart pad
Answer: d
Explanation: Smart pad is a system that displays patients electrocardiogram signals without adhesive pads, wires or active intervention from a clinician. The system automatically selects three electrodes from an array of Cu/Ni fabric based electrodes patterned on a thin pad on which the patient lies. The selected electrodes are used to provide a differential 3 lead measurement of the patient’s ECG, which is then transmitted wirelessly and displayed on a laptop computer.
10. Before placing the electrodes the skin should be __________
a) wet
b) dry
c) hairy
d) oily
Answer: b
Explanation: The skin should be dry. Poor skin prep prompts undesirable curio and not putting the terminals where they ought to be can change the morphology of the waveforms the specialist will decipher. The purpose of decent skin prep is to expel soil, dead skin cells, oils, skin cream, counterfeit tan, body powder, sweat and so forth. These sources can prompt poor contact with the sensors and ancient rarity.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Electrodes for EMG”.
1. Which of the following is a preferred electrode for measuring EMG?
a) surface electrodes
b) needle electrodes
c) pregelled electrodes
d) scalp electrodes
Answer: b
Explanation: Electrodes for EMG work are usually of the needle type. Needle electrodes are used in clinical EMG, neurography and other electrophysiological measurements of the muscle tissues underneath the skin. Surface electrodes are preferred to measure ECG. Scalp electrodes for EEG.
2. Generally what is the material of needle electrodes?
a) stainless steel
b) copper
c) lead
d) iron
Answer: a
Explanation: The material of the needle electrode is generally stainless steel. In spite of the face that stainless steel is unfavorable electrode material from the point of view of noise, it is preferred in EMG work. It is due to its mechanical solidity and low price.
3. Monopolar needle electrodes are having coatings of which material over the stainless steel wires which are bare only at the tips?
a) carbon
b) calcium
c) sodium
d) teflon
Answer: d
Explanation: The monopolar needle electrode consists of a teflon coated stainless steel wire. The wire is bare only at the tip. It is found that after the needle has been used a number of times, the teflon coating will recede, increasing the tip area. The needle should be discarded when this happens.
4. Which electrode can be used to pick up signals from individual fibers of muscle tissues?
a) biopolar needle electrode
b) concentric core needle electrode
c) multi-element needle electrode
d) monopolar needle electrode
Answer: c
Explanation: Multi-element needle electrodes are used to pick up the signals from individual fibers of muscle tissue. Special needles are available using 25-micron diameter electrode surfaces. They have up to 14 pickup surfaces down the side of one needle.
5. _______________ instrument is used to hold patients head and guide the placement of electrodes.
a) Monotaxic
b) Stereotonic
c) Stereotaxic
d) Monotonic
Answer: c
Explanation: For measurement of potential from specific part of the brain, longer needles are inserted inside the head. The needles are precisely located by means of a map or atlas of the brain. A special instrument called stereotaxic instrument is used to hold the subject’s head and guide the placement of the electrodes.
6. Number of cloud deployment models that are recognized are _________
a) 2
b) 5
c) 3
d) 4
Answer: c
Explanation: There are 3 recognized cloud deployment models. They are – Private cloud, Public cloud and Hybrid cloud.
7. The ground electrode is usually positioned over which body structures?
a) bony
b) hairy
c) fleshy
d) sweaty
Answer: a
Explanation: The ground electrode is usually positioned over bony structures rather than over large muscle masses, in the vicinity of the recording and stimulating electrodes, and where possible, equidistant from them. Hairy areas don’t transmit proper signals. It increases impedance of the skin.
8. When intramuscular EMG is required to look into the electrical activities of deeper or overlaid muscles, ________ electrodes are used.
a) plate shape electrodes
b) surface electrodes
c) thin thread electrodes
d) fine wire electrodes
Answer: d
Explanation: When intramuscular EMG is required to look into the electrical activities of deeper or overlaid muscles, thin and flexible fine wire electrodes are used. These electrodes are inserted into the muscle site of interest. The needle or steel cannula is removed, and the electrode wires are connected to the steel spring adapters to minimize movement artefacts.
9. The contraction of the skeletal muscles results in the generation of action potential in the individual muscle fibers. Record of this action potential is called ______________
a) ECG
b) EMG
c) EEG
d) EKG
Answer: b
Explanation: The contraction of the skeletal muscles results in the generation of action potential in the individual muscle fibers, a record of such action potential is known as electromyogram . The activity is similar to that observed in the cardiac muscles , but in the skeletal muscles, repolarization takes place much more rapidly. The action potential lasts for only few milliseconds.
10. In voluntary contraction of the skeletal muscles, the muscle potential ranges from ________
a) 50 uV – 5 mV
b) 50 mV – 5 V
c) 0.05 uV – 2 mV
d) 50 mV – 500 mV
Answer: a
Explanation: In voluntary contraction of the skeletal muscles, the muscle potential ranges from 50 uV – 5 mV and duration from 2 to 15 ms. The values vary with the anatomic position of the muscle and the size and location of the electrode. In a relaxed muscle there are no action potentials.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Electrodes for EEG”.
1. Electrodes to measure EEG are placed on ________
a) forehead
b) scalp
c) cheek
d) ears
Answer: b
Explanation: Electrode to measure EEG are placed on the scalp. The position of each electrode is specified using the International 10/20 system. Each electrode site is labeled with a letter and a number.
2. According to the international 10/20 system to measure EEG, even number denotes which side of the brain?
a) left
b) top
c) bottom
d) right
Answer: d
Explanation: The position of each electrode is specified using the International 10/20 system. Each electrode site is labeled with a letter and a number. Even number denotes the right side of the head.
3. Letter F in the EEG electrode placement system denotes?
a) front
b) face
c) frontal lobe
d) fast
Answer: c
Explanation: F denotes frontal lobe of the head. The position of each electrode is specified using the International 10/20 system. Each electrode site is labeled with a letter and a number.
4. Normal EEG frequency range is _______
a) 50-500Hz
b) 0.5-50HZ
c) 0.05-5Hz
d) 1-200Hz
Answer: b
Explanation: The frequency varies greatly with different behavioral states. The normal EEG frequency content ranges from 0.5 to 50Hz. The nature of the wave varies over the different parts of the scalp.
5. The letter T in the EEG electrode placement system denotes?
a) temporal lope
b) temper lobe
c) trace
d) timpanic
Answer: a
Explanation: T denotes temporal lobe of the head. The position of each electrode is specified using the International 10/20 system. Each electrode site is labeled with a letter and a number.
6. According to the international 10/20 system to measure EEG, odd number denotes which side of the brain?
a) left
b) right
c) top
d) front
Answer: a
Explanation: The position of each electrode is specified using the International 10/20 system. Each electrode site is labeled with a letter and a number. Odd number denotes the left side of the head.
7. The delta wave in EEG ranges from ___________
a) 0.5-4Hz
b) 4-8Hz
c) 8-13Hz
d) 13-22Hz
Answer: a
Explanation: The delta wave in EEG ranges from 0.5-4Hz. The theta wave in EEG ranges from 4-8Hz. The alpha wave in EEG ranges from 8-13Hz and beta from 13-22Hz.
8. Disturbance in the EEG pattern resulting from the external stimuli is called ________
a) provoked response
b) ckoored response
c) evoked response
d) impulse response
Answer: c
Explanation: Disturbance in the EEG pattern resulting from the external stimuli is called evoked response. The stimuli could be a flash light or a click of sound. The stimuli can be repeated and the EEG waveform can be observed to find the activities occurring because of the stimuli.
9. The peak to peak amplitude of the waves that can be picked from the scalp is ______________
a) 100mV
b) 100V
c) 100uV
d) 10mV
Answer: c
Explanation: The EEG signal can be picked up with electrodes either from the scalp or directly from the cerebral cortex. The peak to peak amplitude of the waves that can be picked up from the scalp is normally 100uV. The frequency varies greatly with different behavioral states.
10. Which rhythm is the principal component of the EEG that indicates the alertness of the brain?
a) theta rhythm
b) gamma rhythm
c) beta rhythm
d) alpha rhythm
Answer: d
Explanation: The alpha rhythm is the principal component of the EEG and is an indicator of the state of alertness of the brain. It serves as an indicator of the depth of anesthesia in the operating room. The frequency of the EEG seems to be affected by the mental activity of a person.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Microelectrodes”.
1. Which type of electrodes are employed to study the electrical activities of individual cells?
a) milli-electrodes
b) micro-electrodes
c) surface-electrodes
d) pre-jelled electrodes
Answer: b
Explanation: To study the electrical activities of individual cells, micro electrodes are employed. This type of electrode is small enough with respect to the size of the cells. Typical micro electrodes have tip dimensions ranging from 0.5-5 microns.
2. Glass micro-capillaries are a type of micro electrode.
a) True
b) False
Answer: a
Explanation: Two types of micro electrodes are generally used: metallic and glass microcapillaries. Metallic electrodes are formed from a fine needle of suitable metal drawn for a fine tip. Glass electrodes are drawn from Pyrex glass of special grade.
3. Glass microcapillaries are preferred over metallic electrodes because of the former _______
a) polarizes with input current
b) does not have sustainable current carrying capacity
c) has less contact surface area
d) has sustainable current carrying capacity
Answer: d
Explanation: Metallic electrodes polarize with smaller amplifier input currents. Hence, they tend to develop unstable electrode offset potential and are therefore not preferred for steady state potential measurement. On the other hand, in case of glass micro electrodes have a sustainable current carrying capacity because of the large surface area between the metal and the electrolyte.
4. Do metallic micro electrodes exist.
a) True
b) False
Answer: a
Explanation: Two types of micro electrodes are generally used: metallic and glass microcapillaries. Metallic electrodes are formed from a fine needle of suitable metal drawn for a fine tip. Glass electrodes are drawn from Pyrex glass of special grade.
5. Metallic micro electrodes have impedance ________ compared to conventional electrodes?
a) equal
b) smaller
c) high
d) very high
Answer: d
Explanation: The very high impedance of the metal micro-electrodes is due to the characteristics of the small area metal-electrolyte interface. Because of very high impedance of micro electrodes, amplifiers with extremely high input impedance are required to avoid loading the circuit and to minimize the effects of small change in interface impedance.
6. Which of the following electrode is manufactured by circumferential application of heat to a small area of glass tubing and pulling the glass when it gets soft?
a) macro metallic electrodes
b) micro metallic electrodes
c) micro pipette
d) surface electrodes
Answer: c
Explanation: The most commonly used method for making small tip micropipette consists of the circumferential application of heat to a small area of glass tubing which is placed under some initial tension. When the glass softens, the tension is increased very rapidly and the heat is turned off. Proper timing, controlled adjustment of the amount of heat as well as the initial and final tensions and cooling results in the production of microcapillaries with control dimensions.
7. Which of the following metal is preferred for manufacturing micro electrodes?
a) Stainless steel
b) Tungsten
c) Iron
d) Copper
Answer: b
Explanation: Tungsten is preferred for constructing micro-electrodes due to its mechanical strength and its apparent inertness. Although tungsten itself is reactive, a surface layer of tungsten oxide will, in most situations, protect the metal against corrosion.
8. ________________ are devices which convert one form of energy into another.
a) transducers
b) electrodes
c) impulses
d) opamp
Answer: a
Explanation: Transducers are devices which convert one form of energy into another. A number of factors decide the choice of a particular transducer to be used for the study of a specific phenomenon. Many physical, chemical and optical properties and principles can be applied to construct transducers for applications in the medical field.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Classification of Transducers”.
1. Which type of transducer requires energy to be put into it in order to translate changes due to the measurand?
a) active transducers
b) passive transducers
c) powered transducers
d) local transducers
Answer: b
Explanation: Passive transducers are transducers that require energy to translate changes due to the measurand. Active transducers convert one form of energy directly into another. For example photovolatic cell in which light energy is converted into electrical energy.
2. Active transducers work on the principle of ________
a) energy conversion
b) mass conversion
c) energy alteration
d) volume conversion
Answer: a
Explanation: Active transducers work on the principle of energy conversion. They convert one form of energy to another. They don’t require any power to operate.
3. Accuracy is ______
a) ability of the transducer or sensor to see small differences in reading
b) ability of the transducer or sensor to see small differences in reading
c) algebraic difference between the indicated value and the true or theoretical value of the measurand
d) total operating range of the transducer
Answer: c
Explanation: Accuracy describes the algebraic difference between the indicated value and the true or theoretical value of the measurand. Resolution is the ability of the transducer or sensor to see small differences in reading. Precision refers to the degree of repeatability of a measurant.
4. The smallest change in measurant that will result in a measurable change in the transducer output is called _______
a) offset
b) linearity
c) resolution
d) threshold
Answer: d
Explanation: The threshold of the transducer is the smallest change in measurant that will result in a measurable change in the transducer output. Offset is the output that will exist when it should be zero. Linearity shows closeness of a transducer’s calibration curve to a specific straight line with in a given percentage of full scale output.
5. Unwanted signal at the output due either to internal sources or to interference is called ________
a) offset
b) noise
c) drift
d) threshold
Answer: b
Explanation: Noise is the unwanted signal at the output due either to internal sources or to interference. Offset is the output that will exist when it should be zero. The threshold of the transducer is the smallest change in measurant that will result in a measurable change in the transducer output.
6. The ability of the sensor to see small differences in reading is called ______
a) resolution
b) drift
c) offset
d) linearity
Answer: a
Explanation: The ability of the sensor to see small differences in reading is called the resolution of the sensor. Offset is the output that will exist when it should be zero. Linearity shows closeness os a transducer’s calibration curve to a specific straight line with in a given percentage of full scale output.
7. Change is signal over long period of time is called _______
a) noise
b) offset
c) hysteresis
d) drift
Answer: d
Explanation: Drift indicated a change of base line or of sensitivity with time, temperature etc. Drift is basically the change in a signal over long period of time. Noise is the unwanted signal at the output due either to internal sources or to interference. Offset is the output that will exist when it should be zero.
8. Linearity of transducer is ___________
a) Closeness of the transducer’s calibration curve to a special curved line within a given percentage of full scale output
b) Closeness of the transducer’s calibration curve to a special straight line within a given percentage of full scale output
c) Closeness of the transducer’s calibration curve to a special straight line within a given percentage of half scale output
d) Closeness of the transducer’s calibration curve to a special curved within a given percentage of half scale output
Answer: b
Explanation: Linearity of transducer is closeness of the transducer’s calibration curve to a special straight line within a given percentage of full scale output. Basically, it reflects that the output is in some way proportional to the input. A linear sensor produces an output value which is directly proportional to the input.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Performance Characteristics of Transducers”.
1. The minimum input of physical parameter that will create a detectable out change is called __________
a) threshold
b) sensitivity
c) span
d) precision
Answer: b
Explanation: The sensitivity of the sensor is defined as the slope of the output characteristic curve. In simple words The minimum input of physical parameter that will create a detectable out change is called sensitivity. Total operating range of the transducer is called its span.
2. The total operating range of the transducer is called __________
a) span
b) threshold
c) offset
d) drift
Answer: a
Explanation: The total operating range of the transducer is called span of the transducer. Offset is the output that will exist when it should be zero. Drift is basically the change in a signal over long period of time.
3. Hysteresis is no change in output with the same value of input.
a) True
b) False
Answer: b
Explanation: Hysteresis is change in output with the same value of input but with a different history of input variation. Hysteresis is observed when the input/output characteristics for a transducer are different for increasing inputs than for decreasing outputs. It results when some of the energy applied for increasing inputs is not recovered when the input decreases.
4. The region in which the output does not changes with increase in input is called _________
a) input range
b) threshold
c) offset
d) saturation
Answer: d
Explanation: The region in which the output does not changes with increase in input is called saturation. The threshold of the transducer is the smallest change in measurant that will result in a measurable change in the transducer output. Offset is the output that will exist when it should be zero.
5. Ability of the sensor to repeat a measurement when put back in the same environment is called ______
a) conformance
b) saturation
c) repeatability
d) threshold
Answer: c
Explanation: Ability of the sensor to repeat a measurement when put back in the same environment is called repeatability. The region in which the output does not changes with increase in input is called saturation. The threshold of the transducer is the smallest change in measurant that will result in a measurable change in the transducer output.
6. Closeness of a calibration curve to a specified curve for an inherently non linear transducer is called ___________
a) conformance
b) linearity
c) saturation
d) hysteresis
Answer: a
Explanation: Conformance indicates the closeness of a calibration curve to a specified curve for an inherently non linear transducer. Hysteresis is change in output with the same value of input but with a different history of input variation. The region in which the output does not changes with increase in input is called saturation.
7. The range between the maximum and minimum values is applied to a parameter which can be measured is ___________
a) repeatability
b) span
c) input range
d) output range
Answer: b
Explanation: Input range is the range between the max and min values is applied parameter which can be measured . Ability of the sensor to repeat a measurement when put back in the same environment is called repeatability. The total operating range of the transducer is called span of the transducer.
8. Which of the following is not a static property?
a) repeatability
b) hysteresis
c) frequency response
d) saturation
Answer: c
Explanation: Frequency response is the change of transfer function with frequency, both in magnitude and in phase. It is a dynamic property. Ability of the sensor to repeat a measurement when put back in the same environment is called repeatability. The region in which the output does not changes with increase in input is called saturation.
9. Time for the sensor to reach a stable output once it is turned on is called _________
a) frequency response
b) span
c) response time
d) settling time
Answer: d
Explanation: Settling time is the time for the sensor to reach a stable output once it is turned on. Frequency response is the change of transfer function with frequency, both in magnitude and in phase. The total operating range of the transducer is called span of the transducer.
10. Which of the following is not a dynamic property?
a) frequency response
b) saturation
c) settling time
d) response time
Answer: b
Explanation: The region in which the output does not changes with increase in input is called saturation. It is a static property of the transducer. Settling time is the time for the sensor to reach a stable output once it is turned on. Frequency response is the change of transfer function with frequency, both in magnitude and in phase.
This set of Biomedical Instrumentation Questions and Answers for Freshers focuses on “Displacement, Position and Motion Transducers”.
1. Potentiometer works on which of the following principle?
a) variable resistance
b) variable inductance
c) variable capacitance
d) variable electromagnet
Answer: a
Explanation: Potentiometer works on the principle of variable resistance. The resistance between two terminals of this device is related to the linear or angular displacement of a sliding tape along a resistance element. When the fixed terminals of the potentiometer are connected to the power supply. Either ac or dc, output voltage at the wiper varies with the displacement of the object.
2. On increasing the distance between the plates of a variable capacitor, the displacement- capacitance characteristics changes _______
a) proportionally
b) linearly
c) exceptionally
d) hyperbolically
Answer: d
Explanation: By moving one plate of the capacitor with respect to the other, the capacitance will vary inversely with respect to the plate separation. This will give a hyperbolic displacement capacitance characteristic. This is how variable capacitance is employed as displacement transducers.
3. Lateral displacement of capacitance plates with respect to each other gives linear displacement capacitance characteristics.
a) True
b) False
Answer: a
Explanation: It is true that lateral displacement of capacitance plates with respect to each other gives linear displacement capacitance characteristics. C = 0.0885*k*.
k = dielectric constant of the medium separating the two plates.
C = capacitance in micro farads
A = area of each identical plate in cm 2
d = distance between the plates in cm 2 .
4. LVDT stands for _________
a) Linear Virtual Double Transformer
b) Linear Virtual Differential Transducer
c) Linear Variable Differential Transducer
d) Linear Variable Differential Transformer
Answer: d
Explanation: LVDT stands for Linear Variable Differential Transformer. These transducers are conventionally used for measurement of physiological pressure. They generally work in conjunction with carrier amplifiers.
5. LVDT works on the principle of ________
a) variable resistance
b) variable inductance
c) variable capacitance
d) variable pressure
Answer: b
Explanation: LVDT works on the principle of variable inductance. It has three coils namely the primary coil which is the center coil. The other two are called the secondary coils so connected that their outputs are equal in magnitude but opposite in phase.
6. In LVDT the secondary coils are energized with sine wave oscillator.
a) True
b) False
Answer: b
Explanation: The center coil is the energizing or primary coil connected to a sine wave oscillator. The secondary coils so connected that their outputs are equal in magnitude but opposite in phase. LVDT works on the principle of variable inductance.
7. How many coils are required to make LVDT?
a) 4
b) 6
c) 3
d) 2
Answer: c
Explanation: Total 3 coils are required in LVDT. One centered coil which is the energizing or primary coil connected to the sine wave oscillator. The other two coils are the secondary coils so connected that their outputs are equal in magnitude but opposite in phase.
8. LVTD is a _______ transducer.
a) displacement
b) photoelectric
c) thermal
d) chemical
Answer: a
Explanation: LVDT is a displacement transducer. It works on the principle of variable inductance. The shift in the ferromagnetic core from the centre position induces voltage in the second coild which can be calibrated to determine the linear displacement.
9. Which of the following is a displacement transducer?
a) Thermistor
b) LVDT
c) Strain gauge
d) Thermocouple
Answer: b
Explanation: LVDT is a displacement transducer. Thermocouple and thermistor are temperature transducers. Strain gauge is a pressure transducer.
10. Linear encoders gives ___________ output.
a) angular
b) analog
c) digital
d) unstable
Answer: b
Explanation: Linear encoders give output in digital form. These transducers are basically encoded disks or rulers with digital pattern photographically etched on glass plate. These patterns are decoded using a light source and an array of photodetectors.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Pressure Transducers”.
1. Which of the following is not a piezo-electric material?
a) quartz
b) rochelle salt
c) aluminium
d) barium titanate
Answer: a
Explanation: Aluminium is not a piezo-electric material. Quartz is the most stable natural crystal with high mechanical and thermal stability and has voulme resistivity higher than 10 4 ohm-cm and small internal electric loss. Barium titanate ceramic is a ferroelectric crystal and has small voltage output.
2. Piezo-electricity is ______________
a) sound electricity
b) pressure electricity
c) temperature electricity
d) photo electricity
Answer: b
Explanation: Piezo-electricity is pressure electricity. The piezo electric effect is a property of natural crystalline substance to develop electric potential along a crystallographic axis in response to the movement of charge as a result of mechanical deformation.
3. On applying electricity to piezo-electric material mechanical deformation occurs in the material.
a) True
b) False
Answer: a
Explanation: Yes, on applying electricity to the piezo-electric material mechanical deformation occurs in the material. The piezo electric effect is a property of natural crystalline substance to develop electric potential along a crystallographic axis in response to the movement of charge as a result of mechanical deformation.
4. Which of the following is a material employed making diaphragm to measure pressure?
a) tourmaline
b) barium titanate
c) phosphor bronze
d) zirconate titanate
Answer: c
Explanation: Phosphor bronze is used to make diaphragm to measure pressure. The motion of diaphragm is measured in terms of electric signals. Tourmaline , barium titanate and zirconate titanate are piezo electric materials.
5. Principle behind strain gauge is _____________
a) variable resistance
b) variable inductance
c) variable capacitance
d) variable contact area
Answer: a
Explanation: The principle behind strain gaude is the variable resistance. The transducer is based upon the changed in resistance of a wire produced due to small mechanical displacement. A linear relation exists between the deformation and electrical resistance of a suitable selected gauge over a specified range.
6. On applying pressure to piezo-electric crystal, electricity is not generated.
a) True
b) False
Answer: b
Explanation: On applying pressure to piezo-electric crystal, electricity is generated. The piezo electric effect is a property of natural crystalline substance to develop electric potential along a crystallographic axis in response to the movement of charge as a result of mechanical deformation. Thus, piezo-electricity is pressure electricity.
7. The figure of merit which describes the overall behaviour of the wire under stress is determined from?
a) elastic modulus
b) gauge factor
c) elastic factor
d) gauge resistance
Answer: b
Explanation: The figure of merit which describes the overall behaviour of the wire under stress is determined from the gauge factor of the wire. Gauge factor gives information on the expected resistance change or output signal at maximum permissible elongation.the gauge factor determines to a large extent the sensitivity of the wire when it is made into a practical strain gauge.
8. Gauge factor is defined as _______________
a) *
b) *
c) *
d) *l
Answer: a
Explanation: Gauge factor is defined as *. Gauge factor gives information on the expected resistance change or output signal at maximum permissible elongation.the gauge factor determines to a large extent the sensitivity of the wire when it is made into a practical strain gauge.
9. Compensation for temperature variation in the leads can be provided by using ________ lead method.
a) six
b) four
c) three
d) two
Answer: c
Explanation: Compensation for temperature variation in the leads can be provided by using three lead method. In this method two of the leads are in the adjacent legs of the bridge which cancels their resistance changes and does not disturb the bridge balance. The third lead is in series with the power supply and is therefore independent of bridge balance.
10. Strain gauge is used to measure ______________
a) temperature
b) pressure
c) height
d) displacement
Answer: b
Explanation: Strain gauge is used to measure pressure. Its working principle is change in resistance. There are two type of strain gauges. Bounded strain gauge and unbounded strain gauge. Mostly used to measure the arterial and venous blood pressure in the body.
This set of Biomedical Instrumentation Interview Questions and Answers for freshers focuses on “Transducers for Body Temperature Measurement”.
1. Sudden involuntary drop in body core temperature below 35*C is called __________
a) Accidental hyperthermia
b) Accidental misothermia
c) Accidental exothermia
d) Accidental hypothermia
Answer: d
Explanation: Sudden involuntary drop in body core temperature below 35*C is called Accidental hypothermia. In this, the body temperature drops very quickly. If not treated on time can lead to patients death.
2. Which of the following has the widest range of temperature measurement?
a) RTD
b) Thermocouple
c) Thermistor
d) Mercury thermometer
Answer: b
Explanation: Thermocouple has the widest range of temperature measurement from -184 0 C to +2300 0 C. RTD has a range of -200 0 C to +850 0 C. Thermistor has a range of 0 0 C to 100 0 C where as conventional mercury thermometers range is -37 0 C to +356 0 C.
3. The junction at a higher temperature in thermocouple is termed as measuring junction.
a) True
b) False
Answer: a
Explanation: The junction at a higher temperature in thermocouple is termed as measuring junction. The junction at lower temperature in the thermocouple is called the reference temperature. The cold junction is usually kept at 0 0 C.
4. When two wires of different material are joined together at either end, forming two junctions which are maintained at a different temperature, a thermo-motive force is generated causing a current to flow around the circuit. This arrangement is called ___________
a) thermal pair
b) thermistor
c) thermocouple
d) thermostat
Answer: c
Explanation: This arrangement is called thermocouple. The junction at a higher temperature in thermocouple is termed as measuring junction. The junction at lower temperature in the thermocouple is called the reference temperature.
5. When two wires of different material are joined together at either end, forming two junctions which are maintained at a different temperature, a _________ force is generated.
a) thermo-motive
b) electro-motive
c) chemical reactive
d) mechanical
Answer: a
Explanation: When two wires of different material are joined together at either end, forming two junctions which are maintained at a different temperature, a thermo-motive force is generated causing a current to flow around the circuit. This arrangement is called thermocouple. The junction at higher temperature in thermocouple is termed as measuring junction. The junction at lower temperature in the thermocouple is called the reference temperature.
6. The junction at a lower temperature in the thermocouple called measuring junction.
a) True
b) False
Answer: b
Explanation: The junction at a lower temperature in the thermocouple is called the reference temperature. The cold junction is usually kept at 0 0 C. The junction at a higher temperature in thermocouple is termed as measuring junction.
7. The lower temperature junction in thermocouple is maintained at ________
a) -273 K
b) 0 K
c) -327 K
d) 273 K
Answer: d
Explanation: The lower temperature junction in thermocouple is maintained at 273 K (0 0 C). The junction at lower temperature in the thermocouple is called the reference temperature. The junction at higher temperature in thermocouple is termed as measuring junction.
8. The resistance Rt of a metallic conductor at any temperature t is given by ___________
a) Rt = Roɑ
b) Rt = Roɑ
c) Rt = Roɑ
d) Rt = Roɑ
Answer: a
Explanation: The resistance Rt of a metallic conductor at any temperature t is given by Rt = Roɑ. Ro is the resistance at 0*C. ɑ is temperature coefficient of resistivity.
9. RTD stands for ________
a) resistance temperature device
b) resistance temperature detector
c) reluctance thermal device
d) resistive thermal detector
Answer: b
Explanation: RTD stands for Resistance Temperature Device. It is a passive sensor and requires current excitation to produce an output voltage. RTD has very low temperature coefficient. Voltage drop across RTD is much larger than thermocouple output voltage.
10. Thermister is used to measure _____________
a) temperature
b) pressure
c) height
d) displacement
Answer: a
Explanation: Thermistor is used to measure temperature. It is a temperature transducer. With a change in temperature its resistance changes. Thus its working principle is variable resistance. Thermistors are the oxides of certain metals like manganese, cobalt and nickel which have large negative temperature coefficient, i.e. resistance decreases with increase in temperature.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Photoelectric Transducers”.
1. What is the principle behind photoelectric transducers?
a) conversion of wind energy to electrical energy
b) conversion of light energy to electrical energy
c) conversion of mechanical energy to electrical energy
d) conversion of electrical energy to light energy
Answer: b
Explanation: Photoelectric transducers are based on the principle of conversion of light energy into electrical energy. This is done by causing the radiation to fall on a photosensitive element and measuring the electrical current so generated with a sensitive galvanometer directly or after suitable amplification.
2. Which of the following material is used to build photovoltaic cells?
a) selenium
b) celenuim
c) silicon
d) iron
Answer: a
Explanation: Photovoltaic or barrier layer cells usually consist of a semiconducting substance, which is generally selenium deposited on a metal base which may be iron and which acts as one of the electrodes. The semiconducting substance is covered with a thin layer of silver or gold deposited by cathodic deposition in a vacuum. This layer acts as a collecting electrode.
3. Selenium cells are sensitive to almost the entire range of wavelengths of the spectrum.
a) True
b) False
Answer: a
Explanation: Selenium cells are sensitive to almost the entire range of wavelengths of the spectrum. However, their sensitivity is greater within the visible spectrum and highest in the zones near the yellow wavelengths.
4. Which of the following is not a photoemissive cell?
a) high vacuum photocells
b) barrier layer cell
c) gas-filled photocell
d) photomultiplier tubes
Answer: c
Explanation: Barrier layer cells are photovoltaic cells. They consist of a semiconducting substance, which is generally selenium deposited on a metal base which may be iron and which acts as one of the electrodes. Photovoltaic cells are very robust in construction, need no external electrical supply and produce a photocurrent sometimes stronger than other photosensitive elements.
5. Photo-diodes work in _________
a) forward biased
b) reverse biased
c) independent of forward and reverse biasing
d) any configuration
Answer: b
Explanation: The photodiode is a P-N junction semiconductor diode. It always operated in the reversed biased condition. The light is always focused through a glass lens on the junction of the photo diode.
6. Photovoltaic cells need an external electrical supply to function.
a) True
b) False
Answer: b
Explanation: Photovoltaic cells are very robust in construction, need no external electrical supply and produce a photocurrent sometimes stronger than other photosensitive elements. Typical photocurrents produced by these cells are as high as 120 mA/lumen. At constant temperature, the current set up in the cell usually shows a linear relationship with the incident light intensity.
7. The instruments which give a direct reading of the temperature at the thermistor position are known as _________
a) thermistor
b) telethermometers
c) rtd
d) tempothermometer
Answer: b
Explanation: The instruments which give a direct reading of the temperature at the thermistor position are known by the name telethermometers. This is because of their ability to use leads which are hundreds of feet long without a significant decrease in accuracy. The continuous signal is also suitable for recording without amplification.
8. Which of the following is a photoemissive cell?
a) photomultiplier tubes
b) barrier layer cell
c) galvanic cell
d) rochell-salt cell
Answer: a
Explanation: Photomultiplier tubes are photoemissive cells. These type to cells do require an external power supply to provide a sufficient potential difference between the electrodes to facilitate the flow of electrons generated at the photosensitive cathode surface. Also, amplifier circuits are invariably employed for the amplification of this current.
9. Cesium-silver oxide cells are sensitive to the near infrared wavelengths.
a) True
b) False
Answer: a
Explanation: Cesium-silver oxide cells are sensitive to the near infrared wavelengths. Potassium silver oxide and cesium-antimony cells have maximum sensitivity in the visible and ultraviolet regions. The spectral response also depends partly on the transparency to different wavelengths of the medium to be traversed by the light before reaching the cathode.
10. Thermister is used to measure ____________
a) temperature
b) pressure
c) height
d) displacement
Answer: a
Explanation: Thermistor is used to measure temperature. It is a temperature transducer. With a change in temperature its resistance changes. Thus its working principle is variable resistance. Thermistors are the oxides of certain metals like manganese, cobalt and nickel which have large negative temperature coefficient, i.e. resistance decreases with increase in temperature.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Optical Fiber Sensors”.
1. Optical fiber sensors are electrically ____________
a) active
b) passive
c) active as well as passive
d) cannot be determined
Answer: b
Explanation: Optical fiber sensors are electrically passive and consequently immune to electromagnetic disturbances. They are geometrically flexible and corrosion resistant. They can be miniaturized and are most suitable for telemetry applications.
2. Optical fibers are not immune to ________
a) electronic disturbances
b) magnetic disturbances
c) ambient light interference
d) electromagnetic disturbances
Answer: c
Explanation: Optical fibre sensors are non-electrical and hence are free from electrical interference usually associated with electronically based sensors. Ambient light can interfere. Consequently, the sensor has to be applied in a dark environment or must be optically isolated.
3. Optical fiber sensors are not immune to electromagnetic disturbances.
a) True
b) False
Answer: b
Explanation: Optical fiber sensors are electrically passive and consequently immune to electromagnetic disturbances. They are geometrically flexible and corrosion resistant. They can be miniaturized and are most suitable for telemetry applications.
4. In which of the following optic fiber sensor the fiber is simply used to carry light to and from an external optical device where the sensing takes place?
a) extrinsic fiber optic sensor
b) energized fiber optic sensor
c) all fibers are used to simply carry light to and from the external optical devices
d) intrinsic fiber optic sensor
Answer: a
Explanation: In an extrinsic fiber optic sensor fiber is simply used to carry light to and from an external optical device where the sensing takes place. In an intrinsic fiber optic sensor, one or more of the physical properties of the fiber undergo a change.
5. On the bases of application of optic fiber sensor, which of the following is not considered to be the classification of fiber optic sensor?
a) biomedical/photometric sensors
b) physical sensors
c) thermal sensors
d) chemical sensors
Answer: c
Explanation: The variations in the returning light are sensed using a photodetector. Such sensors monitor variations either in the amplitude or frequency of the reflected light. Two of the most important physical parameters that can be advantageously measured using fibre optics are temperature and pressure.
6. The type of sensor that detects the analyte species directly through their characteristic spectral properties is called _____________
a) chemical sensor
b) thermal sensor
c) light sensor
d) spectroscopic Sensors
Answer: d
Explanation: Spectroscopic Sensors is the one that detects the analyte species directly through their characteristic spectral properties. In these sensors, the optical fibre functions only as a light guide, conveying light from the source to the sampling area and from the sample to the detector. Here, the light interacts with the species being sensed.
7. How many coils are required to make LVDT?
a) 4
b) 6
c) 3
d) 2
Answer: c
Explanation: Total 3 coils are required in LVDT. One centered coil which is the energizing or primary coil connected to the sine wave oscillator. The other two coils are the secondary coils so connected that their outputs are equal in magnitude but opposite in phase.
8. A chemical transduction system is interfaced to the optical fibre at its end. This type of sensor is called?
a) chemical sensor
b) thermal sensor
c) photoelectric sensor
d) light sensor
Answer: a
Explanation: In the chemical sensors, a chemical transduction system is interfaced to the optical fibre at its end. In operation, interaction with analyte leads to a change in optical properties of the reagent phase, which is probed and detected through the fibre optic. The optical property measured can be absorbance, reflectance or luminescence.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Biosensors”.
1. Doppler velocimetry works on the principle of __________
a) frequency measurement of fiber optic sensor
b) amplitude measurement of fiber optic sensor
c) phase measurement of fiber optic sensor
d) time shift measurement of fiber optic sensor
Answer: a
Explanation: Doppler velocimetry works on the principle of frequency measurement of fiber optic sensor. In this method, light from a laser, normally helium/neon, is sent via a fibre onto the skin surface. The moving red blood cells scatter the light and produce a Doppler frequency shift because of their movement.
2. Fluoroptic temperature sensors work on the principle of _______
a) thermistor
b) thermocouple
c) optical fiber
d) rtd
Answer: c
Explanation: Fluoroptic temperature sensors work on the principle of optical fiber sensors. They contain a rare earth phosphor which is illuminated by a white light along a short length of large core optical fibre. The light excites the phosphor which emits a number of lines. By using filters, two of these lines at 540 and 630 nm are selected, and the ratio of their intensities is a single valued function of the temperature of the phosphor.
3. Monopolar needle electrode have a coating of which material over the stainless steel wires which are bare only at the tips?
a) carbon
b) calcium
c) sodium
d) teflon
Answer: d
Explanation: The monopolar needle electrode consists of a teflon coated stainless steel wire. The wire is bare only at the tip. It is found that after the needle has been used a number of times, the teflon coating will recede, increasing the tip area. The needle should be discarded when this happens.
4. Endoscopic imaging uses ___________
a) thermal sensors
b) chemical sensors
c) optic fiber sensors
d) pressure sensors
Answer: c
Explanation: Optic sensors are used for endoscopic imaging. Optical fibre sensors are non-electrical and hence are free from electrical interference usually associated with electronically based sensors. They are suitable for telemetry applications as the bulk of the instrumentation can be at a reasonable distance from the patient.
5. _______________ converts biochemical events into measurable signals.
a) amplifier
b) opamp
c) rectifier
d) transducer
Answer: d
Explanation: Transducers convert biochemical events into measurable signals. They provide the means for detecting the biochemical changes inside the body. Particularly biosensors are employed for this purpose.
6. The biological response of the biosensor is determined by ______
a) biocatalytic membrane
b) physio-chemical membrane
c) chemical membrane
d) artificial membrane
Answer: a
Explanation: The biological response of the biosensor is determined by biocatalytic membrane. The biocatalytic membrane accomplishes the conversion of reactant to product. The product of the reaction diffuses to the transducer. This then causes the electrical response.
7. Home blood glucose sensor works on which principle?
a) electro-physiological
b) electrochemical
c) physio-chemical
d) chemical
Answer: b
Explanation: Home blood glucose detection sensor works on the principle of electrochemical. The biosensor in this instrument relies upon enzymes that recognise and catalyze reactions of glucose with the generation of redox – active species that are detected electrochemically.
8. The chemical reaction of glucose with oxygen is catalyzed in the presence of ________
a) glucose oxidase
b) monoglucose carbodase
c) glusoce dioxidase
d) biglucose oxidase
Answer: a
Explanation: The chemical reaction of glucose with oxygen is catalyzed in the presence of glucose oxidase. In the presence of glucose oxidase as a catalyst, the glucose and oxygen react and gluconic acid is produced as by product. Hydrogen perioxide (H 2 O 2 ) is also produced in some amount.
9. Home blood glucose measurement devices measure the glucose level through non-invasive method.
a) True
b) False
Answer: b
Explanation: Home blood glucose measurement devices measure the glucose level through invasive method. There is a small needle at the tip of the machine that pierces the skin to take blood sample. This blood is then undergoes electrochemical reactions and the glucose level is determined.
10. Blood glucose level measurement device uses a biosensor works on the principle of electrochemical.
a) True
b) False
Answer: a
Explanation: Home blood glucose detection sensor works on the principle of electrochemical. The biosensor in this instrument relies upon enzymes that recognize and catalyze reactions of glucose with the generation of redox – active species that are detected electrochemically.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Smart Sensors”.
1. Which of the following is not a fundamental block in recording systems?
a) electrodes and transducers
b) signal conditioner
c) analysis for the output
d) writing system
Answer: c
Explanation: Analysis of the output is not a fundamental block on the recording system. First, the signals are collected from the host. Then they are sent for signal conditioning where they are amplified to the desirable range and then the writing system prints the signals.
2. In medical recorders, the signal of interest is of the order of _______
a) nanovolts
b) microvolts
c) megavolts
d) volts
Answer: b
Explanation: The signals of interest in medical recorders are in the range of micro volts. They are captured by the help of sensitive electrodes and transducers and then amplified to a certain higher level. After the amplification further processing is carried out.
3. In medical devices, the amplifiers that are used for the amplification purpose of the input signal must have ___________
a) low frequency response
b) high frequency response
c) average frequency response
d) frequency response has no role to play in it
Answer: a
Explanation: The bioelectric signals in medical science contains components of extremely low frequency. Thus the amplifiers must also have a low frequency response. The response should be down to less than one hertz which is a very frequent requirement.
4. To achieve the low frequency response for medical applications, the amplifier configuration must contain?
a) higher resistance
b) higher capacitance
c) lower resistance
d) lower capacitance
Answer: b
Explanation: To achieve the low frequency response required for medical applications, the amplifier must have large values of coupling capacitance. In all RC-coupled amplifiers, low frequency response is limited by the reluctance of the coupling capacitors. The response should be down to less than one hertz which is a very frequent requirement.
5. Filter that amplifies frequency above a certain value is called?
a) low pass filter
b) high pass filter
c) band pass filter
d) band stop filter
Answer: b
Explanation: High pass filter amplifies signal above a certain frequency. Low pass filter amplifies signals below a certain frequency. Band pass filter amplifies frequencies within a certain band. Band stop filter amplifies all the frequencies except those in a certain band.
6. ________________ amplifies all the frequencies except those in a certain band.
a) high pass filter
b) low pass filter
c) band pass filter
d) band stop filter
Answer: d
Explanation: Band stop filter amplifies all the frequencies except those in a certain band. High pass filter amplifies signal above a certain frequency. Low pass filter amplifies signals below a certain frequency. Band pass filter amplifies frequencies within a certain band.
7. Active filters use opamps in addition to passive components in order to obtain better performance.
a) True
b) False
Answer: a
Explanation: True. Active filters use opamps in addition to passive components in order to obtain better performance. Operational amplifiers are frequently used as the gain blocks in active filters. Passive components are resistors capacitors and inductors.
8. Which of the following component is not a part of the passive filter?
a) resistor
b) operational amplifier
c) capacitor
d) inductor
Answer: b
Explanation: Operational amplifier is not a part of passive filters. It is a part of an active filter. Passive components are resistors capacitors and inductors. Active filters use opamps in addition to passive components in order to obtain better performance.
This set of Biomedical Instrumentation Questions and Answers for Experienced people focuses on “General Considerations for Signal Conditioners”.
1. The filter used to reject the 50Hz noise picked up from power lines or machinery is called?
a) band reject filter
b) band stop filter
c) notch filter
d) all reject filter
Answer: c
Explanation: Such filters are called notch filters. Almost all measuring and recording applications are subjected to some degree of 50Hz noise picked up from the power lines or machinery. Therefore, most signal conditioners include low pass filter designed specifically to provide maximum rejection of 50 Hz noise.
2. Devices that pass the signal from its source to the measurement device without a physical or galvanic connection by using transformer, optical or capacitive coupling technique are called?
a) filters
b) rectifiers
c) bridges
d) isolaters
Answer: d
Explanation: Such devices are called isolaters. Improper grounding of the system is one of the most common causes of measurement problem and noise. Signal conditioners with isolation can prevent these problems. Besides breaking ground loops, isolation blocks high voltage surges and rejects high common mode voltages.
3. Which of the following technique is not employed in isolation devices?
a) resistance
b) optical
c) inductance
d) capacitance
Answer: a
Explanation: Resistance technique is not employed in making isolation devices. The isolation devices pass the signal from its source to the measurement device without a physical or galvanic connection by using transformer, optical or capacitive coupling technique.
4. Besides breaking ground loops, isolation blocks high voltage surges and rejects high common mode voltages.
a) True
b) False
Answer: a
Explanation: It is true. Besides breaking ground loops, isolation blocks high voltage surges and rejects high common mode voltages. The isolation devices pass the signal from its source to the measurement device without a physical or galvanic connection by using transformer, optical or capacitive coupling technique.
5. Strain gauges are resistance devices in a Wheat stone bridge configuration _________
a) which does not require bridge completion circuitry and an excitation source
b) which requires bridge completion circuitry and an excitation source
c) which neither requires bridge completion circuitry nor an excitation source
d) which requires bridge completion circuitry but does not an excitation source
Answer: b
Explanation: Strain gauges are resistance devices in a Wheat stone bridge configuration which requires bridge completion circuitry and an excitation source. These devices require external voltage or current excitation. Signal conditioning part of the measurement system usually provides the excitation signals.
6. Which of the following voltage regulator IC gives a variable positive voltage?
a) LM317
b) LM337
c) 7805
d) 7812
Answer: a
Explanation: LM317 is a variable positive voltage regulator IC. It is capable of drawing current up to 1.5A and voltage range from 1.25V- 30V ideally. LM337 is a variable negative voltage regulator IC. 7805 and 7812 are fixed voltage regulator IC that give output voltage as 5V and 12V respectively.
7. ________ IC is a variable negative voltage regulator.
a) 7912
b) 7905
c) LM337
d) LM317
Answer: c
Explanation: LM337 is a variable negative voltage regulator IC. It is capable of drawing current up to 1.5A and voltage range from – ideally. LM317 is a variable positive voltage regulator IC. 7905 and 7912 are fixed voltage regulator IC that give output voltage as -5V and -12V respectively.
8. Digital filters are sensitive to temperature as compared with analog filters.
a) True
b) False
Answer: b
Explanation: False. Digital filters are insensitive to temperature as compared with analog filters. They are also insensitive to ageing, voltage drift and external interference as compared to analog filters. Their response is completely reproducible and predictable, and software simulations can exactly reflect product performance.
9. Signal conditioning is not of much importance in the measuring and recording system.
a) True
b) False
Answer: b
Explanation: Signal conditioning is of great importance in measuring and recording system. They determine the range, accuracy and resolution of the system. Signal conditioning includes either hardware based or software based linearization routines for this purpose.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Preamplifiers”.
1. Which amplifier will reject any common mode signal that appears simultaneously at both amplifier input terminal and amplifies only the voltage difference that appears across its input terminals?
a) ac coupled amplifiers
b) differential amplifiers
c) carrier amplifiers
d) dc amplifiers
Answer: b
Explanation: Differential amplifier is one which will reject any common mode signal that appears simultaneously at both amplifier input terminals and amplifies only the voltage difference that appears across its input terminals. Most of the amplifiers used for measuring bioelectric signals are of the differential type. AC amplifiers have a limited frequency response and are, therefore, used only for special medical applications such as electrocardiograph machine.
2. Which amplifier has a limited frequency response?
a) differential amplifier
b) dc amplifiers
c) ac coupled amplifiers
d) carrier amplifiers
Answer: b
Explanation: AC amplifiers have a limited frequency response and are, therefore, used only for special medical applications such as electrocardiograph machine. For electrocardiograms, an ac amplifier with sensitivity, giving 0.5 mV/cm, and a frequency response up to 1 kHz and an input impedance of 2 to 5 MW is used. For such applications as retinography, EEG and EMG, more sensitive ac amplifiers are required, giving a chart sensitivity of say 50 mV/cm with a high input impedance of over 10 MW.
3. ______________ are used with transducers which require an external source of excitation.
a) carrier amplifiers
b) dc amplifiers
c) ac coupled amplifiers
d) differential amplifier
Answer: a
Explanation: Carrier amplifiers are used with transducers which require an external source of excitation. They are characterized by high gain, negligible drift, extremely low noise and the ability to operate with resistive, inductive or capacitive type transducers. They essentially contain a carrier oscillator, a bridge balance and calibration circuit, a high gain ac amplifier, a phase-sensitive detector and a dc output amplifier.
4. DC amplifiers are employed with _______ feedback type.
a) positive
b) negative
c) depends on the application
d) can be any positive or negative does’t matter
Answer: b
Explanation: DC amplifiers are generally of the negative feedback type. They are used for medium gain applications down to about 1 mV signal levels for full scale. They are not practical for very low level applications because of dc drift and poor common-mode rejection capabilities.
5. DC amplifiers are mostly used for very low level applications because they offer very less dc drift and high common mode rejection capabilities.
a) True
b) False
Answer: b
Explanation: DC amplifiers are not practical for very low level applications because of dc drift and poor common-mode rejection capabilities. They are usually employed as pen drive amplifiers in direct writing recorders. They are used for medium gain applications down to about 1 mV signal levels for full scale.
6. Chopper stabilized dc amplifiers are complex amplifiers having ________ amplifiers incorporated in the module.
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: Chopper stabilized dc amplifiers are used for low level but preferably wideband applications such as oscilloscopes, tape recorders and light beam oscilloscope recorders. These are complex amplifiers having three amplifiers incorporated in the module. This includes an ac amplifier for signals above about 20 Hz, a dc chopper input amplifier for signals from about 20 Hz down to dc plus wideband feedback stabilized dc amplifier.
7. Which of the following amplifier is employed with resistive transducers which require an external source of excitation?
a) differential amplifier
b) ac coupled amplifier
c) carrier amplifier
d) dc bridge amplifier
Answer: d
Explanation: DC bridge amplifiersare employed with resistive transducers which require an external source of excitation. Essentially, the amplifier comprises of a stable dc excitation source, a bridge balance and calibration unit, a high gain differential dc amplifier and a dc output amplifier. They can be used as conventional dc high gain amplifiers and offer operating simplicity and high frequency response.
8. Chopper input dc amplifiersare preferred for low level inputs to instrumentation systems because of their high sensitivity, negligible drift and excellent common mode rejection capability.
a) True
b) False
Answer: a
Explanation: True. Chopper input dc amplifiersare preferred for low level inputs to instrumentation systems because of their high sensitivity, negligible drift and excellent common mode rejection capability. Their high frequency response is limited to about one half of the input chopper frequency.
This set of Biomedical Instrumentation Interview Questions and Answers for Experienced people focuses on “Sources of Noise in Low Level Measurements”.
1. Bio potential amplifiers have ____________ input terminals.
a) 3
b) 4
c) 5
d) 6
Answer: a
Explanation: Bio potential has three input terminals. Out of the three one is arranges at the reference potential. The other two are live terminals. Bio potential amplifiers are also known as differential amplifiers. The differential amplifier is employed when it is necessary to measure the voltage difference between two points, both of them varying in amplitude at different rates and in different patterns.
2. The ability of the amplifier to reject common voltages on its two input leads is known as ________
a) common mode rejection rate
b) coupled mode rejection rate
c) common mode rejection ratio
d) coupled mode rejection ratio
Answer: c
Explanation: The ability of the amplifier to reject common voltages on its two input leads is known as common-mode rejection. It is specified as the ratio of common-mode input to differential input to elicit the same response. It is abbreviated as CMRR .
3. CMRR is measured in ____________
a) V/s
b) dB
c) dB/s
d) dB/ms
Answer: b
Explanation: CMRR is an important specification referred to the differential amplifier and is normally expressed as decibels. The ability of the amplifier to reject common voltages on its two input leads is known as common-mode rejection. It is specified as the ratio of common-mode input to differential input to elicit the same response.
4. CMRR of the preamplifiers should be as high as possible.
a) True
b) False
Answer: a
Explanation: CMRR of the preamplifiers should be as high as possible so that only the wanted signals find a way through the amplifier and all unwanted signals get rejected in the preamplifier stage. The ability of the amplifier to reject these common voltages on its two input leads is known as common-mode rejection and is specified as the ratio of common-mode input to differential input to elicit the same response. CMRR is an important specification referred to the differential amplifier and is normally expressed as decibels.
5. The common mode rejection for most op-amps is typically between __________
a) 10-50dB
b) 20-40dB
c) 60-90dB
d) 100-120dB
Answer: c
Explanation: The common mode rejection for most op-amps is typically between 60 dB and 90 dB. This may not be sufficient to reject common mode noise generally encountered in biomedical measurements. Also, the input impedance is not very high to handle signals from high impedance sources.
6. The output of differential gain is given by _________
a) *
b) *
c) *
d) *
Answer: a
Explanation: The output of differential gain is given by *. gain is given by . The input resistances of but the inputs are the same.
7. In order to be able to minimize the effects of changes occurring in the electrode impedances, it is necessary to employ a preamplifier having a high input impedance.
a) True
b) False
Answer: a
Explanation: True. In order to be able to minimize the effects of changes occurring in the electrode impedances, it is necessary to employ a preamplifier having a high input impedance. It has been found that a low value of input impedance gives rise to considerable distortion of the recordings.
8. The impedance of the input should be ________ in order to obtain high CMRR in the differential amplifier.
a) low
b) High
c) Does not matter
d) Very low
Answer: b
Explanation: This shows that high input impedance is very necessary in order to obtain a high CMRR. Also, the electrode skin resistance should be low and as nearly equal as possible. In order to be able to minimize the effects of changes occurring in the electrode impedances, it is necessary to employ a preamplifier having a high input impedance.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Biomedical Signal Analysis and Processing Techniques”.
1. Which of the following statement is true for an instrumentational amplifier?
a) the input resistance of both the inputs is very high and does not change as the gain is varied
b) the input resistance of both the inputs is very low and does not change as the gain is varied
c) the input resistance of both the inputs is very high and does change as the gain is varied
d) the input resistance of both the inputs is very low and does change as the gain is varied
Answer: a
Explanation: The input resistance of both the inputs is very high and does not change as the gain is varied in and instrumentational amplifier. Voltage gain from differential input to single ended output, is set by one resistor. V0 does not depend on common-mode voltage, but only on their difference.
2. Which of the following is not the property of the instrumentational amplifier?
a) Extremely high input impedance
b) Low bias and offset currents
c) High slew rate
d) Very low CMRR
Answer: d
Explanation: Instrumentational amplifiers have very high CMRR. The instrumentation amplifier offers the following advantages for its applications in the biomedical field. Some of them are like extremely high input impedance, low bias and offset currents, high slew rate.
3. CMRR is measured in ___________
a) v/s
b) dB
c) dB/s
d) dB/ms
Answer: b
Explanation: CMRR is an important specification referred to the differential amplifier and is normally expressed as decibels. The ability of the amplifier to reject common voltages on its two input leads is known as common-mode rejection. It is specified as the ratio of common-mode input to differential input to elicit the same response.
4. The carrier amplifier consists of an oscillator and a capacitance coupled amplifier.
a) True
b) False
Answer: a
Explanation: The carrier amplifier consists of an oscillator and a capacitance coupled amplifier. The oscillator is used to energize the transducer with an alternating carrier voltage. The transducers, which require ac excitation, are those whose impedance is not purely resistive.
5. Electromagnetic coupling cannot be reduced by ___________
a) shielding
b) wire twisting
c) multiple grounding
d) common grounding
Answer: c
Explanation: Having multiple grounds in a single circuit increases the electromagnetic coupling effect by producing ground loop which may generate so much noise that it may completely obscure the useful signal. Thus, the electromagnetic coupling is reduced by shielding, wire twisting and proper grounding which provide a balanced signal pair with satisfactory noise rejection characteristics.
6. Which on the following is not a type of isolation amplifier?
a) capactively coupled isolation amplifiers
b) optically isolated isolation amplifiers
c) resistive coupled isolation amplifiers
d) transformer type isolation amplifiers
Answer: c
Explanation: There is nothing such as the resistive coupled isolation amplifiers. All the other three types are in common use, though the transformer isolation amplifier is more popular. Opto-coupled amplifier uses a minimum number of components and is cost effective, followed by the transformer coupled amplifier. The capacitor coupled amplifier is the most expensive.
7. The isolation includes different supply voltage sources and different grounds on each side of the isolation barrier.
a) True
b) False
Answer: a
Explanation: The isolation includes different supply voltage sources and different grounds on each side of the isolation barrier. Three methods are used in the design of isolation amplifiers: transformer isolation optical isolation capacitive isolation. Isolation amplifiers are commonly used for providing protection against leakage currents.
8. _________ are commonly used for providing protection against leakage currents.
a) Isolation amplifiers
b) Differential amplifiers
c) Instrumentational amplifiers
d) Inverting amplifiers
Answer: a
Explanation: Isolation amplifiers are commonly used for providing protection against leakage currents. They break the ohmic continuity of electric signals between the input and output of the amplifier. The isolation includes different supply voltage sources and different grounds on each side of the isolation barrier.
This set of Basic Biomedical Instrumentation Questions and Answers focuses on “The Main Amplifier and Driver Stage”.
1. The term ___________ is used when referring to the frequency content of a signal.
a) angular momentum
b) spectrum
c) scope
d) bandwidth
Answer: b
Explanation: The term spectrum is used when referring to the frequency content of a signal. The basic motivation for developing frequency analysis tools is to provide a mathematical and pictorial representation for the frequency components that are contained in any given signal. Most biomedical signals of practical interest can be decomposed into a sum of sinusoidal signal components.
2. The process of obtaining the spectrum of a given signal using the basic mathematical tools is known as _______________
a) time domain analysis
b) mathematical analysis
c) spectral analysis
d) pseudo analysis
Answer: c
Explanation: The process of obtaining the spectrum of a given signal using the basic mathematical tools is known as frequency or spectral analysis. The term spectrum is used when referring to the frequency content of a signal. Most biomedical signals of practical interest can be decomposed into a sum of sinusoidal signal components.
3. Most biomedical signals of practical interest can be decomposed into a sum of sinusoidal signal components. For the class of periodic signals, such a decomposition is called a _______ series.
a) fourier
b) discontinuous
c) continuous
d) frequency
Answer: a
Explanation: It is called a Fourier series. The term spectrum is used when referring to the frequency content of a signal. The process of obtaining the spectrum of a given signal using the basic mathematical tools is known as a frequency or spectral analysis.
4. Most biomedical signals of practical interest can be decomposed into a sum of sinusoidal signal components. For the class of finite energy signals, the decomposition is called the ____________
a) Fourier series
b) Fourier transform
c) Laplace transform
d) Laplace series
Answer: b
Explanation: For the class of finite energy signals, the decomposition is called the Fourier transform. For the class of periodic signals, such decomposition is called a Fourier series. The process of obtaining the spectrum of a given signal using the basic mathematical tools is known as a frequency or spectral analysis.
5. The ratio of response to a stimulus is called the transfer function.
a) True
b) False
Answer: a
Explanation: The ratio of response to a stimulus is called the transfer function.
H = R/S
The process of obtaining the spectrum of a given signal using the basic mathematical tools is known as a frequency or spectral analysis.
6. Each component in the FFT series can then be represented as A cos + iB sin where ______________
a) A = The phase angle of the component
b) f = An FFT coefficient
c) t = temperature
d) w = Angular frequency of the component
Answer: d
Explanation: w = Angular frequency of the component is the correct answer. Other all are the incorrect explanation of the variables. A = An FFT coefficient
f = The phase angle of the component and t = time.
7. Which of the following transform is best suited for spatial filtering, edge detection, feature extraction, data compression, pattern recognition, speech recognition, image compression and texture analysis?
a) wavelet transform
b) laplace transform
c) fourier transform
d) short time fourier transform
Answer: a
Explanation: The wavelet transform has very good time resolution at high frequencies and good frequency resolution at low frequencies. In biomedical engineering, wavelet transform have been widely used in many research areas including spatial filtering, edge detection, feature extraction, data compression, pattern recognition, speech recognition, image compression and texture analysis. Wavelets are a relatively new signal processing method. A wavelet transform is almost always implemented as a bank of filters that decompose a signal into multiple signal bands. It separates and retains the signal features in one or a few of these bands.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Writing System”.
1. For faithful reproduction of the input signal linearity over the required range of signal, amplitudes must be satisfied by the individual parts of the system.
a) True
b) False
Answer: a
Explanation: For faithful reproduction of the input signal, three basic conditions must be satisfied by the individual parts of the system. These requirements are linearity over the required range of signal amplitudes and an adequate passband for the frequencies involved without producing any phase shift between the input and recorded signal.
2. CRO stands for _______
a) Common Ray Oscilloscope
b) Cathode Ray Oscilloscope
c) Cathode Ray Oscillator
d) Common Ray Oscillator
Answer: b
Explanation: Cathode ray oscilloscopes are widely used for the display of waveforms encountered in the medical field. These waveforms can be recorded from the CRO screen by running a photographic film through a recording camera fixed in front of the screen. Recorders are either of the single channel type or of the type which record several channels simultaneously.
3. Which of the following is not a passive transducer?
a) Strain gauge
b) Ultrasonic transducer
c) IR sensor
d) Doppler effect transducer
Answer: a
Explanation: Strain gauge transducer is an active transducer. Its working principle is based on a change in resistance. Ultrasonic transducers need power to operate. So do the IR sensors and doppler effect transducers.
4. _____________ refers to the degree of repeatability of a measurant.
a) accuracy
b) precision
c) resolution
d) sensitivity.
Answer: b
Explanation: Precision refers to the degree of repeatability of a measurant. Accuracy describes the algebraic difference between the indicated value and the true or theoretical value of the measurand. Resolution is the ability of the transducer or sensor to see small differences in reading.
5. ____________ filter amplifies signals below a certain frequency.
a) band stop filter
b) high pass filter
c) band pass filter
d) low pass filter
Answer: d
Explanation: Low pass filter amplifies signals below a certain frequency. Band pass filter amplifies frequencies with in a certain band. Band stop filter amplifies all the frequencies except those in a certain band. High pass filter amplifies signal above a certain frequency.
6. Which of the following filter amplifies frequencies with a certain band?
a) band pass filter
b) band stop filter
c) low pass filter
d) high pass filter
Answer: a
Explanation: Band pass filter amplifies frequencies within a certain band. Band stop filter amplifies all the frequencies except those in a certain band. High pass filter amplifies signal above a certain frequency. Low pass filter amplifies signals below a certain frequency.
7. AAMI stands for ____________________
a) American Association of Medical Instrumentation
b) Association for the Advancement of Medical Instrumentation
c) Association of American Medical Instrumentation
d) American Association of Measurement Instruments
Answer: b
Explanation: Association for the Advancement of Medical Instrumentation, USA is an association for propelling the advancement, and protected and powerful utilization of restorative innovation established in 1965 by Robert D. Corridor, Jr. what’s more, Robert J. Allen, President and Vice President individually of Tech/Reps, Inc. AAMI is an intentional association, and in spite of the fact that its suggested practices and gauges once in a while reverberate other social insurance rules, consistency with these models isn’t really required by administrative associations that review medicinal services offices.
8. A wavelet transform is almost always implemented as a bank of filters that decompose a signal into multiple signal bands.
a) True
b) False
Answer: a
Explanation: It is true. A wavelet transform is almost always implemented as a bank of filters that decompose a signal into multiple signal bands. Wavelets are a relatively new signal processing method. Thus, one of the biggest advantages of using the wavelet transform is that signal features can be easily extracted. In many cases, a wavelet transform outperforms the conventional FFT when it comes to feature extraction and noise reduction. predictable, and software simulations can exactly reflect product performance.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Direct Writing Recorders”.
1. How many kidneys does a human have?
a) one
b) two
c) three
d) four
Answer: b
Explanation: The human body has two kidneys which lie in the back of the abdominal cavity just below the diaphragm, one on each side of the vertebral column. Each kidney consists of about a million individual units, all similar in structure and function. The main function of the kidneys is to form urine out of blood plasma.
2. The removal of waste products from blood plasma is performed by ___________
a) kidney
b) liver
c) heart
d) lungs
Answer: a
Explanation: The main function of the kidneys is to form urine out of blood plasma, which basically consists of two processes: the removal of waste products from blood plasma, and the regulation of the composition of blood plasma. The human body has two kidneys which lie in the back of the abdominal cavity just below the diaphragm, one on each side of the vertebral column.
3. The regulation of the composition of blood plasma is done by which of the following organ?
a) skin
b) heart
c) kidney
d) lung
Answer: c
Explanation: The human body has two kidneys which lie in the back of the abdominal cavity just below the diaphragm, one on each side of the vertebral column. The main function of the kidneys is to form urine out of blood plasma, which basically consists of two processes: the removal of waste products from blood plasma, and the regulation of the composition of blood plasma.
4. Each kidney consists of about a million individual units, all similar in structure and function. These tiny units are called __________
a) nerves
b) neurons
c) capillaries
d) nephrons
Answer: d
Explanation: Each kidney consists of about a million individual units, all similar in structure and function. These tiny units are called nephrons. A nephron is composed of two parts—a cluster of capillary loops called the glomerulus and a tubule.
5. Which of the following is the correct anatomical position of the kidney?
a) front of the abdominal cavity just below the diaphragm
b) back of the abdominal cavity just below the diaphragm
c) back of the abdominal cavity just above the diaphragm
d) front of the abdominal cavity just above the diaphragm
Answer: b
Explanation: The human body has two kidneys which lie in the back of the abdominal cavity just below the diaphragm, one on each side of the vertebral column. Each kidney consists of about a million individual units, all similar in structure and function. These tiny units are called nephrons.
6. Each kidney consists _______ number of nephrons.
a) thousands
b) millions
c) billions
d) trillions
Answer: b
Explanation: Each kidney consists of millions number of nephrons. A nephron is composed of two parts—a cluster of capillary loops called the glomerulus and a tubule. The tubule runs a tortuous course and ultimately drains via a collecting duct into the funnel-shaped expansion of the upper end of the ureter, i.e. the tube which conveys urine from the kidney to the bladder.
7. The kidneys work only on plasma.
a) True
b) False
Answer: a
Explanation: The kidneys work only on plasma. The erythrocytes supply oxygen to the kidneys but serve no other function in urine formation. Each substance in plasma is handled in a characteristic manner by the nephron, involving particular combinations of filtration, reabsorption and secretion.
8. The ___________ carry blood at very high pressure from the aorta into the glomerular capillary.
a) renal arteries
b) russal arteries
c) pulmonary arteries
d) fenal arteries
Answer: a
Explanation: The renal arteries carry blood at very high pressure from the aorta into the glomerular capillary tuft. The blood pressure within the glomerular capillaries is 70–90 mm of mercury. The blood flow through the capillary tuft is controlled by the state of contraction of the muscle of the arteriole leading to the tuft.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “The Inkjet Recorders”.
1. The total amount of glomerular filtrate is about ____________ per day.
a) 180 liters
b) 18 liters
c) 18 ml
d) 180 ml
Answer: a
Explanation: The total amount of glomerular filtrate is about 180 litres per day, whereas the amount of urine formed from it is only 1–1.5l. This means that very large amounts of water, and other substances, are re-absorbed by the kidney tubules.
2. The amount of urine formed by an average kidney in one day is ________
a) 10-10.5 L
b) 10-15 ml
c) 1-1.5 L
d) 5 L
Answer: c
Explanation: The amount of urine formed by an average kidney in one day is 1-1.5 L. The total amount of glomerular filtrate is about 180 litres per day. Very large amounts of water and other substances are re-absorbed by the kidney tubules.
3. Which hormone of the pituitary gland helps to automatically reabsorb water from the kidney?
a) Anti-diuretic hormone
b) Diuretic hormone
c) Pro-diuretic hormone
d) Pseudo-diuretic hormone
Answer: c
Explanation: The re-absorption is partly an automatic process because the absorption of water is accurately controlled by the anti-diuretic hormone of the pituitary gland, in relation to the body’s need for water. The absorption of electrolytes such as sodium and potassium is partly controlled by the supra-renal gland and the concentration of others, like chloride and bicarbonate, is related to the acid-base balance.
4. The total blood flow through the kidneys is about _____________
a) 120 ml/min
b) 1200 ml/min
c) 200 ml/min
d) 10 ml/min
Answer: b
Explanation: The total blood flow through the kidneys is about 1200 ml/min. The absorption of electrolytes such as sodium and potassium is partly controlled by the supra-renal gland and the concentration of others, like chloride and bicarbonate, is related to the acid-base balance. Some of the re-absorption from the glomerular filtrate is also a passive, automatic process of diffusion depending upon pressure gradients.
5. The total extra-cellular fluid amounts to about _________
a) 1 litres
b) 15 milli-litres
c) 15 litres
d) 150 litres
Answer: c
Explanation: The total extra-cellular fluid amounts to about 15 litres. Some of the re-absorption from the glomerular filtrate is also a passive, automatic process of diffusion depending upon pressure gradients. The total blood flow through the kidneys is about 1200 ml/min.
6. Kidneys has no role maintaining the acid-base balance.
a) True
b) False
Answer: b
Explanation: It is false. Kidney plays an important role in maintaining the acid-base balance. The water and electrolyte content of the blood plasma and, therefore, indirectly of the extra-cellular fluid are closely controlled by the kidneys. The blood plasma and the extra-cellular fluid are in equilibrium with each other and, therefore, an amount of blood equivalent to all the extra-cellular fluid can pass through the kidneys once every 15 minutes.
7. The symptoms and signs of profound renal malfunction are known as uremia.
a) True
b) False
Answer: a
Explanation: The symptoms and signs of profound renal malfunction are known as uremia, meaning urine in the blood. Since most urinary contents are water-soluble, they reach high concentrations in blood and result in deranged body parts and their physiology.
8. Chronic renal failure results in changes in the body fluids which occur due to a _____________
a) progressive increase in the number of functioning nephrons
b) progressive decrease in the number of functioning nephrons
c) progressive decrease in the number of functioning neurons
d) progressive increase in the number of functioning neurons
Answer: c
Explanation: Chronic renal failure results in changes in the body fluids which occur due to a progressive decrease in the number of functioning nephrons. With the decrease in functional nephrons, the clearance of urea, creatinine and other metabolic waste products will decrease proportionally. In consequence, the plasma concentrations of these substances will rise.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Potentiometric Recorder”.
1. Which of the following statement is correct?
a) movement of waste product molecules from the dialysate to the blood results in cleaning of the blood
b) movement of waste product molecules from the blood to the dialysate results in cleaning of the blood
c) movement of waste product molecules from the blood to the dialysate results in impuring of the blood
d) movement of waste product molecules from the dialysate to the blood results in cleaning of the blood
Answer: b
Explanation: Movement of waste product molecules from the blood to the dialysate results in cleaning of the blood. The dialysate fluid is free of waste product molecules and, therefore, those in the blood would tend to distribute themselves evenly throughout the blood and the dialysate. All other options are completely wrong.
2. A positive pressure is applied to the blood compartment or a negative pressure established in the dialysate compartment. This process in dialyses is called ______________
a) nano filtration
b) mega filtration
c) micro filtration
d) ultra filtration
Answer: d
Explanation: The volume of body fluid cannot be controlled by dialysis. Instead, ultra-filtration across the membrane is employed. For this, a positive pressure is applied to the blood compartment or a negative pressure established in the dialysate compartment. Either way, fluid—both water and electrolytes—will move from the blood compartment to the dialysate, which is subsequently discarded.
3. Electrode paste ______________
a) increases contact impedance
b) equates contact impedance
c) reduces contact impedance
d) absorbs contact impedance
Answer: c
Explanation: In order to obtain a clearly established contact an electrolyte or electrode paste is usually employed as an interface between the electrode and the surface of the source of the event. It is placed between the skin and the electrode. It helps to get better signal acquisition.
4. Heart wall is made up of __________ layers.
a) 2
b) 4
c) 3
d) 7
Answer: c
Explanation: Heart wall is made up of three layers. First pericardium which is the outer layer of the heart. Second is the myocardium which is the middle layer of the hear and finally endocardium which is the inner layer of the heart wall.
5. Uremia is the clinical state resulting from _____________
a) renal failure
b) liver failure
c) kidney failure
d) lung failure
Answer: a
Explanation: Uremia is the clinical state resulting from renal failure. The signs and symptoms of uremia are extremely diverse and frequently appear to point to a disease of other organs. Uremia affects every organ of the body as certain substances that accumulate in uremia are clearly toxic.
6. Dialysis takes place across a membrane of cellophane.
a) True
b) False
Answer: a
Explanation: It is true. The dialysate is an electrolyte solution of suitable composition and the dialysis takes place across a membrane of cellophane. The return of the dialyzed blood is by another plastic tube to an appropriate vein.
7. Blood pressure in the glomerular capillaries is in the range of?
a) 17-19 mmHg
b) 7-9 mmHg
c) 170-190 mmHg
d) 70-90 mmHg
Answer: d
Explanation: The blood pressure within the glomerular capillaries is 70–90 mm of mercury. The blood flow through the capillary tuft is controlled by the state of contraction of the muscle of the arteriole leading to the tuft. The renal arteries carry blood at very high pressure from the aorta into the glomerular capillary tuft.
8. The glomerular filtrate consists of blood plasma with proteins.
a) True
b) False
Answer: b
Explanation: It is false. The glomerular filtrate consists of blood plasma without proteins. The fluid pressure within the tuft forces some of the fluid part of the blood, by filtration, through the thin walls of the capillaries into the glomerulus and on into the tubule of the nephron.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Digital Recorders”.
1. The removal of waste products during dialysis is ___________
a) inversely proportional to the concentration gradient across the membrane
b) proportional to the concentration gradient across the membrane
c) proportional to the flow rate across the membrane
d) inversely proportional to the flow rate across the membrane
Answer: b
Explanation: The removal of waste products during dialysis is proportional to the concentration gradient across the membrane. In order to effect the maximum gradient, the concentration of waste products in the dialysate should be maintained at zero. This is achieved in most currently employed machines by using the dialysate only once and then discarding it.
2. Counter-current flow through the artificial kidney is used so that the dialysate enters the kidney at the blood exit-end. Where the blood concentration of waste products is at the lowest level?
a) lowest level
b) very high level
c) high level
d) medium level
Answer: a
Explanation: Counter-current flow through the artificial kidney is used so that the dialysate enters the kidney at the blood exit-end where blood concentration of waste products is at the lowest level. The removal of waste products during dialysis is proportional to the concentration gradient across the membrane. In order to effect the maximum gradient, the concentration of waste products in the dialysate should be maintained at zero.
3. Parallel flow dialyzer has a low internal resistance. Because of this blood pump is required.
a) True
b) False
Answer: b
Explanation: Parallel flow dialyzer has a low internal resistance which allows adequate blood flow through the dialyzer with the patient’s arterial blood pressure, eliminating the need for a blood pump. The dialyzing surface area of a parallel flow dialyzer is about 1 sq m. At a blood flow rate of 200 ml/min and a dialysate flow of 500 ml/min, the urea and creatinine clearance is about 80 and 64 ml/min.
4. KIIL dialyzer is a type of _________
a) coil hemodialyzer
b) hollow fiber dialyzer
c) series flow dialyzer
d) parallel flow dialyzer
Answer: b
Explanation: The KIIL dialyzer has earlier been the most commonly used form of parallel flow dialyzer. It consists of three polypropylene boards with dialyzing membranes laid between them. The boards are held firmly with a frame on the top and bottom and are fastened by a series of bolts on the side.
5. The KIIL dialyzer is not disposable.
a) True
b) False
Answer: a
Explanation: It is true. The KIIL dialyzer is not disposable. It needs to be cleaned and re-built after each dialysis operation. With this type of dialyzer, a single-pass body temperature dialysate passes through the dialyzer once before going to the drain to obtain higher operational efficiency and to minimize bacterial infection.
6. The volume of blood within the dialyzer is known as __________
a) secondary volume
b) quarterly volume
c) priming volume
d) residual volume
Answer: c
Explanation: The volume of blood within the dialyzer is known as priming volume. It is desirable that this should be minimal. Priming volume of present day dialyzers ranges from 75 to 200 ml, depending on the membrane area geometry and operating conditions.
7. The ideal membrane should possess __________
a) low permeability to water
b) high permeability to water
c) medium permeability to water
d) high permeability to waste
Answer: b
Explanation: The ideal membrane should possess high permeability to water, organic metabolites and ions, and the capability of retaining plasma proteins. The membrane should be of sufficient wet strength to resist tearing or bursting and non-toxic to blood and all body cells.
8. Which of the following is the commonly used membrane for hemodialysis?
a) Cupraphan
b) Cotton
c) Cellulose
d) calcium
Answer: a
Explanation: Cupraphan is the commonly used membrane for haemodialysis. It is a membrane consisting of natural cellulose and is considered puncture-proof, and of high tenacity and elasticity. During haemodialysis, different substances of varying molecular weight are to be removed.
9. The delta wave in EEG ranges from _________
a) 0.5-4Hz
b) 4-8Hz
c) 8-13Hz
d) 13-22Hz
Answer: a
Explanation: The delta wave in EEG ranges from 0.5-4Hz. The theta wave in EEG ranges from 4-8Hz. The alpha wave in EEG ranges from 8-13Hz and beta from 13-22Hz.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Video Printers”.
1. Any disturbance in the heart’s normal rhythmic contraction is called?
a) Heart stroke
b) Cardiac arrest
c) Arrhythmias
d) Premature contraction
Answer: c
Explanation: Any disturbance in the heart’s normal rhythmic contraction is called an arrhythmias or cardiac dysrhythmia. In this arrhythmias heart can’t beat in a regular rhythm. In arrhythmia heart-rate will be higher than normal rate or will be less than the normal rate.
2. Which diagnostic statement is based on ECG wave shapes that attempt to describe the state of the working muscle masses?
a) Rhythm statements
b) Morphological statements
c) Morphological-Rhythm statements
d) Rhythm-Morphological statements
Answer: b
Explanation: Morphological statement-primarily based on ECG wave shapes that attempt to describe the state of the working muscle masses. The other type of diagnostic statement is Rhythm statement. These both diagnostic statements are observed from the ECG records.
3. Rhythm statements concerned with the site and rate of the cardiac pacemaker and the propagation of impulses through the conduction system.
a) True
b) False
Answer: a
Explanation: Rhythm statements concerned with the site and rate of the cardiac pacemaker and the propagation of impulses through the conduction system is true because the other type of the diagnostic statements is Morphological statements and it is primarily based on ECG wave shapes that attempt to describe the state of the working muscle masses.
4. Which wave from ECG waveforms becomes widened when the self-triggering impulse does not arrive through the AV node?
a) P wave
b) QRS wave
c) ST wave
d) T wave
Answer: b
Explanation: Sometimes irritation occurs in the ventricles, the self-triggering impulse does not arrive through the node and thus travels a different and slower path in spreading over the ventricles. The QRS wave then becomes widened and is classified as a ventricular ectopic beat.
5. When the self-triggering impulse does not arrive at the AV node and travels a different and slower path over the ventricles, the QRS becomes widened and is classified as ___________
a) Ectopic beat
b) Ventricular-ectopic beat
c) Ventricular beat
d) Atrio-ventricular beat
Answer: b
Explanation: Sometimes irritation occurs in the ventricles, the self-triggering impulse does not arrive through the node and thus travels a different and slower path in spreading over the ventricles. The QRS wave then becomes widened, and is classified as a ventricular ectopic beat. This ectopic beat is classified from ventricles so it is called as a ventricular ectopic beat.
6. An ectopic beat, which starts in an abnormal location in the heart and is often premature, therefore also called _______
a) Pre ventricular contraction
b) Premature ventricular beat
c) Pre ventricular beat
d) Premature ventricular contraction
Answer: d
Explanation: An ectopic beat is a beat, which starts in an abnormal location in the heart and is often premature, therefore also called premature ventricular contraction , i.e. it occurs sooner than the next expected beat.
7. When the heartbeat is slower than the normal rate of the heart, this type of arrhythmias called _______
a) Bradycardia
b) Tachycardia
c) Arterial contraction
d) Ventricular contraction
Answer: a
Explanation: There are 2 types of arrhythmias, i) Bradycardia-when the heart-rate is to slow, ii)Tachycardia-when the heart-rate is to fast. Here the answer is Bradycardia because heart rate is less than 60.
8. Which of the following are resuscitation techniques?
a) Cepstrum coefficient
b) Prophylactic therapy
c) Transthoracic defibrillation
d) Dynamic time warping
Answer: d
Explanation: The necessity for early detection of the arrhythmias led to the establishment of coronary care units in hospitals for the intensive monitoring and treatment of such patients. The attempt in these units was to effectively carry out resuscitation techniques such as cardiac massage and transthoracic defibrillation.
9. If heart rate is x, then which value of x is known as tachycardia?
a) x < 60
b) x > 60
c) 60 < x < 100
d) x > 100
Answer: d
Explanation: There are 2 types of arrhythmias,i)Bradycardia-when the heartrate is to slow, ii)Tachycardia-when the heartrate is to fast.Here the answer is Bradycardia because,heart rate is less than 60.
10. Photo-diodes work in ___________
a) forward biased
b) reverse biased
c) independent of forward and reverse biasing
d) any configuration
Answer: b
Explanation: The photodiode is a P-N junction semiconductor diode. It always operated in the reversed biased condition. The light is always focused through a glass lens on the junction of the photo diode.
11. Parallel flow dialyzer has a low internal resistance. Because of this blood pump is required.
a) True
b) False
Answer: b
Explanation: Parallel flow dialyzer has a low internal resistance which allows adequate blood flow through the dialyzer with the patient’s arterial blood pressure, eliminating the need for a blood pump. The dialyzing surface area of a parallel flow dialyzer is about 1 sq m. At a blood flow rate of 200 ml/min and a dialysate flow of 500 ml/min, the urea and creatinine clearance is about 80 and 64 ml/min.
12. CMRR is measured in _______________
a) V/s
b) dB
c) dB/s
d) dB/ms
Answer: b
Explanation: CMRR is an important specification referred to the differential amplifier and is normally expressed as decibels. The ability of the amplifier to reject common voltages on its two input leads is known as common-mode rejection. It is specified as the ratio of common-mode input to differential input to elicit the same response.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Electrocardiography”.
1. The frequency range of ECG is ____________
a) 0.05-150 HZ
b) 500-1500 Hz
c) 5-500 kHz
d) 0.5-150 MHz
Answer: a
Explanation: The diagnostically useful frequency range is usually accepted as 0.05 to 150 Hz. Although the electric field generated by the heart can be best characterized by vector quantities, it is generally convenient to directly measure only scalar quantities, i.e. a voltage difference of mV order between the given points of the body.
2. Which of the following amplifier circulatory is employed to reduce the hum noise generated by the power supply in the ECG circuit?
a) band pass filters
b) high pass filters
c) notch filters
d) low pass filters
Answer: c
Explanation: A notch filter is employed to suppress the hum noise generated by the power supply in the ECG circuit. CMRR of the order of 100–120 dB with 5 kW unbalance in the leads is a desirable feature of ECG machines. The instability of the baseline, originating from the changes of the contact impedance, demands the application of the automatic baseline stabilizing circuit.
3. The branch of medicine that deals with the provision and use of artificial devices such as splints and braces is _________
a) prosthetics
b) orthotics
c) laproscopic
d) augmentative communication
Answer: c
Explanation: The branch of medicine that deals with the provision and use of artificial devices such as splints and braces are orthotics. A modality-specific appliance that aids the performance of a function or movement by augmenting or assisting the residual capabilities of that function or movement. An orthopaedic brace is an orthosis.
4. The sensitivity of an electrocardiograph is typically set at 10 mm/mV.
a) True
b) False
Answer: a
Explanation: It is true. The sensitivity of an electrocardiograph is typically set at 10 mm/mV. For routine work, the paper recording speed is 25 mm/s. Amplitude measurements are made vertically in millivolts. Time measurements and heart rate measurements are made horizontally on the electrocardiogram.
5. The volume of blood within the dialyzer is known as ___________
a) secondary volume
b) quarterly volume
c) priming volume
d) residual volume
Answer: c
Explanation: The volume of blood within the dialyzer is known as priming volume. It is desirable that this should be minimal. Priming volume of present day dialyzers ranges from 75 to 200 ml, depending on the membrane area geometry and operating conditions.
6. The ideal membrane should possess ___________ to water.
a) low permeability to water
b) high permeability to water
c) medium permeability to water
d) high permeability to waste
Answer: b
Explanation: The ideal membrane should possess high permeability to water, organic metabolites and ions, and the capability of retaining plasma proteins. The membrane should be of sufficient wet strength to resist tearing or bursting and non-toxic to blood and all body cells.
7. To achieve optimum performance and to enable the relationship of change in resistance with the volume of the cell to hold good, it is recommended that the ratio of the aperture length to the diameter of the aperture should be __________
a) 75:1
b) 0.75:100
c) 0.75:1
d) 0.5:10
Answer: c
Explanation: To achieve optimum performance and to enable the relationship of change in resistance with volume of the cell to hold good, it is recommended that the ratio of the aperture length to the diameter of the aperture should be 0.75:1, i.e. for an orifice of 100 m diameter the length should be 75 m. The instrument based on the Coulter principle works most satisfactorily when the average diameter of the particles ranges between 2 to 40% of the diameter of the measuring hole.
8. The blood is a poor conductor of electricity.
a) True
b) False
Answer: a
Explanation: It is true. Blood is a poor conductor of electricity. This principle is used in Coulter counters to count the number of RBCs in the blood.
9. In floating electrodes metal electrode does not make direct contact with the skin.
a) True
b) False
Answer: a
Explanation: In a floating electrode, the metal electrode does not make direct contact with the skin. The electrode consists of a light weighted metalled screen or plate held away from the subject by a flat washer which is connected to the skin. Floating electrodes can be recharged, i.e. the jelly in the electrodes can be replenished if desired.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Vectorcardiography ”.
1. Which gas saturation is of great importance in clinical practice?
a) oxygen
b) carbon dioxide
c) hydrogen
d) nitrogen
Answer: a
Explanation: In clinical practice, the percentage of oxygen saturation in the blood is of great importance. This saturation being a bio-constant is an indication of the performance of the most important cardio-respiratory functions. It is maintained at a fairly constant value to within a few percents in a healthy organism.
2. Liquid part of blood is __________
a) Platelets
b) Red Blood Cells
c) White Blood Cells
d) Plasma
Answer: d
Explanation: The plasma is a very poor carrier of oxygen. At the pressures available, only 0.3 ml of oxygen can dissolve in 100 ml of plasma, which is quite insufficient for the needs of the body.
3. What does red blood cells contain for combining with a large volume of oxygen?
a) Proteins
b) Haemoglobin
c) Lipids
d) Platelets
Answer: b
Explanation: The red blood cells contain haemoglobin which can combine with a large volume of oxygen so quickly that in the lungs it may become 97% saturated forming a compound called oxyhaemoglobin.
4. How much quantity of oxygen bound with haemoglobin in the normal arterial blood?
a) 20.3ml %
b) 21.5ml %
c) 19.4ml %
d) 20.1ml %
Answer: c
Explanation: The total quantity of oxygen bound with haemoglobin in the normal arterial blood is approximately 19.4 ml percent at a pO2 of 95 mmHg. On passing through the tissue capillaries this amount is reduced to 14.4 ml percent at a pO2 of 40 mmHg.
5. When blood is withdrawn from the subject under anaerobic conditions and measurement for oxygen saturation is made at a later time in the laboratory, the procedure is referred to as _________ oximetry.
a) in vitro
b) in vivo
c) transmission
d) reflection
Answer: a
Explanation: When blood is withdrawn from the subject under anaerobic conditions and measurement for oxygen saturation is made at a later time in the laboratory, the procedure is referred to as in vitro oximetry.
6. For discrete blood samples, a spectrophotometric measurement of oxygen saturation can be made by which method?
a) in vitro
b) in vivo
c) transmission
d) cannot be determined
Answer: c
Explanation: For discrete blood samples, a spectrophotometric measurement of oxygen saturation can be made by either a transmission method or a reflection method.
7. Which principle is used by ear oximeter usually?
a) in vivo
b) transmission
c) reflection
d) in vitro
Answer: b
Explanation: Ear oximeters usually make use of the transmission principle to measure arterial oxygen saturation. In this case, the pinna of the ear acts as a cuvette. Blood in the ear must be made similar to arterial blood in composition.
8. Blood in _________ must be made similar to arterial Blood in composition.
a) heart
b) brain
c) ear
d) eyes
Answer: c
Explanation: Blood in the ear must be made similar to arterial blood in composition. This is done by increasing the flow through the ear without appreciably increasing the metabolism. Maximum vasodilatation is achieved by keeping the ear warm.
9. By keeping the ear warm, maximum vasodilatation is achieved.
a) True
b) False
Answer: a
Explanation: Yes, maximum vasodilatation is achieved by keeping the ear warm. It takes about 5 or 10 min for the ear to become fully dilated after the ear unit has been put up in place and the lamp turned on.
10. What is time taken for the ear to become fully dilated after ear unit has been placed?
a) 5-10 min
b) 10-15 min
c) 15-20 min
d) 20-25 min
Answer: a
Explanation: Maximum vasodilatation is achieved by keeping the ear warm. It takes about 5 or 10 min for the ear to become fully dilated after the ear unit has been put up in place and the lamp turned on.
11. Merrick and Hayes describe details of a _________ oximeter which enables the measurement of oxygen saturation of blood.
a) Pulse
b) Ear
c) Skin Reflactance
d) Intravascular
Answer: b
Explanation: Merrick and Hayes describe details of an ear oximeter which enables the measurement of oxygen saturation of the blood. This measurement is independent of a wide range of encountered variables and is made without involving patients in any calibration or standardization procedure.
12. This technique involves measuring the optical transmittance of the ear at how many wavelengths?
a) 12
b) 6
c) 8
d) 10
Answer: c
Explanation: In brief, the technique involves measuring the optical transmittance of the ear at 8 wavelengths in the 650 to 1050 nm range. A 2.5 m long flexible fibre ear probe connects the patient to the instrument.
13. Ear probe which connects the patient to instrument is ___________ m long.
a) 1.5
b) 2.0
c) 2.5
d) 3.0
Answer: c
Explanation: A 2.5 m long flexible fibre ear probe connects the patient to the instrument. The ear probe can be either held in position for discrete measurements or can be conveniently mounted to a headband for continuous display.
14. Ear oximeter instrument is based on Beer-Lambert law.
a) True
b) False
Answer: a
Explanation: The instrument is based on the Beer-Lambert law. However, it is assumed that the optical absorbers act independently and additively and that the effects of light scattering by the ear tissue can be minimized by a proper source and detector geometry.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Phonocardiography ”.
1. An arrhythmia monitor is basically a ______
a) Sophisticated monitoring system
b) Sophisticated alarm system
c) Patient monitoring system
d) ECG interpretation system
Answer: b
Explanation: An arrhythmia monitor is basically a sophisticated alarm system. It is not an ECG interpretation system. It constantly scans ECG rhythm patterns and issues alarms to events that may be premonitory or life threatening.
2. In arrhythmia monitoring system, it gives alarm light signals whenever the prematured or widened ectopic beats exist up to the rate of ___________
a) 6/min to 10/min
b) 6/min to 12/min
c) 6/min or 10/min
d) 6/min or 12/min
Answer: d
Explanation: In arrhythmia monitoring instrument, it gives alarm light signals whenever the prematured or widened ectopic beat exist up to the rate of 6/min or 12/min.It is one of the operating sequences of the arrhythmia monitoring instrument.
3. In automated arrhythmia monitoring system, which task is performed after the Ventricular fibrillation detection?
a) Rhythm definition
b) Beat labeling
c) Atrial fibrillation detection
d) Noise detection
Answer: a
Explanation: In automated arrhythmia monitoring system, Rhythm definition is performed after the Ventricular fibrillation detection. Rhythm definition is also performed after the beat labeling and atrial fibrillation detection in automated arrhythmia monitoring and analysis system.
4. In signal conditioning, ECG signal is amplified, filtered with 0.05-100 Hz for monitoring purposes and 1-40 Hz for diagnostic purposes.
a) True
b) False
Answer: b
Explanation: ECG signal is amplified and filtered with 0.05-100 Hz for diagnostic purposes and 1-40 Hz for monitoring purposes in signal conditioning.
5. Which analog-to-digital converter is used in the digitization of ECG signal in signal conditioning?
a) 16 bit
b) 12 bit
c) 32 bit
d) 64 bit
Answer: b
Explanation: In signal conditioning, ECG signal is amplified, filtered and digitized using an 8 or 12 bit analog-to-digital converter with a typical sampling rate of 250 Hz.
6. By using a _________ rather than a _________ the amplitude of low frequency noise as well as the low frequency components of the ECG will be reduced without affecting the QRS.
a) High-pass filter, Band-pass filter
b) Low-pass filter, Band-pass filter
c) Band-pass filter, Low-pass filter
d) Band-pass filter, High-pass filter
Answer: c
Explanation: The maximum of the QRS energy spectrum is in the vicinity of 10 Hz, the filter is designed to have a bandwidth of about 15 Hz with a centre frequency of 10-12 Hz. By using a bandpass filter rather than a low-pass filter, the amplitude of low frequency noise as well as the low frequency components of the ECG will be reduced without affecting the QRS.
7. The steep, large amplitude variation of the QRS complex is the obvious characteristics to use and this is the function of the R wave detector.
a) True
b) False
Answer: a
Explanation: Arrhythmia monitors require reliable R wave detectors as a prerequisite for subsequent analysis. The steep, large amplitude variation of the QRS complex is the obvious characteristics to use and this is the function of the R wave detector.
8. In the process of the ECG waveform, the detection filter removes _______ and _______
a) Baseline wander, motion noise
b) Muscle artifact, motion noise
c) Low frequency noise, motion noise
d) Baseline wander, muscle artifact
Answer: c
Explanation: The ECG waveform is processed by two digital filters: a detection filter and a classification filter. The detection filter removes low frequency noise and muscle artifact. P waves and T waves are diminished.
9. How many steps are there in QRS detection?
a) Three steps
b) Two steps
c) Four steps
d) One step
Answer: b
Explanation: QRS detection is now almost universally performed digitally in a two-step process. The ECG is first preprocessed to enhance the QRS complex while suppressing noise, artifact and non-QRS portions of the ECG. The output of the preprocessor stage is subjected to a decision rule that confirms the detection of QRS if the processor output exceeds a threshold.
10. _________ is based on analyzing the shape of the QRS complexes and separating beats into groups or clusters.
a) Timing classification
b) Morphology characterization
c) Beat labeling
d) Noise detection
Answer: b
Explanation: Morphology characterization is based on analyzing the shape of the QRS complexes and separating beats into groups or clusters of similar morphology. Most algorithms for real time arrhythmia analysis maintain no more than 10-20 clusters at a time, order to limit the amount of computation needed to assign a QRS complex to a cluster.
11. When will be R-R interval declared premature?
a) If it is greater than 85% of the predicted interval
b) If it is less than 85% of the predicted interval
c) If it is greater than 75% of the predicted interval
d) If it is less than 75% of the predicted interval
Answer: b
Explanation: In timing classification, the observed R-R interval is compared to an estimate of the expected R-R interval. An R-R interval will be declared premature if it is less than 85% of the predicted interval. Similarly, an R-R interval is long if it is greater than 110% of the predicted value.
12. Which is the final stage in arrhythmia analysis?
a) Beat labeling
b) Alarms
c) Rhythm labeling
d) Summary statistics
Answer: c
Explanation: Rhythm labeling is the final stage in arrhythmia analysis. It is based on defined sequences of QRS complexes. The analysis systems are heavily oriented towards detecting ventricular arrhythmias, particularly single PVCs.
13. Ventricular Fibrillation is detected by _________
a) Shape of the QRS complexes
b) Difference of the R-R interval
c) Timing sequence of QRS complexes
d) Frequency domain analysis
Answer: d
Explanation: Ventricular fibrillation is usually detected by frequency domain analysis. The system is characterized as a narrow-band, low frequency signal with energy concentrated in a band around 5-6 Hz. It can be distinguished from noise by appropriately designing band-pass filters.
14. Which techniques are used in a new algorithm proposed by Jen and Hwang to obtain the long term ECG signal feature and extract the meaningful information hiding in the QRS complex?
a) Cepstrum time warping and Dynamic coefficient
b) Cepstrum coefficient and Dynamic time warping
c) QRS detection and Dynamic coefficient
d) QRS detection and Cepstrum time warping
Answer: b
Explanation: Jen and Hwang proposed a new algorithm using cepstrum coefficient and the dynamic time warping techniques to obtain the long term ECG signal feature and extract the meaningful information hiding in the QRS complex. This algorithm may also be used for arrhythmia detection by simply checking the difference of R-R wave intervals through signal feature extraction comparison for a certain period of time.
15. What is the sampling rate of the analog-to-digital converter in digitizing of ECG signal in signal conditioning?
a) 250 Hz
b) 215 Hz
c) 40-100 Hz
d) 200-215 Hz
Answer: a
Explanation: In signal conditioning, ECG signal is amplified, filtered and digitized using an 8 or 12-bit analog-to-digital converter with a typical sampling rate of 250 Hz.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Digital Stethoscope”.
1. Blood in ___________ must be made similar to arterial Blood in composition.
a) heart
b) brain
c) ear
d) eyes
Answer: c
Explanation: Blood in the ear must be made similar to arterial blood in composition. This is done by increasing the flow through the ear without appreciably increasing the metabolism. Maximum vasodilatation is achieved by keeping the ear warm.
2. By keeping the ear warm, maximum vasodilatation is achieved.
a) True
b) False
Answer: a
Explanation: Yes, maximum vasodilatation is achieved by keeping the ear warm. It takes about 5 or 10 min for the ear to become fully dilated after the ear unit has been put up in place and the lamp turned on.
3. Merrick and Hayes describe details of a __________ oximeter which enables the measurement of oxygen saturation of the blood.
a) Pulse
b) Ear
c) Skin Reflectance
d) Intravascular
Answer: b
Explanation: Merrick and Hayes describe details of an ear oximeter which enables the measurement of oxygen saturation of blood. This measurement is independent of a wide range of encountered variables and is made without involving patients in any calibration or standardization procedure.
4. Ear probe which connects the patient to instrument is __________ m long.
a) 1.5
b) 2.0
c) 2.5
d) 3.0
Answer: c
Explanation: A 2.5 m long flexible fibre ear probe connects the patient to the instrument. The ear probe can be either held in position for discrete measurements or can be conveniently mounted to a headband for continuous display.
5. Ear oximeter instrument is based on Beer- Lambert law.
a) True
b) False
Answer: a
Explanation: The instrument is based on the Beer-Lambert law. However, it is assumed that the optical absorbers act independently and additively and that the effects of light scattering by the ear tissue can be minimized by a proper source and detector geometry.
6. The percentage of functional haemoglobin combined with oxygen is expressed as ______
a) *100
b) *100
c) *100
d) *100
Answer: a
Explanation: The instrument is designed to measure the percentage of functional hemoglobin combined with oxygen. This can be expressed as:
biomedical-instrumentation-questions-answers-digital-stethoscope-q9
where CO is the concentration of oxyhemoglobin and CR is the concentration of deoxyhemoglobin.
7. What is used as a light source in ear oximeter?
a) Mercury-vapor lamp
b) Sodium-vapor lamp
c) Tungsten-iodine lamp
d) Sulfur lamp
Answer: c
Explanation: The light source is a tungsten-iodine lamp that has a high output in the spectrum of interest. A lens system collimates the light beam and directs it through thin-film interference filters that provide wavelength selection.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Electroencephalograph ”.
1. Pulse oximetry is used to measure the oxygen level in blood & heart rate.
a) True
b) False
Answer: a
Explanation: Pulse oximetry is a technology used to measure the oxygen level in your blood and your heart rate. A finger pulse oximeter is equipped with technology to rapidly detect changes in your blood oxygen level.
2. How many wavelengths are used by Pulse Oximeter?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: Pulse oximetry is based on the concept that arterial oxygen saturation determinations can be made using two wavelengths, provided the measurements are made on the pulsatile part of the waveform.
3. Light passing through finger will be adsorbed by ___________
Skin Pigments
Tissue
Arteries
Veins
a) &
b) &
c) &
d) &
Answer: c
Explanation: The two wavelengths assume that only two absorbers are present; namely oxyhaemoglobin and reduced haemoglobin .Light passing through the ear or finger will be absorbed by skin pigments, tissue, cartilage, bone, arterial blood, venous blood.
4. How is the blood flow in arteries and arterioles?
a) plug
b) laminar
c) parabolic
d) pulsatile
Answer: d
Explanation: Most of the absorbances are fixed and do not change with time. Even blood in the capillaries and veins under steady state metabolic circumstances is constant in composition and flow, at least over short periods of time.Only the blood flow in the arteries and arterioles is pulsatile.
5. Law obeyed by Pulse Oximeter is _______
a) Lambert-Bouguer law
b) Beer ‘s law
c) Beer-Lambert law
d) Lamber-Bouguer, Beer’s and Beer-Lambert Law
Answer: d
Explanation: Light passing through the ear or finger will be absorbed by skin pigments, tissue, cartilage, bone, arterial blood, venous blood. The absorbances are additive and obey the Beer-Lambert law. Beer-Lambert is combination of Lambert-Bouguer and Beer’s Law.
6. Which oximeter probe is in the picture?
biomedical-instrumentation-questions-answers-electroencephalograph-eeg-q6
a) Ear
b) Pulse
c) Skin Reflectance
d) Intravascular
Answer: b
Explanation: Components of pulse oximeter Probe.
7. How many LED’s are used in Pulse oximeter probe?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: This has two LEDs , one that transmits infrared light at a wavelength of approximately 940 nm and the other transmitting light at approximately 660 nm.
8. Oxygen saturation is estimated by _________
a) ratio of pulse-added red absorbance at 660 nm to the pulse-added infrared absorbances at 940 nm
b) ratio of pulse-added red absorbance at 940 nm to the pulse-added infrared absorbances at 660 nm
c) ratio of pulse-added red absorbance at 330 nm to the pulse-added infrared absorbances at 940 nm
d) ratio of pulse-added red absorbance at 940 nm to the pulse-added infrared absorbances at 330 nm
Answer: a
Explanation: Oxygen saturation is estimated from the ratio of pulse-added red absorbance at 660 nm to the pulse-added infrared absorbances at 940 nm.
9. What gets affected by lower saturation?
a) blood flow
b) translucency
c) accuracy
d) low atmospheric pressure
Answer: c
Explanation: An accuracy of 1% or better has been reported for the saturation range of above 80% for most transmission type pulse oximeters. Usually, the accuracy is less at lower saturation because of non-linear effects of absorption.
10. What factors has no significant influence on the measurement?
a) skin pigmentation
b) thickness
c) tissue
d) skin pigmentation, thickness and tissue
Answer: d
Explanation: The instrument can be empirically calibrated. Subject variability has no significant influence on the measurement.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Electromyograph ”.
1. Which of the following instrument is used to measure the oxygen saturation level of blood in localized areas of oxygen?
a) Ear Oximeter
b) Pulse Oximeter
c) Skin reflectance Oximeter
d) Intravascular Oximeter
Answer: c
Explanation: For the measurement of oxygen saturation level of blood in localized areas of oxygen deprived tissues on the limbs, head and torso, a skin reflectance oximeter can be employed.
2. Skin Reflectance oximeter depends on monitoring backscattered lights in how many wavelengths?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: The instrument basically depends on monitoring backscattered light from living tissue in two wavelengths. The backscattered light data is then used for the in vivo determination of the blood’s relative oxygen saturation.
3. Who brought out the difficulties in the extraction of useful information from backscattered light intensity from human tissue?
a) Cohen and Wadsworth
b) Cohen and Logini
c) Cohen
d) Logini
Answer: a
Explanation: Cohen and Wadsworth bring out the difficulties in the extraction of useful information from backscattered light intensity from human tissue. There are vast variations of tissue construction and optical properties among various subjects and in different locations on the same subject.
4. Who considered “Human tissues are composed of parallel semi-infinite layers of homogenous materials”.
a) Cohen and Wadsworth
b) Cohen and Logini
c) Cohen
d) Wadsworth
Answer: b
Explanation: Cohen and Longini suggested a theoretical solution to some of these problems. They considered human tissues to be composed of parallel semi-infinite layers of homogeneous materials.
5. Who has poorer signal-to-noise ratio?
a) Transmission Pulse Oximeter
b) Reflection Pulse Oximeter
c) Ear Oximeter
d) Pulse Oximeter
Answer: b
Explanation: However, in comparison to transmission, the reflection pulse oximeter has poorer signal-to noiseratio. Mendelson et al utilized multiple photodiodes around the light source to enhance signal level.
6. What was utilized around the light source to enhance the signal?
a) Photodiodes
b) Optical Shied
c) Ceramic Substrate
d) Red and infrared LED’s
Answer: a
Explanation: However, in comparison to transmission, the reflection pulse oximeter has poorer signal-to noise ratio. Mendelson et al utilized multiple photodiodes around the light source to enhance signal level.
7. What are used as light source in Skin Reflectance Oximeter?
a) Photodiode
b) Red and infrared LED’s
c) Flashtube
d) Arc Lamp
Answer: b
Explanation: A pair of red and infrared light emitting diodes are used for the light source, with peak emission wavelengths of 665 nm and 935 nm . The reflected light from the skin at these two wavelengths is detected by a silicon diode.
8. The reflected light from the skin at wavelengths of 665nm and 935nm is detected by ______________
a) Photo diode
b) Laser diode
c) Silicon diode
d) Zener diode
Answer: c
Explanation: A pair of red and infrared light emitting diodes are used for the light source, with peak emission wavelengths of 665 nm and 935 nm . The reflected light from the skin at these two wavelengths is detected by a silicon diode.
9. The detected signals are processed in the form of photo – plethysmographs to determine ___________
a) SiO 2
b) SO 2
c) CO 2
d) TiO 2
Answer: b
Explanation: A pair of red and infrared light emitting diodes is used for the light source, with peak emission wavelengths of 665 nm and 935 nm . The reflected light from the skin at these two wavelengths is detected by a silicon diode. These detected signals are processed in the form of photo-plethysmographs to determine So 2 .
10. What is incorporated in sensor to warm the tissue so as to increase local blood flow?
a) heater
b) heating plate
c) thermostat
d) thermometer
Answer: a
Explanation: A heater was incorporated in the sensor to warm the tissue so as to increase local blood flow. Excellent correlation in comparison with the transmission oximeter has been shown from the calf and thigh.
This set of Biomedical Instrumentation test focuses on “Other Biomedical Recorders”.
1. How much blood is present in an average adult?
a) 10-12 L
b) 2-3 L
c) 5-6 L
d) 20-25 L
Answer: c
Explanation: In an average adult about 5-6 L of blood is present. Blood consists of corpuscles suspended in a fluid called plasma in the proportion of 45 parts of corpuscles to 55 parts of plasma. The percentage of cells in the blood is called the haematocrit value or packed cell volume .
2. What is the blood percentage of total body weight?
a) 5-10 %
b) 20-30 %
c) 2-3 %
d) 10-15 %
Answer: a
Explanation: The blood constitutes 5–10% of the total body weight and in the average adult, it amounts to 5–6 l. Blood consists of corpuscles suspended in a fluid called plasma in the proportion of 45 parts of corpuscles to 55 parts of plasma. The percentage of cells in the blood is called the haematocrit value or packed cell volume .
3. Blood consists of corpuscles suspended in a fluid called plasma in the proportion of 45 parts of ____________ to 55 parts of _____________
a) Plasma, corpuscles
b) Corpuscles, plasma
c) Protoplasma, cytozomes
d) Cytozomes, protoplasma
Answer: b
Explanation: Blood consists of corpuscles suspended in a fluid called plasma in the proportion of 45 parts of corpuscles to 55 parts of plasma. The percentage of cells in the blood is called the haematocrit value or packed cell volume . The majority of the corpuscles in the blood are red blood cells , others being white blood cells and platelets .
4. The percentage of cells in the blood is called _____________
a) haematocrit value
b) packet corpuscles value
c) packed haematocrit value
d) corpuscles value
Answer: a
Explanation: The percentage of cells in the blood is called the haematocrit value or packed cell volume . The majority of the corpuscles in the blood are red blood cells , others being white blood cells and platelets .
5. Which of the following blood constituent is in the form of a bi-concave disc?
a) lymphocytes
b) leucocutes
c) neutrophils
d) erythrocytes
Answer: d
Explanation: Red blood cells have the form of a bi-concave disc with a mean diameter of about 7.5 m and thickness of about 1.7 m. The mean surface area of the cell is about 134mm 2 . There are about 5.5 million of them in every cubic millimetre of blood in men and nearly 5 million in women.
6. Diameter of erythrocytes is in the range of ___________
a) nano meters
b) micro meters
c) pico meters
d) femto meters
Answer: b
Explanation: Mean diameter of about 7.5 m and a thickness of about 1.7 m. The mean surface area of the cell is about 134mm2. There are about 5.5 million of them in every cubic millimetre of blood in men and nearly 5 million in women.
7. In the whole body, there are about 25 billion erythrocytes and they are constantly being destroyed and replaced at a rate of about 9000 million per hour.
a) True
b) False
Answer: a
Explanation: It is true. In the whole body, there are about 25 billion erythrocytes and they are constantly being destroyed and replaced at a rate of about 9000 million per hour. There are about 5.5 million of them in every cubic millimetre of blood in men and nearly 5 million in women.
8. The normal red cell lasts approximately how many days before it is destroyed?
a) 240
b) 10
c) 12
d) 120
Answer: d
Explanation: The normal red cell lasts approximately 120 days before it is destroyed. There are about 5.5 million of them in every cubic millimetre of blood in men and nearly 5 million in women. In the whole body, there are about 25 billion erythrocytes and they are constantly being destroyed and replaced at a rate of about 9000 million per hour.
9. The erythrocytes have a nucleus.
a) True
b) False
Answer: b
Explanation: The erythrocytes have no nucleus. They are responsible for carrying oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs. In the whole body, there are about 25 billion erythrocytes and they are constantly being destroyed and replaced at a rate of about 9000 million per hour.
10. Anaemia is reduction/increase _________
a) in the carbon dioxide carrying capacity of blood
b) in the oxygen carrying capacity of blood
c) in the oxygen carrying capacity of blood
d) in the carbon dioxide carrying capacity of blood
Answer: b
Explanation: Anaemia is a reduction in the oxygen carrying capacity of the blood. It can develop from a change in the number, volume or Hb concentration of erythrocytes, caused by bone marrow dysfunction resulting in the poor production rate of RBCs. Since these changes are specific, the measurement of packed cell volume , the number of RBCs and the haemoglobin are very important.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Biofeedback Instrumentation”.
1. What is the shape of Leucocytes?
a) Cubic
b) Cuboid
c) Spherical
d) Hollow
Answer: c
Explanation: Leucocytes are spherical cells having a nucleus. There are normally 5000–10,000 white cells per cubic mm of blood but their number varies during the day. They live for seven to fourteen days and there is a rapid turn over, with constant destruction and replacement.
2. Life span of leucocytes is _____________
a) 3 – 4 weeks
b) 7 – 14 days
c) 9 – 10 months
d) 7 – 14 years
Answer: b
Explanation: They live for seven to fourteen days and there is a rapid turn over, with constant destruction and replacement. Leucocytes form the defence mechanism of the body against infection. They are of two main types: the neutrophils and the lymphocytes. Leucocytes are spherical cells having a nucleus.
3. Leucocytes form the defence mechanism of the body against infection.
a) True
b) False
Answer: a
Explanation: Leucocytes form the defence mechanism of the body against infection. They are of two main types: the neutrophils and the lymphocytes. Neutrophils ingest bacteria and lymphocytes are concerned with immunological response. The number and proportion of these types of leucocytes may vary widely in response to various disease conditions.
4. Neutrophills are concerned __________ and lymphocytes are concerned with __________
a) ingestion of bacteria, immunological responses
b) production of bacteria, electrical responses
c) electrical responses, production of bacteria
d) immunological responses, ingestion of bacteria
Answer: a
Explanation: Neutrophils ingest bacteria and lymphocytes are concerned with immunological response. The number and proportion of these types of leucocytes may vary widely in response to various disease conditions. For thus reason, it is important to know the total leucocyte count.
5. Neutrophils are smaller than the red cells.
a) True
b) False
Answer: b
Explanation: It is false. Neutrophils are nearly twice as big as the red cells. They contain both a nucleus divided into several lobes and granules in their protoplasm. Lymphocytes are of the same size as the red cells but contain a large density staining nucleus and no granules.
6. Which of the following option is correct in terms of size?
a) Monocytes > Neutrophils > RBC > lymphocytes
b) Monocytes > Neutrophils > RBC >= lymphocytes
c) Monocytes < Neutrophils < RBC < lymphocytes
d) Monocytes =< Neutrophils < RBC < lymphocytes
Answer: b
Explanation: Monocytes are twice as big as neutrophils. Neutrophils are twice as big as the RBC. The lymphotocytes are of almost of the same size of the RBC of smaller.
7. _________ is the ratio of the integrated platelet volume to the platelet count and is expressed in femolitres.
a) Mean Platelet Volume
b) Platelet Distribution Width
c) Red Cell Distribution Width
d) Mean Cell Haemoglobin Concentration
Answer: a
Explanation: Mean Platelet Volume is the ratio of the integrated platelet volume to the platelet count and is expressed in femolitres. Red Cell Distribution Width is a numerical expression of the width of the size distribution of red cells. Platelet Distribution Width is related to the size range covered by those platelets lying between the sixteenth and eighty fourth percentile.
8. Normal mean red cell volume is _____________
a) 6 ± 10 f/l
b) 16 ± 10 f/l
c) 86 ± 10 f/l
d) 56 ± 10 f/l
Answer: c
Explanation: Normal mean red cell volume is 86 ± 10 f/l. In diseased conditions, it may fall to 50 f/l or rise upto 150 f/l. 1f/l = 10–15. 1 litre of blood contains 0.45 litres of red cells and if there are 5 ¥ 1012 red cells per litre.
9. Normal mean cell haemoglobin is 29.5 ± 2.5 pg.
a) True
b) False
Answer: a
Explanation: It is true. Normal mean cell haemoglobin is 29.5 ± 2.5 pg. In diseased conditions it may rise to 50 pg or fall to 15 pg.
10. The percentage of the total specimen volume occupied by the platelets is called ____________
a) Platelet Distribution Width
b) Red Cell Distribution Width
c) Plateletcrit
d) Mean Platelet Volume
Answer: c
Explanation: The percentage of the total specimen volume occupied by the platelets is called. Mean Platelet Volume is the ratio of the integrated platelet volume to the platelet count and is expressed in femolitres. Red Cell Distribution Width is a numerical expression of the width of the size distribution of red cells.
11. What is used in modern instrument for intravascular oximetry?
a) photodiode
b) red and infrared LED’s
c) optical fibre
d) phototransistor
Answer: c
Explanation: For intravascular oximetry, modern instruments make use of optical fibres to guide the light signal inside the vessel and the reflected light from the red blood cells back to the light detector.
12. For estimating SO2, usually reflectance at ________ wavelengths are used.
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: For estimating SO 2 , usually the reflectance at two wavelengths, one in the red and the other in the near infrared regions, are used.
13. How many wavelengths are utilized by currently available oximeters?
a) More than 2
b) Less than 2
c) Equal to 2
d) Cannot be determined
Answer: a
Explanation: For estimating SO 2 , usually the reflectance at two wavelengths, one in the red and the other in the near infrared regions, are used. Currently available fiber-optic oximeters utilize more than two wavelengths to adjust for haematocrit variation.
14. What is used to measure mix venous saturation?
a) Ear Oximeter
b) Pulse Oximeter
c) Skin Reflectance Oximeter
d) Intravascular Oximeter
Answer: d
Explanation: Intravasacular oximeters are normally used to measure mixed venous saturation, from which the status of the circulatory system can be deduced. Mixed venous saturation varies in reflecting the changes of oxygen saturation, cardiac output, haematocrit or haemoglobin content and oxygen consumption.
15. The RDW index is expressed by which of the following equation?
a) [ Percentile Volume / Percentile Volume] X 100 X K
b) [ Percentile Volume / Percentile Volume] X 100 X K
c) [ Percentile Volume / Percentile Volume] X 100 X K
d) [ Percentile Volume / Percentile Volume] X 100 X K
Answer: a
Explanation: The RDW index is expressed by the following equation [ Percentile Volume / Percentile Volume] X 100 X K. It is a numerical expression of the width of the size distribution of red cells. It is derived by analog computation. The total erythrocyte count is scanned by a continuously variable thresholding circuit. The upper threshold is moved progressively lower from a level equivalent to 360 femolitres until 20 percent of all erythrocytes present have a size above a certain value.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “System Concepts”.
1. Which of the following instrument records the electrical activity of the heart?
a) VCG
b) PCG
c) ECG
d) EEG
Answer: c
Explanation: The electrocardiograph is an instrument, which records the electrical activity of the heart. Electrical signals from the heart characteristically precede the normal mechanical function and monitoring of these signals has great clinical significance.
2. Electrocardiography are used in catheterization laboratories, coronary care units and for routine diagnostic applications in cardiology.
a) True
b) False
Answer: a
Explanation: True, electrocardiographs are used in catheterization laboratories, coronary care units and for routine diagnostic applications in cardiology.
3. Who provides valuable information about a wide range of cardiac disorders?
a) VCG
b) ECG
c) PCG
d) EEG
Answer: b
Explanation: ECG provides valuable information about a wide range of cardiac disorders such as the presence of an inactive part or an enlargement of the heart muscle.
4. What is diagnostically useful frequency range?
a) 0.025 to 0.05 Hz
b) 0.05 to 150 Hz
c) 150 to 200 Hz
d) 0.05 to 150 MHz
Answer: b
Explanation: Although the electric field generated by the heart can be best characterized by vector quantities, it is generally convenient to directly measure only scalar quantities, i.e. a voltage difference of mV order between the given points of the body. The diagnostically useful frequency range is usually accepted as 0.05 to 150 Hz .
5. Which machines CMRR is of order of 100-120 dB?
a) VCG
b) PCG
c) EEG
d) ECG
Answer: d
Explanation: CMRR of the order of 100–120 dB with 5 kW unbalance in the leads is a desirable feature of ECG machines. In addition to this, under specially adverse circumstances, it becomes necessary to include a notch filter tuned to 50 Hz to reject hum due to power mains.
6. How many paper speeds are necessary for ECG recording?
a) One
b) Minimum two
c) Can be any
d) Max two
Answer: b
Explanation: The instability of the baseline, originating from the changes of the contact impedance, demands the application of the automatic baseline stabilizing circuit. A minimum of two paper speeds is necessary for ECG recording.
7. Where are potentials picked up by patient electrodes taken to?
a) Lead Selector switch
b) Preamp
c) Power Amplifier
d) Instrumentational amplifier
Answer: a
Explanation: The potentials picked up by the patient electrodes are taken to the lead selector switch. In the lead selector, the electrodes are selected two by two according to the lead program.
8. How lead selector selects electrodes?
a) one by one
b) two by two
c) three by three
d) four by four
Answer: b
Explanation: The potentials picked up by the patient electrodes are taken to the lead selector switch. In the lead selector, the electrodes are selected two by two according to the lead program.
9. The amplified output signal is picked up single-ended from preamp and is given to the _________
a) Power Amplifier
b) Lead Selector
c) Pen Motor
d) Paper motor
Answer: a
Explanation: The preamplifier is usually a three or four stage differential amplifier having a sufficiently large negative current feedback, from the end stage to the first stage, which gives a stabilizing effect. The amplified output signal is picked up single-ended and is given to the power amplifier. The power amplifier is generally of the push-pull differentical type.
10. Why is preamplifier used?
a) For Amplification
b) For Stabilizing effect
c) For Reducing effect
d) For Modifying effects
Answer: b
Explanation: The preamplifier is usually a three or four stage differential amplifier having a sufficiently large negative current feedback, from the end stage to the first stage, which gives a stabilizing effect.
11. ‘Stand by’ mode of operation is generally provided in which instrument?
a) VCG
b) PCG
c) ECG
d) EMG
Answer: c
Explanation: A‘stand by’ mode of operation is generally provided on the electrocardiograph. In this mode, the stylus moves in response to input signals, but the paper is stationary. This mode allows the operator to adjust the gain and baseline position controls without wasting paper.
12. ________ are made horizontally on electrocardiogram.
a) Time Measurements
b) Heart Rate Measurements
c) Time Measurements and Heart Rate Measurements
d) Not fixed and can be any thing
Answer: c
Explanation: Electrocardiograms are almost invariably recorded on graph paper with horizontal and vertical lines at 1 mm intervals with a thicker line at 5 mm intervals. Time measurements and heart rate measurements are made horizontally on the electrocardiogram.
13. What is paper recording speed for routine work?
a) 10 mm/s
b) 15 mm/s
c) 20 mm/s
d) 25 mm/s
Answer: c
Explanation: Electrocardiograms are almost invariably recorded on graph paper with horizontal and vertical lines at 1 mm intervals with a thicker line at 5 mm intervals. Time measurements and heart rate measurements are made horizontally on the electrocardiogram.
14. What measurements are made vertically on electrocardiogram?
a) Time Measurements
b) Heart Rate Measurements
c) Amplitude Measurements
d) Time Measurements and Heart Rate Measurements
Answer: c
Explanation: Electrocardiograms are almost invariably recorded on graph paper with horizontal and vertical lines at 1 mm intervals with a thicker line at 5 mm intervals. Time measurements and heart rate measurements are made horizontally on the electrocardiogram. Amplitude measurements are made vertically in millivolts.The sensitivity of an electrocardiograph is typically set at 10 mm/mV.
15. What is sensitivity of an electrocardiograph?
a) 10 mm/mV
b) 15 mm/mV
c) 20 mm/mV
d) 25 mm/mV
Answer: a
Explanation: Electrocardiograms are almost invariably recorded on graph paper with horizontal and vertical lines at 1 mm intervals with a thicker line at 5 mm intervals. Time measurements and heart rate measurements are made horizontally on the electrocardiogram. Amplitude measurements are made vertically in millivolts. The sensitivity of an electrocardiograph is typically set at 10 mm/mV.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Cardiac Monitor”.
1. Interruption or interference with normal physiological and developmental processes or structures is called _________
a) Functional Limitation
b) Pathophysiology
c) Societal Limitation
d) Modality-Specific
Answer: b
Explanation: Interruption or interference with normal physiological and developmental processes or structures is called Pathophysiology. Modality-Specific is a task that is specific to a single sense or movement pattern. Functional limitation is a restriction or lack of ability to perform an action in the manner or within the range consistent with the purpose of an organ or organ system.
2. For rehabilitation engineering perspective a task that is specific to a single sense or movement pattern is called ___________
a) Functional Limitation
b) Societal Limitation
c) Modality-Specific
d) Pathophysiology
Answer: c
Explanation: A task that is specific to a single sense or movement pattern is called Modality- Specific. Interruption or interference with normal physiological and developmental processes or structures is called Pathophysiology. Functional limitation is a restriction or lack of ability to perform an action in the manner or within the range consistent with the purpose of an organ or organ system.
3. An artificial limb, a sensory substitution system, or an augmentative communication aid is prosthetic devices __________
a) therapeutic device
b) diagnostics device
c) orthosis device
d) prosthetic device
Answer: d
Explanation: An appliance that substitutes for the loss of a particular function, generally by involving a different modality as an input and/or output channel. An artificial limb, a sensory substitution system, or an augmentative communication aid is prosthetic devices.
4. Aesthetics of appearance is called ____________
a) orthosis
b) cosmesis
c) lymphosis
d) homeostasis
Answer: b
Explanation: Aesthetics of appearance is called cosmesis. Orthosis is a modality-specific appliance that aids the performance of a function or movement by augmenting or assisting the residual capabilities of that function or movement.
5. Filter that amplifies frequency above certain value is called ___________
a) low pass filter
b) high pass filter
c) band pass filter
d) band stop filter
Answer: b
Explanation: High pass filter amplifies signal above a certain frequency. Low pass filter amplifies signals below a certain frequency. Band pass filter amplifies frequencies within a certain band. Band stop filter amplifies all the frequencies except those in a certain band.
6. Transcutaneous means ________
a) passing to the skin
b) passing to the bones
c) passing to the heart
d) passing to the lungs
Answer: a
Explanation: Transcutaneous means passing to the skin. This term generally used with the type of surgical instrument to be used. It is also used to describe the interaction of rehabilitation devices.
7. Which of the following is not a soft tissue?
a) ligament
b) bone
c) tendons
d) skin
Answer: b
Explanation: Hard tissue, mineralized tissue, and calcified tissue are often used as synonyms for bone when describing the structure and properties of bone or tooth. Biological soft tissues are nonlinear, anisotropic, fibrous composites, and a detailed description of their behavior is the subject of active research. One can separate these tissues based on their mode of loading: cartilage is generally loaded in compression; tendons and ligaments are loaded in tension, and muscles generate active tension.
8. Blood vessels are _______
a) soft tissue
b) hard tissue
c) connective and hard tissue
d) connective and soft tissue
Answer: d
Explanation: Connective and soft tissue says blood is soft and connective tissue. Soft tissues include tendon, ligament, blood vessels etc. Hard tissues include bones.
9. Bones serve as a reservoir for calcium and phosphorus, essential minerals for various cellular activities which happen throughout the human body.
a) True
b) False
Answer: a
Explanation: True. Bones serve as a reservoir for calcium and phosphorus, essential minerals for various cellular activities that occurs throughout the body. The composition of bone depends on a large number of factors: the species, which bone, the location from which the sample is taken, and the age, sex, and type of bone tissue, for example, woven, cancellous, cortical.
10. Bones are non – living tissues.
a) True
b) False
Answer: b
Explanation: It is false. Bones are living tissues. They keep growing. They also are responsible for the production of blood cells and act a mineral reservoir in the body. They also play the role of protection of internal soft organs like the brain is protected by the skull and lungs and heart by the rib cage.
This set of Biomedical Instrumentation Quiz focuses on “Bedside Patient Monitoring System”.
1. A model of the normal QRS complex, called ___________
a) ECG model
b) QRS model
c) Template
d) Detection model
Answer: c
Explanation: A popular approach in the detection of arrhythmias is based on template matching. A model of the normal QRS complex, called a template, is derived from the ECG complex of a patient under normal circumstances.
2. Who gave the ST/AR algorithm in 1999?
a) Hewlett Packard
b) Jen and Hwang
c) Clynes
d) Cox and Nolle
Answer: a
Explanation: The ST/AR algorithm from Hewlett Packard is a multi lead ECG algorithm designed for both arrhythmias and ST segment monitoring.
3. In order to detect the QRS, the detection threshold is kept as ________ to prevent the detection of T waves or baseline noise as QRS complexes during a complete heart block or asystole.
a) 0.15 V
b) 0.015 mV
c) 0.015 mV
d) 0.00015 V
Answer: d
Explanation: In order to detect the QRS, the detection threshold is kept as 0.15 mV to prevent the detection of T waves or baseline noise as QRS complexes during a complete heart block or asystole. For optimal performance and to prevent false alarms, the lead selected for monitoring should have adequate amplitude.
4. The contribution from each ECG lead to the QRS detection signal is proportional to its measured quality based on the waveform amplitude, and the amount of muscle and baseline noise.
a) True
b) False
Answer: a
Explanation: The contribution from each ECG lead to the QRS detection signal is proportional to its measured quality based on the waveform amplitude, and the amount of muscle and baseline noise. The weighting factors are updated every 200 ms to allow for a quick adaption to signal quality changes.
5. What is the value of the refractory period from the previously identified QRS complex?
a) 200 ms
b) 198 ms
c) 192 ms
d) 215 ms
Answer: c
Explanation: The QRs detector checks the QRS detection signal for the presence of the peak of an R wave. Search begins after an absolute refractory period from the previously identified QRS complex. The value used for the refractory period is 192 ms. This helps to prevent a T wave from being identified as an R wave.
6. The area of the P wave is ______ wide and ends ______ before the R wave peak.
a) 120 ms, 200 ms
b) 200 ms, 120 ms
c) 100 ms, 215 ms
d) 215 ms, 100 ms
Answer: b
Explanation: After a QRS complex is identified, a search is made on each lead independently in the area prior to the R wave to determine if there is an associated P wave. This area is 200 ms wide and ends 120 ms before the R wave peak.
7. If the height of the P wave is X, then the height of the R wave is _____
a) X/32
b) 32/X
c) X/16
d) 32X
Answer: d
Explanation: To be accepted as a P wave, it must be at least 1/32 of the R wave height and the P-R interval must be close to the average P-R interval.
So, P=R/32
If P=X then, X = R/32
R = 32X.
8. Which wave detection is used to differentiate between a Sinus Rhythm and a Supraventricular Rhythm?
a) P wave
b) QRS complex
c) T wave
d) R wave
Answer: a
Explanation: P wave detection is used to differentiate between a Sinus Rhythm and a Supraventricular Rhythm.
9. In the Beat Labeling, if the signal quality is not good, the algorithm assigns the label ______ and ______
a) Supraventricular premature, inoperative
b) Inoperative, artifact
c) Artifact, Supraventricular premature
d) Ventricular ectopic, inoperative
Answer: b
Explanation: Beat Labeling means that the algorithm assigns the complex one of the following labels: normal N, supraventricular premature S, ventricular ectopic V, paced P, questionable ?, and learning L. If the signal quality is not good, the algorithm assigns the label “inoperative I” and “artifact A”.
10. If a flutter or sinusoidal wave-form persists for more than __________ seconds in any ECG channel, then the monitor alarms for ventricular fibrillation.
a) 8 sec
b) 2 sec
c) 4 sec
d) 12 sec
Answer: c
Explanation: A separate detector continuously examines the ECG signal for ventricular fibrillation. If a flutter or sinusoidal wave-form persists for more than 4 seconds in an ECG channel, then the monitor alarms for ventricular fibrillation.
11. The heart rate is computed by averaging the most recent _________________
a) 12 P waves
b) 12 R-R intervals
c) 12 QRS complex
d) 12 R waves
Answer: b
Explanation: Normally, the heart rate is computed by averaging the most recent 12 R-R intervals. This average gives a stable estimate of the heart rate even when the rhythm is irregular.
12. Friesen compared _______ of nine types of QRS detection algorithms.
a) QRS complex sensitivity
b) Noise sensitivity
c) Motion artifact
d) Muscle artifact
Answer: b
Explanation: Friesen compared noise sensitivity of nine types of QRS detection algorithms. He established that an algorithm using a digital filter had the best performance for the composite noise corrupted data.
13. The frequency of the sinusoid and the filter leakage fraction, these two criteria are used for ____________
a) Detection of arrhythmias
b) Detection of QRS complex
c) Detection of Ventricular fibrillation
d) Detection of Heart-rate
Answer: c
Explanation: The detection of ventricular fibrillation is based on two criteria:
i) The frequency of the sinusoid
ii) The filter leakage fraction.
14. For an ideal sinusoid, the filter leakage fraction will be _____
a) 1
b) 0
c) Infinity
d) Undefined
Answer: b
Explanation: For an ideal sinusoid, the filter leakage fraction will be zero. As the ventricular fibrillation waveform is not an ideal sinusoid, a higher leakage fraction is used as the threshold for detection of this condition.
15. For how much time period, the weighting factors are updated to allow for quick adaptation to signal quality changes?
a) Every 192 ms
b) Every 16 ms
c) Every 215 ms
d) Every 200 ms
Answer: d
Explanation: The contribution from each ECG lead to the QRS detection signal is proportional to its measured quality based on the waveform amplitude, and the amount of muscle and baseline noise. The weighting factors are updated every 200 ms to allow for a quick adaption to signal quality changes.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Central Monitors”.
1. Which one of the following is not the category of ECG compression techniques?
a) Transformation domain
b) Parameter Extraction
c) Frequency domain
d) Time domain
Answer: c
Explanation: Several ECG compression techniques have been proposed in the last few decades. These techniques can be classified into three major categories: i) Time domain ii) Transformation domain iii) Parameter Extraction.
2. The scan-along polygonal approximation and the amplitude zone time epoch coding are the examples of the __________ category of ECG compression techniques.
a) Transformation domain
b) Time domain
c) Parameter extraction
d) Frequency domain
Answer: b
Explanation: In the time domain category, the compression technique is applied directly to the samples of the ECG signal in the time domain to remove redundant information. Examples include the scan-along polygonal approximation and the amplitude zone time epoch coding.
3. Which of the following techniques are not included in the transformation domain category?
a) Wavelet transform
b) Discrete cosine transform
c) Fourier descriptors
d) Combine discrete cosine and Fourier transform
Answer: d
Explanation: In the transformation domain category, ECG samples are transformed to another domain. Examples include Fourier descriptors, discrete cosine transform, wavelet transform and combine discrete cosine and wavelet transform.
4. Who suggests a new discrete wavelet transform for compressing ECG signals with minimum loss of diagnostic information?
a) Alshamali
b) Friesen
c) Al-Ajlouni
d) Cox and Nolle
Answer: c
Explanation: Various Wavelet-based ECG compression techniques have been found to give lower distortion for the same compression ratios. A new discrete wavelet transform has been suggested by Al-Ajlouni for compression ECG signals with minimum loss of diagnostic information.
5. Full form of AZTEC _______________
a) Amplitude Zone Tech Epoch Coding
b) Amplitude Zone Time Epoch Coding
c) Arrhythmia Zone Tech Epoch Coding
d) Arrhythmia Zone Time Epoch Coding
Answer: b
Explanation: Cox and Nolle suggested AZTEC a pre-processing program for real-time ECG rhythm analysis at an approximate data reduction rate of 10:1.
6. AZTEC contains digital logic, which is able to detect?
a) Baseline wander
b) QRS complex
c) R-R interval
d) Motion artifact
Answer: a
Explanation: AZTEC contains digital logic, which is able to detect base line wander. Also, the sum of absolute values of all slopes is used for noise detection, but sudden bursts of muscle artifact or an excursion from baseline are distinguishable from an ECG wave only if the condition persists.
7. A signal of poor quality that cannot be processed is called chaotic.
a) True
b) False
Answer: a
Explanation: The module runs once every second, depending upon the quality of the signal. If the signal is ‘chaotic’ or ‘noisy’ , no processing is carried out.
8. In the detection of the waveform of ECG signal, a wave is considered as a T wave if _______
a) It occurs within a 120 ms interval
b) Its peak occurred within 1/6th the R-R interval
c) It occurs within a 200 ms interval
d) Its peak occurred within 1/3rd the R wave height
Answer: c
Explanation: AT wave following a QRS is also searched. A wave is considered as a T wave if it occurs within a 200 ms interval, its peak occurred within 1/3rd the R–R interval +80 ms or within 240 ms whichever is greater, following the preceding R wave, and its height is half the height of a normal R wave.
9. The four measurements of QRS and a fifth measurement called ________ based on height, duration and offset to those of the patient’s normal QRS are compared.
a) QRS polarity
b) R-to-R interval
c) Wiggle
d) Distance D
Answer: d
Explanation: The four measurements of QRS and a fifth measurement called ‘distance D’ based on height, duration and offset to those of the patient’s normal QRS are compared. Beats are classified on the basis of their deviation from the normal and maybe definitely normal, probably normal, probably PVC or definitely PVC.
10. Cox and Nolle suggested AZTEC – pre-processing program for real time ECG rhythm analysis at an approximate data reduction rate of _______________
a) 1:10
b) 10:1
c) 1:20
d) 20:1
Answer: b
Explanation: Cox and Nolle suggested AZTEC a pre-processing program for real time ECG rhythm analysis at an approximate data reduction rate of 10:1.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Measurement of Heart Rate”.
1. Which of the following instrument is used for recording the electrical activity of the brain?
a) ECG
b) EMG
c) PCG
d) EEG
Answer: d
Explanation: Electroencephalograph is an instrument for recording the electrical activity of the brain, by suitably placing surface electrodes on the scalp. EEG, describing the general function of the brain activity, is the superimposed wave of neuron potentials operating in a non-synchronized manner in the physical sense.
2. EEG electrodes are larger in size than ECG electrodes.
a) True
b) False
Answer: b
Explanation: Several types of electrodes may be used to record EEG. These include: Peel and Stick electrodes, Silver plated cup electrodes and Needle electrodes. EEG electrodes are smaller in size than ECG electrodes.
3. _______ is the superimposed wave of neuron potentials operating in a non-synchrronized manner in a physical sense.
a) VCG
b) ECG
c) EEG
d) PCG
Answer: c
Explanation: Electroencephalograph is an instrument for recording the electrical activity of the brain, by suitably placing surface electrodes on the scalp. EEG, describing the general function of the brain activity, is the superimposed wave of neuron potentials operating in a non-synchronized manner in the physical sense.
4. Which of the following is material is used to improve electrical contact?
a) Silver Tungsten
b) Electrode jelly
c) Silver Graphite
d) Copper Tungsten
Answer: b
Explanation: Electrode jelly or paste is used to improve the electrical contact. If the electrodes are intended to be used under the skin of the scalp, needle electrodes are used. They offer the advantage of reducing movement artefacts.
5. Whose electrodes give high skin impedance as compared to ECG?
a) VCG
b) PCG
c) EMG
d) EEG
Answer: d
Explanation: EEG electrodes give high skin contact impedance as compared to ECG electrodes. Good electrode impedance should be generally below 5 kilohms. The impedance between a pair of electrodes must also be balanced or the difference between them should be less than 2 kilohms.
6. What are generally designed to have a very high value of input impedance to take care of high electrode impedance?
a) Montages
b) Electrodes
c) Preamplifiers
d) Filters
Answer: c
Explanation: Good electrode impedance should be generally below 5 kilohms. Impedance between a pair of electrodes must also be balanced or the difference between them should be less than 2 kilohms. EEG preamplifiers are generally designed to have a very high value of input impedance to take care of high electrode impedance.
7. Voltage difference between an active electrode on the scalp with respect to reference electrode at ear lobe or any other part of body is known as ___________ recording.
a) Monopolar
b) Bipolar
c) Unipolar
d) Nonpolar
Answer: a
Explanation: EEG may be recorded by picking up the voltage difference between an active electrode on the scalp with respect to a reference electrode on the ear lobe or any other part of the body. This type of recording is called ‘monopolar’ recording.
8. How is bipolar recording done?
a) Omni channel EEG
b) Multi channel EEG
c) Uni Channel EEG
d) Non Channel EEG
Answer: b
Explanation: ‘bipolar’ recording is more popular wherein the voltage difference between two scalp electrodes is recorded. Such recordings are done with multi-channel electroencephalographs.
9. EEG signals picked up by surface electrodes are usually small as compared to ECG.
a) True
b) False
Answer: a
Explanation: Yes, EEG signals picked up by the surface electrodes are usually small as compared with the ECG signals. They may be several hundred microvolts, but 50 microvolts peak-to-peak is the most typical.
10. A pattern of electrodes on the head and the channels they are connected to are __________
a) Amplifiers
b) Oscilloscope
c) Montage
d) Wires
Answer: c
Explanation: A pattern of electrodes on the head and the channels they are connected to is called a montage. Montages are always symmetrical. The reference electrode is generally placed on a nonactive site such as the forehead or earlobe.
11. Where is the reference electrode placed?
a) nasal
b) cervical
c) forehead
d) facial
Answer: c
Explanation: A pattern of electrodes on the head and the channels they are connected to is called a montage. Montages are always symmetrical. The reference electrode is generally placed on a nonactive site such as the forehead or earlobe.
12. What is the typical value of the calibration signal?
a) 10 uV/cm
b) 30 uV/cm
c) 50 uV/cm
d) 70 uV/cm
Answer: c
Explanation: A calibrating signal is used for controlling and documenting the sensitivity of the amplifier channels. This supplies a voltage step of adequate amplitude to the input of the channels. A typical value of the calibration signal is 50 uV/cm.
13. Preamplifiers used in electroencephalograph have high gain and low noise characteristics.
a) True
b) False
Answer: a
Explanation: Yes, preamplifier used in electroencephalographs must have high gain and low noise characteristics because the EEG potentials are small in amplitude. In addition, the amplifier must have very high common-mode rejection to minimize stray interference signals from power lines and other electrical equipment.
14. EEG machines have notch filter sharply tuned at _______ Hz as to eliminate mains frequency interference.
a) 10
b) 30
c) 50
d) 70
Answer: c
Explanation: EEG machines have a notch filter sharply tuned at 50 Hz so as to eliminate mains frequency interference. These however have the undesirable property of ‘ringing’ i.e. they produce a damped oscillatory response to a square wave calibration waveform or a muscle potential. The use of notch filters should preferably be restricted to exceptional circumstances when all other methods of eliminating interference have been found to be ineffective.
15. What is the typical frequency range of standard EEG machines?
a) 0.025 to 0.05 Hz
b) 0.05 to 0.1 Hz
c) 0.1 to 70 Hz
d) 70 to 140 Hz
Answer: c
Explanation: The typical frequency range of standard EEG machines is from 0.1 Hz to 70 Hz, though newer machines allow the detection and filtering of frequencies up to several hundred Hertz. This may be of importance in some intracranial recordings.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Measurement of Temperature”.
1. Which of the following is the technique of analyzing the electrical activity of the heart by obtaining ECG’s?
a) VCG
b) EEG
c) EMG
d) PCG
Answer: a
Explanation: Vectorcardiography is the technique of analyzing the electrical activity of the heart by obtaining ECG’s along three axes at right angles to one another and displaying any two of these ECGs as a vector display on an X-Y oscilloscope.
2. Vectorcardiogram displays the electrical events in __________ perpendicular axes.
a) one
b) two
c) three
d) four
Answer: b
Explanation: In contrast, the electrocardiogram which displays the electrical potential in any one single axis, the vectorcardiogram displays the same electrical events simultaneously in two perpendicular axes.
3. ___________ is a vectorial representation of the distribution of electric potentials generated by heart.
a) EEG
b) ECG
c) PCG
d) VCG
Answer: d
Explanation: In contrast, the electrocardiogram which displays the electrical potential in any one single axis, the vectorcardiogram displays the same electrical events simultaneously in two perpendicular axes. This gives a vectorial representation of the distribution of electrical potentials generated by the heart and produces loop type patterns on the CRT screen.
4. How many loops each vectorcardiogram exhibits?
a) one
b) two
c) three
d) four
Answer: c
Explanation: The major information that it provides is the direction of depolarization and repolarization of the atria and the ventricles. Each vectorcardiogram exhibits three loops, showing the vector orientation of the P wave, the QRSaxis and the T wave.
5. Which of the following instrument is used for recording the sounds connected with the pumping action of the heart?
a) ECG
b) VCG
c) PCG
d) EEG
Answer: c
Explanation: The phonocardiograph is an instrument used for recording the sounds connected with the pumping action of the heart. These sounds provide an indication of the heart rate and its rhythmicity. They also give useful information regarding the effectiveness of blood pumping and valve action.
6. Which instrument is used for clinical detection of heart sounds?
a) Stethoscope
b) Endoscope
c) Anoscope
d) Proctoscope
Answer: a
Explanation: Heart sounds are diagnostically useful. Sounds produced by healthy hearts are remarkably identical and abnormal sounds always corelate to specific physical abnormalities. From the beginning till today, the principal instrument used for the clinical detection of heart sounds is the acoustical stethoscope.
7. Who provides a recording of waveforms of heart sounds?
a) Electrocardiograph
b) Vectorcardiograph
c) Phonocardiograph
d) Electromyograph
Answer: c
Explanation: The phonocardiographs provide a recording of the waveforms of the heart sounds. These waveforms are diagnostically more important and revealing than the sounds themselves.
8. What is the frequency range of sound generated from the closure of the mitral and tricuspid valve?
a) 0 to 30 Hz
b) 30 to 100 Hz
c) 100 to 1000 Hz
d) above 1000 Hz
Answer: b
Explanation: The closure of the mitral and tricuspid valve contributes largely to the first sound. The frequencies of these sounds are generally in the range of 30 to 100 Hz and the duration is between 50 to 100 ms.
9. Which of the following microphone is used for recording phonocardiograms?
a) Contact Microphone
b) Shotgun Microphone
c) Handheld Microphone
d) Lapel Microphone
Answer: a
Explanation: Two types of microphones are commonly in use for recording phonocardiograms. They are the contact microphone and the air coupled microphone. They are further categorized into crystal type or dynamic type based on their principle of operation.
10. What is the frequency range of sound produced at the closure of aortic and pulmonic valves?
a) less than 0 Hz
b) 0 to 30 Hz
c) 30 to 100 Hz
d) above 100 Hz
Answer: d
Explanation: The second sound is higher in pitch than the first, with frequencies above 100 Hz and the duration between 25 to 50 ms. This sound is produced by the slight back flow of blood into the heart before the valves close and then by the closure of the valves in the arteries leading out of the ventricles. This means that it occurs at the closure of aortic and the pulmonic valves.
11. What is the thickness of the new acoustic sensor?
a) 0.25 mm
b) 0.5 mm
c) 1.0 mm
d) 1.5 mm
Answer: c
Explanation: A new acoustic sensor, which enhances the audibility of heart sounds and enables recording of quantitative acoustic spectral data is described by Kassal et al, 1994. This device is a polymer based adherent differential-output sensor, which is only 1.0 mm thick.
12. Who described the new acoustic sensor?
a) Golden et al
b) Rijn et al
c) Levkov et al
d) Kassal et al
Answer: d
Explanation: A new acoustic sensor, which enhances the audibility of heart sounds and enables recording of quantitative acoustic spectral data is described by Kassal et al, 1994. This device is a polymer based adherent differential-output sensor, which is only 1.0 mm thick.
13. Acoustic sensor principal sensing component is made up of which polymer?
a) PEO
b) PET
c) PVDF
d) PS
Answer: c
Explanation: Its principle sensing components is PVDF , which is a piezo-electric polymer. It produces charges of equal magnitude and opposite polarity on opposite surfaces when a mechanical strain is imposed on the material.
14. What is the frequency range of amplifier used for a phonocardiograph?
a) less than 0 Hz
b) 0 to 20 Hz
c) 20 to 2000 Hz
d) above 2000 Hz
Answer: c
Explanation: The amplifier used for a phonocardiograph has wide bandwidth with a frequency range of about 20 to 2000 Hz. Filters permit selection of suitable frequency bands, so that particular heart sound frequencies can be recorded.
15. PCG amplifiers usually have gain compensation circuits to increase the amplification of high frequency signals, which are usually of low intensity.
a) True
b) False
Answer: a
Explanation: Yes, PCG amplifiers usually have gain compensation circuits to increase the amplification of high frequency signals, which are usually of low intensity. The frequencies at the higher end of the range are of particular significance in research applications.
This set of Biomedical Instrumentation Questions and Answers for Entrance exams focuses on “Measurement of Respiration Rate”.
1. Which of the following instrument is used for recording the electrical activity of the muscles?
a) ECG
b) EMG
c) PCG
d) EEG
Answer: b
Explanation: Electromyograph is an instrument used for recording the electrical activity of the muscles to determine whether the muscle is contracting or not; or for displaying on the CRO and loudspeaker the action potentials spontaneously present in a muscle or those induced by voluntary contractions as a means of detecting the nature and location of motor unit lesions; or for recording the electrical activity evoked in a muscle by the stimulation of its nerve.
2. EMG is recorded by using surface electrodes.
a) True
b) False
Answer: a
Explanation: EMG is usually recorded by using surface electrodes because the surface electrodes may be disposable, adhesive types or the ones which can be used repeatedly.
3. Whose measurements are important for myoelectric control of prosthetic devices?
a) VCG
b) ECG
c) EEG
d) EMG
Answer: d
Explanation: EMG measurements are also important for the myoelectric control of prosthetic devices . This use involves picking up EMG signals from the muscles at the terminated nerve endings of the remaining limb and using the signals to activate a mechanical arm. This is the most demanding requirement from an EMG since it depends on the working of the prosthetic device.
4. What is used to display EMG waveforms?
a) Cathode Ray Oscilloscope
b) Analog storage Oscilloscope
c) Digital Oscilloscope
d) Dual-beam Oscilloscope
Answer: a
Explanation: The Cathode Ray oscilloscope displays EMG waveforms. Electromyograph is an instrument used for recording the electrical activity of the muscles to determine whether the muscle is contracting or not; or for displaying on the CRO.
5. The amplitude of EMG signals depend upon which of the following factor?
a) Respiration
b) Position of electrode
c) Blood Resistivity
d) Ventricular Volume
Answer: b
Explanation: The amplitude of the EMG signals depends upon various factors, e.g. the type and placement of electrodes used and the degree of muscular exertions. The needle electrode in contact with a single muscle fibre will pick up spike type voltages whereas a surface electrode picks up many overlapping spikes and therefore produces an average voltage effect.
6. What is the typical range of EMG signals?
a) 0.025 to 0.050 mV
b) 0.050 to 0.1 mV
c) 0.1 to 0.5 mV
d) 0.5 to 1 mV
Answer: c
Explanation: A typical EMG signal ranges from 0.1 to 0.5 mV. They may contain frequency components extending up to 10 kHz.Such high frequency signals cannot be recorded on the conventional pen recorders and therefore, they are usually displayed on the CRT screen.
7. EMG instrument contain frequency component extending up to ____________ Khz.
a) 1
b) 5
c) 10
d) 15
Answer: c
Explanation: A typical EMG signal ranges from 0.1 to 0.5 mV. They may contain frequency components extending up to 10 kHz.Such high frequency signals cannot be recorded on the conventional pen recorders and therefore, they are usually displayed on the CRT screen.
8. What is included in the system to facilitate playback and study of EMG sound waveforms at a later convenient time?
a) Preamplifier
b) Oscilloscope
c) Tape Recorder
d) Ground Electrode
Answer: c
Explanation: The tape recorder is included in the system to facilitate playback and study of the EMG sound waveforms at a later convenient time. The waveform can also be photographed from the CRT screen by using a synchronized camera.
9. What is necessary for providing a common reference for measurement?
a) active electrode
b) ground electrode
c) tape recorder
d) oscilloscope
Answer: b
Explanation: A ground electrode is necessary for providing a common reference for measurement. These electrodes pick up the potentials produced by the contracting muscle fibres. The signal can then be amplified and displayed on the screen of a cathode ray tube. It is also applied to an audio amplifier connected to a loudspeaker.
10. Which of the following interpreter can diagnose various muscular disorders by listening to the sounds produced when the muscle potentials are fed to loudspeaker?
a) EEG
b) ECG
c) VCG
d) EMG
Answer: d
Explanation: A trained EMG interpreter can diagnose various muscular disorders by listening to the sounds produced when the muscle potentials are fed to the loudspeaker.
11. What is the diameter of silver electrodes in the amplifier circuit of Johnson et al?
a) 2 mm
b) 4 mm
c) 6 mm
d) 10 mm
Answer: c
Explanation: Johnson et al designed a miniature amplifier circuit fully encapsulated in epoxy resin with two small silver electrodes of 6 mm diameter, exposed flush with the base of the module. The electrode is attached to the skin using adhesive tape.
12. What should be CMRR of preamplifier upto 5 Khz?
a) 10 dB
b) 30 dB
c) 90 dB
d) greater than 90 dB
Answer: d
Explanation: The common-mode rejection should be greater than 90 dB up to 5 kHz. A calibrating square wave signal of 100 mV at a frequency of 100 Hz is usually available. The main amplifier has controls for gain adjustment from 5 mV/div to 10 mV/div for selecting the sensitivity most appropriate to the incoming signal from the patient.
13. Modern EMG machines are PC based.
a) True
b) False
Answer: a
Explanation: Modern EMG machines are PC based available both in the console as well as laptop models as they provide full colour waveform display, automatic cursors for marking and making measurements and a keyboard for access to convenient and important test controls. The system usually incorporates facilities for recording of the EMG and evoked potentials.
14. EMG instrument is useful for making study of ___________
a) cardiovascular function
b) neuromuscular function
c) nervous function
d) Immune function
Answer: b
Explanation: The instrument is useful for making a study of several aspects of neuromuscular function, neuromuscular condition, extent of nerve lesion, reflex responses, etc.
15. Which of the following instrument is used for making a study of reflex responses?
a) EEG
b) ECG
c) VCG
d) EMG
Answer: d
Explanation: The instrument is useful for making a study of several aspects of neuromuscular function, neuromuscular condition, the extent of nerve lesion, reflex responses, etc.
This set of Biomedical Instrumentation MCQs focuses on “Catheterization Laboratory Instrumentation”.
1. Which of the following instrument is used for recording the chest-wall movements over the apex of heart?
a) Apexcardiograph
b) Ballistocardiograph
c) Electro-oculograph
d) Electro-retinograph
Answer: a
Explanation: An apexcardiograph records the chest-wall movements over the apex of the heart. These movements are in the form of vibrations having a frequency range of 0.1 to about 20 Hz.
2. The transducer required for recording these movements in apexcardiograph is similar to the electrocardiograph.
a) True
b) False
Answer: b
Explanation: False, The transducer required for recording these movements in apexcardiograph is similar to that employed for a phonocardiograph but which has a frequency response much below the audio range. It can be an aircoupled microphone or a contact microphone. They are further categorized into crystal type or dynamic type based on their principle of operation. The crystal microphone contains a wafer of piezo-electric material, which generates potentials when subjected to mechanical stresses due to heart sounds. The dynamic type microphone consists of a moving coil having a fixed magnetic core inside it. The coil moves with the heart sounds and produces a voltage because of its interaction with the magnetic flux.
3. Which of the following instrument is used for recording the movements imparted to the body with each beat of the heart cycle?
a) Apexcardiograph
b) Ballistocardiograph
c) Electro-oculograph
d) Electro-retinograph
Answer: b
Explanation: A ballistocardiograph is a machine that records the movement imparted to the body with each beat of the heart cycle. These movements occur during the ventricular contraction of the heart muscle when the blood is ejected with sufficient force.
4. What is mounted on the table to convert the movements into corresponding electrical signals in BCG?
a) Oscilloscope
b) Sensing device
c) Pramplifier
d) Tape recorder
Answer: b
Explanation: In BCG, the patient is made to lie on a table top which is spring suspended or otherwise mounted to respond to very slight movements along the head axis. Sensing devices are mounted on the table to convert these movements into corresponding electrical signals. The sensors usually are piezo-electric crystals, resistive elements or permanent magnets, moving with respect to fixed coils.
5. ________________ is the recording of the bio-potentials generated by the movement of eye ball.
a) Apexcardiography
b) Electro-oculography
c) Electro-retinography
d) Ballistocardiography
Answer: b
Explanation: Electro-oculography is the recording of the bio-potentials generated by the movement of the eyeball. The EOG potentials are picked up by small surface electrodes placed on the skin near the eye.
6. What is used to pick EOG potentials?
a) Oscilloscope
b) Tape Recorder
c) Surface Electrodes
d) Preamplifier
Answer: c
Explanation: Electro-oculography is the recording of the bio-potentials generated by the movement of the eyeball. The EOG potentials are picked up by small surface electrodes placed on the skin near the eye.
7. What is the frequency range of Chest-wall movements?
a) 0.025 to 0.05 Hz
b) 0.05 to 0.1 Hz
c) 0.1 to 20 Hz
d) 20 to 100 Hz
Answer: c
Explanation: An apexcardiograph records the chest-wall movements over the apex of the heart. These movements are in the form of vibrations having a frequency range of 0.1 to about 20 Hz.
8. Which of the following instrument is used for recording the change in potential when light falls on the eye?
a) Apexcardiography
b) Ballistocardiography
c) Electro-oculography
d) Electro-retinography
Answer: d
Explanation: It is found that an electrical potential exists between the cornea and the back of the eye. This potential changes when the eye is illuminated. The process of recording the change in potential when light falls on the eye is called electroretinography.
9. One of the electrode is mounted on the contact lens and the other is placed to the skin adjacent to the outer cornea of the eye.
a) True
b) False
Answer: a
Explanation: True, ERG potentials can be recorded with a pair of electrodes. One of the electrodes is mounted on a contact lens and is in direct contact with the cornea and the other electrode is placed on the skin adjacent to the outer corner of the eye as it is found that an electrical potential exists between the cornea and the back of the eye. This potential changes when the eye is illuminated. A reference electrode may be placed on the forehead.
10. Which of the following is useful in the diagnosis of the enlargement of the heart chambers and some type of valvular disorders?
a) Apexcardiograph
b) Ballistocardiograph
c) Electro-oculograph
d) Electro-retinograph
Answer: a
Explanation: The apexcardiograph has limited applications. It is, however, useful in the diagnosis of the enlargement of the heart chambers and some type of valvular disorders.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Cardiac Arrhythmias”.
1. _____________ is common engineering term and refers to its function to control a process.
a) Open-loop
b) Feedback
c) Reaction
d) Closed-loop
Answer: b
Explanation: Feedback is a common engineering term and refers to its function to control a process. When this concept is applied to biological processes within the body, it is known as biofeedback. Biofeedback is a means for gaining control of the body processes to create a specially required psychological state so as to increase relaxation, relieve pain and develop healthier and more comfortable life patterns.
2. Biofeedback training is an educational process for learning body skills.
a) True
b) False
Answer: a
Explanation: True, Biofeedback training is an educational process for learning specialized mind/body skills as through practice, one learns to recognize physiological responses and to control them rather than having them control us. The objective of biofeedback training is to gain self-regulatory skills which help to adjust the activity in various systems to optimal levels.
3. Which of the following instrument is used for measuring the average activity of sweat glands?
a) EOG
b) ECG
c) GSR
d) PCG
Answer: c
Explanation: Electrodermal activity is measured in two ways: BSR and GSR is a measure of the average activity of the sweat glands and is a measure of the phasic activity of these glands.
4. BSR gives _____________
a) activity of sweat glands
b) baseline value of skin resistance
c) activity of endrocine glands
d) baseline value of breathing
Answer: b
Explanation: BSR and GSR is a measure of the average activity of the sweat glands and is a measure of the phasic activity of these glands. BSR gives the baseline value of the skin resistance where as GSR is due to the activity of the sweat glands.
5. GSR gives ________________
a) activity of sweat glands
b) baseline value of skin resistance
c) activity of endrocine glands
d) baseline value of breathing
Answer: a
Explanation: BSR and GSR is a measure of the average activity of the sweat glands and is a measure of the phasic activity of these glands. BSR gives the baseline value of the skin resistance where as GSR is due to the activity of the sweat glands.
6. At which place GSR is measured?
a) palms of hand
b) nose
c) eye
d) teeth
Answer: a
Explanation: BSR gives the baseline value of the skin resistance where as GSR is due to the activity of the sweat glands. The GSR is measured most conveniently at the palms of the hand, where the body has the highest concentration of sweat glands. The measurement is made using a dc current source.
7. What is used to measure and record BSR and GSR?
a) Tape recorder
b) Amplifier
c) Silver-Silver electrode
d) Piezoelectric device
Answer: c
Explanation: The GSR is measured most conveniently at the palms of the hand, where the body has the highest concentration of sweat glands. The measurement is made using a dc current source. Silver-silver electrodes are used to measure and record the BSR and GSR.
8. The BSR output is connected to RC network with time constant of _________________ seconds.
a) 1 to 3
b) 3 to 5
c) 5 to 7
d) 7 to 9
Answer: b
Explanation: Silver-silver electrodes are used to measure and record the BSR and GSR. The BSR output is connected to an RC network with a time constant of 3 to 5 seconds which enables the measurement of GSR as a change of the skin resistance.
9. Biofeedback instrumentation for the measurement of EMG, temperature and pulse/heart rate.
a) True
b) False
Answer: a
Explanation: True, Biofeedback instrumentation for the measurement of EMG, temperature and pulse/heart rate as it is not different from other instruments used for the measurement of physiological variables. Transducers and amplifiers are employed to measure the variable that is to be controlled by the feedback process.
10. What is employed to measure the variable that is to be controlled by the feedback process?
a) Transducers
b) Sensing device
c) Tape recorder
d) Piezo-electric device
Answer: a
Explanation: Biofeedback instrumentation for the measurement of EMG, temperature and pulse/heart rate is not different from other instruments used for the measurement of physiological variables. Transducers and amplifiers are employed to measure the variable that is to be controlled by the feedback process.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Arrhythmias Monitor”.
1. Which is the most important physiological parameter monitored in the intensive care unit?
a) temperature
b) heart rate
c) blood pressure
d) skin color
Answer: b
Explanation: The most important physiological parameters monitored in the intensive care unit are the heart rate and the morphology or shape of the electrical waveform produced by the heart. This is done to observe the presence of arrhythmias or to detect changes in the heart rate that might be indicative of a serious condition.
2. Which of the following instrument is used for monitoring patients with cardiac problems?
a) Cardiac Monitor
b) Central Monitor
c) Bedside Patient Monitor
d) Blood Pressure Monitor
Answer: a
Explanation: A Cardiac monitor is specifically useful for monitoring patients with cardiac problems and the special areas in the hospitals where they are generally used are known as cardiac care units or coronary care units . These instruments are also called ‘Cardioscopes’.
3. Which of the following instrument is also known as Cardioscopes?
a) Central Monitor
b) Bedside Patient Monitor
c) Cardiac Monitor
d) Blood Pressure Monitor
Answer: c
Explanation: A Cardiac monitor is specifically useful for monitoring patients with cardiac problems and the special areas in the hospitals where they are generally used are known as cardiac care units or coronary care units . These instruments are also called ‘Cardioscopes’.
4. Disposable type pregelled electrodes to pick up ____________ signal in cardiac monitor.
a) EOG
b) EMG
c) ECG
d) PCG
Answer: c
Explanation: A Cardiac monitor is specifically useful for monitoring patients with cardiac problems and the special areas in the hospitals where they are generally used are known as cardiac care units or coronary care units . These instruments are also called ‘Cardioscopes’ and comprise of disposable type pregelled electrodes to pick up ECG signal. Amplifier and a cathode ray tube for the amplification and display the ECG which enable direct observation of the ECG waveform.
5. What is used for amplification of signal in cardiac monitor?
a) Piezoelectric device
b) Transducer
c) Amplifier
d) Tape recorder
Answer: c
Explanation: ‘Cardioscopes’ and comprise of disposable type pregelled electrodes to pick up ECG signal. Amplifier and a cathode ray tube for the amplification and display the ECG which enable direct observation of the ECG waveform.
6. _____________ is used to display ECG which enable direct observation of the ECG waveform.
a) Amplifier
b) Transducer
c) Tape Recorder
d) Cathode ray tube
Answer: d
Explanation: ‘Cardioscopes’ and comprise of disposable type pregelled electrodes to pick up ECG signal. Amplifier and a cathode ray tube for the amplification and display the ECG which enable direct observation of the ECG waveform.
7. A cardioscope differ in one important aspects as compared to the conventional instrument.
a) True
b) False
Answer: b
Explanation: False, Cardioscope differ in two important aspects as compared to the conventional instrument. These are slower sweep speeds and a long persistence screen. The slow sweep speed necessitates the use of a long persistence screen so as to enable a convenient observation of the waveform.
8. The slow sweep is an outcome of the low frequency character of ________________ signal.
a) EMG
b) EOG
c) ECG
d) PCG
Answer: c
Explanation: The slow sweep is an outcome of the low frequency character of the ECG signal. The slow sweep speed necessitates the use of a long persistence screen so as to enable a convenient observation of the waveform. Without a long persistence screen, one can only see a moving dot of light instead of a continuous trace.
9. What is total sweep time for a 13-cm screen?
a) 0 to 0.5 s
b) 0.5 to 2 s
c) 2 to 2.5 s
d) 2.5 to 5 s
Answer: d
Explanation: Without a long persistence screen, one can only see a moving dot of light instead of a continuous trace. Typically for a 13-cm screen, total sweep time is usually kept as 2.5 or 5 s. In this way, one can observe at least four heart beats in a single sweep period.
10. How many heart beat one can observe in a single sweep period?
a) 1
b) 2
c) 3
d) 4
Answer: d
Explanation: Without a long persistence screen, one can only see a moving dot of light instead of a continuous trace. Typically for a 13-cm screen, total sweep time is usually kept as 2.5 or 5 s. In this way, one can observe at least four heart beats in a single sweep period.
11. What indicate average heart rate with audible beep?
a) disposable electrodes
b) heart rate meter
c) amplifier
d) cathode ray tube
Answer: b
Explanation: ‘Cardioscopes’ and comprise of disposable type pregelled electrodes to pick up ECG signal. Amplifier and a cathode ray tube for the amplification and display the ECG which enable direct observation of the ECG waveform.A heart rate meter to indicate average heart rate with audible beep or flashing light or both with each beat.
12. What is diameter of CRT used in small cardioscopes?
a) 1”
b) 3”
c) 5”
d) 7”
Answer: c
Explanation: Small cardioscopes using 3” diameter cathode ray tubes are mounted on anaesthesia trollies. These are called “Anaesthesia monitors”. These monitors are use by the anaesthetist for continuous monitoring of the ECG of anaesthetized patients.
13. An alarm system is used to produce signal in event of abnormalities occurring in heart rate.
a) True
b) False
Answer: a
Explanation: ‘Cardioscopes’ and comprise of disposable type pregelled electrodes to pick up ECG signal. Amplifier and a cathode ray tube for the amplification and display the ECG which enable direct observation of the ECG waveform.An alarm system to produce signal in the event of abnormalities occurring in the heart rate.
14. What is range of RF signals generated by Electrosurgery machine?
a) 0 to 0.4 MHz
b) 0.4 to 5 MHz
c) 5 to 6.5 MHz
d) 6.5 to 10 MHz
Answer: b
Explanation: Electrosurgery machines generate RF signals within a range of 0.4 to 5 MHz with peak-to-peak amplitudes of 100 to 1000 V, pulse modulated at rates from 1.5 to 25 kHz for coagulating or 120 Hz for cutting. Cardiac monitors are often used in operation theatres, where the RF is applied through a pointed scalpel at the point of incision and the return path for the current is through a wide area electrode on the opposite side of the patient’s body.
15. Which of the following storage device is used for storing digital information in memory monitors?
a) Hard disk
b) Magnetic Tape
c) RAM
d) DVD
Answer: c
Explanation: Two basic types of storage devices are used to store digital information in memory monitors: shift registers and random access memories. Both of them are equally good for this application. The other important component of memory monitors is the analog-to-digital converter.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “QRS Detection Techniques”.
1. ______ is used to determine the physical performance characteristics of a cardiac patient.
a) Data compression techniques
b) Stress test electrocardiography
c) Stress amplitude ECG
d) QRS detection techniques
Answer: b
Explanation: Stress test or exercise electrocardiography is used when the diagnosis of coronary arterial disease is suspected or to determine the physical performance characteristics of a cardiac patient. The test involves the recording of the electrocardiogram during dynamic or occasionally isometric exercise.
2. Which of the following are devices used for testing physical fitness?
a) Treadmill and sphygmomanometer
b) Ergometer and sphygmomanometer
c) Treadmill and Ergometer
d) Sphygmomanometer and Event recorders
Answer: c
Explanation: Both the treadmill and ergometer can be used as stand-alone devices for testing physical fitness. Advanced ergometers and treadmills can store and display activity data, transfer it to a PC and download patient data from PC.
3. Which of the following is the type of exercise protocols used in treadmill tests?
a) The Balke-Bruce Protocol
b) The Bruce-Ware Protocol
c) The Balke-Ware Protocol
d) The Balke Protocol
Answer: c
Explanation: There are two basic kinds of exercise protocols used in treadmill tests: i) The Balke-Ware Protocol and ii) The Bruce Protocol. Both protocols are satisfactory for most clinical purposes. However, they may have to be modified to suit the condition of the individual being subjected to exercise testing.
4. In the Balke-Ware Protocol, how much speed it uses with progressive increments in the load every 2 minutes?
a) 3.3 km/hour
b) 3.3 km to 5.3 km /hour
c) 3.3 miles to 5.3 miles /hour
d) 3.3 miles/hour
Answer: d
Explanation: In the Balke-Ware Protocol, it uses a constant speed of 3.3 miles/hour , with progressive increments in the load every 2 minutes. This is achieved by increasing the grade or incline of the motor-driven treadmill.
5. ______ is a blood pressure measuring instrument.
a) Sphygmomanometer
b) Ergometer
c) Treadmill
d) Holtemanometer
Answer: a
Explanation: Sphygmomanometer, an instrument for measuring blood pressure, typically consisting of an inflatable rubber cuff which is applied to the arm and connected to a column of mercury next to a graduated scale, enabling the determination of systolic and diastolic blood pressure by increasing and gradually releasing the pressure in the cuff.
6. In the ST segment measurement _________ is either between the P and Q waves or in front of the P wave.
a) J point
b) Isoelectric baseline
c) ST measurement point
d) ST value
Answer: b
Explanation: The current standard for determining the ST segment measurement is by measuring the voltage difference between the value at a point 60-80 ms after the J point and the isoelectric baseline. The isoelectric baseline is either between the P and Q waves or in front of the P-wave .
7. _________ is a signal of low amplitude and low frequency content.
a) QRS complex
b) R-R interval
c) ST segment
d) T-P interval
Answer: c
Explanation: The ST segment is a signal of low amplitude and low-frequency content. Therefore, a sampling rate of 250 samples /s is adequate. To ensure that the ST segment can be measured accurately, the incoming ECG signals must have a low-end bandwidth of 0.05 Hz.
8. In the ST segment measurement, what is the bandwidth of the ST filter which is used to remove unwanted baseline noise?
a) 0.05 Hz
b) 0.67 Hz
c) 0.5 Hz
d) 0.067 Hz
Answer: b
Explanation: To ensure that the ST segment can be measured accurately, the incoming ECG signals must have a low-end bandwidth of 0.05 Hz. A special ST filter with a higher low-end bandwidth of 0.67 Hz is used to further remove unwanted baseline noise.
9. ________compare various algorithms employed for processing stress ECG signals.
a) Friesen
b) Jen and Hwang
c) Clynes
d) Alfonso
Answer: d
Explanation: Alfonso compares various algorithms employed for processing stress ECG signals. It may be observed that the exercise test when applied in an appropriate manner and interpreted by an experienced cardiologist is a very useful tool in the functional assessment of normal and abnormal cardiovascular physiology.
10. At an interval of _______ the Bruce Protocol uses simultaneous increments in both speed and treadmill grade.
a) 250 sec
b) 120 sec
c) 160 sec
d) 198 sec
Answer: c
Explanation: At an interval of 3 minutes the Bruce Protocol uses simultaneous increments in both speed and treadmill grade. Typically during a Bruce Protocol, Heart Rate and Rating of Perceived Exertion are taken every minute and Blood Pressure is taken at the end of each stage .
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Data Compression Techniques”.
1. The instrument which carries out a continuous and simultaneous recording of the instantaneous foetal heart rate and labour activity is called ____________
a) Ergometer
b) Cardiotocograph
c) Cardiotocometer
d) Cardiotonometer
Answer: b
Explanation: Cardiotocography is a technical means of recording the fetal heartbeat and the uterine contractions during pregnancy. The machine used to perform the monitoring is called a cardiotocograph, more commonly known as an electronic fetal monitor.
2. In the cardiotocograph, the sensitivity of _______ of recording chart allows adequate reading of the recorder FHR.
a) 30 bpm / cm
b) 10 bpm / cm
c) 20 bpm / cm
d) 15 bpm / cm
Answer: c
Explanation: Normally, an accuracy of measurement of foetal heart rate may be 2-3% for classification for responses. Sensitivity of 20 bpm /cm of the recording chart allows adequate reading of the recorder FHR. Labour activity and FHR traces are usually recorded simultaneously on the same time scale.
3. What is the chart speed in cardiotocograph to provide sufficient resolution of the stimulus-response relationship?
a) 1-2 cm / sec
b) 2-3 cm / min
c) 1-2 cm / min
d) 2-3 cm / sec
Answer: c
Explanation: Normally, accuracy of measurement of foetal heart rate may be 2-3% for classification for responses. Sensitivity of 20 bpm /cm of the recording chart allows adequate reading of the recorder FHR. Labour activity and FHR traces are usually recorded simultaneously on the same time scale. Chart speed of 1-2 cm/min is adequate to provide sufficient resolution of the stimulus-response relationship.
4. Which of the following is not an indirect method of foetal heart rate in cordiotocography monitoring?
a) Foetal ECG with scalp electrode
b) Foetal phonocardiogram
c) Abdominal foetal electrocardiogram
d) Ultrasound techniques
Answer: a
Explanation: The following methods are commonly employed in most of the cardiotocographic monitoring during labour: I) Indirect method: Abdominal foetal electrocardiogram, foetal phonocardiogram, ultrasound techniques II) Direct method: Foetal ECG with scalp electrode .
5. Which of the following is a direct technique of uterine contraction in cardiotocographic monitoring?
a) Tocodynamometry
b) Intrauterine pressure measurement
c) Phonocardiometry
d) Ultrasound technique
Answer: b
Explanation: The following techniques are commonly used in uterine contraction in most of the cardiotocographic monitoring: I) Indirect method: Tocodynamometry II) Direct method: Intrauterine pressure measurement .
6. What is the range of instantaneous “beat-to-beat” rate which is displayed on a calibrated linear scale?
a) 200-220 bpm
b) 150-210 bpm
c) 50-200 bpm
d) 50-210 bpm
Answer: d
Explanation: Instantaneous “beat-to-beat” rate is displayed on a calibrated linear scale or digitally displayed with a range from 50 to 210 bpm. A two channel chart recorder is incorporated in instruments used for monitoring labour activity.
7. One channel records FHR on a calibrated chart in beats per minute while the other channel is used for recording uterine contractions calibrated _______
a) 50-210 mmHg
b) 0-210 mmHg
c) 0-100 mmHg
d) 0-50 mmHg
Answer: c
Explanation: A two channel chart recorder is incorporated in instruments used for monitoring labour activity. One channel records FHR on a calibrated chart in beats per minute while the other channel is used for recording uterine contractions calibrated 0-100 mmHg. The record is printed on thermo-sensitive z-fold paper using a high-resolution thermal matrix printer.
8. The intrauterine pressure can reach values of _______ or more during the expulsion period.
a) 150 mmHg
b) 200 mmHg
c) 220 mmHg
d) 250 mmHg
Answer: a
Explanation: During labour, the uterus muscle starts contraction of increasing intensity in a bid to expel out the child. The intrauterine pressure can reach values of 150 mmHg or more during the expulsion period. However, a normal patient in spontaneous active labour will demonstrate uterine contractions occurring at intervals of three to five minutes, with a duration of 30 to 70 s and a peak intensity of 50 to 75 mmHg.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Exercise Stress Testing”.
1. FHR yields important information about the status of ________
a) fats
b) eye
c) fibrous joint
d) foetus
Answer: d
Explanation: The obstetrician is faced with the problem of having very few parameters available on which to base a diagnosis of foetal well-being or distress. In most cases, the condition of the foetus is assessed by studying the blood flow in the foetal heart and its heart rate. The foetal heart rate yields important information about the status of the foetus, and therefore, has become a widely studied parameter in maternity cases.
2. Foetal Heart sounds are listened by digital stethoscope.
a) True
b) False
Answer: b
Explanation: False, Foetal heart rate monitoring in the labour ward has generally been carried out on an intermittent basis. It has been traditional to listen to the foetal heart sounds at intervals of up to every 15 minutes. This is done by using the Pinard stethoscope.
3. To listen to the foetal heart sounds at intervals of up to every _______ minutes is tradition.
a) 5
b) 10
c) 15
d) 20
Answer: c
Explanation: Foetal heart rate monitoring in the labour ward has generally been carried out on an intermittent basis. It has been traditional to listen to the foetal heart sounds at intervals of up to every 15 minutes. This is done by using the Pinard stethoscope.
4. How is the assessment of the condition of foetus can be made during labour?
a) activity of sweat glands
b) baseline value of skin resistance
c) by foetal heart action
d) baseline value of breathing
Answer: c
Explanation: An assessment of the condition of the foetus can be made during labour from the foetal heart action. Simultaneously, recording beat-to-beat foetal heart rate and uterine activity provides basic information for assessing the compensatory potential of the foetal circulatory system.
5. Which of the following instrument carries out a continuous and simultaneous recording of the instantaneous foetal heart rate and labour activity?
a) Electrocardiograph
b) Cardiotocograph
c) Electromyograph
d) Vectorcardiograph
Answer: b
Explanation: The instrument which carries out a continuous and simultaneous recording of the instantaneous foetal heart rate and labour activity is called cardiotocograph. In addition to detecting long-term bradycardia or tachycardia, this instrument helps in the evaluation of foetal heart rate response of the undisturbed circulatory system and response stimulated by uterine contractions.
6. Sensitivity of _______ bpm/cm of the recording chart allows adequate reading of the recorded FHR.
a) 5
b) 10
c) 15
d) 20
Answer: d
Explanation: Cardiotocographs are designed to measure and record foetal heart rate on a beat-to-beat basis rather than on an average basis. Normally, accuracy of measurement may be 2–3% for the classification of responses. The sensitivity of 20 bpm/cm of the recording chart allows adequate reading of the recorded FHR.
7. What is the used in Tocodynamometry to sense changes in uterine tension transmitted to abdominal skin surface?
a) U-Manometer
b) Barometer
c) Tocotonometer
d) Picometer
Answer: c
Explanation: Tocodynamometry is an indirect method to measure uterine contraction in cardiotographic monitoring during labour in which tocotonometer is used to sense changes in uterine tension transmitted to abdominal skin surface.
8. Which of the following is a direct method for measuring foetal heart rate?
a) Abdominal foetal electrocardiogram
b) Foetal phonocardiogram
c) Ultrasound technique
d) Foetal ECG with scalp electrode
Answer: d
Explanation: Abdominal foetal electrocardiogram, foetal phonocardiogram and Ultrasound technique are indirect methods of measuring foetal heart rate where as Foetal ECG with scalp electrode is a direct method as in it spiral, clip or suction electrode is attached to the presenting part of foetus.
9. Cardiotocographs are designed to measure and record foetal heart rate on an average basis.
a) True
b) False
Answer: b
Explanation: False, Cardiotocographs are designed to measure and record foetal heart rate on a beat-to-beat basis rather than on an average basis. Normally, accuracy of measurement may be 2–3% for the classification of responses.
10. What is the accuracy of measurement for the classification of responses?
a) 1-2%
b) 2-3%
c) 3-4%
d) 4-5%
Answer: b
Explanation: Cardiotocographs are designed to measure and record foetal heart rate on a beat-to-beat basis rather than on an average basis. Normally, accuracy of measurement may be 2–3% for the classification of responses.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Ambulatory Monitoring Instruments”.
1. Where are the electrodes placed for recording foetal electrocardiogram?
a) heart
b) abdomen
c) brain
d) veins
Answer: b
Explanation: Foetal electrocardiogram is recorded by suitably placing the electrodes on the mother’s abdomen and recording the combined maternal and foetal ECG. The maximum amplitude of FECG recorded during pregnancy is about 100 to 300 mV. This magnitude is much smaller than in the typical adult ECG which is about 1 mV in the standard lead connection.
2. What is the maximum amplitude of FECG recorded during pregnancy?
a) 100 to 300 mV
b) 300 to 500 mV
c) 500 to 700 mV
d) 700 to 900 mV
Answer: a
Explanation: Foetal electrocardiogram is recorded by suitably placing the electrodes on the mother’s abdomen and recording the combined maternal and foetal ECG. The maximum amplitude of FECG recorded during pregnancy is about 100 to 300 mV. This magnitude is much smaller than in the typical adult ECG which is about 1 mV in the standard lead connection.
3. The foetus heart rate is approximately _______ time/s of normal adult foetal heart rate.
a) one
b) two
c) three
d) four
Answer: b
Explanation: The foetal heart rate is computed from the foetal ECG by appropriately shaping the foetal QRS wave. The foetus heart rate is approximately twice that of the normal adult ranging approximately from 110 to 180 bpm. The main problem in processing the foetal heart signals is the poor SNR.
4. Which of the following is periodic noise source in the foetal ECG signal from the maternal abdomen?
a) Amplifier input noise
b) Maternal Muscle noise
c) Fluctuations in electrode polarization potential
d) Maternal ECG
Answer: d
Explanation: The major sources of noise in the foetal ECG signal recorded from the maternal abdomen are amplifier input noise, maternal muscle noise , fluctuations in electrode polarization potential, and maternal ECG. For practical purposes, the first three of these sources can be considered as random whereas the maternal ECG is a periodic noise source.
5. What is the magnitude of ECG for a typical adult in the standard lead connection?
a) 1 mV
b) 2 mV
c) 3 mV
d) 4 mV
Answer: a
Explanation: Foetal electrocardiogram is recorded by suitably placing the electrodes on the mother’s abdomen and recording the combined maternal and foetal ECG. The maximum amplitude of FECG recorded during pregnancy is about 100 to 300 mV. This magnitude is much smaller than in the typical adult ECG which is about 1 mV in the standard lead connection.
6. Which of the following technique is used to measure foetal heart rate?
a) ECG
b) FECG
c) PCG
d) VCG
Answer: b
Explanation: Abdominal FECG processing circuit is used for computing foetal heart rate. After proper placement of the electrodes, the signals are amplified in a preamplifier which provides a very high input impedance and high sensitivity and good common mode rejection ratio .
7. What is the CMRR of Foetal electrocardiogram?
a) 0-150 dB
b) 0- 130 dB
c) 0-120 dB
d) 0-200 dB
Answer: c
Explanation: Abdominal FECG processing circuit is used for computing foetal heart rate. After proper placement of the electrodes, the signals are amplified in a preamplifier which provides a very high input impedance and high sensitivity and good common mode rejection ratio .
8. What is responsible for most of the common-mode interfering signal?
a) Preamplifier
b) Notch Filter
c) Power Line Hum
d) Band Pass Filter
Answer: c
Explanation: A sizable common-mode signal manages to pass through the input amplifier, a circumstance to be expected whenever electrodes spaced a few centimetres apart are attached to the human body in a hospital environment. Power line hum is responsible for most of the common-mode interfering signal. This is suppressed by a notch filter following the input amplifier.
9. What is present in the processing circuit for signal separation?
a) Preamplifier
b) Power Line Hum
c) Notch Filter
d) Band Pass Filter
Answer: d
Explanation: The signal path then splits into two channels: the maternal ECG channel or Mchannel and the foetal or F channel. Since the frequency spectrum of the foetal ECG differs somewhat from the maternal ECG, some initial signal separation is achieved by using the appropriate bandpass filtering in each channel.
10. The F channel has a _______ ms pulse generator that is triggered by the foetal ECG.
a) 5
b) 10
c) 20
d) 30
Answer: d
Explanation: The F channel has a 30 ms pulse generator that is triggered by the foetal ECG. It is inhibited, however, by the blanking pulse from the M channel, so it will not generate a pulse in response to the maternal ECG signal feeding through to the F channel.
11. Foetal ECG signal detected via electrodes placed on mother’s abdomen is complex and requires accertion of maternal signals for obtaining FHR.
a) True
b) False
Answer: b
Explanation: False, Foetal ECG signal detected via electrodes placed on the mother’s abdomen is complex and requires attenuation of maternal signals for obtaining FHR. Also, due to the overlapping of the foetal ECG with the maternal ECG, about 20% to 50% of the expected pulses may be missing.
12. AECG technique fails in those rare cases where the amniotic fluid fails to provide adequate electrical coupling from foetus to mother.
a) True
b) False
Answer: a
Explanation: Clinical trials have shown that the AECG technique is usually effective in most cases except in those rare cases where the amniotic fluid fails to provide adequate electrical coupling from foetus to mother. However, during labour, the uterine and abdominal wall electromyogram signals tend to obliterate the FECG signal, making FHR counting quite difficult. At present, the abdominal FECG, therefore, does not seem to offer a practical reliable means of FHR monitoring during labour and delivery.
13. What is delay time to establish a missing foetal trigger pulse by substitution logic?
a) 150 ms
b) 200 ms
c) 250 ms
d) 270 ms
Answer: d
Explanation: The substitution logic requires a delay time to establish a missing foetal trigger pulse. On the one hand, this delay has to be longer than the maximum permissible change in heart period and on the other hand, it has to be shorter than the shortest period duration . It is thus kept as 270 ms.
14. What is the range of FHR measurement due to substitution logic?
a) 0-200 bpm
b) 40-240 bpm
c) 20-220 bpm
d) 60-260 bpm
Answer: b
Explanation: The substitution logic requires a delay time to establish a missing foetal trigger pulse. It is thus kept as 270 ms. The range of FHR measurement is limited to 40–240 bpm because of the substitution logic. Thereafter, the output of logic circuits goes to standard heart rate computing circuits.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Cardiotocograph”.
1. Ambulatory monitoring of ECG is called ____________
a) Event Cardiography
b) Holter Cardiography
c) Real-Time Cardiography
d) Implantable Cardiography
Answer: b
Explanation: Ambulatory monitoring of ECG is called ‘Holter Cardiography’, after Dr. Norman Holter who introduced this concept in 1962. A Holter monitor is a type of ambulatory electrocardiography device, a portable device for cardiac monitoring for at least 24 hours .
2. Which of the following type of systems are not available for ambulatory ECG monitoring?
a) Holter monitors
b) Event Recorders
c) Time Recorders
d) Implantable Loop Recorders
Answer: c
Explanation: Currently, the following four types of systems are available for ambulatory ECG monitoring: I) Holter Monitors II) Event Recorders III) Real-Time Continuous Cardiac Monitoring System IV) Implantable Loop Recorders.
3. The current state of Holter technology uses small recorders, which size is about _______
a) 75 x 20 x 90 cm
b) 75 x 95 x 20 cm
c) 75 x 20 x 95 mm
d) 75 x 95 x 20 mm
Answer: d
Explanation: The current state of Holter technology uses small recorders with flashcard technology to record and store data from 2 to 3 ECG leads attached to the patient’s chest and collected continuously over 24 to 48 hours.
4. Who provides an excellent review of ambulatory cardiac event recorders?
a) Handelsman
b) Benz
c) Alfonso
d) Friesen
Answer: b
Explanation: An excellent review of ambulatory cardiac event recorders is provided by Benz in 1999. The major advantage of these devices compared with a traditional Holter monitor is that they are small, allow ECG monitoring for longer time periods, and can provide nearly real time data analysis when the patient transmits a recording in proximity to the symptomatic event.
5. The monitor automatically transmits recorded data transtelephonically to a central monitoring station for subsequent analysis when an arrhythmia is detected by an arrhythmia algorithm.
a) True
b) False
Answer: a
Explanation: In Real-Time Continuous Cardiac Monitoring Systems, the monitor is equipped with software that analyzes the rhythm data continuously and automatically. The monitor automatically transmits recorded data transtelephonically to a central monitoring station for subsequent analysis when an arrhythmia is detected by an arrhythmia algorithm.
6. In the data recording, the normal speed of sub miniature tape recorder is ___________
a) 3 cm/s
b) 2 cm/s
c) 3 mm/s
d) 2 mm/s
Answer: d
Explanation: In data recording, the core of the modern ambulatory monitoring system is a multichannel sub-miniature tape recorder running normally at a speed of 2 mm/s. At this speed, a C-120 entertainment cassette will run for 24 hours.
7. In data recorders, during replay, the tape is run at ________ to achieve rapid manual or automatic scanning of ambulatory records.
a) 80 times of recording speed
b) 70 times of recording speed
c) 60 times of recording speed
d) 50 times of recording speed
Answer: c
Explanation: In data recorders, during replay, the tape is run at 120 mm/s to achieve rapid manual or automatic scanning of ambulatory records. The tape recorders used for this purpose have some special features as compared to the usually available entertainment tape recorders.
8. Which of the following is not an arrhythmic condition?
a) Cardiographic beat
b) Bradycardia
c) Dropped beat
d) Ectopic beat
Answer: a
Explanation: The analyzer part in automatic scanning of ambulatory records look for four arrhythmic conditions. These are bradycardia, tachycardia, dropped beat and premature beat. A threshold control is associated with each of these and when the appropriate threshold is exceeded, an alarm condition is generated.
9. Which CPU has an overall system control responsibility?
a) Control
b) Acquisition
c) Control and timing
d) Acquisition and display
Answer: c
Explanation: The control and timing CPU has an overall system control responsibility. It also handles individuals functions such as keyboard and direct writer interface, tape deck control, timing data processing, and arrhythmia count totalizing via a high speed interrupt system.
10. Full form of P-FCB is ________
a) Planar-Functional Circuit Board
b) Planar-Fashionable Circuit Branch
c) Planar-Functional Circuit Board
d) Planar-Fashionable Circuit Board
Answer: d
Explanation: The full form of F-PCB is Planar-Fashionable Circuit Board. Sometimes in Holter monitoring, the patient needs typically 6 to 10 wires worn around the body throughout the day. To overcome these problems, a wearable electrocardiogram acquisition system implemented with planar-fashionable circuit board -based shirt is explained by Yoo.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Methods of Monitoring Foetal Heart Rate – 1”.
1. Which system may include lenses, mirrors, slits, diaphragm etc?
a) Radiant system
b) Optical system
c) Cardiac system
d) Photo system
Answer: b
Explanation: An optical system for producing a parallel beam of filtered light for passage through an absorption cell . The system may include lenses, mirrors, slits, diaphragm, etc. A detecting system for the measurement of unabsorbed radiant energy, which could be the human eye, a barrier-layer cell, phototube or photo-multiplier tube.
2. What is the most common and convenient source of light?
a) Xenon-mercury arc
b) Hydrogen discharge lamp
c) Neon-xenon arc
d) Tungsten lamp
Answer: d
Explanation: The most common and convenient source of light is the tungsten lamp. This lamp consists of a tungsten filament enclosed in a glass envelope. It is cheap, intense and reliable. A major portion of the energy emitted by a tungsten lamp is in the visible region and only about 15 to 20% is in the infrared region.
3. In the radiation source, for work in the ultraviolet region, a _______ is used.
a) Tungsten lamp
b) Xenon-mercury arc
c) Deuterium discharge lamp
d) Hydrogen arc
Answer: c
Explanation: For work in the ultraviolet region, a hydrogen or deuterium discharge lamp is used. In these lamps, the envelope material of the lamp puts a limit on the smallest wavelength which can be transmitted.
4. What are the wavelengths of quartz and fused silica respectively in a hydrogen discharge lamp?
a) 200 nm, 185 nm
b) 200 nm, 145 nm
c) 185 nm, 200 nm
d) 145 nm, 200 nm
Answer: a
Explanation: In these lamps, the envelope material of the lamp puts a limit on the smallest wavelength which can be transmitted. For example, quartz is suitable only up to 200 nm and fused silica up to 185 nm. The radiation from the discharge lamps is concentrated into narrow wavelength regions of emission lines. Practically, there is no emission beyond 400 nm in these lamps.
5. Modern instruments use ________ light source in calorimeters and spectrophotmetry.
a) Xenon-mercury lamp
b) Tungsten-halogen lamp
c) Mercury arc
d) Deuterium discharge lamp
Answer: b
Explanation: Modern instruments use a tungsten-halogen light source, which has a higher intensity output than the normal tungsten lamp in the change over the region of 320–380 nm used in colorimetry and spectrophotometry. It also has a larger life and does not suffer from the blackening of the bulb glass envelope.
6. The absorption type optical filter usually consists of coloured glasses, gelatin etc. and solutions of the coloured substances.
a) True
b) False
Answer: a
Explanation: The absorption type optical filter usually consists of colour media: colour glasses, coloured films , and solutions of the coloured substances. This type of filter has a wide spectral bandwidth, which may be 40 to 50 m in width at one-half the maximum transmittance.
7. Which of the following is the dielectric?
a) MgF3
b) ZnF2
c) ZnS
d) ZnF3
Answer: c
Explanation: Interference filters usually consist of two semi-transparent layers of silver, deposited on glass by evaporation in a vacuum and separated by a layer of dielectric . In this arrangement, the semi-transparent layers are held very close.
8. The transmittance of interference filters varies between ________ % with a spectral bandwidth of 10 to 15 nm.
a) 15 to 20 %
b) 20 to 60 %
c) 10 to 20 %
d) 15 to 60 %
Answer: d
Explanation: Interference filters allow a much narrower band of wavelengths to pass and are similar to monochromators in selectivity. They are simpler and less expensive. However, as the selectivity increases, the transmittance decreases. The transmittance of these filters varies between 15 to 60 percent with a spectral bandwidth of 10 to 15 nm.
9. The expression relating the wavelength of the radiation and the angle at which it is reflected is given by _________
a) ml = 2d sin q, where l= lambda
b) m = 2d sin q
c) ml = d sin q, where l= lambda
d) m = d sin q
Answer: a
Explanation: The expression relating the wavelength of the radiation and the angle at which it is reflected is given by
ml = 2d sin q, where l= lambda.
where d is the distance separating the grooves and is known as the grating constant and m is the order of interference.
When m = 1, the spectrum is known as first order and with m = 2, the spectrum is known as second order.
10. _______ are optical systems, which provide better isolation of spectral energy than the optical filters.
a) Spectromators
b) Monochromators
c) Tocochromators
d) Baromators
Answer: b
Explanation: Monochromators are optical systems, which provide better isolation of spectral energy than the optical filters, and are therefore preferred where it is required to isolate narrow bands of radiant energy. Monochromators usually incorporate a small glass of quartz prism or a diffraction grating system as the dispersing media.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Methods of Monitoring Foetal Heart Rate – 2”.
1. The energy must be reflected and returned through a single 30° prism, so that it passes through the prism in both directions is called __________
a) Cornu mounting
b) Mono mounting
c) Littrow mounting
d) Trio mounting
Answer: c
Explanation: Quartz shows the property of double refraction. Therefore, two pieces of quartz, one right-handed and one left handed are taken and cemented back-to-back in the construction of 60° prism , or the energy must be reflected and returned through a single 30° prism, so that it passes through the prism in both directions .
2. Most modern instruments now use a _______ as a dispersing element in the monochromator.
a) Prism monochromators
b) Holographic gratings
c) Diffraction gratings
d) Replica gratings
Answer: c
Explanation: Most modern instruments now use a diffraction grating as a dispersing element in the monochromator, as prisms in general have a poorer stray light performance and require complex precision cams to give a linear wavelength scale. Replica gratings can even be produced more cheaply than prisms and require only a simple sine bar mechanism for the wavelength scale.
3. A typical reflection grating may have 1200 grooves/mm, which means the grooves are spaced at about _______ intervals.
a) 800 nm
b) 600 nm
c) 860 nm
d) 680 nm
Answer: a
Explanation: A typical reflection grating may have 1200 grooves/mm, which means the grooves are spaced at about 800 nm intervals. The grating may have a width of 20 mm or more, giving a total of at least 24,000 grooves.
4. What is reproduced from a master holographic grating by moulding its grooves onto a resin surface or silica substrate?
a) Diffraction grating
b) Replica grating
c) Silicate glasses
d) Fused silica
Answer: b
Explanation: Holographic gratings used in commercial spectrophotometers are either original master gratings produced directly by an interferometer or are replica gratings. Replica gratings are reproduced from a master holographic grating by moulding its grooves onto a resin surface on a glass or silica substrate.
5. What is the utilization wavelength limit for quartz?
a) 300 nm
b) 350 nm
c) 180 nm
d) 210 nm
Answer: d
Explanation: Normally, the absorbance of any material should be less than 0.2 at the wavelength of use. Below 300 nm, quartz or fused silica is utilized. The limit for quartz is 210 nm.
6. Which material is used to reduce the reflections from glass surfaces?
a) Manganese Flouride
b) Magnesium oxide
c) Magnesium Flouride
d) Manganese oxide
Answer: c
Explanation: Reflections from glass surfaces are reduced by coating these with magnesium fluoride, which is one-quarter wavelength in optical thickness. With this, scattering effects are also greatly reduced.
7. With the use of _______ chromatic aberrations and other imperfections of the lenses are minimized.
a) Lenses
b) Mirrors
c) Slits
d) Diaphragm
Answer: b
Explanation: To minimize light losses, lenses are sometimes replaced by front-surfaced mirrors to focus or collimate light beam in absorption instruments. Mirrors are aluminized on their front surfaces. With the use of mirrors, chromatic aberrations and other imperfections of the lenses are minimized.
8. _______ are often used for splitting the beam.
a) Multilayer coated lenses
b) Silvered films
c) Silicate glasses
d) Half-silvered mirrors
Answer: d
Explanation: The two beams must retain the spectral properties of the incident beam. Half-silvered mirrors are often used for splitting the beam. However, they absorb some of the light in the thin metallic coating. Beam splitting can also be achieved by using a prismatic mirror or stack of thin horizontal glass plates, silvered on their edges and alternatively oriented to the incident beam.
9. The sample holder is generally inserted somewhere in the interval between the ______and _______
a) Silvered film and multi-layered coating
b) The light source and the detector
c) The light source and silvered film
d) Silvered film and the detector
Answer: b
Explanation: Gases may be contained in cells which are sealed or stoppered to make them air-tight. The sample holder is generally inserted somewhere in the interval between the light source and the detector. For the majority of analyses, a 10 mm path-length rectangular cell is usually satisfactory.
10. In sample holders, for such applications, a 50 cm path-length with about a ________ volume cell is employed.
a) 0.3 ml
b) 3 liters
c) 0.3 liters
d) 3 ml
Answer: c
Explanation: Studies of dilute or weakly-absorbing liquid samples, or of samples where trace components must be detected, require a cell with a long path-length. For such applications, a 50 cm path-length with about a 300 ml volume cell is employed.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Monitoring Labour Activity”.
1. Which section of the clinical laboratory deals with determinations of the number and characteristics of the constituents of the blood, particularly the blood cells?
a) Chemistry
b) Haematology
c) Microbiology
d) Sample collection
Answer: b
Explanation: There are three different areas within the clinical laboratory set up. These are:
• Chemistry section deals with the analysis of blood, urine, cerebrospinal fluid and other fluids to determine the quantity of various important substances they contain. Most of the electronic instruments in the clinical laboratory are available in this section.
• Haematology section deals with the determinations of the number and characteristics of the constituents of the blood, particularly the blood cells.
• Microbiology section in which studies are performed on various body tissues and fluids to determine the presence of pathological micro-organisms.
2. What is the percentage of blood plasma and the blood cells respectively in blood volume?
a) 60, 40
b) 40, 60
c) 70, 30
d) 30, 70
Answer: a
Explanation: The liquid part of the blood—the blood plasma, and the formed elements—the blood cells are analyzed during a chemical examination. The blood plasma accounts for about 60% of the blood volume and the blood cells occupy the other 40%. The plasma is obtained by centrifuging a blood sample.
3. The plasma is a viscous, light yellow liquid, i.e. almost clear in the fasting stage.
a) True
b) False
Answer: a
Explanation: The plasma is obtained by centrifuging a blood sample. During centrifugation, the heavy blood cells get packed at the bottom of the centrifuge tube and the plasma can thus be separated. The plasma is a viscous, light yellow liquid, i.e. almost clear in the fasting stage.
4. Which of the following method is based on the absorption of electromagnetic radiation in the visible, ultraviolet and infrared ranges?
a) Cardiotocography
b) Ultrasonic therapy
c) Spectrophotometry
d) Diathermy
Answer: c
Explanation: Spectrophotometry is the most important of all the instrumental methods of analysis in clinical chemistry. This method is based on the absorption of electromagnetic radiation in the visible, ultraviolet and infrared ranges.
5. Which of the following waves have short wave-length?
a) Microwave
b) Radio wave
c) Gamma rays
d) IR waves
Answer: c
Explanation: Electromagnetic spectrum ranges from very short wavelengths to very long wavelengths . The range of wavelength of gamma rays and X-rays is 10 -4 to 10 nm. The range of wavelengths of microwaves and radio-waves is 10 6 to 10 9 nm.
6. The method based on the absorption of radiation of a substance is known as?
a) Absorption photometry
b) Spectrophotometry
c) Absorption tocometry
d) Absorption spectrophotoscopy
Answer: d
Explanation: Electronic transitions correspond to the ultraviolet and visible regions, vibrational transitions to the near infrared and infrared regions and rotational transitions to the infrared and far-infrared regions. The method based on the absorption of radiation of a substance is known as Absorption Spectroscopy.
7. What is the range of visible light of electromagnetic spectrum?
a) 380 to 780 mm
b) 780 to 1080 nm
c) 380 to 780 nm
d) 380 to 1080 nm
Answer: c
Explanation: The region in the electromagnetic spectrum which is normally used in spectroscopic work is very limited. Visible light represents only a very small portion of the electromagnetic spectrum and generally covers a range from 380 to 780 nm. The ultraviolet region extends from 185 mm to the visible.
8. The ratio of the radiant power transmitted by a sample to the radiant power incident on the sample is known as ______
a) Absorbance
b) Transmittance
c) Optical density
d) Photometric concentration
Answer: b
Explanation: Let us suppose, Po is the incident radiant energy and P is the energy which is transmitted. The ratio of the radiant power transmitted by a sample to the radiant power incident on the sample is known as the transmittance.
Transmittance = P/Po
9. If absorbance is plotted graphically against concentration, the graph is _________
a) Parabola
b) Increasing
c) Straight line
d) Decreasing
Answer: c
Explanation: If absorbance is plotted graphically against concentration, a straight line is obtained. A graph derived from the transmittance data will not be a straight line unless transmittance is plotted on the log axis of a semi-log paper.
10. Which of the following is not a source of radiant energy?
a) Tungsten-mercury lamp
b) Tungsten lamp
c) Xenon-mercury arc
d) Deuterium discharge lamp
Answer: a
Explanation: Radiant just means energy that can move from one place to another without a medium to carry it. A source of radiant energy, which may be a tungsten lamp, a xenon-mercury arc, hydrogen or deuterium discharge lamp, etc.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Recording System”.
1. How are foetal heart sounds picked up from the maternal abdomen?
a) Piezoelectric device
b) Sensitive Microphone
c) Crystal microphone
d) Dynamic microphone
Answer: b
Explanation: Foetal heart sounds can be picked up from the maternal abdomen by a sensitive microphone. The heart sounds in the form of mechanical vibrations have to pass through tissue structure and the signals picked up are rather weak because of distance effects and the small size of foetal heart valves.
2. Crystal microphone is used for picking _______ signals.
a) cardiac
b) brain
c) phono
d) muscles
Answer: c
Explanation: To pick up the heart sounds, it is essential that the transducer is properly placed and its impedance carefully matched. A crystal microphone is used for picking up phono signals. The phono transducer signals are amplified by a low noise preamplifier and fed to a bandpass filter which rejects all frequencies outside the 70 to 110 Hz range.
3. Bandpass filter used in foetal phonocardiogram rejects all frequencies outside the ________ Hz range.
a) 0-40
b) 40-80
c) 70-110
d) 110-150
Answer: c
Explanation: To pick up the heart sounds, it is essential that the transducer be properly placed and its impedance carefully matched. A crystal microphone is used for picking up phono signals. The phono transducer signals are amplified by a low noise preamplifier and fed to a bandpass filter which rejects all frequencies outside the 70 to 110 Hz range.
4. The preamplifier is incorporated in the transducer housing to maximize interference signals being picked up.
a) True
b) False
Answer: b
Explanation: The preamplifier is incorporated in the transducer housing to minimize interference signals being picked up. Much of the random noise is eliminated during this process and the record on paper after this stage is called foetal phonocardiograph.
5. How many sounds are produced from the normal foetal heart action?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: From the normal foetal heart action, generally two sounds are produced corresponding to the contraction and relaxation of the heart muscles. These two bursts of heart sounds are mixed up with unwanted signals which may succeed in passing through the filters.
6. What is the fixed pulse width of the pulse after process of one-shot circuit?
a) 110 ms
b) 170 ms
c) 230 ms
d) 280 ms
Answer: c
Explanation: After peak detection, the processed pulses operate a one-shot circuit which gives a fixed pulse width of 230 ms. The output of one-shot triggers a variable pulse width multi-vibrator which adds and gives either 43 or 116 ms time depending on the heart rate. The pulse width at the output will be either 230 + 43 = 273 ms or 230 + 116 = 346 ms.
7. What is used to detect heart frequency in foetal phonocardiograph?
a) 230 ms one shot
b) 400 ms one shot
c) 20 ms one shot
d) 440 ms one shot
Answer: b
Explanation: To detect the heart frequency, the 400 ms one-shot is used. If the period duration is greater than 400 ms, the one-shot will deliver a pulse. The negative slope of this pulse is used to trigger the 20 ms one-shot. These 20 ms pulses are integrated by the integrator and the output of this integrator is compared with a fixed voltage -V.
8. If the period duration is lesser than 400 ms, the one-shot will deliver a pulse.
a) True
b) False
Answer: b
Explanation: False, to detect the heart frequency, the 400 ms one-shot is used. If the period duration is greater than 400 ms, the one-shot will deliver a pulse. The negative slope of this pulse is used to trigger the 20 ms one-shot. These 20 ms pulses are integrated by the integrator and the output of this integrator is compared with a fixed voltage -V.
9. What is used to delay the change in the time constant in foetal phonocardiograph?
a) Preamplifier
b) Notch Filter
c) Integrator
d) Band Pass Filter
Answer: c
Explanation: The integrator is used to delay the change in the time constant and to make sure that a change of on-time takes place only if several heart beats with the longer period duration are present.
10. No output pulse will occur when the period between two pulses is less than _____ ms.
a) 230
b) 20
c) 400
d) 440
Answer: c
Explanation: No output pulse will occur if the period between two pulses is less than 400 ms. The 20 ms pulses are, therefore, not generated and the integrator discharges slowly from the negative output voltage to a positive output voltage. If the output of the integrator is less negative than-V, the output of the comparator will become negative.
11. Ultrasound provides basically clearer signal than does phonocardiography.
a) True
b) False
Answer: b
Explanation: False, Phonocardiography provides a basically cleaner signal than does ultrasound, thus allowing a greater chance of detecting a smooth baseline FHR. Unfortunately, phonocardiography is more susceptible to artefacts introduced from ambient noise, patient movement or other intra-abdominal sounds.
12. Which of the following instrument makes use of the Doppler shift principle?
a) Abdominal Foetal Electrocardiogram
b) Foetal Phonocardiogram
c) Foetus blood flow detector
d) Foetal ECG with scalp electrode
Answer: c
Explanation: An important clinical instrument for obstetric applications which makes use of the Doppler shift principle is the foetus blood flow detector. The technique is extended to derive an integrated rate of the foetus heart from blood flow signals and to display it on a suitable display system.
13. Which technique is used to derive an integrated rate of the foetus heart from blood flow signals and to display it on a suitable display system?
a) Abdominal Foetal Electrocardiogram
b) Foetal Phonocardiogram
c) Ultrasound
d) Foetal ECG with scalp electrode
Answer: c
Explanation: An important clinical instrument for obstetric applications which makes use of the Doppler shift principle is the foetus blood flow detector. The ultrasound technique is extended to derive an integrated rate of the foetus heart from blood flow signals and to display it on a suitable display system.
14. What is ultrasonic frequency employed for obstetric studies?
a) 0.5 to 1 MHz
b) 1 to 1.5 MHz
c) 1.5 to 2 MHz
d) 2 to 2.5 MHz
Answer: d
Explanation: For obstetric studies, ultrasonic frequency of about 2 to 2.5 MHz is usually employed, whereas in the study of blood flow in arteries and superficial blood vessels frequencies around 5–10 MHz are preferred. The level of ultrasonic energy transmitted into the body is generally kept between 10–15 mW/cm 2 .
15. What is range of ultrasonic energy transmitted into the body?
a) 0-5 mW/cm 2
b) 5-10 mW/cm 2
c) 10-15 mW/cm 2
d) 15-20 mW/cm 2
Answer: c
Explanation: For obstetric studies, ultrasonic frequency of about 2 to 2.5 MHz is usually employed, whereas in the study of blood flow in arteries and superficial blood vessels frequencies around 5–10 MHz are preferred. The level of ultrasonic energy transmitted into the body is generally kept between 10–15 mW/cm 2 .
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Oximeters”.
1. Blood flow detectors based on Doppler shift start detecting foetal pulses as early as in which week of pregnancy?
a) tenth
b) eleventh
c) twelfth
d) ninth
Answer: b
Explanation: Blood flow detectors based on ultrasonic Doppler shift can detect foetal pulse as early as the tenth week of pregnancy and in nearly all cases by the twelfth week. At about 20 weeks it is possible to detect multiple pregnancies especially if two instruments are used together and the pulse rates compared. Intrauterine death of the foetus can also be diagnosed.
2. When it is possible to detect multiple pregnancies?
a) 10th week
b) 12th week
c) 15th week
d) 20th week
Answer: d
Explanation: Blood flow detectors based on ultrasonic Doppler shift can detect foetal pulse as early as the tenth week of pregnancy and in nearly all cases by the twelfth week. At about 20 weeks it is possible to detect multiple pregnancies especially if two instruments are used together and the pulse rates compared. Intrauterine death of the foetus can also be diagnosed.
3. Which of the following is the most reliable method for detecting FHR pattern?
a) Abdominal foetal electrocardiogram
b) Foetal phonocardiogram
c) Ultrasound technique
d) Foetal ECG with scalp electrode
Answer: c
Explanation: We can hear the signal through a loudspeaker with a scarce chance of failing to recognize any beat, but a simple electronic circuit may fail to trigger from this signal. Still, the ultrasound Doppler shift method is more practical and easy to use during labour. It is currently the most reliable method for detecting the FHR pattern that is interpretable.
4. Signal processing for FHR determination can be based either on detecting the foetal heart valve motion or on detecting the heart wall motion in Abdominal foetal electrocardiogram technique.
a) True
b) False
Answer: b
Explanation: False, Signal processing for FHR determination can be based either on detecting the foetal heart valve motion or on detecting the heart wall motion in Ultrasound technique as The heart valve motion detection technique is based on the distinct ultrasound frequency shift produced by the fast opening and closing of the heart valves. The technique, however, requires that the ultrasound beam must be directed against the relatively small heart valves involving a longer search period and frequent repositioning of the transducer. Therefore, it is not preferred for continuous monitoring applications.
5. What is maximum ultrasound intensity of narrow beam transducer?
a) 15 mW/cm 2
b) 20 mW/cm 2
c) 25 mW/cm 2
d) 30 mW/cm 2
Answer: c
Explanation: The narrow beam transducer uses a single ultrasound transmitter/receiver piezo-electric crystal pair. The maximum ultrasound intensity is generally kept below 25 mW/cm 2 . The typical transducer diameter is 25 mm. The narrow beam transducer is very sensitive and produces a good trigger signal for instantaneous heart rate determination.
6. What is the diameter of a narrow beam transducer?
a) 15 mm
b) 20 mm
c) 25 mm
d) 30 mm
Answer: c
Explanation: The narrow beam transducer uses a single ultrasound transmitter/receiver piezo-electric crystal pair. The maximum ultrasound intensity is generally kept below 25 mW/cm2. The typical transducer diameter is 25 mm. The narrow beam transducer is very sensitive and produces a good trigger signal for instantaneous heart rate determination.
7. What is used to detect foetal heart movements in broad beam transducer?
a) Quartz crystal
b) Piezo electric crystal
c) Topaz crystal
d) Berlinite crystal
Answer: b
Explanation: The broad beam transducers are available in many configurations. The transducers comprise a number of piezo-electric crystals mounted in such a way as to be able to detect foetal heart movements over a wider area.
8. The narrow beam transducer is very sensitive and produces a good trigger signal for instantaneous heart rate determination.
a) True
b) False
Answer: a
Explanation: True, The narrow beam transducer is very sensitive and produces a good trigger signal for instantaneous heart rate determination because it takes time to detect a good signal and, therefore, frequent transducer repositioning is necessary.
9. Which of the following transducer is used to detect foetal heart movements over a wider area?
a) piezo-electric
b) ultrasonic
c) array
d) pressure
Answer: a
Explanation: The broad beam transducers are available in many configurations. The transducers comprise a number of piezo-electric crystals mounted in such a way as to be able to detect foetal heart movements over a wider area.
10. Which transducer is arranged in the shape of a clover leaf so that it provides a large area of illumination?
a) piezo-electric
b) ultrasonic
c) array
d) pressure
Answer: b
Explanation: The ultrasonic transducer is arranged in the shape of a clover-leaf so that it provides a large area of ultrasonic illumination which allows the monitoring considerable lateral and descending foetal motion before requiring repositioning. The transducer housing is flexible to permit it to follow the contour of the abdomen regardless of shape changes with contractions.
11. The array transducer housing is flexible to permit it to follow the contour of the abdomen regardless of shape changes with contractions.
a) True
b) False
Answer: b
Explanation: False, the ultrasonic transducer is arranged in the shape of a clover-leaf so that it provides a large area of ultrasonic illumination which allows the monitoring considerable lateral and descending foetal motion before requiring repositioning. The ultrasonic transducer housing is flexible to permit it to follow the contour of the abdomen regardless of shape changes with contractions.
12. At what angle divergent beam is transmitted by a crystal in array transducer?
a) 10°
b) 20°
c) 30°
d) 40°
Answer: d
Explanation: An alternative arrangement is the array transducer which has one transmitter and six peripheral ceramic receiving crystals. The transmitting crystal emits a 40° divergent beam so that at 10 cm from the skin surface the beam covers an area of approximately 10 cm diameter.
13. The transmitting crystal emits 40° divergent beam so that the beam covers an area of approximately _____ cm diameter.
a) 10
b) 20
c) 30
d) 40
Answer: a
Explanation: An alternative arrangement is the array transducer which has one transmitter and six peripheral ceramic receiving crystals. The transmitting crystal emits a 40° divergent beam so that at 10 cm from the skin surface the beam covers an area of approximately 10 cm diameter.
14. What is the diameter of an array transducer?
a) 2
b) 4
c) 6
d) 8
Answer: c
Explanation: The transmitting crystal emits a 40° divergent beam so that at 10 cm from the skin surface the beam covers an area of approximately 10 cm diameter. This construction ensures continuous recording of the foetal heart activity without the need to reposition the transducer which is otherwise necessitated due to normal foetal movement. The transducer has a diameter of 6 cm and can be held in place either by a simple buckle or a stretch belt.
15. The array transducer can be held in place by a simple buckle.
a) True
b) False
Answer: a
Explanation: True, the transmitting crystal emits a 40° divergent beam so that at 10 cm from the skin surface the beam covers an area of approximately 10 cm diameter. This construction ensures continuous recording of the foetal heart activity without the need to reposition the transducer which is otherwise necessitated due to normal foetal movement. The transducer has a diameter of 6 cm and can be held in place either by a simple buckle or a stretch belt.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Ear Oximeter”.
1. What is intrauterine pressure during the expulsion period?
a) 130 mm Hg
b) 140 mm Hg
c) 150 mm Hg
d) 160 mm Hg
Answer: c
Explanation: During labour, the uterus muscle starts contractions of increasing intensity in a bid to expel out the child. The intrauterine pressure can reach values of 150 mmHg or more during the expulsion period. However, a normal patient in spontaneous active labour will demonstrate uterine contractions occurring at intervals of three to five minutes, with a duration of 30 to 70 s and a peak intensity of 50 to 75 mmHg.
2. What is the interval of uterine contractions in a normal patient in spontaneous active labour?
a) 1 to 3 minutes
b) 3 to 5 minutes
c) 5 to 7 minutes
d) 7 to 9 minutes
Answer: c
Explanation: During labour, the uterus muscle starts contractions of increasing intensity in a bid to expel out the child. The intrauterine pressure can reach values of 150 mmHg or more during the expulsion period. However, a normal patient in spontaneous active labour will demonstrate uterine contractions occurring at intervals of three to five minutes, with a duration of 30 to 70 s and a peak intensity of 50 to 75 mmHg.
3. What is the duration of uterine contractions in a normal patient in spontaneous active labour?
a) 0 to 30 s
b) 30 to 70 s
c) 80 to 100 s
d) 110 to 150 s
Answer: b
Explanation: During labour, the uterus muscle starts contractions of increasing intensity in a bid to expel out the child. The intrauterine pressure can reach values of 150 mmHg or more during the expulsion period. However, a normal patient in spontaneous active labour will demonstrate uterine contractions occurring at intervals of three to five minutes, with a duration of 30 to 70 s and a peak intensity of 50 to 75 mmHg.
4. The toco-transducers are temperature sensitive.
a) True
b) False
Answer: b
Explanation: False, the toco-transducers are location sensitive. They should be placed over the fundus where there is maximum motion with the contractions. The toco-tonometer transducer cannot be used in the same place as the foetal heart rate detector, thus the patient must have two transducers on her abdomen.
5. What is the peak intensity of uterine contractions in a normal patient in spontaneous active labour?
a) 0 to 35 mm Hg
b) 50 to 75 mm Hg
c) 90 to 120 mm Hg
d) 120 to 150 mm Hg
Answer: b
Explanation: During labour, the uterus muscle starts contractions of increasing intensity in a bid to expel out the child. The intrauterine pressure can reach values of 150 mmHg or more during the expulsion period. However, a normal patient in spontaneous active labour will demonstrate uterine contractions occurring at intervals of three to five minutes, with a duration of 30 to 70 s and a peak intensity of 50 to 75 mmHg.
6. What are labour-activity transducers?
a) temperature transducer
b) ultrasonic transducer
c) pressure transducer
d) piezoelectric transducer
Answer: c
Explanation: The labour-activity transducers are pressure transducers that drive circuits for obtaining an electrical indication of pressure by conventional means. The pressure channel on the recorder is provided with a positioning control. This is done because the baseline is affected by the static pressure on the transducer that results from the tension on the belt holding the transducer in place.
7. What is used to convert the movement of transducer due to an increase of tension in uterus into an electric signal?
a) AC Amplifier
b) Strain guage
c) Synchronous detector
d) piezoelectric crystal
Answer: b
Explanation: The transducer carries a protruding tip which is pressed to the mother’s abdomen with a light force to ensure an effective coupling. The protruding surface of the transducer is displaced as the tension in the uterus increases. This movement is converted into an electrical signal by a strain gauge in the transducer housing. The abdominal transducer provides a reliable indication of the occurrence frequency, duration and relative intensity of the contraction.
8. The narrow beam transducer permits the operator to position the baseline on the zero-level line of recording chart.
a) True
b) False
Answer: b
Explanation: False, the labour-activity transducers are pressure transducers that drive circuits for obtaining an electrical indication of pressure by conventional means. The pressure channel on the recorder is provided with a positioning control. This is done because the baseline is affected by the static pressure on the transducer that results from the tension on the belt holding the transducer in place. The control permits the operator to position the baseline on the zero-level line of the recording chart.
9. In external toco-tonometry, movement of _____ may be superimposed on labour activity.
a) heart
b) eye
c) foetus
d) muscle
Answer: c
Explanation: In external toco-tonometry, movement of the foetus may be superimposed on the labour activity curve. Stress imposed on the foetal circulatory system by the uterine contractions, foetal movements or other factors are seen in the response of the foetal heart to these stimuli and are studied in the correct time relationship.
10. What is measured in the internal method using fluid-filled catheter?
a) IUP
b) ECG
c) IUC
d) EMG
Answer: a
Explanation: The internal method measures intra-uterine pressure via a fluid-filled catheter. The catheter is inserted into the uterus through a guide after the rupture of the foetal membranes. After allowing free flow of amniotic fluid to ensure correct placement, the distal end of the catheter is usually attached to a pressure transducer of the type used for cardiac studies.
11. What is the range of Instantaneous beat to beat rate digitally displayed?
a) 0 to 50 bpm
b) 50 to 210 bpm
c) 210 to 350 bpm
d) 350 to 410 bpm
Answer: b
Explanation: Instantaneous “beat-to-beat” rate is displayed on a calibrated linear scale or digitally displayed with a range from 50 to 210 bpm. A two-channel chart recorder is incorporated in instruments used for monitoring labour activity. One channel records FHR on a calibrated chart in beats per minute while the other channel is used for recording uterine contractions calibrated 0-100 mmHg.
12. A _______ channel chart recorder is incorporated in instruments used for monitoring labour activity.
a) one
b) two
c) three
d) four
Answer: b
Explanation: Instantaneous “beat-to-beat” rate is displayed on a calibrated linear scale or digitally displayed with a range from 50 to 210 bpm. A two-channel chart recorder is incorporated in instruments used for monitoring labour activity. One channel records FHR on a calibrated chart in beats per minute while the other channel is used for recording uterine contractions calibrated 0-100 mmHg.
13. What is the standard chart speed?
a) 2 cm/min
b) 3 cm/min
c) 4 cm/min
d) 5 cm/min
Answer: a
Explanation: A two-channel chart recorder is incorporated in instruments used for monitoring labour activity. One channel records FHR on a calibrated chart in beats per minute while the other channel is used for recording uterine contractions calibrated 0-100 mmHg. The standard chart speed is usually 1 or 2 cm/min.
14. In two-channel chart recorder, FHR is recorded on a calibrated chart in ________
a) cm/min
b) m/min
c) beats/min
d) pulses/min
Answer: c
Explanation: A two-channel chart recorder is incorporated in instruments used for monitoring labour activity. One channel records FHR on a calibrated chart in beats per minute while the other channel is used for recording uterine contractions calibrated 0-100 mmHg. The standard chart speed is usually 1 or 2 cm/min.
15. Uterine contractions are calibrated in range of ______ in two-channel chart recorder.
a) 0-100 mm Hg
b) 100-200 mm Hg
c) 200-300 mm Hg
d) 300-400 mm Hg
Answer: a
Explanation: A two-channel chart recorder is incorporated in instruments used for monitoring labour activity. One channel records FHR on a calibrated chart in beats per minute while the other channel is used for recording uterine contractions calibrated 0-100 mmHg. The standard chart speed is usually 1 or 2 cm/min.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Pulse Oximeter”.
1. _____ is non-invasive method allowing the monitoring of the saturation of a patient’s hemoglobin.
a) Ear Oximetry
b) Pulse Oximetry
c) Skin-Reflectance Oximetry
d) Intravascular Oximetry
Answer: b
Explanation: Pulse oximetry is a non-invasive method allowing the monitoring of the saturation of a patient’s hemoglobin. A pulse oximeter shows the percentage of arterial hemoglobin in the oxyhemoglobin and hemoglobin . These observations:
A = -logT = log I0/I =ɛDC.
2. A = log I0/I,where I0 is_____
a) Incident light Intensity
b) Transmitted light Intensity
c) Extinction coefficient
d) Concentration
Answer: a
Explanation: A pulse oximeter shows the percentage of arterial hemoglobin in the oxyhemoglobin and hemoglobin . This observation A = -logT = log I0/I = ɛDC where Io and I are incident and transmitted light intensities, e is the extinction coefficient, D is the depth of the absorbing layer and C is concentration.
3. A = ɛDC, where ɛ is _______
a) Incident light Intensity
b) Transmitted light Intensity
c) Extinction coefficient
d) Concentration
Answer: c
Explanation: A pulse oximeter shows the percentage of arterial hemoglobin in the oxyhemoglobin and hemoglobin . This observation A = -logT = log I0/I = ɛDC where Io and I are incident and transmitted light intensities, e is the extinction coefficient, D is the depth of the absorbing layer and C is concentration.
4. A pulse oximeter shows the percentage of venous hemoglobin in the oxyhemoglobin and hemoglobin .
a) True
b) False
Answer: b
Explanation: False, pulse oximetry is a non-invasive method allowing the monitoring of the saturation of a patient’s hemoglobin. A pulse oximeter shows the percentage of arterial hemoglobin in the oxyhemoglobin and hemoglobin . These observations:
A = -logT = log I0/I =ɛDC.
5. What is used as a photodetector in pulse oximetry?
a) Phototransistor
b) Solar cell
c) Photodiode
d) Photographic plates
Answer: c
Explanation: Pulse oximetry is a particularly convenient noninvasive measurement method. Typically it utilizes a pair of small light-emitting diodes facing a photodiode through a translucent part of the patient’s body, usually a fingertip or an earlobe. One LED is red, with a wavelength of 660 nm, and the other is infrared, 905, 910, or 940 nm.
6. What is the wavelength of the red LED in pulse oximetry?
a) 660 nm
b) 740 nm
c) 905 nm
d) 950 nm
Answer: a
Explanation: Pulse oximetry is a particularly convenient noninvasive measurement method. Typically it utilizes a pair of small light-emitting diodes facing a photodiode through a translucent part of the patient’s body, usually a fingertip or an earlobe. One LED is red, with a wavelength of 660 nm, and the other is infrared, 905, 910, or 940 nm.
7. What is the wavelength of infrared LED in pulse oximetry?
a) 660 nm
b) 740 nm
c) 905 nm
d) 950 nm
Answer: c
Explanation: Pulse oximetry is a particularly convenient noninvasive measurement method. Typically it utilizes a pair of small light-emitting diodes facing a photodiode through a translucent part of the patient’s body, usually a fingertip or an earlobe. One LED is red, with a wavelength of 660 nm, and the other is infrared, 905, 910, or 940 nm.
8. A pulse oximeter is useful in any setting where a patients oxygenation is unstable.
a) True
b) False
Answer: a
Explanation: True, pulse oximeter is useful in any setting where a patient’s oxygenation is unstable, including intensive care, operating, recovery, emergency and hospital ward settings, pilots in unpressurized aircraft, for assessment of any patient’s oxygenation, and determining the effectiveness of or need for supplemental oxygen.
9. Portable pulse oximeters are useful for ______ whose oxygen levels may decrease at high altitude.
a) Athlete
b) Swimmer
c) Mountain climber
d) Fisher
Answer: c
Explanation: Portable pulse oximeter is also useful for mountain climbers and athletes whose oxygen levels may decrease at high altitudes or with exercise. Some portable pulse oximeters employ software that charts a patient’s blood oxygen and pulse, serving as a reminder to check blood oxygen levels.
10. ______ is very useful for patients having respiratory or cardiac problems because of their simplicity of use and the ability to provide continuous and immediate oxygen saturation levels.
a) Pulse Oximeter
b) Ear Oximeter
c) Skin Reflactance Oximeter
d) Intravascular Oximeter
Answer: a
Explanation: Because of their simplicity of use and the ability to provide continuous and immediate oxygen saturation values, pulse oximeters are of critical importance in emergency medicine and are also very useful for patients with respiratory or cardiac problems, especially COPD, or for diagnosis of some sleep disorders such as apnea and hypopnea.
This set of Biomedical Instrumentation Questions and Answers for Aptitude test focuses on “Skin Reflectance Oximeters”.
1. Which module consists of a pair of Perspex plates?
a) The dialyzer module
b) The recorder module
c) The sampling module
d) Heating bath module
Answer: a
Explanation: In analytical chemistry, it is often necessary to remove protein cells to obtain an interference-free analysis. This is accomplished by dialysis in the auto-analyzer. The dialyzer module consists of a pair of perspex plates, the mating surfaces of which are mirror grooved in a continuous channel, which goes in towards the centre, on itself and returns to the outside.
2. The part of the automated system that shown in the figure is ____________
biomedical-instrumentation-questions-answers-aptitude-test-q2
a) Dialyzer
b) Pump
c) Recorder
d) Sampler
Answer: d
Explanation: The automated system consists of a group of modular instruments interconnected together by a manifold system and electrical systems. The sample to be analyzed is introduced into a stream of diluting liquid flowing in the narrow bore of a flexible plastic tube. The stages of the analytical reaction are completed by the successive combination of other flowing streams of liquids with the sample stream, by means of suitably shaped glass functions.
3. In the sampling unit, when it is in its earlier form consisted of a circular turntable carrying around its rim 40 disposable __________ of 2 ml capacity.
a) Polyvinyl cups
b) Polythene cups
c) Polyester cups
d) Polystyrene cups
Answer: d
Explanation: The unit in its earlier form consisted of a circular turntable carrying around its rim 40 disposable polystyrene cups of 2 ml capacity. The sample plate carrying these cups rotates at a predetermined speed. The movement of the turntable is synchronized with the movements of a sampling crook.
4. What is the ratio of the sampling time to wash time?
a) 1:2
b) 3:1
c) 2:1
d) 1:3
Answer: c
Explanation: Between each sampling, the crook enters a receptacle of water or other suitable wash fluid, to reduce cross-contamination of one sample with another. The ratio of sampling time to wash time is normally 2:1.
5. Which of the following is not the part of the manifold?
a) Transmission tubing
b) Pump tubes
c) Platter
d) Plastic tubes
Answer: d
Explanation: A manifold mainly consists of a platter, pump tubes, coils, transmission tubing, fittings and connections. A separate manifold is required for each determination and the change can be effected within a few minutes. The pump tubing and the connected coils are placed on a manifold platter, which keeps them in proper order for each test.
6. Which of the following is not the type of tubing?
a) Acidflex tubing
b) Glass tubing
c) Polypropylene tubing
d) Tygon
Answer: c
Explanation: Several other tubes are required to introduce reagents and to transport the specimen from one module to another. There are five types of such tubings. They are of varying sizes and are to be selected according to the requirements. These are standard transmission tubing , solvaflex tubing, acidflex tubing, polyethylene tubing and glass tubing.
7. There are two types of coils employed in the system, which are ____
a) Tygon coils and mixing coils
b) Mixing coils and tubing coils
c) Delay coils and tygon coils
d) Mixing coils and delay coils
Answer: d
Explanation: Two types of coils are employed in the system—mixing coils and delay coils. Coils are glass spirals of critical dimensions, in which the mixing liquids are inverted several times, so that complete mixing can result. Mixing coils are used to mix the sample and/or reagents. Delay coils are employed when a specimen must be delayed for the completion of a chemical reaction before reaching the colorimeter.
8. In phasing, if the cholesterol stream arrives at Y time, albumin must arrive at ______
a) Y + 5 s
b) Y + 10 s
c) Y + 15 s
d) Y + 20 s
Answer: c
Explanation: With 12 tests to be recorded on each sample and a sampling rate of 60 samples per hour, it follows that 5 s are allowed to record each steady state plateau. The reaction streams in the 12 channels and up to four blank channels must, therefore, be phased to arrive at the colorimeter in waves 5 s apart. For example, if the cholesterol stream arrives at X time, calcium must arrive at X + 5 s, total protein at X + 10 s, albumin at X + 15 s, etc.
9. Which coils are used to permit the channels to enter the calorimeter in the proper sequence?
a) Mixing coils
b) Delay coils
c) Solvaflex coils
d) Phasing coils
Answer: d
Explanation: In order to ensure a proper sequencing for the presentation of results, a number of devices have been provided to make this adjustment an extremely simple operation. Phasing coils are used to permit the channels to enter the colorimeter in the proper sequence.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Intravascular Oximeters”.
1. What is the amount of blood in the average adult?
a) 5-10 liters
b) 10-15 liters
c) 5-6 liters
d) 5-15 liters
Answer: c
Explanation: The blood constitutes 5–10% of the total body weight and in the average adult, it amounts to 5–6 l. Blood consists of corpuscles suspended in a fluid called plasma in the proportion of 45 parts of corpuscles to 55 parts of plasma.
2. Which of the following is not the type of blood cell?
a) Erythrocytes
b) Thrombocytes
c) Leukocytes
d) Eosinocytes
Answer: d
Explanation: The percentage of cells in the blood is called the haematocrit value or packed cell volume . The majority of the corpuscles in the blood are red blood cells , others being white blood cells and platelets .
3. Which of the following is the Red Blood Cells?
a) Erythrocytes
b) Leukocytes
c) Basophils
d) Monocytes
Answer: a
Explanation: Erythrocytes : Red blood cells have the form of a bi-concave disc with a mean diameter of about 7.5 m and thickness of about 1.7 m. The mean surface area of the cell is about 134mm2. There are about 5.5 million of them in every cubic millimetre of blood in men and nearly 5 million in women.
4. The normal red cell lasts approximately ______ before it is destroyed.
a) 90 days
b) 210 days
c) 120 days
d) 60 days
Answer: c
Explanation: In the whole body, there are about 25 billion erythrocytes and they are constantly being destroyed and replaced at a rate of about 9000 million per hour. The normal red cell lasts approximately 120 days before it is destroyed.
5. Who is responsible for carrying oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs?
a) Basophils
b) Eosinophils
c) RBC
d) Thrombocytes
Answer: c
Explanation: The erythrocytes have no nucleus. They are responsible for carrying oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs. Anaemia can develop from a change in the number, volume or Hb concentration of erythrocytes, caused by bone marrow dysfunction resulting in the poor production rate of RBCs.
6. The main two types of leukocytes are ____________
a) The neutrophils and the thrombophils
b) The lymphocytes and the neutrophils
c) The neutrophils and the monophils
d) The lymphocytes and the monophils
Answer: b
Explanation: Leucocytes form the defence mechanism of the body against infection. They are of two main types: the neutrophils and the lymphocytes. Neutrophils ingest bacteria and lymphocytes are concerned with an immunological response.
7. ______ play an important role in the blood coagulation process.
a) Platelets
b) Leukocytes
c) RBC
d) Neutrophils
Answer: a
Explanation: Platelets are usually tiny, round, oblong or irregularly shaped cells of the blood with an average diameter of approximately 2 m. They play an important role in the blood coagulation process. There are usually 250,000–750,000 platelets in every cubic mm of blood.
8. Which of the following is not the method of cell counting?
a) Microscopic method
b) Electrical conductivity method
c) Automatic optical method
d) Electroscopic method
Answer: d
Explanation: There are three methods of cell counting: i) Microscopic method, ii) Automatic optical method, iii) Electrical conductivity method.
9. What is the difference of measuring accuracy between microscopic counting and electronic counters?
a) + or – 20 %
b) + or – 17%
c) + or – 3%
d) + or – 23%
Answer: b
Explanation: Agoston and Zillich compared the results of microscopic counting with those made by electronic counters. It may be observed that instead of the + 0r – 20% measuring accuracy in microscopic counting, the electronic counters can provide an accuracy of + or – 3%.
10. What is the ratio of a sample of red blood cells in dilute blood?
a) 500:1
b) 50000:1
c) 1:500
d) 1:50000
Answer: d
Explanation: The method is based on collecting scattered light from the blood cells and converting them into electrical pulses for counting. A sample of dilute blood is taken in a glass container. It is drawn through a counting chamber in which the blood stream is reduced in cross-section by a concentric high velocity liquid sheath.
11. The instrument of an optical method of counting cells, that require about _____ of blood sample.
a) 100 ml
b) 1 liter
c) 1 ml
d) 10 ml
Answer: c
Explanation: Instruments based on optical technique take about 30 s for completing the count. An accuracy of 2% is attainable. The instruments require about 1 ml of the blood sample.
12. 1 f/l = ____
a) 10 18
b) 10 15
c) 10 -18
d) 10 -15
Answer: d
Explanation: f/l = Femolitres
1f/l = 10 -15 .
13. _______ will be calculated if the value of PCV and Hb per deciliters are known.
a) MCV
b) MCHC
c) MCH
d) PCT
Answer: b
Explanation: It can be calculated if PCV and Hb per dl are known. For example, if PCV is 0.45 and there are 15 g Hb per dl of blood, then
MCHC = g/dl
= 33.3 g/dl.
14. PDW index is related to the size range covered by those platelets lying between _______ and _______ percentile.
a) 20th and 84th percentile
b) 16th and 20th percentile
c) 16th and 84th percentile
d) 20th and 80th percentile
Answer: c
Explanation: Platelet Distribution Width : This index is related to the size range covered by those platelets lying between the sixteenth and eighty fourth percentile. This is the conventional geometric standard deviation of the mean platelet size and is derived from the distribution curve based on the data in a 64-channel pulse height analyzer.
15. Instruments based on the automatic optical technique take about _____ for completing the count blood cells.
a) 30 sec
b) 120 sec
c) 60 sec
d) 90 sec
Answer: a
Explanation: Instruments based on this automatic optical technique take about 30 s for completing the count. An accuracy of 2% is attainable. The instruments require about 1 ml of the blood sample.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Mechanism of Hearing”.
1. The tympanic membrane separates the ear canal from the _____________
a) upper ear cavity
b) lower ear cavity
c) middle ear cavity
d) inner ear cavity
Answer: c
Explanation: The tympanic membrane separates the ear canal from the middle ear cavity. The pinna scatters acoustic waves so that some of the scattered energy enters the auditory canal and pushes against the tympanic membrane during a wave of compression. The distance membrane moves is a function of the force and velocity with which the air molecules strike it and is, therefore, related to the loudness of sound.
2. The middle ear is exposed to atmospheric pressure only through the _______
a) eustachian tube
b) tympanic membrane
c) pinna
d) auditory nerve
Answer: a
Explanation: The middle ear is exposed to atmospheric pressure only through the eustachian tube, which connects it to the pharynx and nose or mouth. The sound energy from the tympanic membrane is transmitted through the cavity of the middle ear, to the receptor cells in the inner ear, which are surrounded by fluid. The tympanic membrane separates the ear canal from the middle ear cavity.
3. The major function of the middle ear is ____________
a) to transfer movements of the air in the outer ear to the cochlea
b) to transfer movements of the air in the outer ear to the auditory nerves
c) to transfer movements of the air in the outer ear to the tympanic membrane
d) to transfer movements of the air in the outer ear to the fluid-filled chambers of the inner ear
Answer: d
Explanation: Thus, the major function of the middle ear is to transfer movements of the air in the outer ear to the fluid-filled chambers of the inner ear. A chain of three small, middle ear bones couple the tympanic membrane to a membrane covered opening, called the oval window. The total force on the oval window is the same as that on the tympanic membrane.
4. The human ear responses to vibrations ranging from ___________
a) 20KHz – 20MHz
b) 2KHz – 20MHz
c) 20Hz – 20KHz
d) 2Hz – 2KHz
Answer: c
Explanation: The human ear responds to vibrations ranging from 20 to 20,000 Hz. The waves of speech and many other common sounds are not of single frequency but are complex waves made up of several frequencies of vibration. The number of sound frequencies in addition to the fundamental tone, i.e. the degree of purity of the sound wave is related to the quality or timbre of the sound. The human ear can in fact, distinguish some 400,000 different sounds.
5. Name the bone that rests upon the lower end of the cochlea and passes the vibrations directly into the fluid within.
a) malleus
b) stapes
c) incus
d) hammer
Answer: b
Explanation: One of the bones, called the stapes, rests upon the lower end of the cochlea and passes the vibrations directly into the fluid within. A chain of three small, middle ear bones couple the tympanic membrane to a membrane covered opening, called the oval window. The total force on the oval window is the same as that on the tympanic membrane.
6. Air conduction, by definition, is the transmission of sound through the external and middle ear to the internal ear.
a) True
b) False
Answer: a
Explanation: It is true. Air conduction, by definition, is the transmission of sound through the external and middle ear to the internal ear. Bone conduction, on the other hand, refers to the transmission of sound to the internal ear mediated by mechanical vibration of the cranial bones and soft tissues. Clinical observation has shown that hard-of-hearing patients with middle ear disease usually have normal hearing by bone conduction, whereas patients with inner ear involvement have decreased or diminished bone-conduction.
7. The hearing threshold is an invariable fixed intensity above which sound is always heard and below which sound is never heard.
a) True
b) False
Answer: a
Explanation: It is False. The hearing threshold is not an invariable fixed intensity above which sound is always heard and below which sound is never heard. In fact, the sensitivity of the auditory mechanism is found to vary with interactions between certain physiological, psychological and physical factors. Therefore, the threshold may be regarded as an intensity range within which sound stimuli at or near the statistically determined threshold may or may not be perceived.
8. Unit of sound intensity ________
a) joules per sq. cm
b) watt per sq. cm
c) joules per cm
d) watt per cm
Answer: b
Explanation: Sound intensity may be defined as the amount of energy flow per unit time through a unit area perpendicular to the direction of energy flow. It is expressed as watts per square centimetre. However, the common receivers of sound are microphones, which do not measure sound intensity directly.
9. Sound intensity is proportional to the _________ of sound pressure.
a) cube
b) square
c) inverse square
d) inverse square root
Answer: b
Explanation: Sound intensity is proportional to the square of sound pressure. Sound pressure, for a given sinusoidal event, is related linearly to both amplitude and frequency. Sound intensity may be defined as the amount of energy flow per unit time through a unit area perpendicular to the direction of energy flow.
10. Decibel expresses the logarithm of the ratio between two sound _________
a) intensities
b) powers
c) pressures
d) intensities, powers and pressures
Answer: d
Explanation: Decibel expresses the logarithm of the ratio between two sound intensities, powers or sound pressures. The convenient unit for making such comparisons and to express the sound intensity and sound pressure data for all practical purposes is the decibel . The dB is 1/10 of a larger unit, the bell, named after Alexander Graham Bell.
11. What is the unit of dB?
a) watts per sq cm
b) dyne per sq cm
c) unit less
d) watts per cm
Answer: c
Explanation: Since dB is merely a ratio, it is a dimensionless entity. Decibel expresses the logarithm of the ratio between two sound intensities, powers or sound pressures. Use of decibels as units for comparison of intensities help to avoid all mathematical calculations except algebraic addition or subtraction of small numbers. The transmission efficiency of any medium like air, a hearing aid or an amplifier is usually expressed in dB as a gain when the output is greater and as a loss, if less.
12. If I1 and I2 are two intensities in watts per square centimetre, then the number of decibels with which they are related can be expressed as _________
a) N = 10 log I1/I2
b) N = 10 log I2/I1
c) N = -10 log I1/I2
d) N = log I1/I2
Answer: a
Explanation: If I1 and I2 are two intensities in watts per square centimetre, then the number of decibels with which they are related can be expressed as N = 10 log I1/I2. Attenuation is commonly expressed in negative dB numbers whereas amplification is given in positive dB numbers. Use of decibels as units for comparison of intensities help to avoid all mathematical calculations except algebraic addition or subtraction of small numbers. The transmission efficiency of any medium like air, a hearing aid or an amplifier is usually expressed in dB as a gain when the output is greater and as a loss, if less.
13. __________ is specialized equipment, which is used for the identification of hearing the loss in individuals.
a) gaugemeter
b) tachometer
c) manometer
d) audiometer
Answer: d
Explanation: An audiometer is specialized equipment, which is used for the identification of hearing the loss in individuals, and the quantitative determination of the degree and nature of such a loss. Both frequency and output are adjustable over the audio range. The instrument is also provided with a calibrated noise source and bone-conductor vibrator. It is essentially an oscillator driving a pair of headphones and is calibrated in terms of frequency and acoustic output.
14. Which threshold of hearing is measured by a pure-tone audiometer?
a) air-conduction thresholds of hearing
b) bone-conduction thresholds of hearing
c) speech reception thresholds for diagnostic purposes
d) air-conduction and bone-conduction thresholds of hearing
Answer: d
Explanation: A pure-tone audiometer is used primarily to obtain air-conduction and bone-conduction thresholds of hearing. Audiometers may be divided into two main groups on the basis of the type of stimulus they provide to elicit an auditory response: pure-tone audiometers and speech audiometers. These thresholds are helpful in the diagnosis of hearing loss.
15. Speech audiometers are normally used to determine ______________
a) speech reception thresholds for diagnostic purposes
b) air-conduction and bone-conduction thresholds of hearing
c) bone-conduction thresholds of hearing
d) air-conduction thresholds of hearing
Answer: a
Explanation: Speech audiometers are normally used to determine speech reception thresholds for diagnostic purposes and to assess and evaluate the performance of hearing aids. A pure-tone audiometer is used primarily to obtain air-conduction and bone-conduction thresholds of hearing. These thresholds are helpful in the diagnosis of hearing loss. Pure-tone screening tests are employed extensively in industrial and school hearing conservation programmes.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Measurement of Hearing”.
1. Pure-tone audiometers usually generate test tones in octave steps from ___________
a) 125 to 800 Hz
b) 125 to 8000 Hz
c) 25 to 8000 Hz
d) 15 to 800 Hz
Answer: b
Explanation: Pure-tone audiometers usually generate test tones in octave steps from 125 to 8000 Hz, the signal intensity ranging from –10 dB to +100 dB. Pure-tone audiometry is used in routine tests and, therefore, it is the most widely used technique for determining hearing loss. Pure-tone audiometry has several advantages, which makes it specifically suitable for making threshold sensitivity measurements. A pure-tone is the simplest type of auditory stimulus. It can be specified accurately in terms of frequency and intensity.
2. Speech audiometry normally allows measurements to be made within the frequency range of _____
a) 300–3000 Hz
b) 30–300 Hz
c) 300–3000 KHz
d) 3–30K Hz
Answer: a
Explanation: Speech audiometry normally allows measurements to be made within the frequency range of 300–3000 Hz. Pure-tone audiometers usually generate test tones in octave steps from 125 to 8000 Hz, the signal intensity ranging from –10 dB to +100 dB. Some patients may have impaired high frequency response due to high intensity level occupational noise at 4000 or 6000 Hz.
3. The signal intensity of Pure-tone audiometers ranging from ______
a) 10 dB to +100 dB
b) –10 dB to -100 dB
c) –10 dB to +100 dB
d) –10 dB to +10 dB
Answer: c
Explanation: Pure-tone audiometers usually generate test tones in octave steps from 125 to 8000 Hz, the signal intensity ranging from –10 dB to +100 dB. A wave in the air, which involves only one frequency of vibration, is known as pure-tone. Pure-tone audiometry is used in routine tests and, therefore, it is the most widely used technique for determining hearing loss. Pure-tone audiometry has several advantages, which makes it specifically suitable for making threshold sensitivity measurements.
4. The frequency range of pure-tone audiometer is more than that of speech audiometer.
a) True
b) False
Answer: a
Explanation: It is True. The frequency range of pure-tone audiometer is more than that of speech audiometer. Pure-tone audiometers usually generate test tones in octave steps from 125 to 8000 Hz, the signal intensity ranging from –10 dB to +100 dB. Speech audiometry normally allows measurements to be made within the frequency range of 300–3000 Hz. Pure-tone audiometry has several advantages, which makes it specifically suitable for making threshold sensitivity measurements.
5. ___________ amplifier circulatory is employed to reduce the hum noise generated by the power supply in the ECG circuit.
a) low pass filters
b) high pass filters
c) band pass filters
d) notch filters
Answer: d
Explanation: CMRR of the order of 100–120 dB with 5 kW unbalance in the leads is a desirable feature of ECG machines. A notch filter is employed to suppress the hum noise generated by the power supply in the ECG circuit.The instability of the baseline, originating from the changes of the contact impedance, demands the application of the automatic baseline stabilizing circuit.
6. The unit of sensitivity of an electrocardiograph is ________
a) m/mV
b) mm/V
c) mm/mV
d) m/V
Answer: c
Explanation: The unit of the sensitivity of an electrocardiograph is mm/mV. The sensitivity of an electrocardiograph is typically set at 10 mm/mV. Time measurements and heart rate measurements are made horizontally on the electrocardiogram. For routine work, the paper recording speed is 25 mm/s.
7. The volume of blood outside the dialyzer is known as priming volume.
a) True
b) False
Answer: b
Explanation: False, The volume of blood within the dialyzer is known as priming volume. It is desirable that this should be minimal. Priming volume of present day dialyzers ranges from 75 to 200 ml, depending on the membrane area geometry and operating conditions.
8. The range of CMRR of Foetal electrocardiogram is ______________
a) 0-120 dB
b) 0-200 dB
c) 0-150 dB
d) 0- 130 dB
Answer: a
Explanation: The range of CMRR of Foetal electrocardiogram is 0-120 dB. After proper placement of the electrodes, the signals are amplified in a preamplifier which provides a very high input impedance and a high sensitivity and good common mode rejection ratio . Abdominal FECG processing circuit is used for computing foetal heart rate.
9. Power Line Hum is responsible for most of common-mode interfering signal.
a) True
b) False
Answer: a
Explanation: It is True. Power Line Hum is responsible for most of common-mode interfering signal. This is suppressed by a notch filter following the input amplifier. A sizable common-mode signal manages to pass through the input amplifier, a circumstance to be expected whenever electrodes spaced a few centimetres apart are attached to the human body in a hospital environment.
10. What is the role of Cupraphan in haemodialysis?
a) used to check conductivity of dialyzer
b) used as membrane
c) used to check blood leakage
d) not at all used
Answer: b
Explanation: Cupraphan is the commonly used membrane for haemodialysis. During haemodialysis, different substances of varying molecular weight are to be removed. It is a membrane consisting of natural cellulose and is considered puncture-proof, and of high tenacity and elasticity.
11. Which of the following is the property of instrumentational amplifier?
a) Extremely low input impedance
b) High bias and offset currents
c) Low slew rate
d) Very high CMRR
Answer: d
Explanation: Instrumentational amplifiers have very high CMRR. Instrumentational amplifiers have extremely high input impedance. Instrumentational amplifiers have low bias and offset currents. Instrumentational amplifiers have high slew rate.
12. Foetal ECG signal detected via electrodes placed on mother’s abdomen is complex and requires attenuation of maternal signals for obtaining FHR.
a) True
b) False
Answer: a
Explanation: It is True. Foetal ECG signal detected via electrodes placed on the mother’s abdomen is complex and requires attenuation of maternal signals for obtaining FHR. Also, due to the overlapping of the foetal ECG with the maternal ECG, about 20% to 50% of the expected pulses may be missing.
13. The blood is a good conductor of electricity.
a) True
b) False
Answer: b
Explanation: It is False. The blood is not a good conductor of electricity. Blood is a poor conductor of electricity. This principle is used in Coulter counters to count the number of RBCs in the blood.
14. The range of FHR measurement due to substitution logic is between __________ bpm.
a) 20-220
b) 60-260
c) 40-240
d) 0-200
Answer: c
Explanation: The range of FHR measurement due to substitution logic is between 40-240 bpm. The range of FHR measurement is limited to 40–240 bpm because of the substitution logic. Thereafter, the output of logic circuits go to standard heart rate computing circuits. The substitution logic requires a delay time to establish a missing foetal trigger pulse. It is thus kept as 270 ms.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Biotelemetry”.
1. Leucocytes are in the shape of ________
a) sphere
b) cube
c) hollow
d) cuboid
Answer: a
Explanation: Leucocytes are in the shape of a sphere. Leucocytes have a nucleus. They live for seven to fourteen days and there is a rapid turn over, with constant destruction and replacement. There are normally 5000–10,000 white cells per cubic mm of blood but their number varies during the day.
2. What should be the frequency response of the amplifiers that are used for the amplification purpose of the input signal in medical devices?
a) high frequency response
b) low frequency response
c) frequency response has no role to play in it
d) average frequency response
Answer: b
Explanation: The response should be down to less than one hertz which is a very frequent requirement. The bioelectric signals in medical science contain components of extremely low frequency. Thus the amplifiers must also have a low frequency response.
3. Leucocytes are not responsible for the formation of the defence mechanism of the body that fights against infection.
a) True
b) False
Answer: b
Explanation: It is False. Leucocytes form the defence mechanism of the body against infection. The number and proportion of these types of leucocytes may vary widely in response to various disease conditions. They are of two main types: the neutrophils and the lymphocytes. Neutrophils ingest bacteria and lymphocytes are concerned with immunological response.
4. To achieve the ______________ required for medical applications, the amplifier must have large values of coupling capacitance.
a) random frequency response
b) high frequency response
c) average frequency response
d) low frequency response
Answer: d
Explanation: In all RC-coupled amplifiers, low frequency response is limited by the reluctance of the coupling capacitors. The response should be down to less than one hertz which is a very frequent requirement. To achieve the low frequency response required for medical applications, the amplifier must have large values of coupling capacitance.
5. Neutrophils are bigger than the red cells.
a) True
b) False
Answer: a
Explanation: It is True. Neutrophils are nearly twice as big as the red cells.Lymphocytes are of the same size as the red cells but contain a large density staining nucleus and no granules. Neutrophils contain both a nucleus divided into several lobes and granules in their protoplasm.
6. High pass filter amplifies frequency _____________
a) above certain value
b) below certain value
c) above and below certain value
d) at certain value
Answer: a
Explanation: High pass filter amplifies signal above a certain frequency. Band pass filter amplifies frequencies with in a certain band. Band stop filter amplifies all the frequencies except those in a certain band. Low pass filter amplifies signals below a certain frequency.
7. Mean Platelet Volume is the ratio of the ___________ and is expressed in femolitres.
a) integrated platelet volume to the platelet count
b) integrated platelet volume to the WBC count
c) integrated RBC volume to the platelet count
d) integrated platelet volume to the RBC count
Answer: a
Explanation: Mean Platelet Volume is the ratio of the integrated platelet volume to the platelet count and is expressed in femolitres. Platelet Distribution Width is related to the size range covered by those platelets lying between the sixteenth and eighty fourth percentile. Red Cell Distribution Width is a numerical expression of the width of the size distribution of red cells.
8. Unit of Mean Platelet Volume is expressed in?
a) millilitres
b) femolitres
c) picolitres
d) decilitres
Answer: c
Explanation: Unit of Mean Platelet Volume is expressed in femolitres. 1f/l = 10–15 . 1 litre of blood contains 0.45 litres of red cells. Mean Platelet Volume is the ratio of the integrated platelet volume to the platelet count and is expressed in femolitres.
9. Low pass filter amplifies signals below a certain frequency.
a) True
b) False
Answer: a
Explanation: It is true. Low pass filter amplifies signals below a certain frequency. Band stop filter amplifies all the frequencies except those in a certain band. High pass filter amplifies signal above a certain frequency. Band pass filter amplifies frequencies within a certain band.
10. _______ is the percentage of the total specimen volume occupied by the platelets.
a) Mean Platelet Volume
b) Plateletcrit
c) Red Cell Distribution Width
d) Platelet Distribution Width
Answer: b
Explanation: Plateletcrit is the percentage of the total specimen volume occupied by the platelets. Red Cell Distribution Width is a numerical expression of the width of the size distribution of red cells. Mean Platelet Volume is the ratio of the integrated platelet volume to the platelet count and is expressed in femolitres.
11. Modern instrument use ________ for intravascular oximetry?
a) photodiode
b) red and infrared LED’s
c) optical fibre
d) phototransistor
Answer: c
Explanation: For intravascular oximetry, modern instruments make use of optical fibres to guide the light signal inside the vessel and the reflected light from the red blood cells back to the light detector.
12. Optical fiber sensors are immune to electromagnetic disturbances.
a) True
b) False
Answer: a
Explanation: It is True. Optical fiber sensors are electrically passive and consequently immune to electromagnetic disturbances. They can be miniaturized and are most suitable for telemetry applications. They are geometrically flexible and corrosion resistant.
13. Currently available oximeters utilize __________ wavelengths.
a) Equal to 2
b) Cannot be determined
c) Less than 2
d) More than 2
Answer: d
Explanation: Currently available fiber-optic oximeters utilize more than two wavelengths to adjust for haematocrit variation. For estimating SO 2 , usually the reflectance at two wavelengths, one in the red and the other in the near infrared regions, are used.
14. Mix venous saturation is measured by __________
a) Ear Oximeter
b) Intravascular Oximeter
c) Skin Reflectance Oximeter
d) Pulse Oximeter
Answer: b
Explanation: Mixed venous saturation varies in reflecting the changes of oxygen saturation, cardiac output, haematocrit or haemoglobin content and oxygen consumption. Intravasacular oximeters are normally used to measure mixed venous saturation, from which the status of the circulatory system can be deduced.
15. Which of the following is correct expression for RDW index?
a) [(20 th – 80 th ) Percentile Volume / (20 th – 80 th ) Percentile Volume] X 100 X K
b) [(20 th – 80 th ) Percentile Volume / (20 th + 80 th ) Percentile Volume] X 100 X K
c) [(20 th + 80 th ) Percentile Volume / (20 th – 80 th ) Percentile Volume] X 100 X K
d) [(20 th + 80 th ) Percentile Volume / (20 th + 80 th ) Percentile Volume] X 100 X K
Answer: b
Explanation: The total erythrocyte count is scanned by a continuously variable thresholding circuit. The RDW index is expressed by the following equation [(20 th – 80 th ) Percentile Volume / (20 th + 80 th ) Percentile Volume ] X 100 X K. It is a numerical expression of the width of the size distribution of red cells. It is derived by analog computation. The upper threshold is moved progressively lower from a level equivalent to 360 femolitres until 20 per cent of all erythrocytes present have a size above a certain value.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Single Channel Telemetry System”.
1. ___________ system may include lenses, mirrors, slits, diaphragm etc.
a) Photo system
b) Radiant system
c) Cardiac system
d) Optical system
Answer: d
Explanation: A detecting system for the measurement of unabsorbed radiant energy, which could be the human eye, a barrier-layer cell, phototube or photo-multiplier tube. An optical system for producing a parallel beam of filtered light for passage through an absorption cell . The system may include lenses, mirrors, slits, diaphragm, etc.
2. __________ is not the property of instrumentational amplifier.
a) Extremely high input impedance
b) Very low CMRR
c) Low bias and offset currents
d) High slew rate
Answer: b
Explanation: Instrumentational amplifiers have very high CMRR. The instrumentation amplifier offers the following advantages for its applications in the biomedical field. Some of them are like extremely high input impedance, low bias and offset currents, high slew rate.
3. Which of the following feedback type is employed with DC amplifiers?
a) negative
b) can be any positive or negative doesn’t matter
c) depends on the application
d) positive
Answer: a
Explanation: DC amplifiers are generally of the negative feedback type. They are used for medium gain applications down to about 1 mV signal levels for full scale. They are not practical for very low level applications because of dc drift and poor common-mode rejection capabilities.
4. The CMRR is expressed in _____________
a) V/s
b) dB/ms
c) dB/s
d) dB
Answer: d
Explanation: The ability of the amplifier to reject common voltages on its two input leads is known as common-mode rejection. It is specified as the ratio of common-mode input to differential input to elicit the same response. CMRR is an important specification referred to the differential amplifier and is normally expressed as decibels.
5. An oscillator and a capacitance coupled amplifier are present in a carrier amplifier.
a) True
b) False
Answer: a
Explanation: It is True. The transducers, which require ac excitation, are those whose impedance is not purely resistive. The carrier amplifier consists of an oscillator and a capacitance coupled amplifier. The oscillator is used to energize the transducer with an alternating carrier voltage.
6. Reduction in electromagnetic coupling is achieved by _____
a) shielding
b) common grounding
c) multiple grounding
d) wire twisting
Answer: c
Explanation: Electromagnetic coupling is reduced by shielding, wire twisting and proper grounding which provide a balanced signal pair with satisfactory noise rejection characteristics. Having multiple grounds in a single circuit increases the electromagnetic coupling effect by producing ground loop which may generate so much noise that it may completely obscure the useful signal.
7. ________________ is employed with resistive transducers which require an external source of excitation?
a) dc bridge amplifier
b) ac coupled amplifier
c) carrier amplifier
d) differential amplifier
Answer: a
Explanation: Essentially, the amplifier comprises a stable dc excitation source, a bridge balance and calibration unit, a high gain differential dc amplifier and a dc output amplifier. DC bridge amplifiers are employed with resistive transducers which require an external source of excitation. They can be used as conventional dc high gain amplifiers and offer operating simplicity and high frequency response.
8. From the options given below select the one which is not a type of isolation amplifier?
a) transformer type isolation amplifiers
b) resistive coupled isolation amplifiers
c) optically isolated isolation amplifiers
d) capactively coupled isolation amplifiers
Answer: b
Explanation: Opto-coupled amplifier uses a minimum number of components and is cost effective, followed by the transformer coupled amplifier. The capacitor coupled amplifier is the most expensive. There is nothing such as the resistive coupled isolation amplifiers. All the other three types are in common use, though the transformer isolation amplifier is more popular.
9. The isolation includes common supply voltage sources and common grounds on each side of the isolation barrier.
a) True
b) False
Answer: b
Explanation: It is False. Three methods are used in the design of isolation amplifiers: transformer isolation optical isolation capacitive isolation. Isolation amplifiers are commonly used for providing protection against leakage currents. The isolation includes different supply voltage sources and different grounds on each side of the isolation barrier.
10. Which of the following amplifier is commonly used for providing protection against leakage currents?
a) Isolation amplifiers
b) Instrumentational amplifiers
c) Inverting amplifiers
d) Differential amplifiers
Answer: a
Explanation: Isolation amplifiers are commonly used for providing protection against leakage currents. They break the ohmic continuity of electric signals between the input and output of the amplifier. The isolation includes different supply voltage sources and different grounds on each side of the isolation barrier.
This set of Biomedical Instrumentation online test focuses on “Multi-Channel Wireless Telemetry System”.
1. _________ instrument is used for recording the electrical activity of the muscles.
a) ECG
b) EMG
c) PCG
d) EEG
Answer: b
Explanation: Electromyograph is an instrument used for recording the electrical activity of the muscles to determine whether the muscle is contracting or not; or for displaying on the CRO and loudspeaker the action potentials spontaneously present in a muscle or those induced by voluntary contractions as a means of detecting the nature and location of motor unit lesions; or for recording the electrical activity evoked in a muscle by the stimulation of its nerve.
2. EMG cannot be recorded by using surface electrodes.
a) True
b) False
Answer: b
Explanation: It is False. EMG is usually recorded by using surface electrodes because the surface electrodes may be disposable, adhesive types or the ones which can be used repeatedly.
3. Which of the following signal is used to myoelectric prosthetic devices?
a) EEG
b) EMG
c) ECG
d) VCG
Answer: b
Explanation: EMG measurements are also important for the myoelectric control of prosthetic devices . This is the most demanding requirement from an EMG since on it depends on the working of the prosthetic device. This use involves picking up EMG signals from the muscles at the terminated nerve endings of the remaining limb and using the signals to activate a mechanical arm.
4. _________ is the most common and convenient source of light.
a) Neon-xenon arc
b) Xenon-mercury arc
c) Tungsten lamp
d) Hydrogen discharge lamp
Answer: c
Explanation: The most common and convenient source of light is the tungsten lamp. This lamp consists of a tungsten filament enclosed in a glass envelope. It is cheap, intense and reliable. A major portion of the energy emitted by a tungsten lamp is in the visible region and only about 15 to 20% is in the infrared region.
5. Which of the following factor determines the amplitude of EMG signal?
a) Respiration
b) Ventricular Volume
c) Blood Resistivity
d) Position of electrode
Answer: d
Explanation: The amplitude of the EMG signals depends upon various factors, e.g. the type and placement of electrodes used and the degree of muscular exertions. The needle electrode in contact with a single muscle fibre will pick up spike type voltages whereas a surface electrode picks up many overlapping spikes and therefore produces an average voltage effect.
6. EMG signals range from ______________
a) 0.1 to 0.5 mV
b) 0.050 to 0.1 mV
c) 0.5 to 1 mV
d) 0.025 to 0.050 mV
Answer: a
Explanation: A typical EMG signal ranges from 0.1 to 0.5 mV. They may contain frequency components extending up to 10 kHz.Such high frequency signals cannot be recorded on the conventional pen recorders and therefore, they are usually displayed on the CRT screen.
7. Modern day calorimeters and spectrophotmetry instruments use ________ light source.
a) Tungsten-halogen lamp
b) Xenon-mercury lamp
c) Deuterium discharge lamp
d) Mercury arc
Answer: d
Explanation: Modern instruments use a tungsten-halogen light source, which has a higher intensity output than the normal tungsten lamp in the change over a region of 320–380 nm used in colorimetry and spectrophotometry. It also has a larger life and does not suffer from blackening of the bulb glass envelope.
8. Which of the following from the options is included in the system to facilitate playback and study of EMG sound waveforms at a later convenient time?
a) Tape Recorder
b) Preamplifier
c) Oscilloscope
d) Ground Electrode
Answer: a
Explanation: The waveform can also be photographed from the CRT screen by using a synchronized camera. The tape recorder is included in the system to facilitate playback and study of the EMG sound waveforms at a later convenient time.
9. ____________ is necessary for providing a common reference for measurement?
a) active electrode
b) ground electrode
c) tape recorder
d) oscilloscope
Answer: b
Explanation: A ground electrode is necessary for providing a common reference for measurement. The signal can then be amplified and displayed on the screen of a cathode ray tube. It is also applied to an audio amplifier connected to a loudspeaker. These electrodes pick up the potentials produced by the contracting muscle fibres.
10. Which among the following are optical systems, which provide better isolation of spectral energy than the pptical filters.
a) Spectromators
b) Monochromators
c) Baromators
d) Tocochromators
Answer: b
Explanation: Monochromators are optical systems, which provide better isolation of spectral energy than the optical filters, and are therefore preferred where it is required to isolate narrow bands of radiant energy. Monochromators usually incorporate a small glass of quartz prism or a diffraction grating system as the dispersing media.
11. _______________ is not an arrhythmic condition.
a) Cardiographic beat
b) Bradycardia
c) Ectopic beat
d) Dropped beat
Answer: a
Explanation: These are bradycardia, tachycardia, dropped beat and premature beat. The analyzer part in automatic scanning of ambulatory records looks for four arrhythmic conditions. A threshold control is associated with each of these and when the appropriate threshold is exceeded, an alarm condition is generated.
12. CMRR of preamplifier upto 5 Khz should be _____________
a) 10 dB
b) greater than 90 dB
c) less than 90 dB
d) 30 dB
Answer: b
Explanation: The common-mode rejection should be greater than 90 dB up to 5 kHz. The main amplifier has controls for gain adjustment from 5 mV/div to 10 mV/div for selecting the sensitivity most appropriate to the incoming signal from the patient. A calibrating square wave signal of 100 mV at a frequency of 100 Hz is usually available.
13. Holter Cardiography is ambulatory monitoring of ECG signal.
a) True
b) False
Answer: a
Explanation: Modern EMG machines are PC based available both in a console as well as laptop models as they provide full colour waveform display, automatic cursors for marking and making measurements and a keyboard for access to convenient and important test controls. Ambulatory monitoring of ECG is called ‘Holter Cardiography’, after Dr. Norman Holter who introduced this concept in 1962. A Holter monitor is a type of ambulatory electrocardiography device, a portable device for cardiac monitoring for at least 24 hours .
14. _____________ provides an excellent review of ambulatory cardiac event recorders.
a) Alfonso
b) Benz
c) Handelsman
d) Friesen
Answer: b
Explanation: An excellent review of ambulatory cardiac event recorders is provided by Benz in 1999. The major advantage of these devices compared with a traditional Holter monitor is that they are small, allow ECG monitoring for longer time periods, and can provide nearly real time data analysis when the patient transmits a recording in proximity to the symptomatic event.
15. ________ CPU has overall system control responsibility.
a) Control
b) Acquisition
c) Control and timing
d) Acquisition and display
Answer: c
Explanation: It also handles individuals functions such as keyboard and direct writer interface, tape deck control, timing data processing, and arrhythmia count totalizing via a high speed interrupt system. The control and timing CPU has an overall system control responsibility.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Multi-Patient Telemetry”.
1. _____________ instrument is used for recording the electrical activity of the brain.
a) ECG
b) PCG
c) EEG
d) EMG
Answer: c
Explanation: EEG, describing the general function of the brain activity, is the superimposed wave of neuron potentials operating in a non-synchronized manner in the physical sense. Electroencephalograph is an instrument for recording the electrical activity of the brain, by suitably placing surface electrodes on the scalp.
2. EEG electrodes are smaller in size than ECG electrodes.
a) True
b) False
Answer: a
Explanation: EEG electrodes are smaller in size than ECG electrodes. Several types of electrodes may be used to record EEG. These include: Peel and Stick electrodes, Silver plated cup electrodes and Needle electrodes.
3. Which of the following is the superimposed wave of neuron potentials operating in a non-synchronized manner in a physical sense?
a) EEG
b) ECG
c) VCG
d) PCG
Answer: a
Explanation: Electroencephalograph is an instrument for recording the electrical activity of the brain, by suitably placing surface electrodes on the scalp. EEG, describing the general function of the brain activity, is the superimposed wave of neuron potentials operating in a non-synchronized manner in the physical sense.
4. ______________ material is used to improve electrical contact in electrodes with the skin.
a) Silver Tungsten
b) Copper Tungsten
c) Electrode jelly
d) Silver Graphite
Answer: c
Explanation: If the electrodes are intended to be used under the skin of the scalp, needle electrodes are used. Electrode jelly or paste is used to improve the electrical contact. They offer the advantage of reducing movement artefacts.
5. Which among the following electrode gives high skin impedance as compared to ECG?
a) VCG
b) EEG
c) EMG
d) PCG
Answer: b
Explanation: EEG electrodes give high skin contact impedance as compared to ECG electrodes. Good electrode impedance should be generally below 5 kilohms. Impedance between a pair of electrodes must also be balanced or the difference between them should be less than 2 kilohms.
6. Which of the following component is generally designed to have a very high value of input impedance to take care of high electrode impedance?
a) Montages
b) Filters
c) Electrodes
d) Preamplifiers
Answer: c
Explanation: EEG preamplifiers are generally designed to have a very high value of input impedance to take care of high electrode impedance. Good electrode impedance should be generally below 5 kilohms. Impedance between a pair of electrodes must also be balanced or the difference between them should be less than 2 kilohms.
7. What is the recording called in which voltage difference between an active electrode on scalp with respect to reference electrode at ear lobe or any other part of the body is recorded?
a) Unipolar
b) Bipolar
c) Monopolar
d) Nonpolar
Answer: c
Explanation: This type of recording is called ‘monopolar’ recording. EEG may be recorded by picking up the voltage difference between an active electrode on the scalp with respect to a reference electrode on the ear lobe or any other part of the body.
8. Which of the following is employed for a bipolar recording done?
a) Uni Channel EEG
b) Omni channel EEG
c) Non Channel EEG
d) Multi channel EEG
Answer: d
Explanation: Such recordings are done with multi-channel electroencephalographs. ‘bipolar’ recording is more popular wherein the voltage difference between two scalp electrodes is recorded.
9. EEG signals picked up by surface electrodes are usually larger as compared to ECG.
a) True
b) False
Answer: b
Explanation: They may be several hundred microvolts, but 50 microvolts peak-to-peak is the most typical. Yes, EEG signals picked up by the surface electrodes are usually small as compared with the ECG signals.
10. A pattern of electrodes on the head and the channels they are connected to is called a montage. Montages are always ___________
a) inverse
b) random
c) symmetrical
d) asymmetrical
Answer: c
Explanation: Montages are always symmetrical. A pattern of electrodes on the head and the channels they are connected to is called a montage. The reference electrode is generally placed on a nonactive site such as the forehead or earlobe.
11. Reference electrode for recording EEG is placed on __________
a) forehead
b) cervical
c) nasal
d) facial
Answer: a
Explanation: The reference electrode is generally placed on a nonactive site such as the forehead or earlobe. A pattern of electrodes on the head and the channels they are connected to is called a montage. Montages are always symmetrical.
12. The typical value of calibration signal is ________
a) 10 uV/cm
b) 70 uV/cm
c) 50 uV/cm
d) 30 uV/cm
Answer: c
Explanation: A typical value of the calibration signal is 50 uV/cm. A calibrating signal is used for controlling and documenting the sensitivity of the amplifier channels. This supplies a voltage step of adequate amplitude to the input of the channels.
13. Preamplifiers used in electroencephalograph have low gain and high noise characteristics for EEG.
a) True
b) False
Answer: b
Explanation: It is False. Preamplifier used in electroencephalographs must have high gain and low noise characteristics because the EEG potentials are small in amplitude. In addition, the amplifier must have a very high common-mode rejection to minimize stray interference signals from power lines and other electrical equipments.
14. At what frequency is the notch filter in EEG machines sharply tuned to eliminate mains frequency interference?
a) 60
b) 90
c) 10
d) 70
Answer: a
Explanation: EEG machines have a notch filter sharply tuned at 60 Hz so as to eliminate mains frequency interference. The use of notch filters should preferably be restricted to exceptional circumstances when all other methods of eliminating interference have been found to be ineffective. These however have the undesirable property of ‘ringing’ i.e. they produce a damped oscillatory response to a square wave calibration waveform or a muscle potential.
15. ______________ is typical frequency range of standard EEG machines.
a) 70 to 140 Hz
b) 0.1 to 70 Hz
c) 0.05 to 0.1 Hz
d) 0.025 to 0.05 Hz
Answer: b
Explanation: The typical frequency range of standard EEG machines is from 0.1 Hz to 70 Hz, though newer machines allow the detection and filtering of frequencies up to several hundred Hertz. This may be of importance in some intracranial recordings.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Implantable Telemetry Systems”.
1. ______________ is not a piezo-electric material.
a) quartz
b) rochelle salt
c) aluminium
d) barium titanate
Answer: a
Explanation: Quartz is the most stable natural crystal with high mechanical and thermal stability and has volume resistivity higher than 10^4 ohm-cm and small internal electric loss. Barium titanate ceramic is a ferroelectric crystal and has small voltage output. Aluminium is not a piezo-electric material.
2. Which of the following is the correction option in relation to piezo-electricity?
a) sound electricity
b) pressure electricity
c) temperature electricity
d) photo electricity
Answer: b
Explanation: Piezo-electricity is pressure electricity. The piezo electric effect is a property of natural crystalline substance to develop electric potential along a crystallographic axis in response to the movement of charge as a result of mechanical deformation.
3. Mechanical deformation occurs in the piezo-electric material on applying electricity.
a) True
b) False
Answer: a
Explanation: It is True. The piezo electric effect is a property of a natural crystalline substance to develop electric potential along a crystallographic axis in response to the movement of charge as a result of mechanical deformation. On applying electricity to the piezo-electric material mechanical deformation occurs in the material.
4. ________________ material employed for making diaphragm to measure pressure.
a) zirconate titanate
b) barium titanate
c) tourmaline
d) phosphor bronze
Answer: d
Explanation: The motion of the diaphragm is measured in terms of electric signals. Tourmaline, barium titanate and zirconate titanate are piezo electric materials. Phosphor bronze is used to make diaphragm to measure pressure.
5. Which of the following is the principle behind strain gauge?
a) variable contact area
b) variable inductance
c) variable capacitance
d) variable resistance
Answer: d
Explanation: The principle behind strain gaude is the variable resistance. A linear relation exists between the deformation and electrical resistance of a suitable selected gauge over a specified range. The transducer is based upon the changed in resistance of a wire produced due to small mechanical displacement.
6. Electricity is generated by a piezo-electric crystal on applying pressure to it.
a) True
b) False
Answer: a
Explanation: It is True. On applying pressure to piezo-electric crystal, electricity is generated. The piezo electric effect is a property of a natural crystalline substance to develop electric potential along a crystallographic axis in response to the movement of charge as a result of mechanical deformation. Thus, piezo-electricity is pressure electricity.
7. ________________ is used to describe the figure of merit which determines the overall behaviour of the wire under stress.
a) gauge resistance
b) elastic factor
c) gauge factor
d) elastic modulus
Answer: c
Explanation: Gauge factor gives information on the expected resistance change or output signal at maximum permissible elongation. The gauge factor determines to a large extent the sensitivity of the wire when it is made into a practical strain gauge. The figure of merit which describes the overall behaviour of the wire under stress is determined from the gauge factor of the wire.
8. Which of the following is the correct definition for Gauge factor?
a) *
b) *
c) *
d) *
Answer: d
Explanation: Gauge factor is defined as *. Gauge factor gives information on the expected resistance change or output signal at maximum permissible elongation. The gauge factor determines to a large extent the sensitivity of the wire when it is made into a practical strain gauge.
9. Which lead method is employed to compensate for temperature variation in the leads?
a) three
b) eight
c) six
d) two
Answer: c
Explanation: The third lead is in series with the power supply and is therefore independent of bridge balance. Compensation for temperature variation in the leads can be provided by using three lead methods. In this method, two of the leads are in the adjacent legs of the bridge which cancels their resistance changes and does not disturb the bridge balance.
10. Which of the following parameter is measured by strain gauge?
a) temperature
b) displacement
c) height
d) pressure
Answer: d
Explanation: Strain gauge is used to measure pressure. There are two types of strain gauges. Bounded strain gauge and unbounded strain gauge. Its working principle is a change in resistance. Mostly used to measure the arterial and venous blood pressure in the body.
This set of Biomedical Instrumentation Problems focuses on “Biotelemetry Application on Wimax Networks”.
1. ________________ records the electrical activity of heart.
a) ECG
b) PCG
c) VCG
d) EEG
Answer: a
Explanation: Electrical signals from the heart characteristically precede the normal mechanical function and monitoring of these signals has great clinical significance.The electrocardiograph is an instrument, which records the electrical activity of the heart.
2. Which of the following material used in limb surface electrode?
a) german silver
b) platinum
c) gold
d) copper
Answer: a
Explanation: The most common type of electrode most routinely used for recording ECG are rectangular or circular surface limb electrodes. They are applied to the surface of the body with electrode jelly. The material used in them are German silver, nickel silver or nickel plated steel.
3. Which of the following reason is responsible for the Welsh cup electrodes to record the electrical signal of the heart?
a) low contact impedance
b) zero contact impedance
c) high contact impedance
d) negligible contact impedance
Answer: c
Explanation: It has a high contact impedance as only the rim of the electrode is in contact with the skin. Welsh cup electrodes or suction electrodes is a metallic cup shaped electrode which is used for recording ECG from various positions from the chest. It is commonly used to record the unipolar chest leads.
4. Among the following, which has CMRR is of an order of 100-120 dB?
a) VCG
b) ECG
c) PCG
d) EEG
Answer: b
Explanation: CMRR of the order of 100–120 dB with 5 kW unbalance in the leads is a desirable feature of ECG machines. In addition to this, under specially adverse circumstances, it becomes necessary to include a notch filter tuned to 50 Hz to reject hum due to power mains.
5. In floating electrodes metal electrode make direct contact with the skin.
a) True
b) False
Answer: b
Explanation: The electrode consists of a light weighted metalled screen or plate held away from the subject by a flat washer which is connected to the skin. In floating electrode the metal electrode does not make direct contact with the skin. Floating electrodes can be recharged, i.e. the jelly in the electrodes can be replenished if desired.
6. __________ is considered to be the primary pacemaker of the heart.
a) bundle of his
b) sino-atrial node
c) purkinje fibres
d) atrio-ventricular node
Answer: b
Explanation: Located in the top right atrium near the entry of the vena cava, are a group of cells known as the sion-atrial node that initiates the heart activity. Because of this is also considered as the primary pacemaker of the heart. The SA node is 25 to 30 mm in length and 2 to 5 mm in thickness.
7. Which is the correct location of Atrio ventricular node?
a) upper part of the heart wall between the two atrial
b) lower part of the heart wall above the two atrial
c) upper part of the heart wall above the two atrial
d) lower part of the heart wall between the two atrial
Answer: d
Explanation: The AV node delays the spread of excitation for about 0.12s, due to the presence of a fibrous barrier of non-excitable cells that effectively prevent its propagation from continuing beyond the limits of stria. The AV node is located in the lower part of the wall between the two atria.
8. Which of the following option is correct regarding the Buffer Amplifier?
a) low impedance signals to high impedance signals
b) high impedance signals to low impedance signals
c) ac impedance signals to dc impedance signals
d) dc impedance signals to ac impedance signals
Answer: b
Explanation: A buffer amplifies is essentially an impedance converter, that converts high impedance signals to low impedance signals. Noise is typically generated from motion artefacts and power line interference. A common solution used to suppress noise in dry electrode signals is a buffer amplifier.
9. Preamplifier is used ________
a) For Amplification
b) For Stabilizing effect
c) For Modifying effects
d) For Reducing effect
Answer: b
Explanation: The preamplifier is usually a three or four stage differential amplifier having a sufficiently large negative current feedback, from the end stage to the first stage, which gives a stabilizing effect.
10. ______________ is a wireless ECG acquiring system.
a) limb electrodes
b) smart pad
c) pasteless electrodes
d) pregelled disposable electrodes
Answer: b
Explanation: The system automatically selects three electrodes from an array of Cu/Ni fabric based electrodes patterned on a thin pad on which the patient lies. The smart pad is a system that displays a patients electrocardiogram signals without adhesive pads, wires or active intervention from a clinician. The selected electrodes are used to provide a differential 3 lead measurement of the patient’s ECG, which is then transmitted wirelessly and displayed on a laptop computer.
11. What is made horizontally on electrocardiogram?
a) time measurements and heart rate measurements
b) only heart Rate Measurements
c) only time Measurements
d) not fixed and can be any thing
Answer: a
Explanation: Time measurements and heart rate measurements are made horizontally on the electrocardiogram. Electrocardiograms are almost invariably recorded on graph paper with horizontal and vertical lines at 1 mm intervals with a thicker line at 5 mm intervals.
12. _____________ is paper recording speed for routine work.
a) 10 mm/s
b) 20 mm/s
c) 25 mm/s
d) 15 mm/s
Answer: b
Explanation: Time measurements and heart rate measurements are made horizontally on the electrocardiogram. Electrocardiograms are almost invariably recorded on graph paper with horizontal and vertical lines at 1 mm intervals with a thicker line at 5 mm intervals.
13._______________ is measured on the vertical axis of electrocardiogram.
a) Time Measurements and Heart Rate Measurements
b) Amplitude Measurements
c) Time Measurements
d) Heart Rate Measurements
Answer: c
Explanation: Time measurements and heart rate measurements are made horizontally on the electrocardiogram. Electrocardiograms are almost invariably recorded on graph paper with horizontal and vertical lines at 1 mm intervals with a thicker line at 5 mm intervals. Amplitude measurements are made vertically in millivolts. The sensitivity of an electrocardiograph is typically set at 10 mm/mV.
14. Which of the following option is correct regarding the sensitivity of an electrocardiograph?
a) 10 mm/mV
b) 15 mm/mV
c) 20 mm/mV
d) 25 mm/mV
Answer: a
Explanation: Time measurements and heart rate measurements are made horizontally on the electrocardiogram. Electrocardiograms are almost invariably recorded on graph paper with horizontal and vertical lines at 1 mm intervals with a thicker line at 5 mm intervals. Amplitude measurements are made vertically in millivolts. The sensitivity of an electrocardiograph is typically set at 10 mm/mV.
This set of Biomedical Instrumentation online quiz focuses on “Transmission of Analog Physiological Signals Over Telephone”.
1. What is the principle behind Doppler velocimetry working?
a) amplitude measurement of fiber optic sensor
b) frequency measurement of fiber optic sensor
c) time shift measurement of fiber optic sensor
d) phase measurement of fiber optic sensor
Answer: b
Explanation: Doppler velocimetry works on the principle of frequency measurement of fiber optic sensor. The moving red blood cells scatter the light and produce a Doppler frequency shift because of their movement. In this method, light from a laser, normally helium/neon, is sent via a fibre onto the skin surface.
2. Which of the following is the principle behind Fluoroptic temperature sensors working?
a) optical fiber
b) thermistor
c) thermocouple
d) rtd
Answer: a
Explanation: They contain a rare earth phosphor which is illuminated by a white light along a short length of large core optical fibre. Fluoroptic temperature sensors work on the principle of optical fiber sensors. The light excites the phosphor which emits a number of lines. By using filters, two of these lines at 540 and 630 nm are selected, and the ratio of their intensities is a single valued function of the temperature of the phosphor.
3. Monopolar needle electrode has a coating of______________ material over the stainless steel wires which are bare only at the tips.
a) carbon
b) calcium
c) teflon
d) sodium
Answer: c
Explanation: The wire is bare only at the tip. The monopolar needle electrode consists of a teflon coated stainless steel wire. It is found that after the needle has been used a number of times, the teflon coating will recede, increasing the tip area. The needle should be discarded when this happens.
4. Which of the following sensor is used for Endoscopic imaging?
a) thermal sensors
b) optic fiber sensors
c) chemical sensors
d) pressure sensors
Answer: b
Explanation: Optical fibre sensors are non-electrical and hence are free from electrical interference usually associated with electronically based sensors. Optic sensors are used for endoscopic imaging. They are suitable for telemetry applications as the bulk of the instrumentation can be at a reasonable distance from the patient.
5. Which of the following component converts biochemical events into measurable signals?
a) amplifier
b) opamp
c) rectifier
d) transducer
Answer: d
Explanation: Transducers convert biochemical events into measurable signals. They provide the means for detecting the biochemical changes inside the body. Particularly biosensors are employed for this purpose.
6. Which of the following is used to determine the biological response of the biosensor?
a) artificial membrane
b) chemical membrane
c) physio-chemical membrane
d) biocatalytic membrane
Answer: d
Explanation: The biocatalytic membrane accomplishes the conversion of reactant to product. The product of the reaction diffuses to the transducer. The biological response of the biosensor is determined by biocatalytic membrane. This then causes the electrical response.
7. What is the working principle behind Home blood glucose sensor?
a) electro-physiological
b) electrochemical
c) chemical
d) physio-chemical
Answer: b
Explanation: Home blood glucose detection sensor works on the principle of electrochemical. The biosensor in this instrument relies upon enzymes that recognize and catalyze reactions of glucose with the generation of redox – active species that are detected electrochemically.
8. ____________ is a wireless ECG acquiring system.
a) pregelled disposable electrodes
b) smart pad
c) pasteless electrodes
d) limb electrodes
Answer: b
Explanation: Smart pad is a system that displays patients electrocardiogram signals without adhesive pads, wires or active intervention from a clinician. The selected electrodes are used to provide a differential 3 lead measurement of the patient’s ECG, which is then transmitted wirelessly and displayed on a laptop computer. The system automatically selects three electrodes from an array of Cu/Ni fabric based electrodes patterned on a thin pad on which the patient lies.
9. Home blood glucose measurement devices measure the glucose level through an invasive method.
a) True
b) False
Answer: a
Explanation: There is a small needle at the tip of the machine that pierces the skin to take a blood sample. Home blood glucose measurement devices measure the glucose level through invasive method. This blood is then undergoes electrochemical reactions and the glucose level is determined.
10. Blood glucose level measurement device uses a biosensor works on the principle of _____________
a) electromechanical
b) electrochemical
c) electrothermal
d) electroresistive
Answer: b
Explanation: The biosensor in this instrument relies upon enzymes that recognise and catalyze reactions of glucose with the generation of redox – active species that are detected electrochemically. Home blood glucose detection sensor works on the principle of electrochemical.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Essential Parameters for Telemedicine”.
1. Which of the following option is the correct full form of CRO?
a) Common Ray Oscilloscope
b) Common Ray Oscillator
c) Cathode Ray Oscillator
d) Cathode Ray Oscilloscope
Answer: d
Explanation: Cathode ray oscilloscopes are widely used for the display of waveforms encountered in the medical field. These waveforms can be recorded from the CRO screen by running a photographic film through a recording camera fixed in front of the screen. Recorders are either of the single channel type or of the type which record several channels simultaneously.
2. __________has the widest range of temperature measurement.
a) RTD
b) Mercury thermometer
c) Thermocouple
d) Thermistor
Answer: c
Explanation: Thermocouple has the widest range of temperature measurement from -184*C to +2300*C. RTD has a range of -200*C to +850*C. Thermistor has a range of 0*C to 100*C whereas conventional mercury thermometers range is -37*C to +356*C.
3. The junction at a lower temperature in thermocouple is termed as measuring junction.
a) True
b) False
Answer: b
Explanation: The junction at a higher temperature in thermocouple is termed as measuring junction. The junction at a lower temperature in the thermocouple is called the reference temperature. The cold junction is usually kept at 0*C.
4. Select the correct option from below for the particular description of arrangement. When two wires of different material are joined together at either end, forming two junctions which are maintained at different temperature, a thermo-motive force is generated causing a current to flow around the circuit.
a) thermocouple
b) thermalpair
c) thermistor
d) thermostat
Answer: a
Explanation: The junction at a higher temperature in thermocouple is termed as measuring junction. This arrangement is called thermocouple. The junction at a lower temperature in the thermocouple is called the reference temperature.
5. What force is generated when two wires of different material are joined together at either end, forming two junctions which are maintained at a different temperature?
a) chemical reactive
b) electro-motive
c) thermo-motive
d) mechanical
Answer: c
Explanation: When two wires of different material are joined together at either ends, forming two junctions which are maintained at a different temperature, a thermo-motive force is generated causing a current to flow around the circuit. This arrangement is called a thermocouple. The junction at a lower temperature in the thermocouple is called the reference temperature. The junction at a higher temperature in thermocouple is termed as measuring junction.
6. The junction at a higher temperature in the thermocouple called is measuring junction.
a) True
b) False
Answer: a
Explanation: The junction at a lower temperature in the thermocouple is called the reference temperature. The cold junction is usually kept at 0*C. The junction at a higher temperature in thermocouple is termed as measuring junction.
7. What is the temperature at which the lower junction in thermocouple is maintained?
a) 0 K
b) 273 K
c) -327 K
d) -273 K
Answer: b
Explanation: The lower temperature junction in thermocouple is maintained at 273 K . The junction at lower temperature in the thermocouple is called the reference temperature. The junction at a higher temperature in thermocouple is termed as measuring junction.
8. Which is the correct formula for the resistance Rt of a metallic conductor at any temperature t?
a) Rt = Roɑ
b) Rt = Roɑ
c) Rt = Roɑ
d) Rt = Roɑ
Answer: c
Explanation: The resistance Rt of a metallic conductor at any temperature t is given by Rt = Roɑ. Ro is the resistance at 0*C. ɑ is a temperature coefficient of resistivity.
9. The full form of RTD is _________________
a) resistive thermal detector
b) resistance temperature detector
c) resistance temperature device
d) reluctance thermal device
Answer: b
Explanation: It is a passive sensor and requires current excitation to produce an output voltage. RTD has very low temperature coefficient.RTD stands for Resistance Temperature Device. Voltage drop across RTD is much larger than the thermocouple output voltage.
10. Which of the following quantity is measured by Thermister?
a) pressure
b) displacement
c) temperature
d) height
Answer: c
Explanation: Thermistors are the oxides of certain metals like manganese, cobalt and nickel which have large negative temperature coefficient, i.e. resistance decreases with increase in temperature. A thermistor is used to measure temperature. It is a temperature transducer. With a change in temperature its resistance changes. Thus its working principle is variable resistance.
This set of Biomedical Instrumentation Assessment Questions and Answers focuses on “Delivery Models in Telemedicine”.
1. ___________ is the interruption or interference with normal physiological and developmental processes or structures.
a) Pathophysiology
b) Societal Limitation
c) Functional Limitation
d) Modality-Specific
Answer: a
Explanation: Modality-Specific is a task that is specific to a single sense or movement pattern. Interruption or interference with normal physiological and developmental processes or structures is called Pathophysiology. A functional limitation is a restriction or lack of ability to perform an action in the manner or within the range consistent with the purpose of an organ or organ system.
2. A task that is specific to a single sense or movement pattern is called _________ in a rehabilitation engineering perspective.
a) Functional Limitation
b) Modality-Specific
c) Societal Limitation
d) Pathophysiology
Answer: b
Explanation: Interruption or interference with normal physiological and developmental processes or structures is called Pathophysiology. A task that is specific to a single sense or movement pattern is called Modality- Specific. A functional limitation is a restriction or lack of ability to perform an action in the manner or within the range consistent with the purpose of an organ or organ system.
3. _______________ is not a passive transducer.
a) Doppler effect transducer
b) IR sensor
c) Strain gauge
d) Ultrasonic transducer
Answer: c
Explanation: Strain gauge transducer is an active transducer. Its working principle is based on change in resistance. Ultrasonic transducers need power to operate. So do the IR sensors and doppler effect transducers.
4. _________ is called the Aesthetics of appearance.
a) lymphosis
b) cosmesis
c) orthosis
d) homeostasis
Answer: b
Explanation: Orthosis is a modality-specific appliance that aids the performance of a function or movement by augmenting or assisting the residual capabilities of that function or movement. Aesthetics of appearance is called cosmesis.
5. Which of the following filter is used to amplify frequency above a certain value?
a) band stop filter
b) low pass filter
c) band pass filter
d) high pass filter
Answer: d
Explanation: Low pass filter amplifies signals below a certain frequency. High pass filter amplifies signal above a certain frequency. Band pass filter amplifies frequencies within a certain band. Band stop filter amplifies all the frequencies except those in a certain band.
6. From the options given below, select the one that best describes: Transcutaneous.
a) passing to the heart
b) passing to the bones
c) passing to the skin
d) passing to the lungs
Answer: c
Explanation: This term generally used with the type of surgical instrument to be used. It is also used to describe the interaction of rehabilitation devices. Transcutaneous means passing to the skin.
7. _____________ is not a soft tissue.
a) ligament
b) bone
c) tendons
d) skin
Answer: b
Explanation: Biological soft tissues are nonlinear, anisotropic, fibrous composites, and a detailed description of their behavior is the subject of active research. Hard tissue, mineralized tissue, and calcified tissue are often used as synonyms for bone when describing the structure and properties of bone or tooth. One can separate these tissues based on their mode of loading: cartilage is generally loaded in compression; tendons and ligaments are loaded in tension, and muscles generate active tension.
8. Which is the correct characteristic of Blood vessels?
a) Soft tissue
b) Connective and soft tissue
c) Connective and hard tissue
d) Hard tissue
Answer: d
Explanation: Hard tissue is correct which says blood is soft and connective tissue. Soft tissues include tendon, ligament, blood vessels etc. Hard tissues include bones.
9. Muscles are the reservoir for calcium and phosphorus, essential minerals for various cellular activities which happen throughout the human body.
a) True
b) False
Answer: b
Explanation: It is False. Muscles are not the reservoir for calcium and phosphorus, essential minerals for various cellular activities which happen throughout the human body. Bones serve as a reservoir for calcium and phosphorus, essential minerals for various cellular activities that occur throughout the body. The composition of bone depends on a large number of factors: the species, which bone, the location from which the sample is taken, and the age, sex, and type of bone tissue, for example, woven, cancellous, cortical.
10. Bones are living tissues.
a) True
b) False
Answer: a
Explanation: It is True. Bones are living tissues. hey also are responsible for the production of blood cells and act a mineral reservoir in the body. They keep growing. They also play the role of protection of internal soft organs like the brain is protected by skull and lungs and heart by the rib cage.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Telemedicine System”.
1. _______________ will reject any common mode signal that appears simultaneously at both amplifier input terminal.
a) ac coupled amplifiers
b) dc amplifiers
c) carrier amplifiers
d) differential amplifiers
Answer: d
Explanation: Most of the amplifiers used for measuring bioelectric signals are of the differential type. A differential amplifier is one which will reject any common mode signal that appears simultaneously at both amplifier input terminals and amplifies only the voltage difference that appears across its input terminals. AC amplifiers have a limited frequency response and are, therefore, used only for special medical applications such as electrocardiograph machine.
2. The amplifier from the following that has a limited frequency response is _________
a) dc amplifiers
b) differential amplifier
c) ac coupled amplifiers
d) carrier amplifiers
Answer: a
Explanation: AC amplifiers have a limited frequency response and are, therefore, used only for special medical applications such as electrocardiograph machine. For electrocardiograms, an ac amplifier with sensitivity, giving 0.5 mV/cm, and frequency response up to 1 kHz and an input impedance of 2 to 5 MW is used. For such applications as retinography, EEG and EMG, more sensitive ac amplifiers are required, giving a chart sensitivity of say 50 mV/cm with a high input impedance of over 10 MW.
3. Which of the following amplifiers are used with transducers which require an external source of excitation?
a) ac coupled amplifiers
b) dc amplifiers
c) carrier amplifiers
d) differential amplifier
Answer: c
Explanation: Carrier amplifiers are used with transducers which require an external source of excitation. They essentially contain a carrier oscillator, a bridge balance and calibration circuit, a high gain ac amplifier, a phase-sensitive detector and a dc output amplifier. They are characterized by high gain, negligible drift, extremely low noise and the ability to operate with resistive, inductive or capacitive type transducers.
4. Which feedback system is employed in DC amplifiers?
a) Can be any positive or negative doesn’t matter
b) Negative
c) Depends on the application
d) Positive
Answer: b
Explanation: DC amplifiers are generally of the negative feedback type. They are not practical for very low level applications because of dc drift and poor common-mode rejection capabilities. They are used for medium gain applications down to about 1 mV signal levels for full scale.
5. Digital filters are not sensitive to temperature as compared with analog filters.
a) True
b) False
Answer: a
Explanation: It is True. Digital filters are insensitive to temperature as compared with analog filters. They are also insensitive to ageing, voltage drift and external interference as compared to analog filters. Their response is completely reproducible and predictable, and software simulations can exactly reflect product performance.
6. The number of amplifiers incorporated in the module of a Chopper stabilized dc amplifiers are ___________
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: Chopper stabilized dc amplifiers are used for low level but preferably wideband applications such as oscilloscopes, tape recorders and light beam oscilloscope recorders. This includes an ac amplifier for signals above about 20 Hz, a dc chopper input amplifier for signals from about 20 Hz down to dc plus wideband feedback stabilized dc amplifier. These are complex amplifiers having three amplifiers incorporated in the module.
7. _____________ is employed with resistive transducers which require an external source of excitation.
a) differential amplifier
b) dc bridge amplifier
c) carrier amplifier
d) ac coupled amplifier
Answer: b
Explanation: Essentially, the amplifier comprises a stable dc excitation source, a bridge balance and calibration unit, a high gain differential dc amplifier and a dc output amplifier. DC bridge amplifiers are employed with resistive transducers which require an external source of excitation. They can be used as conventional dc high gain amplifiers and offer operating simplicity and high-frequency response.
8. Which of the following IC is a variable negative voltage regulator?
a) 7912
b) 7905
c) LM337
d) LM317
Answer: c
Explanation: LM337 is a variable negative voltage regulator IC. It is capable of drawing current up to 1.5A and voltage range from – ideally. LM317 is a variable positive voltage regulator IC. 7905 and 7912 are fixed voltage regulator IC that give output voltage as -5V and -12V respectively.
9. Chopper input dc amplifiers are preferred for high level inputs to instrumentation systems because of their high sensitivity, negligible drift and excellent common mode rejection capability.
a) True
b) False
Answer: b
Explanation: It is False. Chopper input dc amplifiers are preferred for low level inputs to instrumentation systems because of their high sensitivity, negligible drift and excellent common mode rejection capability. Their high frequency response is limited to about one half of the input chopper frequency.
10. The amplifier configuration must contain _____________ to achieve the low frequency response for medical applications?
a) higher resistance
b) lower resistance
c) lower capacitance
d) higher capacitance
Answer: d
Explanation: To achieve the low frequency response required for medical applications, the amplifier must have large values of coupling capacitance. The response should be down to less than one hertz which is a very frequent requirement. In all RC-coupled amplifiers, low frequency response is limited by the reluctance of the coupling capacitors.
This set of Biomedical Instrumentation Question Bank focuses on “Clinical Data Interchange/Exchange Standards”.
1. What is an arrhythmia monitor?
a) Patient monitoring system
b) Sophisticated alarm system
c) Sophisticated monitoring system
d) ECG interpretation system
Answer: b
Explanation: An arrhythmia monitor is basically a sophisticated alarm system. It is not an ECG interpretation system. It constantly scans ECG rhythm patterns and issues alarms to events that may be premonitory or life threatening.
2. Which task is performed after the Ventricular fibrillation detection in automated arrhythmia monitoring system?
a) Noise detection
b) Beat labeling
c) Atrial fibrillation detection
d) Rhythm definition
Answer: d
Explanation: In automated arrhythmia monitoring system, Rhythm definition is performed after the Ventricular fibrillation detection. Rhythm definition is also performed after the beat labeling and atrial fibrillation detection in automated arrhythmia monitoring and analysis system.
3. In arrhythmia monitoring system, it gives alarm light signals whenever the prematured or widened ectopic beats exist up to the rate of __________
a) 6/min to 10/min
b) 6/min to 12/min
c) 6/min or 10/min
d) 6/min or 12/min
Answer: d
Explanation: In the arrhythmia monitoring instrument, it gives alarm light signals whenever the prematured or widened ectopic beat exist up to the rate of 6/min or 12/min.It is one of the operating sequences of the arrhythmia monitoring instrument.
4. ECG signal is amplified and filtered with 0.05-100 Hz for diagnostic purposes and 1-40 Hz for monitoring purposes in signal conditioning.
a) True
b) False
Answer: a
Explanation: It is True. ECG signal is amplified and filtered with 0.05-100 Hz for diagnostic purposes and 1-40 Hz for monitoring purposes in signal conditioning.
5. _________ resolution analog-to-digital converter is used in digitization of ECG signal in signal conditioning.
a) 16 bit
b) 12 bit
c) 32 bit
d) 64 bit
Answer: b
Explanation: In signal conditioning, ECG signal is amplified, filtered and digitized using an 8- or 12- bit analog-to-digital converter with a typical sampling rate of 250 Hz.
6. A disturbance in the heart’s normal rhythmic contraction is called ____________
a) Heart stroke
b) Cardiac arrest
c) Arrhythmias
d) Premature contraction
Answer: c
Explanation: Any disturbance in the heart’s normal rhythmic contraction is called an arrhythmias or cardiac dysrhythmia. In this arrhythmias heart can’t beat in a regular rhythm. In arrhythmia heart-rate will be higher than normal rate or will be less than the normal rate.
7. The steep, large amplitude variation of the QRS complex is the obvious characteristics to use and this is the function of the Q wave detector.
a) True
b) False
Answer: b
Explanation: It is False. Arrhythmia monitors require reliable R wave detectors as a prerequisite for subsequent analysis. The steep, large amplitude variation of the QRS complex is the obvious characteristics to use and this is the function of the R wave detector.
8. Which of the following two elements are removed by the detection filter in the process of the ECG waveform?
a) Low frequency noise, motion noise
b) Muscle artifact, motion noise
c) Baseline wander, motion noise
d) Baseline wander, muscle artifact
Answer: a
Explanation: The detection filter removes low frequency noise and muscle artifact. The ECG waveform is processed by two digital filters: a detection filter and a classification filter. P waves and T waves are diminished.
9. The number of steps involved in the detection of QRS complex is ______
a) One step
b) Two steps
c) Three steps
d) Four steps
Answer: b
Explanation: The ECG is first preprocessed to enhance the QRS complex while suppressing noise, artifact and non-QRS portions of the ECG. QRS detection is now almost universally performed digitally in a two-step process. The output of the preprocessor stage is subjected to a decision rule that confirms detection of QRS if the processor output exceeds a threshold.
10. Which of the following is based on analyzing the shape of the QRS complexes and separating beats into groups or clusters?
a) Morphology characterization
b) Noise detection
c) Beat labeling
d) Timing classification
Answer: a
Explanation: Morphology characterization is based on analyzing the shape of the QRS complexes and separating beats into groups or clusters of similar morphology. Most algorithms for real time arrhythmia analysis maintain no more than 10-20 clusters at a time, order to limit the amount of computation needed to assign a QRS complex to a cluster.
11. What is the condition in which the R-R interval is declared premature?
a) If it is less than 75% of the predicted interval
b) If it is greater than 75% of the predicted interval
c) If it is less than 85% of the predicted interval
d) If it is greater than 85% of the predicted interval
Answer: c
Explanation: In timing classification, the observed R-R interval is compared to an estimate of the expected R-R interval. An R-R interval will be declared premature if it is less than 85% of the predicted interval. Similarly, an R-R interval is long if it is greater than 110% of the predicted value.
12. ___________ is the final stage in arrhythmia analysis.
a) Summary statistics
b) Alarms
c) Rhythm labeling
d) Beat labeling
Answer: c
Explanation: It is based on defined sequences of QRS complexes. Rhythm labeling is the final stage in arrhythmia analysis. The analysis systems are heavily oriented towards detecting ventricular arrhythmias, particularly single PVCs.
13. ______________ techniques are used in a new algorithm proposed by Jen and Hwang to obtain the long term ECG signal feature and extract the meaningful information hiding in the QRS complex.
a) Cepstrum time warping and Dynamic coefficient
b) Cepstrum coefficient and Dynamic time warping
c) QRS detection and Dynamic coefficient
d) QRS detection and Cepstrum time warping
Answer: b
Explanation: This algorithm may also be used for arrhythmia detection by simply checking the difference of R-R wave intervals through signal feature extraction comparison for a certain period of time. Jen and Hwang proposed a new algorithm using cepstrum coefficient and the dynamic time warping techniques to obtain the long term ECG signal feature and extract the meaningful information hiding in the QRS complex.
14. Which of the following is used to detect Ventricular Fibrillation?
a) Shape of the QRS complexes
b) Frequency domain analysis
c) Timing sequence of QRS complexes
d) Difference of the R-R interval
Answer: b
Explanation: Ventricular fibrillation is usually detected by frequency domain analysis. It can be distinguished from noise by appropriately designing band-pass filters. The system is characterized as a narrow-band, low frequency signal with energy concentrated in a band around 5-6 Hz.
15. ____________ is the sampling rate of analog-to-digital converter in digitizing of ECG signal in signal conditioning.
a) 200-215 Hz
b) 215 Hz
c) 40-100 Hz
d) 250 Hz
Answer: d
Explanation: In signal conditioning, ECG signal is amplified, filtered and digitized using an 8- or 12-bit analog-to-digital converter with a typical sampling rate of 250 Hz.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Transmission of Still Images”.
1. The minimum input of physical parameter that will create a detectable out change. This is the definition of which of the following parameter?
a) threshold
b) span
c) sensitivity
d) precision
Answer: c
Explanation: The sensitivity of the sensor is defined as the slope of the output characteristic curve. In simple words The minimum input of physical parameter that will create a detectable out change is called sensitivity. Total operating range of the transducer is called its span.
2. What is the total operating range of the transducer is called?
a) offset
b) threshold
c) span
d) drift
Answer: c
Explanation: The total operating range of the transducer is called the span of the transducer. Offset is the output that will exist when it should be zero. Drift is basically the change in a signal over a long period of time.
3. Hysteresis is changed in output with the same value of the input.
a) True
b) False
Answer: a
Explanation: Hysteresis is observed when the input/output characteristics for a transducer are different for increasing inputs than for decreasing outputs. Hysteresis is changed in output with the same value of input but with a different history of input variation. It results when some of the energy applied for increasing inputs is not recovered when the input decreases.
4. What is the region called in which the output does not change with an increase in input?
a) saturation
b) threshold
c) offset
d) input range
Answer: a
Explanation: The region in which the output does not change with an increase in input is called saturation. The threshold of the transducer is the smallest change in measurant that will result in a measurable change in the transducer output. Offset is the output that will exist when it should be zero.
5. Which of the following characteristic is defined for the material: Ability of the sensor to repeat a measurement when put back in the same environment.
a) saturation
b) conformance
c) threshold
d) repeatability
Answer: d
Explanation: Ability of the sensor to repeat a measurement when put back in the same environment is called repeatability. The threshold of the transducer is the smallest change in measurant that will result in a measurable change in the transducer output. The region in which the output does not change with an increase in input is called saturation.
6. ___________ is called the closeness of a calibration curve to a specified curve for an inherently non linear transducer.
a) saturation
b) linearity
c) conformance
d) hysteresis
Answer: c
Explanation: Hysteresis is changed in output with the same value of input but with a different history of input variation. Conformance indicates the closeness of a calibration curve to a specified curve for an inherently non linear transducer. The region in which the output does not change with an increase in input is called saturation.
7. The range between the max and min values is applied parameter which can be measured is called ____________
a) repeatability
b) span
c) output range
d) input range
Answer: b
Explanation: Ability of the sensor to repeat a measurement when put back in the same environment is called repeatability. Input range is the range between the max and min values is applied parameter which can be measured. The total operating range of the transducer is called span of the transducer.
8. ___________ is not a static property.
a) repeatability
b) frequency response
c) hysteresis
d) saturation
Answer: b
Explanation: Frequency response is the change of transfer function with frequency, both in magnitude and in phase. It is a dynamic property. The region in which the output does not change with an increase in the input is called saturation. Ability of the sensor to repeat a measurement when put back in the same environment is called repeatability.
9. Time for the sensor to reach a stable output once it is turned on. This is the definition of ________________
a) settling time
b) span
c) frequency response
d) response time
Answer: a
Explanation: Frequency response is the change of transfer function with frequency, both in magnitude and in phase. Settling time is the time for the sensor to reach a stable output once it is turned on. The total operating range of the transducer is called the span of the transducer.
10. _______________ is not a dynamic property.
a) frequency response
b) response time
c) settling time
d) saturation
Answer: d
Explanation: Settling time is the time for the sensor to reach a stable output once it is turned on. The region in which the output does not change with an increase in the input is called saturation. It is a static property of the transducer. Frequency response is the change of transfer function with frequency, both in magnitude and in phase.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Transmission of Video Images”.
1. Blood cell counters, operating on the principle of conductivity change, which occurs each time a cell passes through an orifice, are generally known as ________________
a) optical method
b) electrical conductivity
c) coulter Counter
d) microscopic method
Answer: c
Explanation: Blood cell counters, operating on the principle of conductivity change, which occurs each time a cell passes through an orifice, are generally known as Coulter Counters. The method was patented by Coulter in 1956 and it forms the basis of several particle counting instruments manufactured by a number of firms throughout the world.
2. Which electrode is placed inside the orifice tube, in coulter counter?
a) Metal electrode
b) Platinum electrode
c) Silicon electrode
d) Magnesium electrode
Answer: b
Explanation: In a coulter counter, a platinum electrode is placed inside the orifice tube and a second electrode is submerged into the beaker containing the cell dilution, creating an electrical circuit between the two electrodes.
3. Which of the following information is not provided by the Coulter Counter?
a) Relative cell size distribution
b) Settings of the threshold level control
c) Relative cell size
d) Mean cell volume
Answer: d
Explanation: The Coulter counters are usually provided with an oscilloscope monitor to display the pulse information, which has passed through the amplifier, and acts as a visible check on the counting process indicating instantaneously any malfunctions such as a blocked orifice. In particular, it provides information regarding relative cell size, relative cell size distribution, settings of the threshold level control, and means to check the performance of the instrument for the reliability of counts.
4. In Coulter counter, for such an aperture, a length of about ______ and flow rate of ______ ml/s would be optimum.
a) 100 u, 0.04
b) 200 u, 0.02
c) 100 u, 0.02
d) 200 u, 0.04
Answer: d
Explanation: Taylor suggests that an aperture diameter of 100 m would be generally useful. For such an aperture, a length of about 200 μ and flow rate of 0.04 ml/s would be optimum. The aperture can be made using ruby watch jewels bonded to a glass surface.
5. Typically, an aperture of 100 m diameter and 200 m length, separating two solutions of sulphate buffered saline, has a resistance of about 25 kW and capacitance of 120 pF.
a) True
b) False
Answer: b
Explanation: Typically, an aperture of 100 u diameter and 200 m length, separating two solutions of phosphate buffered saline, has a resistance of about 25 kW and capacitance of 120 pF.
6. The required bandwidth of the preamplifier used in cell counter must be?
a) 70 kHz
b) 120 kHz
c) 70 Hz
d) 120 Hz
Answer: a
Explanation: The electronic circuit must have upper frequency response greater than 70 kHz. The preamplifier used in cell counters must be of very low noise preferably having noise voltage less than 2 nA at the required bandwidth of 70 kHz.
7. Which following is not constant for the calibration factor in Coulter counter?
a) Electrolyte resistivity
b) Amplifier gain setting
c) Given aperture size
d) Setting of the threshold level control
Answer: d
Explanation: The calibration factor is constant for given aperture size, electrolyte resistivity and amplifier gain setting. It is used for the conversion of threshold settings to particle volumes or their cube roots to equivalent spherical diameters.
8. What is the diameter of Ragweed pollen?
a) 6 micron
b) 19 micron
c) 14 micron
d) 15 micron
Answer: b
Explanation: Ragweed pollen and polystyrene latex particles seem to meet these requirements. Of the two, polystyrene latex is preferred for calibration purposes . The particles when used seldom plug the orifice. These can be conveniently obtained in the range of 5 million particles per cubic mm.
9. Which of the following is not the provide by multi-parameter coulter counter?
a) Mean cell volume
b) Red cell count
c) Mean cell hemoglobin volume
d) White cell count
Answer: c
Explanation: It provides the universally accepted profile of white cell count, red cell count, mean cell volume, haemotocrit, mean cell haemoglobin concentration, mean cell haemoglobin and haemoglobin. Besides this, the following five parameters are presented: platelet count, red cell distribution width, mean platelet volume, plateletcrit, and platelet distribution width.
10. The diameter of the polystyrene latex particles are ______________________
a) 6 micron
b) 6-20 micron
c) 20 micron
d) 6-14 micron
Answer: d
Explanation: Ragweed pollen and polystyrene latex particles seem to meet these requirements. Of the two, polystyrene latex is preferred for calibration purposes . The particles when used seldom plug the orifice. These can be conveniently obtained in the range of 5 million particles per cubic mm.
11. In multi-parameter coulter counter, what is the time taken by 1 ml of blood to obtain all parameters?
a) 34 sec
b) 45 sec
c) 34-50 sec
d) 34-45 sec
Answer: c
Explanation: All the directly measured parameters are measured in triplicate and the average results are displayed. All the 14 parameters are obtained from 1 ml of whole blood in 34–50 s depending on the number of platelets present.
12. What occurs when two or more particles are present in the sensing zone at the same time?
a) Calibration
b) Troubleshooting
c) Delay in results
d) Coincidence error
Answer: d
Explanation: Coincidence error occurs when two or more particles are present in the sensing zone at the same time. This will result in the instrument detecting fewer particles that are actually present. This will also result in the instrument adding the pulses together to produce a single much longer pulse.
13. Model ____________ automatically compensates for the loss of pulses during coincidence error.
a) 4008 S Coulter counter
b) S plus Coulter counter
c) A plus Coulter counter
d) 4008 A Coulter counter
Answer: b
Explanation: As the instrument detects fewer pulses than are actually present, to render the total count accurate, it is necessary to add on the pulses that have been ‘lost’ due to coincidence. The rate at which this happens has been mathematically determined. Model S-plus Coulter counter automatically compensates for this loss.
14. Under a total count of _______ pulses, primary coincidence is negligible and can be ignored.
a) 5000
b) 1000
c) 8000
d) 10000
Answer: d
Explanation: With some instruments, a correction chart is available to allow the correct number to be determined. Under a total count of 10,000 pulses, primary coincidence is negligible and can be ignored.
15. Coulter counters have a serious drawback linked with the mercury manometer arrangement.
a) True
b) False
Answer: a
Explanation: Coulter counters have a serious drawback linked with the mercury manometer arrangement. The surface of the mercury gets dirty as a consequence of which the contact bordering the volume becomes uncertain, which may make the measured values uncertain.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Transmission of Digital Audio”.
1. The instrument picoscale primarily counting for?
a) MCH
b) MCV
c) PBC
d) PCT
Answer: c
Explanation: Based on the same principle of detecting a change in conductivity in the presence of a cell in the orifice of a measuring tube, there is another cell counting instrument known by the name Picoscale. This instrument does not make use of a mercury manometer for fixing the volume thus eliminating the problems associated with its use. This instrument is primarily meant for counting RBC, WBC and PBC and is manufactured by MEDICOR, Budapest.
2. In picoscale, the number of particles N in a unit volume is determined from the relation if H stands for a factor of dilution, L is scaling factor of the counter, V is measured volume and E is result display on the digital display.
a) N = HL/VE
b) N = H/LVE
c) N = HV/LE
d) N = HLV/E
Answer: d
Explanation: One great advantage of this instrument is that the clogging of the capillary is greatly eliminated by applying a bi-directional flow during the measurement procedure. The number of particles N in a unit volume is determined from the relation,
N = HLV/E
where
H = factor of dilution
I = scaling factor of the counter
V = measured volume
E = result displayed on the digital display.
3. For white cells, the diameter of capillaries are?
a) 58 micrometer
b) 72 micrometer
c) 116 micrometer
d) 102 micrometer
Answer: d
Explanation: The capillary diameter for red cell count is 72 um and the dilution factor is 63,000. For white cells, the diameter is 102 um, and the dilution factor is 630. For platelet count, the diameter of the capillary is 72 um and a dilution of 6300 is used.
4. What is the dilution factor of platelet count?
a) 63000
b) 630
c) 6300
d) 63
Answer: c
Explanation: The capillary diameter for red cell count is 72 um and the dilution factor is 63,000. For white cells, the diameter is 102 um, and the dilution factor is 630. For platelet count, the diameter of the capillary is 72 um and a dilution of 6300 is used.
5. Which of the following is not the error of the electronic counter?
a) Settling error
b) Coincidence error
c) Concentration error
d) Dilution errors
Answer: c
Explanation: There are a number of errors that may occur in the electronic cell counting technique. Briefly, these errors are categorized as follows:
Aperture Clogging, Uncertainty of Discriminator Threshold, Coincidence Error, Settling Error, Statistical Error, Error in Sample Volume, Error due to Temperature Variation, Biological Factors, Dilution Errors, Error due to External Disturbances.
6. In the settling error, if the readings are taken within 4–5 min., the settling error is?
a) Less than 1%
b) Less than 10%
c) More than 1%
d) Equals 1%
Answer: a
Explanation: Settling Error: This error arises due to the settling of the particles in the solution, with the result that the measurements show a decreasing tendency with time. If the readings are taken within 4–5 min., the settling error is less than 1%.
7. To obtain the statistical error, the instrument reading should be multiplied by the scaling factor of the counter.
a) True
b) False
Answer: a
Explanation: Assuming Gaussian distribution, the mean statistical error means that 67% of tests fall into the interval with 33% of the measurements greater than that. To obtain the statistical error, the instrument reading should be multiplied by the scaling factor of the counter. This will yield the value of n.
8. Miller describes a differential white blood cell classifier based upon a ______ approach.
a) A four-colour flying spot-scanner
b) A four-colour flying-scanner
c) A three-colour flying spot-scanner
d) A three-colour flying-scanner
Answer: c
Explanation: Miller describes a differential white blood cell classifier based upon a three-colour flying spot-scanner approach. It utilizes recognition parameters based on the principle of geometrical probability functions, which are generated at high speed in a dedicated computer.
9. The system is built around a Zeiss microscope with two______ eyepieces and a _____ oil immersion objective and with computer controlled focusing.
a) 40 x, 10 x
b) 10 x, 40 x
c) 15 x, 40 x
d) 15 x, 10 x
Answer: c
Explanation: The system uses a conventional microscope with automatic focus and stage motion. The system is built around a Zeiss microscope with two 15 x eyepieces and a 40 x oil immersion objective and with computer controlled focusing. A television monitor displays the data and shows the relative position of the cells in each field.
10. Which of the following is not determined by the cell identification system?
a) Lymphocytes
b) Basophils
c) Monocytes
d) Erythrocytes
Answer: d
Explanation: The system is capable of determining segmented neutrophils, bands, eosinophils, basophils, lymphocytes, and monocytes, as well as abnormal cells such as atypical lymphocytes, blasts, nucleated red cells, and immature granulocytes. In addition, the system carries out the red cell morphology, evaluating size, shape, and colour, counts the reticulocytes, estimates the platelet count and plots a distribution of red cell diameters.
11. There are two types of coils employed in the system, which are ______________
a) Tygon coils and mixing coils
b) Mixing coils and tubing coils
c) Delay coils and tygon coils
d) Mixing coils and delay coils
Answer: d
Explanation: Two types of coils are employed in the system—mixing coils and delay coils. Coils are glass spirals of critical dimensions, in which the mixing liquids are inverted several times, so that complete mixing can result. Mixing coils are used to mix the sample and/or reagents. Delay coils are employed when a specimen must be delayed for the completion of a chemical reaction before reaching the colorimeter.
12. What is used to check the wavelength calibration of a spectrometer?
a) Absorption filter
b) Helium oxide filter
c) Homium oxide filter
d) Helium dioxide filter
Answer: c
Explanation: Wavelength calibration of a spectrophotometer can be checked by using a holmium oxide filter as a wavelength standard. Holmium oxide glass has a number of sharp absorption bands, which occur at precisely known wavelengths in the visible and ultraviolet regions of the spectrum.
13. In diff-3 system, counts and differentiates _______ important categories of red blood cells.
a) Three
b) Seven
c) Four
d) Two
Answer: b
Explanation: The system electronically examines conventional microscope blood smear slides and employs optical pattern recognition techniques to achieve the following:
Counts and differentiates seven important categories of red blood cells ; three based on size, two on colour, one on shape and one covering red cells with nuclei .
14. The system is designed to analyze standard slides at a_______ slides per hour rate.
a) 30 to 35
b) 20 to 30
c) 40 to 50
d) 35 to 40
Answer: d
Explanation: The system is designed to analyze standard slides at a 35 to 40 slides per hour rate. The actual analysis task takes only 90 s. In fact, the system largely duplicates mechanically and opto-electronically, the manual procedures followed while examining blood smears with a microscope.
15. What enables the system to transfer cell pattern recognition information into differential results in an image processor?
a) A flying spot-scanner
b) A three-colour flying spot-scanner
c) Golay logic processor
d) Golay linear processor
Answer: c
Explanation: Image Processor: The system uses two computers. The second computer is a special purpose pattern recognition computer, the Golay Logic Processor , which enables the system to transform cell pattern recognition information into differential results. Golay logic enables the system to ‘see’ a cell in much the same way as a technologist does.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Cyber Medicine”.
1. In which type of electromagnetic flowmeter, the probe magnet is energized with sine wave?
a) Sine wave electromagnetic flowmeter
b) Square wave electromagnetic flowmeter
c) Sawtooth wave electromagnetic flowmeter
d) Impulse wave electromagnetic flowmeter
Answer: a
Explanation: In a sine wave flowmeter, the probe magnet is energized with a sine wave and consequently the induced voltage will also be sinusoidal in nature. The major problem encountered with the sinusoidal type of magnetic field is that the blood vessel and the fluid contained in it act as the secondary coil of a transformer when the probe magnet is excited.
2. In which type of electromagnetic blood flowmeter, the energizing voltage is given to magnet is a square wave?
a) Sine wave electromagnetic flowmeter
b) Square wave electromagnetic flowmeter
c) Sawtooth wave electromagnetic flowmeter
d) Impulse wave electromagnetic flowmeter
Answer: b
Explanation: This differs from a sine wave flowmeter in that the energizing voltage given to the magnet is a square wave and therefore, the induced voltage is also a square wave. The square wave flowmeter has less stringent requirements of phase stability than the sine wave type as it can suppress the quadrature voltages relatively easily.
3. The preamplifier used in square wave blood flowmeter has a CMRR of _______ dB.
a) 96
b) 100
c) 106
d) 110
Answer: c
Explanation: The preamplifier used by Goodman ) has a CMRR of 106 dB with a common mode input impedance of 150 MW. The preamplifier gain is of the order of 1000. The preamplifier also must incorporate the facility for ‘probe balance’ by which signals in phase with the magnet current can be selected to balance background voltages in phase with flow voltages.
4. What is the common mode input impedance of preamplifier used in square wave blood flowmeter?
a) 110 MW
b) 130 MW
c) 150 MW
d) 180 MW
Answer: c
Explanation: The preamplifier used by Goodman ) has a CMRR of 106 dB with a common mode input impedance of 150 MW. The preamplifier gain is of the order of 1000. The preamplifier also must incorporate the facility for ‘probe balance’ by which signals in phase with the magnet current can be selected to balance background voltages in phase with flow voltages. A calibrating signal of 30 mV amplitude can be connected to the preamplifier with an input selector switch.
5. A calibrating signal of _____ mV amplitude can be connected to preamplifier with an input selector switch.
a) 10
b) 20
c) 30
d) 40
Answer: c
Explanation: The preamplifier used by Goodman ) has a CMRR of 106 dB with a common mode input impedance of 150 MW. The preamplifier gain is of the order of 1000. The preamplifier also must incorporate the facility for ‘probe balance’ by which signals in phase with the magnet current can be selected to balance background voltages in phase with flow voltages. A calibrating signal of 30 mV amplitude can be connected to the preamplifier with an input selector switch.
6. What is used to recover the signal, which is analogue of the flow rate being measured?
a) Low-pass filter
b) Phase sensitive detector
c) Gating Circuit
d) Bandpass filter
Answer: b
Explanation: A phase sensitive detector is used to recover the signal, which is an analogue of the flow rate being measured. This type of demodulator not only offers maximum signal-to-noise ratio but also helps in the rejection of interfering voltages at frequencies well below the carrier frequency.
7. The major problem encountered with the sinusoidal type of magnetic field is that the blood vessel and the fluid contained in it act as the primary coil of a transformer when the probe magnet is excited.
a) True
b) False
Answer: b
Explanation: False, the major problem encountered with the sinusoidal type of magnetic field is that the blood vessel and the fluid contained in it act as the secondary coil of a transformer when the probe magnet is excited. As a result, in addition to the induced flow voltage, there is an induced artefact voltage generally referred to as ‘transformer voltage’.
8. _______ instruments are now available for the measurement of blood velocity, volume flow, flow direction, flow profile and to visualize the internal lumen of blood vessel.
a) Transit-time
b) Doppler-shift
c) Square wave
d) Sine wave
Answer: b
Explanation: For routine clinical measurements, the transcutaneous Doppler instrument has, by far, superseded the transit-time type. Therefore, most of the recent efforts have been concentrated on the development of Doppler-shift instruments, which are now available for the measurement of blood velocity, volume flow, flow direction, flow profile and to visualize the internal lumen of a blood vessel.
9. Which of the following is a non-invasive technique to measure blood velocity in a particular vessel from surface of the body?
a) Electromagnetic
b) Ultrasonic
c) NMR
d) Laser Doppler
Answer: b
Explanation: Ultrasonic is a non-invasive technique to measure blood velocity in a particular vessel from the surface of the body. It is based on the analysis of echo signals from the erythrocytes in the vascular structures. Because of the Doppler effect, the frequency of these echo signals changes relative to the frequency which the probe transmits.
10. Which of the following is a non invasive method for measurement of peripheral blood flow or blood flow in various organs?
a) Electromagnetic
b) Ultrasonic
c) NMR
d) Laser Doppler
Answer: c
Explanation: Nuclear magnetic resonance principle offers yet another non-invasive method for the measurement of peripheral blood flow or blood flow in various organs. The method pertains to a quantum mechanical phenomenon related to the magnetic energy levels of the nucleus of some elements and their isotopes.
11. The Angular frequency of precession is given by W=2pv=rBo,where Bo is _______
a) ratio of magnetic moment to angular momentum
b) density of steady magnetic field
c) frequency of radiation
d) length of coil
Answer: b
Explanation: The angular frequency of this precession is given by:
W = 2p v = r Bo
Where r is the ratio of the magnetic moment to the angular momentum and Bo is the density of the steady magnetic field and v is the frequency of radiation.
12. For blood flow measurement work, the behavior of the two hydrogen atoms of water is studied.
a) True
b) False
Answer: a
Explanation: True, for blood flow measurement work, behaviour of the two hydrogen atoms of water is studied, since blood is approximately 83% water. Due to the magnetic moment of the hydrogen atom, the nucleus behaves as a microminiature magnet which can be affected by externally applied magnetic fields.
13. The Angular frequency of precession is given by W=2pv=rBo, where r is ____________
a) ratio of magnetic moment to angular momentum
b) density of steady magnetic field
c) frequency of radiation
d) length of coil
Answer: a
Explanation: The angular frequency of this precession is given by:
W = 2p v = r Bo
Where r is the ratio of the magnetic moment to the angular momentum and Bo is the density of the steady magnetic field and v is the frequency of radiation.
14. The Angular frequency of precession is given by W=2pv=rBo, where v is _____________
a) ratio of magnetic moment to angular momentum
b) density of steady magnetic field
c) frequency of radiation
d) length of coil
Answer: c
Explanation: The angular frequency of this precession is given by:
W = 2p v = r Bo
Where r is the ratio of the magnetic moment to the angular momentum and Bo is the density of the steady magnetic field and v is the frequency of radiation.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Application of Telemedicine”.
1. Which of the following physiological parameter is most difficult to measure accurately?
a) Blood pressure
b) Blood Flow
c) Blood Volume
d) Skin color
Answer: b
Explanation: Blood flow is one of the most important physiological parameters and also one of the most difficult to measure accurately. This is because instruments for measuring the flow through blood vessels within the body have to meet certain stringent specifications; e.g. sensitivity and stability requirements depend upon the magnitude of flow, location and the diameter of the individual vessels.
2. Which of the following instrument is most commonly used for measurement of blood flow?
a) NMR Blood Flowmeter
b) Ultrasonic Blood Flowmeter
c) Electromagnetic Blood Flowmeter
d) Laser Doppler Blood Flowmeter
Answer: c
Explanation: The most commonly used instrument for the measurement of blood flow is of the electromagnetic type. With this type of instrument, blood flow can be measured in intact blood vessels without cannulation and under conditions which would otherwise be impossible. However, this method requires that the blood vessel be exposed so that the flow head or the measuring probe can be put across it.
3. Magnitude of voltage picked up is denoted as e = CHVd, where H is ___________
a) velocity of blood flow
b) strength of magnetic field
c) diameter of blood vessel
d) constant of proportionality
Answer: b
Explanation: The magnitude of the voltage picked up is directly proportional to the strength of the magnetic field, the diameter of the blood vessel and the velocity of blood flow, i.e. e = CHVd, where e = induced voltage, H = strength of the magnetic field, V = velocity of blood flow,d = diameter of the blood vessel and C = constant of proportionality.
4. Magnitude of voltage picked up is denoted as e = CHVd, where C is __________
a) velocity of blood flow
b) strength of magnetic field
c) diameter of blood vessel
d) constant of proportionality
Answer: c
Explanation: The magnitude of the voltage picked up is directly proportional to the strength of the magnetic field, the diameter of the blood vessel and the velocity of blood flow, i.e. e = CHVd, where e = induced voltage, H = strength of the magnetic field, V = velocity of blood flow, d = diameter of the blood vessel and C = constant of proportionality.
5. The induced emf is picked by point electrodes made from ______ in electromagnetic blood flowmeter.
a) copper
b) graphite
c) platinium
d) copper tungsten
Answer: c
Explanation: In actual practice, the electromagnetic flowmeter transducer is a tube of non-magnetic material to ensure that the magnetic flux does not bypass the flowing liquid and go into the walls of the tube. The tube is made of a conducting material and generally has an insulating lining to prevent short circuiting of the induced emf. The induced emf is picked up by point electrodes made from stainless steel or platinum.
6. What is the external diameter of flow heads?
a) 0.5 mm
b) 1 mm
c) 1.5 mm
d) 2 mm
Answer: b
Explanation: The flow head contains a slot through which the intact blood vessel can be inserted to make a snug fit. Several probes of different sizes must therefore accompany the flowmeter to match the full range of sizes of the blood vessels which have various diameters. It is naturally more difficult to construct flow heads suitable for use with very small blood vessels. However, flow heads having as small as 1 mm external diameter have been reported in the literature.
7. The operating principle underlying all electromagnetic type flowmeters is based upon Kirchoff’s law.
a) True
b) False
Answer: b
Explanation: False, The operating principle underlying all electromagnetic type flowmeters is based upon Faraday’s law of electromagnetic induction which states that when a conductor is moved at right angles through a magnetic field in a direction at right angles both to the magnetic field and its length, an emf is induced in the conductor. In the flowmeter, an electromagnetic assembly provides the magnetic field placed at right angles to the blood vessel in which the flow is to be measured.
8. The average flow velocity appears to be _______ cm/s in arteries.
a) 5 to 10
b) 10 to 12
c) 12 to 18
d) 20 to 25
Answer: d
Explanation: The flow-induced voltage of an electromagnetic flowmeter is, within certain limitations, proportional to the velocity of the flow. This velocity is the average across the flow stream with an axis symmetric velocity profile. The average flow velocity appears to be 20 to 25 cm/s in arteries and 10 to 12 cm/s in veins.
9. What is the average flow velocity in veins?
a) 5 to 10 cm/s
b) 10 to 12 cm/s
c) 12 to 18 cm/s
d) 20 to 25 cm/s
Answer: b
Explanation: The flow-induced voltage of an electromagnetic flowmeter is, within certain limitations, proportional to the velocity of the flow. This velocity is the average across the flow stream with an axis symmetric velocity profile. The average flow velocity appears to be 20 to 25 cm/s in arteries and 10 to 12 cm/s in veins.
10. What is velocity for the cardiovascular system taken for designing the probe?
a) 5 cm/s
b) 10 cm/s
c) 15 cm/s
d) 20 cm/s
Answer: c
Explanation: For designing the probe, velocity for the cardiovascular system is taken as 15 cm/s. For non-cannulated probes, a uniform magnetic field over the measuring area is so selected that it has a convenient shape and the smallest size .
11. Iron cored electromagnets are used in probes having a diameter between ______
a) 0.1 to 1 mm
b) 1 to 8.2 mm
c) 8.2 to 10 mm
d) 10 to 15 mm
Answer: b
Explanation: Iron cored electromagnets are used in probes having a diameter between 1 to 8.2 mm, and air cored electromagnets are used in diameters above 8.2 mm. Cannulated probes for extracorporeal use can have greater field strengths and magnet size as the constraint of small size is no longer present.
12. To protect probe from chemical attack, it must be encapsulated in silicon rubber.
a) True
b) False
Answer: a
Explanation: True, To protect the probe from chemical attack, it must be encapsulated in a biologically inert material having a high electrical and chemical resistance, e.g. silicone rubber. The probes can generally be sterilized by chemical means. Probe calibration is carried out in 0.9% saline during manufacture and each probe is given a calibration factor that is engraved on the connector.
13. The cable from the transducer to an instrument is sleeved with medical grade silicon rubber.
a) True
b) False
Answer: a
Explanation: True, the cable from the transducer to the instrument should comprise of a teflon insulated wire completely shielded with a tinned copper braid. The entire cable is sleeved with medical grade silicone rubber tubing and impregnated with silicone rubber to minimize leakage and electrical noise.
14. Air cored electromagnets are used in probes having a diameter _________
a) between 0.5 to 1 mm
b) between 1 to 2 mm
c) below 8.2 mm
d) above 8.2 mm
Answer: d
Explanation: Iron cored electromagnets are used in probes having a diameter between 1 to 8.2 mm, and air cored electromagnets are used in diameters above 8.2 mm. Cannulated probes for extracorporeal use can have greater field strengths and magnet size as the constraint of small size is no longer present.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “PACS ”.
1. Which of the following instrument is used to measure blood flow in the skin?
a) NMR Blood Flowmeter
b) Ultrasonic Blood Flowmeter
c) Electromagnetic Blood Flowmeter
d) Laser Doppler Blood Flowmeter
Answer: d
Explanation: A system utilizing the Doppler-shift of monochromatic laser light to measure blood flow in the skin is described by Watkins and Holloway . When a laser beam is directed towards the tissue under study, absorption and scattering take place. Radiation scattered in movable structures, such as red cells, is shifted in frequency due to the Doppler effect, while radiation scattered in nonmoving soft tissue is unshifted in frequency.
2. What is the effective radiation penetration depth in soft tissue?
a) 1 mm
b) 2 mm
c) 3 mm
d) 4 mm
Answer: a
Explanation: The effective radiation penetration depth is approximately 1 mm in soft tissue and scattering and absorption take place mostly in the papilla region and the underlying corium—two dermal layers containing the capillary network of the skin.
3. What is the power of laser light used in Laser Doppler Blood flowmeter?
a) 2 mW
b) 3 mW
c) 4 mW
d) 5 mW
Answer: d
Explanation: In principle, light from a low power He–Ne laser is coupled into a quartz fibre and transmitted to the skin. The light is reflected from both the non-moving tissues and moving red blood cells . The two beams are received by a plastic fibre and transmitted back to a photo-diode where optical heterodyning takes place.
4. Which laser is used in Laser doppler blood flowmeter?
a) Nd-YAG
b) Argon
c) He-Ne
d) CO 2
Answer: c
Explanation: In principle, light from a low power He–Ne laser is coupled into a quartz fibre and transmitted to the skin. The light is reflected from both the non-moving tissues and moving red blood cells . The two beams are received by a plastic fibre and transmitted back to a photo-diode where optical heterodyning takes place.
5. What is used to receive beams of light?
a) Plastic fibre
b) Photo diode
c) He-Ne Laser
d) CO 2 Laser
Answer: a
Explanation: In principle, light from a low power He–Ne laser is coupled into a quartz fibre and transmitted to the skin. The light is reflected from both the non-moving tissues and moving red blood cells . The two beams are received by a plastic fibre and transmitted back to a photo-diode where optical heterodyning takes place.
6. Where optical heterodyning takes place in Laser Doppler Blood Flowmeter?
a) Plastic fibre
b) Photo diode
c) He-Ne Laser
d) CO 2 Laser
Answer: b
Explanation: In principle, light from a low power He–Ne laser is coupled into a quartz fibre and transmitted to the skin. The light is reflected from both the non-moving tissues and moving red blood cells . The two beams are received by a plastic fibre and transmitted back to a photo-diode where optical heterodyning takes place.
7. The laser output is coupled into the fibre using a converging lens.
a) True
b) False
Answer: a
Explanation: True, The He–Ne laser operating at 632.8 nm wavelength is used. The laser output is coupled into the fibre using a converging lens, which results in an increased power density at the skin surface and thus enables the detection of flow in the more deeply seated veins and arteries.
8. What is the operating wavelength of He-Ne laser?
a) 610.8 nm
b) 622.6 nm
c) 632.8 nm
d) 650 nm
Answer: c
Explanation: The He–Ne laser operating at 632.8 nm wavelength is used. The laser output is coupled into the fibre using a converging lens, which results in an increased power density at the skin surface and thus enables the detection of flow in the more deeply seated veins and arteries.
9. What functions as a square law device and gives out current?
a) Plastic fibre
b) Photodetector
c) He-Ne Laser
d) CO 2 Laser
Answer: b
Explanation: The photodetector functions as a square law device and gives out current, which is proportional to the intensity of the incident light and, therefore, to the frequency of beating of the shifted and unshifted signals. The light falling on the photodetector is an optically mixed signal involving a Doppler-shifted signal back scattered from the moving red blood cells with the ‘reference’ signal reflected from the non-moving skin surface.
10. Which technique seems to offer several advantages like light reproducibility and sensitivity?
a) NMR
b) Laser Doppler
c) Electromagnetic
d) Ultrasonic
Answer: b
Explanation: Laser Doppler flowmetry is a non-invasive technique and seems to offer several advantages like light reproducibility and sensitivity. However, its disadvantages like poor selectivity, baseline instability and restriction in a site of measurement are still limiting factors in its successful clinical utilization.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Pulmonary Function Measurement”.
1. Most of the ________ processes result in chemical changes in the internal environment of the human body.
a) micromorphological
b) pathological
c) immunological
d) neuropschycological
Answer: b
Explanation: Most of the pathological processes result in chemical changes in the internal environment of the human body. These changes can generally be detected by the analysis of various samples taken from the body. The analysis not only helps in the diagnosis of various ailments but also in determining the progress of treatment and for making a prognosis.
2. Which section deals with the analysis of blood, urine, CSF and other fluids to determine the quantity of various important substance?
a) Chemistry
b) Haemotology
c) Microbiology
d) Blood Bank
Answer: a
Explanation: Chemistry: section deals with the analysis of blood, urine, cerebrospinal fluid and other fluids to determine the quantity of various important substances they contain. Most of the electronic instruments in the clinical laboratory are available in this section. Haematology: section deals with the determinations of the number and characteristics of the constituents of the blood, particularly the blood cells. Microbiology: section in which studies are performed on various body tissues and fluids to determine the presence of pathological micro-organisms.
3. Which section deals with the determinations of the number and characteristics of the constituents of the blood, particularly the blood cells?
a) Chemistry
b) Haemotology
c) Microbiology
d) Blood Bank
Answer: b
Explanation: Chemistry: section deals with the analysis of blood, urine, cerebrospinal fluid and other fluids to determine the quantity of various important substances they contain. Most of the electronic instruments in the clinical laboratory are available in this section. Haematology: section deals with the determinations of the number and characteristics of the constituents of the blood, particularly the blood cells. Microbiology: section in which studies are performed on various body tissues and fluids to determine the presence of pathological micro-organisms.
4. In which section studies are performed on various body tissues and fluids to determine the presence of pathological micro-organisms?
a) Chemistry
b) Haemotology
c) Microbiology
d) Blood Bank
Answer: c
Explanation: Chemistry: section deals with the analysis of blood, urine, cerebrospinal fluid and other fluids to determine the quantity of various important substances they contain. Most of the electronic instruments in the clinical laboratory are available in this section. Haematology: section deals with the determinations of the number and characteristics of the constituents of the blood, particularly the blood cells. Microbiology: section in which studies are performed on various body tissues and fluids to determine the presence of pathological micro-organisms.
5. Which of the following is the most common substance for analysis from the body?
a) CSF
b) Urine
c) Blood
d) Glucose
Answer: c
Explanation: The most common substance for analysis from the body is blood. This is because the blood carries out the most important function of transportation and many pathological processes manifest themselves as demonstrable changes in the blood.
6. _____ accounts for 60% of blood volume.
a) Blood cells
b) Water
c) Carbon Dioxide
d) Blood plasma
Answer: d
Explanation: The liquid part of the blood—the blood plasma, and the formed elements—the blood cells are analyzed during a chemical examination. The blood plasma accounts for about 60% of the blood volume and the blood cells occupy the other 40%. The plasma is obtained by centrifuging a blood sample.
7. The blood plasma gets separated by centrifugation.
a) True
b) False
Answer: a
Explanation: True, During centrifugation, the heavy blood cells get packed at the bottom of the centrifuge tube and the plasma can thus be separated. The plasma is a viscous, light yellow liquid, i.e. almost clear in the fasting stage.
8. _____ accounts for 40% of the blood volume.
a) Blood cells
b) Water
c) Carbon Dioxide
d) Blood plasma
Answer: a
Explanation: The liquid part of the blood—the blood plasma, and the formed elements—the blood cells are analyzed during a chemical examination. The blood plasma accounts for about 60% of the blood volume and the blood cells occupy the other 40%. The plasma is obtained by centrifuging a blood sample.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Spirometry”.
1. What is the pH range of extracellular fluid?
a) 7.25 to 730
b) 7.30 to 7.35
c) 7.35 to 7.45
d) 7.50 to 7.60
Answer: c
Explanation: The normal pH of the extracellular fluid lies in the range of 7.35 to 7.45, indicating that the body fluid is slightly alkaline. When the pH exceeds 7.45, the body is considered to be in a state of alkalosis. A body pH below 7.35 indicates acidosis. Both acidosis or alkalosis are disease conditions widely encountered in clinical medicine.
2. What is the pH of Arterial blood?
a) 7.25
b) 7.30
c) 7.35
d) 7.40
Answer: d
Explanation: Arterial blood has a pH of approximately 7.40. As venous blood acquires carbon dioxide, forms carbonic acid and hydrogen ions, the venous blood pH falls to approximately 7.36. This pH drop of 0.04 units occurs when the CO 2 enters the tissue capillaries. When CO 2 diffuses from the pulmonary capillaries into the alveoli, the blood pH rises 0.04 units to bring the normal arterial value of 7.40.
3. What is the pH range of intracellular fluid?
a) 7.0 to 7.2
b) 7.3 to 7.35
c) 7.35 to 7.45
d) 7.50 to 7.60
Answer: a
Explanation: When CO 2 diffuses from the pulmonary capillaries into the alveoli, the blood pH rises 0.04 units to bring the normal arterial value of 7.40. It is quite difficult to measure the pH of fluids inside the tissue cells, but from estimates based on CO 2 and ion concentration, intracellular pH probably ranges from 7.0 to 7.2.
4. What is E0 in given equation?
biomedical-instrumentation-questions-answers-spirometry-q4
a) induced emf
b) Faradays Constant
c) pH value deviation from 7
d) standard potential
Answer: d
Explanation: The potential of the glass electrode may be written by means of the Nernst
equation:
biomedical-instrumentation-questions-answers-spirometry-q4
where, Eo = standard potential R = gas constant T = absolute temperature F = Faraday constant DpH = pH value deviation from 7.The above relation shows that the emf developed in the electro-chemical pH cell is a linear function of DpH.
5. What is E in given equation?
biomedical-instrumentation-questions-answers-spirometry-q4
a) induced emf
b) Faradays Constant
c) pH value deviation from 7
d) standard potential
Answer: a
Explanation: The potential of the glass electrode may be written by means of the Nernst
equation:
biomedical-instrumentation-questions-answers-spirometry-q4
where, Eo = standard potential R = gas constant T = absolute temperature F = Faraday constant DpH = pH value deviation from 7. The above relation shows that the emf developed in the electro-chemical pH cell is a linear function of DpH.
6. With a 1°C change in temperature, the emf changes by ________ mV.
a) 0.1
b) 0.2
c) 0.5
d) 0.8
Answer: b
Explanation: The factor –2.3036 RTF is called the slope factor and is clearly dependent upon the solution temperature. With a 1°C change in temperature, the emf changes by 0.2 mV. It is also obvious that the measurement of pH is essentially a measurement of millivolt signals by special methods.
7. The venous blood pH falls to approximately 7.36.
a) True
b) False
Answer: a
Explanation: True, as venous blood acquires carbon dioxide, forms carbonic acid and hydrogen ions, the venous blood pH falls to approximately 7.36. This pH drop of 0.04 units occurs when the CO2 enters the tissue capillaries. When CO 2 diffuses from the pulmonary capillaries into the alveoli, the blood pH rises 0.04 units to bring the normal arterial value of 7.40.
8. How much amount of capillary blood is required by a micro-electrode for determination of pH?
a) 5 to 10 ml
b) 10 to 12 ml
c) 12 to 18 ml
d) 20 to 25 ml
Answer: d
Explanation: A micro-electrode for clinical applications requires only 20–25 ml of capillary blood for the determination of pH. The electrode is enclosed in a water jacket with circulating water at a constant temperature of 38°C. The water contains 1% NACI for shielding against static interference.
9. The micro-electrode is enclosed in a water jacket with circulating water at a constant temperature of ___________ °C for determination of pH.
a) 25
b) 34
c) 38
d) 42
Answer: c
Explanation: A micro-electrode for clinical applications requires only 20–25 ml of capillary blood for the determination of pH. The electrode is enclosed in a water jacket with circulating water at a constant temperature of 38°C. The water contains 1% NACI for shielding against static interference.
10. Internal Reference electrode is of _______
a) gold
b) silver
c) platinum
d) graphite
Answer: b
Explanation: The internal reference electrode is silver/silver chloride and the calomel reference electrode is connected to a small pool of saturated KCI, through a porous pin. Accuracy of 0.001 pH can be obtained with this electrode against a constant buffer.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Pneumotachometers”.
1. Which of the following component is used for selection of narrow band in spectrophotometer?
a) Optical system
b) Radiating source
c) Filtering Arrangement
d) Detecting system
Answer: c
Explanation: A source of radiant energy, which may he a tungsten lamp, a xenon-mercury arc, hydrogen or deuterium discharge lamp, etc. Filtering arrangement for the selection of a narrow band of radiant energy. It could be a single wavelength absorption filter, an interference filter, a prism or a diffraction grating.
2. Which of the following component is used to produce a parallel beam of filtered light for passage through an absorption cell in spectrophotometer?
a) Optical system
b) Radiating source
c) Filtering Arrangement
d) Detecting system
Answer: a
Explanation: An optical system for producing a parallel beam of filtered light for passage through an absorption cell . The system may include lenses, mirrors, slits, diaphragm, etc. A detecting system for the measurement of unabsorbed radiant energy, which could be the human eye, a barrier-layer cell, phototube or photo-multiplier tube.
3. What is used for the measurement of unabsorbed radiant energy in spectrophotometer?
a) Optical system
b) Radiating source
c) Filtering Arrangement
d) Detecting system
Answer: d
Explanation: An optical system for producing a parallel beam of filtered light for passage through an absorption cell . The system may include lenses, mirrors, slits, diaphragm, etc. A detecting system for the measurement of unabsorbed radiant energy, which could be the human eye, a barrier-layer cell, phototube or photo-multiplier tube.
4. Which of the following method uses only the human eye as a measuring instrument?
a) Telemetric
b) Colorimetric
c) Polarimetric
d) Calorimetric
Answer: b
Explanation: A colorimetric method in its simplest form uses only the human eye as a measuring instrument. This involves the comparison by visual means of the colour of an unknown solution, with the colour produced by a single standard or a series of standards. The comparison is made by obtaining a match between the colour of the unknown and that of a particular standard by comparison with a series of standards prepared in a similar manner, as the unknown.
5. Which of the following instrument isolates monochromatic radiation in a more efficient and versatile manner than colour filters in filter photometers?
a) Calorimeter
b) Colorimeter
c) Spectrophotometer
d) Polarimeter
Answer: c
Explanation: A spectrophotometer is an instrument which isolates monochromatic radiation in a more efficient and versatile manner than colour filters used in filter photometers. In these instruments, light from the source is made into a parallel beam and passed to a prism or diffraction grating, where light of different wavelengths is dispersed at different angles.
6. Which of the following detector is required in spectrophotometer?
a) Phototransistor
b) Photodiode
c) LDR
d) Photomultiplier
Answer: d
Explanation: The amount of light reaching the detector of a spectrophotometer is generally much smaller than that available for a colorimeter, because of the small spectral bandwidth. Therefore, a more sensitive detector is required. A photomultiplier or vacuum photocell is generally employed.
7. Spectrophotometer generally employs a 6V Xenon Arc Lamp, which emits radiation in a wavelength region of visible light.
a) True
b) False
Answer: b
Explanation: False, Spectrophotometers generally employ a 6 V tungsten lamp, which emits radiation in the wavelength region of visible light. Typically, it is 32 candle power. These lamps should preferably be operated at a potential of say 5.4 V when its useful life is estimated at 1200 h.
8. The recorder used with spectrophotometers has _____ wavelength scanning speeds.
a) one
b) two
c) three
d) four
Answer: d
Explanation: The recorder used with spectrophotometers have four wavelength scanning speeds and seven chart speeds . It has a sensitivity of 100 mV absorbance units or 100 mV/100% T.
9. The recorder used in spectrophotometers has ______ chart speeds.
a) three
b) five
c) seven
d) nine
Answer: c
Explanation: The recorder used with spectrophotometers have four wavelength scanning speeds and seven chart speeds . It has a sensitivity of 100 mV absorbance units or 100 mV/100% T.
10. Which component is used in spectrophotometer for control, Signal Processing, and Communication functions?
a) Detector
b) Microprocessor
c) Deuterium Lamp
d) Tungsten Lamp
Answer: b
Explanation: A microprocessor, in a spectrophotometer, could be used for the following functions: Control functions: Wavelength scanning, automatic light source selection, control of slit width, detector sensitivity, etc. Signal processing functions: Baseline correction, signal smoothing, calculation of % T, absorbance and concentration, derivative, etc. Communication functions: Keyboard entry, menu-driven operations, data presentation, warning display, communication with external systems, etc.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Measurement of Volume”.
1. Which of the following parameter would provide information about the nature of the material?
a) Number of photons
b) Frequencies of photons
c) Number of atom
d) Molecules of atom
Answer: b
Explanation: The study of the frequencies of the photons which are absorbed would thus provide information about the nature of the material. Also, the number of photons absorbed may provide information about the number of atoms or molecules of the material present in a particular state. It thus provides us with a method to have a qualitative and quantitative analysis of a substance.
2. Molecules posses _____________ types of internal energy.
a) one
b) two
c) three
d) four
Answer: c
Explanation: Molecules possess three types of internal energy—electronic, vibrational and rotational. When a molecule absorbs radiant energy, it can increase its internal energy in a variety of ways. The various molecular energy states are quantized and the amount of energy necessary to cause any change in any one of the above energy states would generally correspond to specific regions of the electromagnetic spectrum.
3. Electronic transitions corresponds to ___________ region.
a) near Infrared
b) infrared
c) gar Infrared
d) visible
Answer: d
Explanation: Electronic transitions correspond to the ultraviolet and visible regions, vibrational transitions to the near infrared and infrared regions and rotational transitions to the infrared and far-infrared regions. The method based on the absorption of radiation of a substance is known as Absorption Spectroscopy.
4. Vibrational transition corresponds to ____ region.
a) ultarviolet
b) infrared
c) far Infrared
d) visible
Answer: b
Explanation: Electronic transitions correspond to the ultraviolet and visible regions, vibrational transitions to the near infrared and infrared regions and rotational transitions to the infrared and far-infrared regions. The method based on the absorption of radiation of a substance is known as Absorption Spectroscopy.
5. Which of the following transition corresponds to the far-infrared region?
a) Electronic
b) Vibrational
c) Rotational
d) Mechanical
Answer: c
Explanation: Electronic transitions correspond to the ultraviolet and visible regions, vibrational transitions to the near infrared and infrared regions and rotational transitions to the infrared and far-infrared regions. The method based on the absorption of radiation of a substance is known as Absorption Spectroscopy.
6. Which method is based on the absorption of radiation of a substance?
a) Absorption Endoscopy
b) Absorption Spectroscopy
c) Absorption Arthroscopy
d) Absorption Colonoscopy
Answer: b
Explanation: Electronic transitions correspond to the ultraviolet and visible regions, vibrational transitions to the near infrared and infrared regions and rotational transitions to the infrared and far-infrared regions. The method based on the absorption of radiation of a substance is known as Absorption Spectroscopy.
7. Spectrometric methods are speedy and sensitive.
a) True
b) False
Answer: a
Explanation: True, the main advantages of spectrometric methods are speed, sensitivity to very small amounts of change and a relatively simple operational methodology. The time required for the actual measurement is very short and most of the analysis time, in fact, goes into the preparation of the samples.
8. Which of the following component is used to provide a sufficient intensity of light which is suitable for making measurement in Spectrophotometer?
a) Optical system
b) Radiating source
c) Filtering Arrangement
d) Detecting system
Answer: b
Explanation: The function of the radiation source is to provide a sufficient intensity of light which is suitable for making a measurement. The most common and convenient source of light is the tungsten lamp. This lamp consists of a tungsten filament enclosed in a glass envelope. It is cheap, intense and reliable. A major portion of the energy emitted by a tungsten lamp is in the visible region and only about 15 to 20% is in the infrared region.
9. Which of the following radiating source is most common and convenient for use in spectrophotometer?
a) Carbon Arc Lamp
b) Mercury-vapor Lamp
c) Tungsten Lamp
d) Xenon Arc Lamp
Answer: c
Explanation: The function of the radiation source is to provide a sufficient intensity of light which is suitable for making a measurement. The most common and convenient source of light is the tungsten lamp. This lamp consists of a tungsten filament enclosed in a glass envelope. It is cheap, intense and reliable. A major portion of the energy emitted by a tungsten lamp is in the visible region and only about 15 to 20% is in the infrared region.
10. Deuterium arc lamp provides emission of high intensity and adequate continuity in the _____ nm range.
a) 0-90
b) 90-180
c) 190-380
d) 390-650
Answer: c
Explanation: Deuterium arc lamp provides emission of high intensity and adequate continuity in the 190–380 nm range. A quartz or silica envelope is necessary not only to provide a heat shield but also to transmit the shorter wavelengths of the ultraviolet radiation. The limiting factor is normally the lower limit of atmospheric transmission at about 190 nm.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Pulmonary Function Analysers”.
1. The instrument which carries out a continuous and simultaneous recording of the instantaneous foetal heart rate and labour activity is called _________
a) Ergometer
b) Cardiotocograph
c) Cardiotocometer
d) Cardiotonometer
Answer: b
Explanation: Cardiotocography is a technical means of recording the fetal heartbeat and the uterine contractions during pregnancy. The machine used to perform the monitoring is called a cardiotocograph, more commonly known as an electronic fetal monitor.
2. ________ is not an indirect method of foetal heart rate in cordiotocography monitoring.
a) Foetal ECG with scalp electrode
b) Foetal phonocardiogram
c) Abdominal foetal electrocardiogram
d) Ultrasound techniques
Answer: a
Explanation: The following methods are commonly employed in most of the cardiotocographic monitoring during labour: I) Indirect method: Abdominal foetal electrocardiogram, foetal phonocardiogram, ultrasound techniques II) Direct method: Foetal ECG with scalp electrode .
3. _______ is a direct technique of uterine contraction in cardiotocographic monitoring.
a) Tocodynamometry
b) Intrauterine pressure measurement
c) Phonocardiometry
d) Ultrasound technique
Answer: b
Explanation: The following techniques are commonly used in uterine contraction in most of the cardiotocographic monitoring: I) Indirect method: Tocodynamometry II) Direct method: Intrauterine pressure measurement .
4. The galvanometer, which needs a frequency response of only 3 MHz, is positioned by a servo motor through a silent step-down belt drive.
a) True
b) False
Answer: b
Explanation: The galvanometer, which needs a frequency response of only 3 Hz, is positioned by a servo motor through a silent step-down belt drive. Recording sensitivity is 20 bpm/cm giving a basic resolution of 1 bpm for seeing small changes in the heart rate.
5. The intrauterine pressure can reach values of 150 mmHg or more during the expulsion period.
a) True
b) False
Answer: a
Explanation: True, because during labour, the uterus muscle starts contraction of increasing intensity in a bid to expel out the child. The intrauterine pressure can reach values of 150 mmHg or more during the expulsion period. However, a normal patient in spontaneous active labour will demonstrate uterine contractions occurring at intervals of three to five minutes, with a duration of 30 to 70 s and a peak intensity of 50 to 75 mmHg.
6. Which transducer cannot be used in the same place as the foetal heart rate detector, thus the patient must have two transducers on her abdomen?
a) Cardiotocometer
b) Toco-tonometer
c) LVDT
d) IUPC
Answer: b
Explanation: The toco-transducers are location sensitive. They should be placed over the fundus where there is maximum motion with the contractions. The toco-tonometer transducer cannot be used in the same place as the foetal heart rate detector, thus the patient must have two transducers on her abdomen.
7. Which is the most important of all instrumental methods of analysis in clinical chemistry?
a) Colorimetry
b) Spectrophotometry
c) Pneumotachometry
d) Oximetry
Answer: b
Explanation: Spectrophotometry is the most important of all the instrumental methods of analysis in clinical chemistry. This method is based on the absorption of electromagnetic radiation in the visible, ultraviolet and infrared ranges.
8. Which method of the following is based on the absorption of electromagnetic radiation in visible, ultraviolet and infrared ranges?
a) Colorimetry
b) Spectrophotometry
c) Pneumotachometry
d) Oximetry
Answer: b
Explanation: Spectrophotometry is the most important of all the instrumental methods of analysis in clinical chemistry. This method is based on the absorption of electromagnetic radiation in the visible, ultraviolet and infrared ranges.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Respiratory Gas Analysers”.
1. The plasma is a viscous, light red liquid, i.e. almost clear in the fasting stage.
a) True
b) False
Answer: b
Explanation: False, because the plasma is obtained by centrifuging a blood sample. During centrifugation, the heavy blood cells get packed at the bottom of the centrifuge tube and the plasma can thus be separated. The plasma is a viscous, light yellow liquid, i.e. almost clear in the fasting stage.
2. __________ method is based on the absorption of electromagnetic radiation in the visible, ultraviolet and infrared ranges.
a) Cardiotocography
b) Ultrasonic therapy
c) Spectrophotometry
d) Diathermy
Answer: c
Explanation: Spectrophotometry is the most important of all the instrumental methods of analysis in clinical chemistry. This method is based on the absorption of electromagnetic radiation in the visible, ultraviolet and infrared ranges.
3. ________ waves have short wave-length.
a) Microwave
b) Radio wave
c) Gamma rays
d) IR waves
Answer: c
Explanation: Electromagnetic spectrum ranges from very short wavelengths to very long wavelengths . The range of wavelength of gamma rays and X-rays is 10-4 to 10 nm. The range of wavelengths of microwaves and radio-waves is 106 to 109 nm.
4. The method based on the absorption of radiation of a substance is known as ________
a) Absorption photometry
b) Spectrophotometry
c) Absorption tocometry
d) Absorption spectrophotoscopy
Answer: d
Explanation: Electronic transitions correspond to the ultraviolet and visible regions, vibrational transitions to the near infrared and infrared regions and rotational transitions to the infrared and far-infrared regions. The method based on the absorption of radiation of a substance is known as Absorption Spectroscopy.
5. The ratio of the radiant power transmitted by a sample to the radiant power incident on the sample is known as ________
a) Absorbance
b) Transmittance
c) Optical density
d) Photometric concentration
Answer: b
Explanation: Let us suppose, Po is the incident radiant energy and P is the energy which is transmitted. The ratio of the radiant power transmitted by a sample to the radiant power incident on the sample is known as the transmittance.
Transmittance = P/Po.
6. If absorbance is plotted graphically against concentration, the graph is _________
a) Parabola
b) Increasing
c) Straight line
d) Decreasing
Answer: c
Explanation: If absorbance is plotted graphically against concentration, a straight line is obtained. A graph derived from the transmittance data will not be a straight line unless transmittance is plotted on the log axis of a semi-log paper.
7. ________________ is not a source of radiant energy.
a) Tungsten-mercury lamp
b) Tungsten lamp
c) Xenon-mercury arc
d) Deuterium discharge lamp
Answer: a
Explanation: Radiant just means energy that can move from one place to another without a medium to carry it. A source of radiant energy, which may be a tungsten lamp, a xenon-mercury arc, hydrogen or deuterium discharge lamp, etc.
This set of Biomedical Instrumentation Questions and Answers for Campus interviews focuses on “Medical Diagnosis with Chemical Tests”.
1. Which of the following is not the electrolyte?
a) Bicarbonate
b) Potassium
c) Magnesium
d) Sodium
Answer: c
Explanation: For instance, the group of important anions and cations of the blood plasma like sodium, potassium, chloride and bicarbonate, which together with serum urea form a related set of tests— performed on patients with electrolyte disturbances.
2. The blood pressure within the glumerular capillaries is _________ of mercury.
a) 80 mm
b) 70-80 mm
c) 90 mm
d) 70-90 mm
Answer: d
Explanation: The renal arteries carry blood at very high pressure from the aorta into the glomerular capillary tuft. The blood pressure within the glomerular capillaries is 70–90 mm of mercury. The blood flow through the capillary tuft is controlled by the state of contraction of the muscle of the arteriole leading to the tuft.
3. In the sampling control, one complete rotation of the plate thus presents _______
a) 35 samples
b) 40 samples
c) 20 samples
d) 30 samples
Answer: b
Explanation: The plate rotates a distance sufficient to allow the tube, when it next moves down, to dip into the next cup. One complete rotation of the plate thus presents 40 samples. As the sample plate completes a cycle, a switch is operated, which stops the rotating action of the plate and the sampling action of the sample probe. The sampling rate can be adjusted to 20, 40 or 60 per hour.
4. In the sampler, the range of the sample size is from _______
a) 0.1 to 8.5 ml
b) 1 to 8.5 ml
c) 0.85 to 0.1 ml
d) 8.5 to 10 ml
Answer: a
Explanation: With this sampler, the sample size may range from 0.1 to 8.5 ml. It utilizes cups of sizes 0.5, 2, 3 and 10 ml. The sample plate is kept covered to prevent evaporation, which may sometimes lead to errors up to 5%. Sampling and washing periods are controlled by a programming cam.
5. Which cams are used in the earlier modules of auto-analyzers to initiate and control sample aspiration and wash cycles?
a) Electrical cams
b) Digital cams
c) Analog cams
d) Mechanical cams
Answer: d
Explanation: Mechanical cams were used in the earlier modules of auto-analyzers to initiate and control sample aspiration and wash cycles. Modern systems use electronic timers to do the same function. These timers provide greater flexibility in the control of the sample-to-wash ratios, which in turn allows flexibility in setting up parameters for analyses.
6. The function of the _________ is to continuously and simultaneously push fluids, air and gases through the analytical chain.
a) sampling unit
b) proportioning pump
c) manifold
d) dialyzer
Answer: b
Explanation: The function of the proportioning pump is to continuously and simultaneously push fluids, air and gases through the analytical chain. In fact, it is the heart of the automatic analysis system.
7. In the proportioning pump, two speed pump has a non-synchronous _____ rpm motor.
a) 10 rpm
b) 30 rpm
c) 45 rpm
d) 15 rpm
Answer: c
Explanation: Proportioning pumps are available either for single-speed or for two-speed operations. The single-speed pump has the capacitor synchronous gear head utilizing 10 rpm output shaft at 50 Hz. The two-speed pump has a non-synchronous 45 rpm motor.
8. ________ is not part of the manifold.
a) Transmission tubing
b) Pump tubes
c) Platter
d) Plastic tubes
Answer: d
Explanation: A manifold mainly consists of a platter, pump tubes, coils, transmission tubing, fittings and connections. A separate manifold is required for each determination and the change can be effected within a few minutes. The pump tubing and the connected coils are placed on a manifold platter, which keeps them in proper order for each test.This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Origin of Bioelectric Signals”.
1. Source of Bioelectric potential is ____________ in nature.
a) electronic
b) electric
c) ionic
d) mechanical
Answer: c
Explanation: Bioelectric potentials are generated at cellular level and the source of these potentials is ionic in nature. The prominent ions are K + , Na + , and Cl – . Electronic potential is seen in commonly used cells for example the Galvanic cell. Mechanical potential is found nowhere. Electrical potential is found in electricity.
2. Palsied muscles mean _____________
a) paralyzed muscles
b) active muscles
c) voluntary muscles
d) involuntary muscles
Answer: a
Explanation: Palsied is an adjective that means paralyzed. It is used to describe a muscle on which an individual has lost all control . Voluntary muscles are the muscles on which the individual has complete control. Involuntary muscles are the ones on which the individual has no control for example heart wall muscles.
3. The principal ion that is not involved with the phenomena of producing cell potentials is ______________
a) sodium
b) potassium
c) chlorine
d) hydrogen
Answer: d
Explanation: Sodium (Na + ), Potassium (K + ), and Chlorine (Cl – ) are the principal ions involved with the phenomena of producing cell potentials. Na+ is present outside the cell membrane and creates a positively charged environment outside the cell membrane. Cl – is present inside the cell membrane and is responsible for the negative environment inside the cell membrane.
4. What is the relatively static membrane potential of quiescent cells called?
a) half-cell potential
b) action potential
c) resting membrane potential
d) cell potential
Answer: c
Explanation: Resting membrane potential or the resting potential is the relative static membrane potential of quiescent cell. That is if the resting membrane potential of a neuron is about -70 mV it means that the inside of the neuron is 70 mV less than the outside of the neuron. An action potential occurs when the potential of the membrane of a given axonal position increases and decreases rapidly. This depolarization causes depolarization of adjacent positions in a similar way.
5. The variation of the electrical potential associated with the passage of a pulse along the membrane of a muscle cell or a nerve cell is called __________
a) muscle potential
b) action potential
c) resting potential
d) half cell potential
Answer: b
Explanation: An action potential occurs when the potential of the membrane of a given axonal position increases and decreases rapidly. This depolarization causes depolarization of adjacent positions in a similar way. Resting membrane potential or the resting potential is the relative static membrane potential of a quiescent cell.
6. Cells depolarize and action potential in generated as soon as a stimulus is applied.
a) True
b) False
Answer: b
Explanation: This statement is False. This is because unless a stimulus above a certain minimum value is applied, the cell will not be depolarized and no action potential will be generated. This value of potential above which the depolarizes and an action potential is generated is known as the stimulus threshold.
7. After a cell is stimulated, a finite period of time is required for the cell to return to its pre-stimulus state. This period is known as ____________
a) restoration period
b) refactory period
c) regain period
d) regenerative period
Answer: b
Explanation: After a cell is stimulated, a finite period of time is required for the cell to return to its pre-stimulus state. This is because the energy associated with the action potential is developed from metabolic process within the cell which takes time for completion. This time period is called refactory period.
8. Electrooculography is a technique for measuring what?
a) abnormal function of the retina
b) heart rate
c) respiration rate
d) cornea-retinal standing potential
Answer: d
Explanation: Electrooculography is a technique for measuring the potential of the corneal retinal standing potential that exists between the front and back of the human eye. The resulting signal is called electrooculogram. The main applications are in the diagnosis of ophthalmology and the recording of eye movements.
9. EKG stands for _________________
a) Electrocardiography
b) Electroencephalography
c) Electromyography
d) Electrtokinetcography
Answer: a
Explanation: Electrocardiography is the way toward recording the electrical action of the heart over some stretch of time utilizing anodes put on the skin. It could simply be understood as the electrical representation of heart beat. Electroencephalography is the electrical recording of brain.
10. Phonocardiography is listening to __________
a) arm muscle sound
b) lungs sound
c) heart sound
d) respiratory tract sound
Answer: c
Explanation: A phonocardiogram is a record high-constancy recording of sounds and mumble made by the heart with the assistance of the machine called phonocardiography. Consequently, phonocardiography is the chronicle of the considerable number of sounds made by the heart amid a heart cycle. Mostly stethoscope is used phonocardiography.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Recording Electrodes”.
1. Electrodes make a transfer from the __________ in the tissue to the electronic conduction which is necessary to make measurements.
a) electronic conduction
b) ionic conduction
c) electric conduction
d) impulsive conduction
Answer: b
Explanation: Electrodes make an exchange from the ionic conduction in the tissue to the electronic conduction which is important to make measurements. An electrolytic paste is applied between the electrodes and the skin to reduce skin contact impedance. The electrolyte also facilitates ionic conduction from the skin to the electrodes.
2. Surface electrodes damage the living tissues.
a) True
b) False
Answer: b
Explanation: The surface electrodes pick up the potential difference from the tissue surface when placed over it without damaging the living tissues. They are placed above the skin and cause no harm to the living tissues. They capture the electrical activities of bunch of tissues together.
3. Deep-seated electrodes indicates the electric potential difference arising ________ the living tissues or cells.
a) inside
b) outside
c) around
d) adjacent
Answer: a
Explanation: Deep-seated electrodes indicate the electric potential difference arising inside the living tissues or cells. Surface electrodes indicates the electric potentials arising outside the living tissues that is on the surface of the skin. Needle electrodes are example of deep seated electrodes.
4. Impedance pneumography is a commonly-used technique to monitor a person’s _______
a) respiration rate
b) heart rate
c) pulse rate
d) skin impedance
Answer: a
Explanation: Impedance pneumography is a commonly-used technique to monitor a person’s respiration rate, or breathing rate. It is implemented by using two electrodes or four electrodes. Skin impedance is the resistance between the skin and the electrode. Heart rate measurement is called ECG.
5. Electrode paste ____________
a) increases contact impedance
b) equates contact impedance
c) reduces contact impedance
d) absorbs contact impedance
Answer: c
Explanation: In order to obtain a clearly established contact an electrolyte or electrode paste is usually employed as an interface between the electrode and the surface of the source of the event. It is placed between the skin and the electrode. It helps to get better signal acquisition.
6. All electrode potentials are measured with respect to which reference electrode?
a) hydrogen electrode
b) platinum electrode
c) calomel electrode
d) hydrogen absorbed on platinum electrode
Answer: d
Explanation: All electrode potentials are measured with respect to a reference electrode, usually that of hydrogen absorbed on platinum black. Thus, considering potential of hydrogen absorbed on platinum electrode to be zero, other all have positive of negative potentials.
7. What is the frequency range of ECG?
a) 70-120 Hz
b) 0.05-120 Hz
c) 5-120 Hz
d) 12-120 Hz
Answer: b
Explanation: Primary signal characteristics of ECG are:
Frequency range: 0.05-120 Hz.
Signal amplitude: 0.1-5 mV.
Typical signal: 1mV.
8. What is the signal amplitude of EEG?
a) 2-200 µV
b) 2-200mV
c) 2-2000 µV
d) 2-2000mV
Answer: a
Explanation: The signal amplitude of EEG is between 2-200 µV. It is very small and requires special type of electrodes namely scalp electrodes. EEGs are difficult to capture because its signal range in very small and motion artifacts are much greater.
9. Needle electrode is used to measure ____________
a) EKG
b) EEG
c) EOG
d) EMG
Answer: d
Explanation: EMG stands of Electromyogram. For recording action potential for individual motor units of muscle fiber, needle electrodes are used for better diagnostic information. These electrodes fall in the category of deep seated electrodes.
10. From equipment point of view, the respiratory system in the human body is a _________ system.
a) hydraulic
b) pneumatic
c) mechanical
d) electrical
Answer: b
Explanation: Respiratory system is a pneumatic system in which an air pump alternately creates negative and positive pressures in a sealed chamber and causes air to be sucked into and forced out of a pair of elastic bags . Blood circulatory system is related to hydraulic system.
11. Off-set potential is _____________
a) difference in half-cell potentials between two electrodes
b) sum of half-cell potentials between two electrodes
c) average of half-cell potentials between two electrodes
d) complement of half-cell potentials between two electrodes
Answer: a
Explanation: The difference in half cell potential that exists between two electrodes is called off-set potential. The differential amplifies used to measure potentials between two electrodes are generally designed to cancel the electrode offset potential so that only the signals of interest are recorded.
12. Which of the following is not preferred for electrode making?
a) Ag-AgCl
b) Copper
c) Stainless-steel
d) Gold
Answer: c
Explanation: Stainless steel in contact with a saline electrolyte produce a potential difference of 10 mV between the electrodes which is much more than the limit . Ad-AgCl electrodes give almost noise free characteristics. They are also found to be acceptable from the point of view of long term drift.
13. Which of the following statement is false about polarizable electrodes?
a) they are made using stainless steel
b) used for recording resting ECG
c) retain a residual charge when exposed to large pulse of energy
d) can transmit small bioelectric signals even after getting exposed to large pulse of energy
Answer: d
Explanation: Polarizable electrodes usually employ stainless steel and are used for resting ECG or other situations where there is small likelihood that the electrode would be exposed to a large pulse of energy in which case they would retain a residual charge, become polarized, and will no longer transmit the relatively small bioelectric signals, thus become useless.
14. Which electrodes can work even after being induced to large electric discharge such as defibrillation?
a) polarizing electrodes
b) magnetic electrodes
c) non-polarizing electrodes
d) electrolytic electrodes
Answer: c
Explanation: Non-polarizing electrodes are designed to rapidly dissipate any charge imbalance induced by powerful electric discharges such as a defibrillation procedure. Rapid depolarization enables the immediate reappearance of bioelectric signals on the monitor after defibrillation. For this reason, non-polarizing electrodes have become the electrodes of choice for monitoring in the intensive care units and stress testing procedures.
This set of Biomedical Instrumentation Interview Questions and Answers focuses on “Silver-Silver Chloride Electrodes”.
1. On increasing the chloride deposit the Ag-AgCl electrode ______________
a) increases the impedance
b) reduces impedance
c) has no effect on impedance
d) cannot be determined
Answer: a
Explanation: Studies have shown that the impedance of the electrode was different layers of chloride. There is an optimum chloriding, which gives the lowest impedance. Above and below that value the impedance is high.
2. Ag-AgCl electrodes are ___________
a) polarized
b) non-polarized
c) partially polarized
d) cannot be said
Answer: b
Explanation: The most important and desirable property of the electrodes designed to pick up signals from biological objects is that they should not polarize. This means that the electrodes potential must not vary considerably even when current passes through it. Electrodes made of Ag-AgCl yield acceptable standards of performance.
3. Silver -Silver Chloride electrodes are prepared by the process of ____________
a) centrifugation
b) etching
c) manually
d) electrolysis
Answer: d
Explanation: Silver-Silver Chloride electrodes are normally prepared by electrolysis. Two silver discs are suspended in a saline solution. The positive pole of dc supply is connected to the disc to be chloride and the negative pole goes to the other disc.
4. Electrocardiography was invented by ___________
a) Willem Einthoven
b) Robert Koch
c) Werner Forssmann
d) Gertrude B.Elion
Answer: a
Explanation: Willem Einthoven a Dutch physician and physiologist. He invented the first Electrocardiogram in 1903. He received the Nobel Prize for Medicine in 1924 for it.
5. MRI stands for ____________
a) Mechanical Resonance Imaging
b) Magnetic Resonance Imaging
c) Mutually Related Imaging
d) Magnetic Resultant Imaging
Answer: b
Explanation: MRI stands for Magnetic Resonance Imaging. The MRI is a diagnostic technique that uses magnetic fields and radio waves to produce a detailed picture of soft tissues and body bones. An MR mirrors the spine using a magnet crossing the body to excite hydrogen atoms.
6. The interior of the neuron is at a potential of about _____ mV relative to the exterior.
a) -70
b) +70
c) -170
d) +170
Answer: a
Explanation: The neurons, like the other cells of the body, are electrically polarized at rest. The interior of the neuron is at a potential of about -70 mV relative to the exterior. When a neuron is exposed to a stimulus above a certain threshold, a nerve impulse, seen as a change in membrane potential, is generated which spreads in the cell resulting in the depolarization of the cell.
7. Tricuspid valve is also called _______________
a) Left Atrio-ventricular valve
b) Right Atrio-ventricular valve
c) Pulmonary valve
d) Cardiac valve
Answer: b
Explanation: It’s placed between right atrium and ventricle. It consists of three flaps or cusps. It prevents backward flow of blood from right ventricle to the right atrium.
8. From instruments point of view, heart is a ______ system.
a) pneumatic
b) electric
c) electronic
d) hydraulic
Answer: d
Explanation: Heart pumps blood. It is analogous to water. Thus heart can be considered as a hydraulic system.
9. The basic functional unit of nervous system is ____________
a) nerves
b) axon
c) neuron
d) dendrite
Answer: c
Explanation: The basic functional unit of the nervous system is a neuron. A typical neuron consists of a nucleated cell body and has several processes and branches. The dendrites normally conduct impulses towards the cell body and the axon conducts away from it.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Electrodes for ECG”.
1. The material used in limb surface electrode is ___________
a) German silver
b) Copper
c) Gold
d) Platinum
Answer: a
Explanation: The most common type of electrode most routinely used for recording ECG are rectangular or circular surface limb electrodes. The material used in them is German silver, nickel silver or nickel plated steel. They are applied to the surface of the body with electrode jelly.
2. Welsh cup electrodes have __________
a) low contact impedance
b) negligible contact impedance
c) high contact impedance
d) zero contact impedance
Answer: c
Explanation: Welsh cup electrodes or suction electrodes is a metallic cup shaped electrode which is used for recording ECG from various positions from the chest. It has a high contact impedance as only the rim of the electrode is in contact with the skin. It is commonly used to record the unipolar chest leads.
3. In floating electrodes metal electrode does not make direct contact with the skin.
a) True
b) False
Answer: a
Explanation: In floating electrode the metal electrode does not make direct contact with the skin. The electrode consists of a light weighted metalled screen or plate held away from the subject by a flat washer which is connected to the skin. Floating electrodes can be recharged, i.e. the jelly in the electrodes can be replenished if desired.
4. The main design feature of pregelled disposable electrodes which helps to reduce the possibility of artefacts, drift and baseline wandering is _____________
a) low absorbency buffer layer with isotonic electrolyte
b) high absorbency buffer layer with isotonic electrolyte
c) high absorbency buffer layer without isotonic electrolyte
d) low absorbency buffer layer without isotonic electrolyte
Answer: b
Explanation: The main design feature of pregelled disposable electrode that helps in reducing the possibility of artefacts, drift and baseline wandering is the provision of high absorbency buffer layers with isotonic electrolyte. This layer absorbs the effects of movement of the electrode in relationship to the skin and attempts to maintain the polarization associated with the half-cell potential constant.
5. Recording electrical activities associated with heart is known as ____________
a) EEG
b) EOG
c) EMG
d) ECG
Answer: d
Explanation: The recording of the electrical activities associated with the functioning of the heart is known as electrocardiogram. ECG is a quasi-periodical, rhythmically repeating signals synchronized by the function of the heart, which acts as a generator of bioelectric events. This generated signals can be described by the means of a simple electric dipole.
6. Which of the following is considered to be the primary pacemaker of the heart?
a) sino-atrial node
b) atrio-ventricular node
c) purkinje fibres
d) bundle of his
Answer: a
Explanation: Located in the top right atrium near the entry of the vena cava, are a group of cells known as the sino-atrial node that initiates the heart activity. Because this is also considered as the primary pacemaker of the heart. The SA node is 25 to 30 mm in length and 2 to 5 mm in thickness.
7. Atrio ventricular node is located at __________
a) upper part of the heart wall between the two atrial
b) lower part of the heart wall above the two atrial
c) lower part of the heart wall between the two atrial
d) upper part of the heart wall above the two atrial
Answer: c
Explanation: The AV node is located in the lower part of the wall between the two atria. The AV node delays the spread of excitation for about 0.12s, due to the presence of a fibrous barrier of non-excitable cells that effectively prevent its propagation from continuing beyond the limits of stria.
8. Buffer amplifier converts ____________
a) low impedance signals to high impedance signals
b) high impedance signals to low impedance signals
c) ac impedance signals to dc impedance signals
d) dc impedance signals to ac impedance signals
Answer: b
Explanation: Noise is typically generated from motion artefacts and power line interference. A common solution used to suppress noise in dry electrode signals is a buffer amplifier. A buffer amplifies is essentially an impedance converter, that converts high impedance signals to low impedance signals.
9. Which of the following is a wireless ECG acquiring system?
a) pregelled disposable electrodes
b) limb electrodes
c) pasteless electrodes
d) smart pad
Answer: d
Explanation: Smart pad is a system that displays patients electrocardiogram signals without adhesive pads, wires or active intervention from a clinician. The system automatically selects three electrodes from an array of Cu/Ni fabric based electrodes patterned on a thin pad on which the patient lies. The selected electrodes are used to provide a differential 3 lead measurement of the patient’s ECG, which is then transmitted wirelessly and displayed on a laptop computer.
10. Before placing the electrodes the skin should be __________
a) wet
b) dry
c) hairy
d) oily
Answer: b
Explanation: The skin should be dry. Poor skin prep prompts undesirable curio and not putting the terminals where they ought to be can change the morphology of the waveforms the specialist will decipher. The purpose of decent skin prep is to expel soil, dead skin cells, oils, skin cream, counterfeit tan, body powder, sweat and so forth. These sources can prompt poor contact with the sensors and ancient rarity.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Electrodes for EMG”.
1. Which of the following is a preferred electrode for measuring EMG?
a) surface electrodes
b) needle electrodes
c) pregelled electrodes
d) scalp electrodes
Answer: b
Explanation: Electrodes for EMG work are usually of the needle type. Needle electrodes are used in clinical EMG, neurography and other electrophysiological measurements of the muscle tissues underneath the skin. Surface electrodes are preferred to measure ECG. Scalp electrodes for EEG.
2. Generally what is the material of needle electrodes?
a) stainless steel
b) copper
c) lead
d) iron
Answer: a
Explanation: The material of the needle electrode is generally stainless steel. In spite of the face that stainless steel is unfavorable electrode material from the point of view of noise, it is preferred in EMG work. It is due to its mechanical solidity and low price.
3. Monopolar needle electrodes are having coatings of which material over the stainless steel wires which are bare only at the tips?
a) carbon
b) calcium
c) sodium
d) teflon
Answer: d
Explanation: The monopolar needle electrode consists of a teflon coated stainless steel wire. The wire is bare only at the tip. It is found that after the needle has been used a number of times, the teflon coating will recede, increasing the tip area. The needle should be discarded when this happens.
4. Which electrode can be used to pick up signals from individual fibers of muscle tissues?
a) biopolar needle electrode
b) concentric core needle electrode
c) multi-element needle electrode
d) monopolar needle electrode
Answer: c
Explanation: Multi-element needle electrodes are used to pick up the signals from individual fibers of muscle tissue. Special needles are available using 25-micron diameter electrode surfaces. They have up to 14 pickup surfaces down the side of one needle.
5. _______________ instrument is used to hold patients head and guide the placement of electrodes.
a) Monotaxic
b) Stereotonic
c) Stereotaxic
d) Monotonic
Answer: c
Explanation: For measurement of potential from specific part of the brain, longer needles are inserted inside the head. The needles are precisely located by means of a map or atlas of the brain. A special instrument called stereotaxic instrument is used to hold the subject’s head and guide the placement of the electrodes.
6. Number of cloud deployment models that are recognized are _________
a) 2
b) 5
c) 3
d) 4
Answer: c
Explanation: There are 3 recognized cloud deployment models. They are – Private cloud, Public cloud and Hybrid cloud.
7. The ground electrode is usually positioned over which body structures?
a) bony
b) hairy
c) fleshy
d) sweaty
Answer: a
Explanation: The ground electrode is usually positioned over bony structures rather than over large muscle masses, in the vicinity of the recording and stimulating electrodes, and where possible, equidistant from them. Hairy areas don’t transmit proper signals. It increases impedance of the skin.
8. When intramuscular EMG is required to look into the electrical activities of deeper or overlaid muscles, ________ electrodes are used.
a) plate shape electrodes
b) surface electrodes
c) thin thread electrodes
d) fine wire electrodes
Answer: d
Explanation: When intramuscular EMG is required to look into the electrical activities of deeper or overlaid muscles, thin and flexible fine wire electrodes are used. These electrodes are inserted into the muscle site of interest. The needle or steel cannula is removed, and the electrode wires are connected to the steel spring adapters to minimize movement artefacts.
9. The contraction of the skeletal muscles results in the generation of action potential in the individual muscle fibers. Record of this action potential is called ______________
a) ECG
b) EMG
c) EEG
d) EKG
Answer: b
Explanation: The contraction of the skeletal muscles results in the generation of action potential in the individual muscle fibers, a record of such action potential is known as electromyogram . The activity is similar to that observed in the cardiac muscles , but in the skeletal muscles, repolarization takes place much more rapidly. The action potential lasts for only few milliseconds.
10. In voluntary contraction of the skeletal muscles, the muscle potential ranges from ________
a) 50 uV – 5 mV
b) 50 mV – 5 V
c) 0.05 uV – 2 mV
d) 50 mV – 500 mV
Answer: a
Explanation: In voluntary contraction of the skeletal muscles, the muscle potential ranges from 50 uV – 5 mV and duration from 2 to 15 ms. The values vary with the anatomic position of the muscle and the size and location of the electrode. In a relaxed muscle there are no action potentials.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Electrodes for EEG”.
1. Electrodes to measure EEG are placed on ________
a) forehead
b) scalp
c) cheek
d) ears
Answer: b
Explanation: Electrode to measure EEG are placed on the scalp. The position of each electrode is specified using the International 10/20 system. Each electrode site is labeled with a letter and a number.
2. According to the international 10/20 system to measure EEG, even number denotes which side of the brain?
a) left
b) top
c) bottom
d) right
Answer: d
Explanation: The position of each electrode is specified using the International 10/20 system. Each electrode site is labeled with a letter and a number. Even number denotes the right side of the head.
3. Letter F in the EEG electrode placement system denotes?
a) front
b) face
c) frontal lobe
d) fast
Answer: c
Explanation: F denotes frontal lobe of the head. The position of each electrode is specified using the International 10/20 system. Each electrode site is labeled with a letter and a number.
4. Normal EEG frequency range is _______
a) 50-500Hz
b) 0.5-50HZ
c) 0.05-5Hz
d) 1-200Hz
Answer: b
Explanation: The frequency varies greatly with different behavioral states. The normal EEG frequency content ranges from 0.5 to 50Hz. The nature of the wave varies over the different parts of the scalp.
5. The letter T in the EEG electrode placement system denotes?
a) temporal lope
b) temper lobe
c) trace
d) timpanic
Answer: a
Explanation: T denotes temporal lobe of the head. The position of each electrode is specified using the International 10/20 system. Each electrode site is labeled with a letter and a number.
6. According to the international 10/20 system to measure EEG, odd number denotes which side of the brain?
a) left
b) right
c) top
d) front
Answer: a
Explanation: The position of each electrode is specified using the International 10/20 system. Each electrode site is labeled with a letter and a number. Odd number denotes the left side of the head.
7. The delta wave in EEG ranges from ___________
a) 0.5-4Hz
b) 4-8Hz
c) 8-13Hz
d) 13-22Hz
Answer: a
Explanation: The delta wave in EEG ranges from 0.5-4Hz. The theta wave in EEG ranges from 4-8Hz. The alpha wave in EEG ranges from 8-13Hz and beta from 13-22Hz.
8. Disturbance in the EEG pattern resulting from the external stimuli is called ________
a) provoked response
b) ckoored response
c) evoked response
d) impulse response
Answer: c
Explanation: Disturbance in the EEG pattern resulting from the external stimuli is called evoked response. The stimuli could be a flash light or a click of sound. The stimuli can be repeated and the EEG waveform can be observed to find the activities occurring because of the stimuli.
9. The peak to peak amplitude of the waves that can be picked from the scalp is ______________
a) 100mV
b) 100V
c) 100uV
d) 10mV
Answer: c
Explanation: The EEG signal can be picked up with electrodes either from the scalp or directly from the cerebral cortex. The peak to peak amplitude of the waves that can be picked up from the scalp is normally 100uV. The frequency varies greatly with different behavioral states.
10. Which rhythm is the principal component of the EEG that indicates the alertness of the brain?
a) theta rhythm
b) gamma rhythm
c) beta rhythm
d) alpha rhythm
Answer: d
Explanation: The alpha rhythm is the principal component of the EEG and is an indicator of the state of alertness of the brain. It serves as an indicator of the depth of anesthesia in the operating room. The frequency of the EEG seems to be affected by the mental activity of a person.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Microelectrodes”.
1. Which type of electrodes are employed to study the electrical activities of individual cells?
a) milli-electrodes
b) micro-electrodes
c) surface-electrodes
d) pre-jelled electrodes
Answer: b
Explanation: To study the electrical activities of individual cells, micro electrodes are employed. This type of electrode is small enough with respect to the size of the cells. Typical micro electrodes have tip dimensions ranging from 0.5-5 microns.
2. Glass micro-capillaries are a type of micro electrode.
a) True
b) False
Answer: a
Explanation: Two types of micro electrodes are generally used: metallic and glass microcapillaries. Metallic electrodes are formed from a fine needle of suitable metal drawn for a fine tip. Glass electrodes are drawn from Pyrex glass of special grade.
3. Glass microcapillaries are preferred over metallic electrodes because of the former _______
a) polarizes with input current
b) does not have sustainable current carrying capacity
c) has less contact surface area
d) has sustainable current carrying capacity
Answer: d
Explanation: Metallic electrodes polarize with smaller amplifier input currents. Hence, they tend to develop unstable electrode offset potential and are therefore not preferred for steady state potential measurement. On the other hand, in case of glass micro electrodes have a sustainable current carrying capacity because of the large surface area between the metal and the electrolyte.
4. Do metallic micro electrodes exist.
a) True
b) False
Answer: a
Explanation: Two types of micro electrodes are generally used: metallic and glass microcapillaries. Metallic electrodes are formed from a fine needle of suitable metal drawn for a fine tip. Glass electrodes are drawn from Pyrex glass of special grade.
5. Metallic micro electrodes have impedance ________ compared to conventional electrodes?
a) equal
b) smaller
c) high
d) very high
Answer: d
Explanation: The very high impedance of the metal micro-electrodes is due to the characteristics of the small area metal-electrolyte interface. Because of very high impedance of micro electrodes, amplifiers with extremely high input impedance are required to avoid loading the circuit and to minimize the effects of small change in interface impedance.
6. Which of the following electrode is manufactured by circumferential application of heat to a small area of glass tubing and pulling the glass when it gets soft?
a) macro metallic electrodes
b) micro metallic electrodes
c) micro pipette
d) surface electrodes
Answer: c
Explanation: The most commonly used method for making small tip micropipette consists of the circumferential application of heat to a small area of glass tubing which is placed under some initial tension. When the glass softens, the tension is increased very rapidly and the heat is turned off. Proper timing, controlled adjustment of the amount of heat as well as the initial and final tensions and cooling results in the production of microcapillaries with control dimensions.
7. Which of the following metal is preferred for manufacturing micro electrodes?
a) Stainless steel
b) Tungsten
c) Iron
d) Copper
Answer: b
Explanation: Tungsten is preferred for constructing micro-electrodes due to its mechanical strength and its apparent inertness. Although tungsten itself is reactive, a surface layer of tungsten oxide will, in most situations, protect the metal against corrosion.
8. ________________ are devices which convert one form of energy into another.
a) transducers
b) electrodes
c) impulses
d) opamp
Answer: a
Explanation: Transducers are devices which convert one form of energy into another. A number of factors decide the choice of a particular transducer to be used for the study of a specific phenomenon. Many physical, chemical and optical properties and principles can be applied to construct transducers for applications in the medical field.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Classification of Transducers”.
1. Which type of transducer requires energy to be put into it in order to translate changes due to the measurand?
a) active transducers
b) passive transducers
c) powered transducers
d) local transducers
Answer: b
Explanation: Passive transducers are transducers that require energy to translate changes due to the measurand. Active transducers convert one form of energy directly into another. For example photovolatic cell in which light energy is converted into electrical energy.
2. Active transducers work on the principle of ________
a) energy conversion
b) mass conversion
c) energy alteration
d) volume conversion
Answer: a
Explanation: Active transducers work on the principle of energy conversion. They convert one form of energy to another. They don’t require any power to operate.
3. Accuracy is ______
a) ability of the transducer or sensor to see small differences in reading
b) ability of the transducer or sensor to see small differences in reading
c) algebraic difference between the indicated value and the true or theoretical value of the measurand
d) total operating range of the transducer
Answer: c
Explanation: Accuracy describes the algebraic difference between the indicated value and the true or theoretical value of the measurand. Resolution is the ability of the transducer or sensor to see small differences in reading. Precision refers to the degree of repeatability of a measurant.
4. The smallest change in measurant that will result in a measurable change in the transducer output is called _______
a) offset
b) linearity
c) resolution
d) threshold
Answer: d
Explanation: The threshold of the transducer is the smallest change in measurant that will result in a measurable change in the transducer output. Offset is the output that will exist when it should be zero. Linearity shows closeness of a transducer’s calibration curve to a specific straight line with in a given percentage of full scale output.
5. Unwanted signal at the output due either to internal sources or to interference is called ________
a) offset
b) noise
c) drift
d) threshold
Answer: b
Explanation: Noise is the unwanted signal at the output due either to internal sources or to interference. Offset is the output that will exist when it should be zero. The threshold of the transducer is the smallest change in measurant that will result in a measurable change in the transducer output.
6. The ability of the sensor to see small differences in reading is called ______
a) resolution
b) drift
c) offset
d) linearity
Answer: a
Explanation: The ability of the sensor to see small differences in reading is called the resolution of the sensor. Offset is the output that will exist when it should be zero. Linearity shows closeness os a transducer’s calibration curve to a specific straight line with in a given percentage of full scale output.
7. Change is signal over long period of time is called _______
a) noise
b) offset
c) hysteresis
d) drift
Answer: d
Explanation: Drift indicated a change of base line or of sensitivity with time, temperature etc. Drift is basically the change in a signal over long period of time. Noise is the unwanted signal at the output due either to internal sources or to interference. Offset is the output that will exist when it should be zero.
8. Linearity of transducer is ___________
a) Closeness of the transducer’s calibration curve to a special curved line within a given percentage of full scale output
b) Closeness of the transducer’s calibration curve to a special straight line within a given percentage of full scale output
c) Closeness of the transducer’s calibration curve to a special straight line within a given percentage of half scale output
d) Closeness of the transducer’s calibration curve to a special curved within a given percentage of half scale output
Answer: b
Explanation: Linearity of transducer is closeness of the transducer’s calibration curve to a special straight line within a given percentage of full scale output. Basically, it reflects that the output is in some way proportional to the input. A linear sensor produces an output value which is directly proportional to the input.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Performance Characteristics of Transducers”.
1. The minimum input of physical parameter that will create a detectable out change is called __________
a) threshold
b) sensitivity
c) span
d) precision
Answer: b
Explanation: The sensitivity of the sensor is defined as the slope of the output characteristic curve. In simple words The minimum input of physical parameter that will create a detectable out change is called sensitivity. Total operating range of the transducer is called its span.
2. The total operating range of the transducer is called __________
a) span
b) threshold
c) offset
d) drift
Answer: a
Explanation: The total operating range of the transducer is called span of the transducer. Offset is the output that will exist when it should be zero. Drift is basically the change in a signal over long period of time.
3. Hysteresis is no change in output with the same value of input.
a) True
b) False
Answer: b
Explanation: Hysteresis is change in output with the same value of input but with a different history of input variation. Hysteresis is observed when the input/output characteristics for a transducer are different for increasing inputs than for decreasing outputs. It results when some of the energy applied for increasing inputs is not recovered when the input decreases.
4. The region in which the output does not changes with increase in input is called _________
a) input range
b) threshold
c) offset
d) saturation
Answer: d
Explanation: The region in which the output does not changes with increase in input is called saturation. The threshold of the transducer is the smallest change in measurant that will result in a measurable change in the transducer output. Offset is the output that will exist when it should be zero.
5. Ability of the sensor to repeat a measurement when put back in the same environment is called ______
a) conformance
b) saturation
c) repeatability
d) threshold
Answer: c
Explanation: Ability of the sensor to repeat a measurement when put back in the same environment is called repeatability. The region in which the output does not changes with increase in input is called saturation. The threshold of the transducer is the smallest change in measurant that will result in a measurable change in the transducer output.
6. Closeness of a calibration curve to a specified curve for an inherently non linear transducer is called ___________
a) conformance
b) linearity
c) saturation
d) hysteresis
Answer: a
Explanation: Conformance indicates the closeness of a calibration curve to a specified curve for an inherently non linear transducer. Hysteresis is change in output with the same value of input but with a different history of input variation. The region in which the output does not changes with increase in input is called saturation.
7. The range between the maximum and minimum values is applied to a parameter which can be measured is ___________
a) repeatability
b) span
c) input range
d) output range
Answer: b
Explanation: Input range is the range between the max and min values is applied parameter which can be measured . Ability of the sensor to repeat a measurement when put back in the same environment is called repeatability. The total operating range of the transducer is called span of the transducer.
8. Which of the following is not a static property?
a) repeatability
b) hysteresis
c) frequency response
d) saturation
Answer: c
Explanation: Frequency response is the change of transfer function with frequency, both in magnitude and in phase. It is a dynamic property. Ability of the sensor to repeat a measurement when put back in the same environment is called repeatability. The region in which the output does not changes with increase in input is called saturation.
9. Time for the sensor to reach a stable output once it is turned on is called _________
a) frequency response
b) span
c) response time
d) settling time
Answer: d
Explanation: Settling time is the time for the sensor to reach a stable output once it is turned on. Frequency response is the change of transfer function with frequency, both in magnitude and in phase. The total operating range of the transducer is called span of the transducer.
10. Which of the following is not a dynamic property?
a) frequency response
b) saturation
c) settling time
d) response time
Answer: b
Explanation: The region in which the output does not changes with increase in input is called saturation. It is a static property of the transducer. Settling time is the time for the sensor to reach a stable output once it is turned on. Frequency response is the change of transfer function with frequency, both in magnitude and in phase.
This set of Biomedical Instrumentation Questions and Answers for Freshers focuses on “Displacement, Position and Motion Transducers”.
1. Potentiometer works on which of the following principle?
a) variable resistance
b) variable inductance
c) variable capacitance
d) variable electromagnet
Answer: a
Explanation: Potentiometer works on the principle of variable resistance. The resistance between two terminals of this device is related to the linear or angular displacement of a sliding tape along a resistance element. When the fixed terminals of the potentiometer are connected to the power supply. Either ac or dc, output voltage at the wiper varies with the displacement of the object.
2. On increasing the distance between the plates of a variable capacitor, the displacement- capacitance characteristics changes _______
a) proportionally
b) linearly
c) exceptionally
d) hyperbolically
Answer: d
Explanation: By moving one plate of the capacitor with respect to the other, the capacitance will vary inversely with respect to the plate separation. This will give a hyperbolic displacement capacitance characteristic. This is how variable capacitance is employed as displacement transducers.
3. Lateral displacement of capacitance plates with respect to each other gives linear displacement capacitance characteristics.
a) True
b) False
Answer: a
Explanation: It is true that lateral displacement of capacitance plates with respect to each other gives linear displacement capacitance characteristics. C = 0.0885*k*.
k = dielectric constant of the medium separating the two plates.
C = capacitance in micro farads
A = area of each identical plate in cm 2
d = distance between the plates in cm 2 .
4. LVDT stands for _________
a) Linear Virtual Double Transformer
b) Linear Virtual Differential Transducer
c) Linear Variable Differential Transducer
d) Linear Variable Differential Transformer
Answer: d
Explanation: LVDT stands for Linear Variable Differential Transformer. These transducers are conventionally used for measurement of physiological pressure. They generally work in conjunction with carrier amplifiers.
5. LVDT works on the principle of ________
a) variable resistance
b) variable inductance
c) variable capacitance
d) variable pressure
Answer: b
Explanation: LVDT works on the principle of variable inductance. It has three coils namely the primary coil which is the center coil. The other two are called the secondary coils so connected that their outputs are equal in magnitude but opposite in phase.
6. In LVDT the secondary coils are energized with sine wave oscillator.
a) True
b) False
Answer: b
Explanation: The center coil is the energizing or primary coil connected to a sine wave oscillator. The secondary coils so connected that their outputs are equal in magnitude but opposite in phase. LVDT works on the principle of variable inductance.
7. How many coils are required to make LVDT?
a) 4
b) 6
c) 3
d) 2
Answer: c
Explanation: Total 3 coils are required in LVDT. One centered coil which is the energizing or primary coil connected to the sine wave oscillator. The other two coils are the secondary coils so connected that their outputs are equal in magnitude but opposite in phase.
8. LVTD is a _______ transducer.
a) displacement
b) photoelectric
c) thermal
d) chemical
Answer: a
Explanation: LVDT is a displacement transducer. It works on the principle of variable inductance. The shift in the ferromagnetic core from the centre position induces voltage in the second coild which can be calibrated to determine the linear displacement.
9. Which of the following is a displacement transducer?
a) Thermistor
b) LVDT
c) Strain gauge
d) Thermocouple
Answer: b
Explanation: LVDT is a displacement transducer. Thermocouple and thermistor are temperature transducers. Strain gauge is a pressure transducer.
10. Linear encoders gives ___________ output.
a) angular
b) analog
c) digital
d) unstable
Answer: b
Explanation: Linear encoders give output in digital form. These transducers are basically encoded disks or rulers with digital pattern photographically etched on glass plate. These patterns are decoded using a light source and an array of photodetectors.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Pressure Transducers”.
1. Which of the following is not a piezo-electric material?
a) quartz
b) rochelle salt
c) aluminium
d) barium titanate
Answer: a
Explanation: Aluminium is not a piezo-electric material. Quartz is the most stable natural crystal with high mechanical and thermal stability and has voulme resistivity higher than 10 4 ohm-cm and small internal electric loss. Barium titanate ceramic is a ferroelectric crystal and has small voltage output.
2. Piezo-electricity is ______________
a) sound electricity
b) pressure electricity
c) temperature electricity
d) photo electricity
Answer: b
Explanation: Piezo-electricity is pressure electricity. The piezo electric effect is a property of natural crystalline substance to develop electric potential along a crystallographic axis in response to the movement of charge as a result of mechanical deformation.
3. On applying electricity to piezo-electric material mechanical deformation occurs in the material.
a) True
b) False
Answer: a
Explanation: Yes, on applying electricity to the piezo-electric material mechanical deformation occurs in the material. The piezo electric effect is a property of natural crystalline substance to develop electric potential along a crystallographic axis in response to the movement of charge as a result of mechanical deformation.
4. Which of the following is a material employed making diaphragm to measure pressure?
a) tourmaline
b) barium titanate
c) phosphor bronze
d) zirconate titanate
Answer: c
Explanation: Phosphor bronze is used to make diaphragm to measure pressure. The motion of diaphragm is measured in terms of electric signals. Tourmaline , barium titanate and zirconate titanate are piezo electric materials.
5. Principle behind strain gauge is _____________
a) variable resistance
b) variable inductance
c) variable capacitance
d) variable contact area
Answer: a
Explanation: The principle behind strain gaude is the variable resistance. The transducer is based upon the changed in resistance of a wire produced due to small mechanical displacement. A linear relation exists between the deformation and electrical resistance of a suitable selected gauge over a specified range.
6. On applying pressure to piezo-electric crystal, electricity is not generated.
a) True
b) False
Answer: b
Explanation: On applying pressure to piezo-electric crystal, electricity is generated. The piezo electric effect is a property of natural crystalline substance to develop electric potential along a crystallographic axis in response to the movement of charge as a result of mechanical deformation. Thus, piezo-electricity is pressure electricity.
7. The figure of merit which describes the overall behaviour of the wire under stress is determined from?
a) elastic modulus
b) gauge factor
c) elastic factor
d) gauge resistance
Answer: b
Explanation: The figure of merit which describes the overall behaviour of the wire under stress is determined from the gauge factor of the wire. Gauge factor gives information on the expected resistance change or output signal at maximum permissible elongation.the gauge factor determines to a large extent the sensitivity of the wire when it is made into a practical strain gauge.
8. Gauge factor is defined as _______________
a) *
b) *
c) *
d) *l
Answer: a
Explanation: Gauge factor is defined as *. Gauge factor gives information on the expected resistance change or output signal at maximum permissible elongation.the gauge factor determines to a large extent the sensitivity of the wire when it is made into a practical strain gauge.
9. Compensation for temperature variation in the leads can be provided by using ________ lead method.
a) six
b) four
c) three
d) two
Answer: c
Explanation: Compensation for temperature variation in the leads can be provided by using three lead method. In this method two of the leads are in the adjacent legs of the bridge which cancels their resistance changes and does not disturb the bridge balance. The third lead is in series with the power supply and is therefore independent of bridge balance.
10. Strain gauge is used to measure ______________
a) temperature
b) pressure
c) height
d) displacement
Answer: b
Explanation: Strain gauge is used to measure pressure. Its working principle is change in resistance. There are two type of strain gauges. Bounded strain gauge and unbounded strain gauge. Mostly used to measure the arterial and venous blood pressure in the body.
This set of Biomedical Instrumentation Interview Questions and Answers for freshers focuses on “Transducers for Body Temperature Measurement”.
1. Sudden involuntary drop in body core temperature below 35*C is called __________
a) Accidental hyperthermia
b) Accidental misothermia
c) Accidental exothermia
d) Accidental hypothermia
Answer: d
Explanation: Sudden involuntary drop in body core temperature below 35*C is called Accidental hypothermia. In this, the body temperature drops very quickly. If not treated on time can lead to patients death.
2. Which of the following has the widest range of temperature measurement?
a) RTD
b) Thermocouple
c) Thermistor
d) Mercury thermometer
Answer: b
Explanation: Thermocouple has the widest range of temperature measurement from -184 0 C to +2300 0 C. RTD has a range of -200 0 C to +850 0 C. Thermistor has a range of 0 0 C to 100 0 C where as conventional mercury thermometers range is -37 0 C to +356 0 C.
3. The junction at a higher temperature in thermocouple is termed as measuring junction.
a) True
b) False
Answer: a
Explanation: The junction at a higher temperature in thermocouple is termed as measuring junction. The junction at lower temperature in the thermocouple is called the reference temperature. The cold junction is usually kept at 0 0 C.
4. When two wires of different material are joined together at either end, forming two junctions which are maintained at a different temperature, a thermo-motive force is generated causing a current to flow around the circuit. This arrangement is called ___________
a) thermal pair
b) thermistor
c) thermocouple
d) thermostat
Answer: c
Explanation: This arrangement is called thermocouple. The junction at a higher temperature in thermocouple is termed as measuring junction. The junction at lower temperature in the thermocouple is called the reference temperature.
5. When two wires of different material are joined together at either end, forming two junctions which are maintained at a different temperature, a _________ force is generated.
a) thermo-motive
b) electro-motive
c) chemical reactive
d) mechanical
Answer: a
Explanation: When two wires of different material are joined together at either end, forming two junctions which are maintained at a different temperature, a thermo-motive force is generated causing a current to flow around the circuit. This arrangement is called thermocouple. The junction at higher temperature in thermocouple is termed as measuring junction. The junction at lower temperature in the thermocouple is called the reference temperature.
6. The junction at a lower temperature in the thermocouple called measuring junction.
a) True
b) False
Answer: b
Explanation: The junction at a lower temperature in the thermocouple is called the reference temperature. The cold junction is usually kept at 0 0 C. The junction at a higher temperature in thermocouple is termed as measuring junction.
7. The lower temperature junction in thermocouple is maintained at ________
a) -273 K
b) 0 K
c) -327 K
d) 273 K
Answer: d
Explanation: The lower temperature junction in thermocouple is maintained at 273 K (0 0 C). The junction at lower temperature in the thermocouple is called the reference temperature. The junction at higher temperature in thermocouple is termed as measuring junction.
8. The resistance Rt of a metallic conductor at any temperature t is given by ___________
a) Rt = Roɑ
b) Rt = Roɑ
c) Rt = Roɑ
d) Rt = Roɑ
Answer: a
Explanation: The resistance Rt of a metallic conductor at any temperature t is given by Rt = Roɑ. Ro is the resistance at 0*C. ɑ is temperature coefficient of resistivity.
9. RTD stands for ________
a) resistance temperature device
b) resistance temperature detector
c) reluctance thermal device
d) resistive thermal detector
Answer: b
Explanation: RTD stands for Resistance Temperature Device. It is a passive sensor and requires current excitation to produce an output voltage. RTD has very low temperature coefficient. Voltage drop across RTD is much larger than thermocouple output voltage.
10. Thermister is used to measure _____________
a) temperature
b) pressure
c) height
d) displacement
Answer: a
Explanation: Thermistor is used to measure temperature. It is a temperature transducer. With a change in temperature its resistance changes. Thus its working principle is variable resistance. Thermistors are the oxides of certain metals like manganese, cobalt and nickel which have large negative temperature coefficient, i.e. resistance decreases with increase in temperature.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Photoelectric Transducers”.
1. What is the principle behind photoelectric transducers?
a) conversion of wind energy to electrical energy
b) conversion of light energy to electrical energy
c) conversion of mechanical energy to electrical energy
d) conversion of electrical energy to light energy
Answer: b
Explanation: Photoelectric transducers are based on the principle of conversion of light energy into electrical energy. This is done by causing the radiation to fall on a photosensitive element and measuring the electrical current so generated with a sensitive galvanometer directly or after suitable amplification.
2. Which of the following material is used to build photovoltaic cells?
a) selenium
b) celenuim
c) silicon
d) iron
Answer: a
Explanation: Photovoltaic or barrier layer cells usually consist of a semiconducting substance, which is generally selenium deposited on a metal base which may be iron and which acts as one of the electrodes. The semiconducting substance is covered with a thin layer of silver or gold deposited by cathodic deposition in a vacuum. This layer acts as a collecting electrode.
3. Selenium cells are sensitive to almost the entire range of wavelengths of the spectrum.
a) True
b) False
Answer: a
Explanation: Selenium cells are sensitive to almost the entire range of wavelengths of the spectrum. However, their sensitivity is greater within the visible spectrum and highest in the zones near the yellow wavelengths.
4. Which of the following is not a photoemissive cell?
a) high vacuum photocells
b) barrier layer cell
c) gas-filled photocell
d) photomultiplier tubes
Answer: c
Explanation: Barrier layer cells are photovoltaic cells. They consist of a semiconducting substance, which is generally selenium deposited on a metal base which may be iron and which acts as one of the electrodes. Photovoltaic cells are very robust in construction, need no external electrical supply and produce a photocurrent sometimes stronger than other photosensitive elements.
5. Photo-diodes work in _________
a) forward biased
b) reverse biased
c) independent of forward and reverse biasing
d) any configuration
Answer: b
Explanation: The photodiode is a P-N junction semiconductor diode. It always operated in the reversed biased condition. The light is always focused through a glass lens on the junction of the photo diode.
6. Photovoltaic cells need an external electrical supply to function.
a) True
b) False
Answer: b
Explanation: Photovoltaic cells are very robust in construction, need no external electrical supply and produce a photocurrent sometimes stronger than other photosensitive elements. Typical photocurrents produced by these cells are as high as 120 mA/lumen. At constant temperature, the current set up in the cell usually shows a linear relationship with the incident light intensity.
7. The instruments which give a direct reading of the temperature at the thermistor position are known as _________
a) thermistor
b) telethermometers
c) rtd
d) tempothermometer
Answer: b
Explanation: The instruments which give a direct reading of the temperature at the thermistor position are known by the name telethermometers. This is because of their ability to use leads which are hundreds of feet long without a significant decrease in accuracy. The continuous signal is also suitable for recording without amplification.
8. Which of the following is a photoemissive cell?
a) photomultiplier tubes
b) barrier layer cell
c) galvanic cell
d) rochell-salt cell
Answer: a
Explanation: Photomultiplier tubes are photoemissive cells. These type to cells do require an external power supply to provide a sufficient potential difference between the electrodes to facilitate the flow of electrons generated at the photosensitive cathode surface. Also, amplifier circuits are invariably employed for the amplification of this current.
9. Cesium-silver oxide cells are sensitive to the near infrared wavelengths.
a) True
b) False
Answer: a
Explanation: Cesium-silver oxide cells are sensitive to the near infrared wavelengths. Potassium silver oxide and cesium-antimony cells have maximum sensitivity in the visible and ultraviolet regions. The spectral response also depends partly on the transparency to different wavelengths of the medium to be traversed by the light before reaching the cathode.
10. Thermister is used to measure ____________
a) temperature
b) pressure
c) height
d) displacement
Answer: a
Explanation: Thermistor is used to measure temperature. It is a temperature transducer. With a change in temperature its resistance changes. Thus its working principle is variable resistance. Thermistors are the oxides of certain metals like manganese, cobalt and nickel which have large negative temperature coefficient, i.e. resistance decreases with increase in temperature.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Optical Fiber Sensors”.
1. Optical fiber sensors are electrically ____________
a) active
b) passive
c) active as well as passive
d) cannot be determined
Answer: b
Explanation: Optical fiber sensors are electrically passive and consequently immune to electromagnetic disturbances. They are geometrically flexible and corrosion resistant. They can be miniaturized and are most suitable for telemetry applications.
2. Optical fibers are not immune to ________
a) electronic disturbances
b) magnetic disturbances
c) ambient light interference
d) electromagnetic disturbances
Answer: c
Explanation: Optical fibre sensors are non-electrical and hence are free from electrical interference usually associated with electronically based sensors. Ambient light can interfere. Consequently, the sensor has to be applied in a dark environment or must be optically isolated.
3. Optical fiber sensors are not immune to electromagnetic disturbances.
a) True
b) False
Answer: b
Explanation: Optical fiber sensors are electrically passive and consequently immune to electromagnetic disturbances. They are geometrically flexible and corrosion resistant. They can be miniaturized and are most suitable for telemetry applications.
4. In which of the following optic fiber sensor the fiber is simply used to carry light to and from an external optical device where the sensing takes place?
a) extrinsic fiber optic sensor
b) energized fiber optic sensor
c) all fibers are used to simply carry light to and from the external optical devices
d) intrinsic fiber optic sensor
Answer: a
Explanation: In an extrinsic fiber optic sensor fiber is simply used to carry light to and from an external optical device where the sensing takes place. In an intrinsic fiber optic sensor, one or more of the physical properties of the fiber undergo a change.
5. On the bases of application of optic fiber sensor, which of the following is not considered to be the classification of fiber optic sensor?
a) biomedical/photometric sensors
b) physical sensors
c) thermal sensors
d) chemical sensors
Answer: c
Explanation: The variations in the returning light are sensed using a photodetector. Such sensors monitor variations either in the amplitude or frequency of the reflected light. Two of the most important physical parameters that can be advantageously measured using fibre optics are temperature and pressure.
6. The type of sensor that detects the analyte species directly through their characteristic spectral properties is called _____________
a) chemical sensor
b) thermal sensor
c) light sensor
d) spectroscopic Sensors
Answer: d
Explanation: Spectroscopic Sensors is the one that detects the analyte species directly through their characteristic spectral properties. In these sensors, the optical fibre functions only as a light guide, conveying light from the source to the sampling area and from the sample to the detector. Here, the light interacts with the species being sensed.
7. How many coils are required to make LVDT?
a) 4
b) 6
c) 3
d) 2
Answer: c
Explanation: Total 3 coils are required in LVDT. One centered coil which is the energizing or primary coil connected to the sine wave oscillator. The other two coils are the secondary coils so connected that their outputs are equal in magnitude but opposite in phase.
8. A chemical transduction system is interfaced to the optical fibre at its end. This type of sensor is called?
a) chemical sensor
b) thermal sensor
c) photoelectric sensor
d) light sensor
Answer: a
Explanation: In the chemical sensors, a chemical transduction system is interfaced to the optical fibre at its end. In operation, interaction with analyte leads to a change in optical properties of the reagent phase, which is probed and detected through the fibre optic. The optical property measured can be absorbance, reflectance or luminescence.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Biosensors”.
1. Doppler velocimetry works on the principle of __________
a) frequency measurement of fiber optic sensor
b) amplitude measurement of fiber optic sensor
c) phase measurement of fiber optic sensor
d) time shift measurement of fiber optic sensor
Answer: a
Explanation: Doppler velocimetry works on the principle of frequency measurement of fiber optic sensor. In this method, light from a laser, normally helium/neon, is sent via a fibre onto the skin surface. The moving red blood cells scatter the light and produce a Doppler frequency shift because of their movement.
2. Fluoroptic temperature sensors work on the principle of _______
a) thermistor
b) thermocouple
c) optical fiber
d) rtd
Answer: c
Explanation: Fluoroptic temperature sensors work on the principle of optical fiber sensors. They contain a rare earth phosphor which is illuminated by a white light along a short length of large core optical fibre. The light excites the phosphor which emits a number of lines. By using filters, two of these lines at 540 and 630 nm are selected, and the ratio of their intensities is a single valued function of the temperature of the phosphor.
3. Monopolar needle electrode have a coating of which material over the stainless steel wires which are bare only at the tips?
a) carbon
b) calcium
c) sodium
d) teflon
Answer: d
Explanation: The monopolar needle electrode consists of a teflon coated stainless steel wire. The wire is bare only at the tip. It is found that after the needle has been used a number of times, the teflon coating will recede, increasing the tip area. The needle should be discarded when this happens.
4. Endoscopic imaging uses ___________
a) thermal sensors
b) chemical sensors
c) optic fiber sensors
d) pressure sensors
Answer: c
Explanation: Optic sensors are used for endoscopic imaging. Optical fibre sensors are non-electrical and hence are free from electrical interference usually associated with electronically based sensors. They are suitable for telemetry applications as the bulk of the instrumentation can be at a reasonable distance from the patient.
5. _______________ converts biochemical events into measurable signals.
a) amplifier
b) opamp
c) rectifier
d) transducer
Answer: d
Explanation: Transducers convert biochemical events into measurable signals. They provide the means for detecting the biochemical changes inside the body. Particularly biosensors are employed for this purpose.
6. The biological response of the biosensor is determined by ______
a) biocatalytic membrane
b) physio-chemical membrane
c) chemical membrane
d) artificial membrane
Answer: a
Explanation: The biological response of the biosensor is determined by biocatalytic membrane. The biocatalytic membrane accomplishes the conversion of reactant to product. The product of the reaction diffuses to the transducer. This then causes the electrical response.
7. Home blood glucose sensor works on which principle?
a) electro-physiological
b) electrochemical
c) physio-chemical
d) chemical
Answer: b
Explanation: Home blood glucose detection sensor works on the principle of electrochemical. The biosensor in this instrument relies upon enzymes that recognise and catalyze reactions of glucose with the generation of redox – active species that are detected electrochemically.
8. The chemical reaction of glucose with oxygen is catalyzed in the presence of ________
a) glucose oxidase
b) monoglucose carbodase
c) glusoce dioxidase
d) biglucose oxidase
Answer: a
Explanation: The chemical reaction of glucose with oxygen is catalyzed in the presence of glucose oxidase. In the presence of glucose oxidase as a catalyst, the glucose and oxygen react and gluconic acid is produced as by product. Hydrogen perioxide (H 2 O 2 ) is also produced in some amount.
9. Home blood glucose measurement devices measure the glucose level through non-invasive method.
a) True
b) False
Answer: b
Explanation: Home blood glucose measurement devices measure the glucose level through invasive method. There is a small needle at the tip of the machine that pierces the skin to take blood sample. This blood is then undergoes electrochemical reactions and the glucose level is determined.
10. Blood glucose level measurement device uses a biosensor works on the principle of electrochemical.
a) True
b) False
Answer: a
Explanation: Home blood glucose detection sensor works on the principle of electrochemical. The biosensor in this instrument relies upon enzymes that recognize and catalyze reactions of glucose with the generation of redox – active species that are detected electrochemically.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Smart Sensors”.
1. Which of the following is not a fundamental block in recording systems?
a) electrodes and transducers
b) signal conditioner
c) analysis for the output
d) writing system
Answer: c
Explanation: Analysis of the output is not a fundamental block on the recording system. First, the signals are collected from the host. Then they are sent for signal conditioning where they are amplified to the desirable range and then the writing system prints the signals.
2. In medical recorders, the signal of interest is of the order of _______
a) nanovolts
b) microvolts
c) megavolts
d) volts
Answer: b
Explanation: The signals of interest in medical recorders are in the range of micro volts. They are captured by the help of sensitive electrodes and transducers and then amplified to a certain higher level. After the amplification further processing is carried out.
3. In medical devices, the amplifiers that are used for the amplification purpose of the input signal must have ___________
a) low frequency response
b) high frequency response
c) average frequency response
d) frequency response has no role to play in it
Answer: a
Explanation: The bioelectric signals in medical science contains components of extremely low frequency. Thus the amplifiers must also have a low frequency response. The response should be down to less than one hertz which is a very frequent requirement.
4. To achieve the low frequency response for medical applications, the amplifier configuration must contain?
a) higher resistance
b) higher capacitance
c) lower resistance
d) lower capacitance
Answer: b
Explanation: To achieve the low frequency response required for medical applications, the amplifier must have large values of coupling capacitance. In all RC-coupled amplifiers, low frequency response is limited by the reluctance of the coupling capacitors. The response should be down to less than one hertz which is a very frequent requirement.
5. Filter that amplifies frequency above a certain value is called?
a) low pass filter
b) high pass filter
c) band pass filter
d) band stop filter
Answer: b
Explanation: High pass filter amplifies signal above a certain frequency. Low pass filter amplifies signals below a certain frequency. Band pass filter amplifies frequencies within a certain band. Band stop filter amplifies all the frequencies except those in a certain band.
6. ________________ amplifies all the frequencies except those in a certain band.
a) high pass filter
b) low pass filter
c) band pass filter
d) band stop filter
Answer: d
Explanation: Band stop filter amplifies all the frequencies except those in a certain band. High pass filter amplifies signal above a certain frequency. Low pass filter amplifies signals below a certain frequency. Band pass filter amplifies frequencies within a certain band.
7. Active filters use opamps in addition to passive components in order to obtain better performance.
a) True
b) False
Answer: a
Explanation: True. Active filters use opamps in addition to passive components in order to obtain better performance. Operational amplifiers are frequently used as the gain blocks in active filters. Passive components are resistors capacitors and inductors.
8. Which of the following component is not a part of the passive filter?
a) resistor
b) operational amplifier
c) capacitor
d) inductor
Answer: b
Explanation: Operational amplifier is not a part of passive filters. It is a part of an active filter. Passive components are resistors capacitors and inductors. Active filters use opamps in addition to passive components in order to obtain better performance.
This set of Biomedical Instrumentation Questions and Answers for Experienced people focuses on “General Considerations for Signal Conditioners”.
1. The filter used to reject the 50Hz noise picked up from power lines or machinery is called?
a) band reject filter
b) band stop filter
c) notch filter
d) all reject filter
Answer: c
Explanation: Such filters are called notch filters. Almost all measuring and recording applications are subjected to some degree of 50Hz noise picked up from the power lines or machinery. Therefore, most signal conditioners include low pass filter designed specifically to provide maximum rejection of 50 Hz noise.
2. Devices that pass the signal from its source to the measurement device without a physical or galvanic connection by using transformer, optical or capacitive coupling technique are called?
a) filters
b) rectifiers
c) bridges
d) isolaters
Answer: d
Explanation: Such devices are called isolaters. Improper grounding of the system is one of the most common causes of measurement problem and noise. Signal conditioners with isolation can prevent these problems. Besides breaking ground loops, isolation blocks high voltage surges and rejects high common mode voltages.
3. Which of the following technique is not employed in isolation devices?
a) resistance
b) optical
c) inductance
d) capacitance
Answer: a
Explanation: Resistance technique is not employed in making isolation devices. The isolation devices pass the signal from its source to the measurement device without a physical or galvanic connection by using transformer, optical or capacitive coupling technique.
4. Besides breaking ground loops, isolation blocks high voltage surges and rejects high common mode voltages.
a) True
b) False
Answer: a
Explanation: It is true. Besides breaking ground loops, isolation blocks high voltage surges and rejects high common mode voltages. The isolation devices pass the signal from its source to the measurement device without a physical or galvanic connection by using transformer, optical or capacitive coupling technique.
5. Strain gauges are resistance devices in a Wheat stone bridge configuration _________
a) which does not require bridge completion circuitry and an excitation source
b) which requires bridge completion circuitry and an excitation source
c) which neither requires bridge completion circuitry nor an excitation source
d) which requires bridge completion circuitry but does not an excitation source
Answer: b
Explanation: Strain gauges are resistance devices in a Wheat stone bridge configuration which requires bridge completion circuitry and an excitation source. These devices require external voltage or current excitation. Signal conditioning part of the measurement system usually provides the excitation signals.
6. Which of the following voltage regulator IC gives a variable positive voltage?
a) LM317
b) LM337
c) 7805
d) 7812
Answer: a
Explanation: LM317 is a variable positive voltage regulator IC. It is capable of drawing current up to 1.5A and voltage range from 1.25V- 30V ideally. LM337 is a variable negative voltage regulator IC. 7805 and 7812 are fixed voltage regulator IC that give output voltage as 5V and 12V respectively.
7. ________ IC is a variable negative voltage regulator.
a) 7912
b) 7905
c) LM337
d) LM317
Answer: c
Explanation: LM337 is a variable negative voltage regulator IC. It is capable of drawing current up to 1.5A and voltage range from – ideally. LM317 is a variable positive voltage regulator IC. 7905 and 7912 are fixed voltage regulator IC that give output voltage as -5V and -12V respectively.
8. Digital filters are sensitive to temperature as compared with analog filters.
a) True
b) False
Answer: b
Explanation: False. Digital filters are insensitive to temperature as compared with analog filters. They are also insensitive to ageing, voltage drift and external interference as compared to analog filters. Their response is completely reproducible and predictable, and software simulations can exactly reflect product performance.
9. Signal conditioning is not of much importance in the measuring and recording system.
a) True
b) False
Answer: b
Explanation: Signal conditioning is of great importance in measuring and recording system. They determine the range, accuracy and resolution of the system. Signal conditioning includes either hardware based or software based linearization routines for this purpose.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Preamplifiers”.
1. Which amplifier will reject any common mode signal that appears simultaneously at both amplifier input terminal and amplifies only the voltage difference that appears across its input terminals?
a) ac coupled amplifiers
b) differential amplifiers
c) carrier amplifiers
d) dc amplifiers
Answer: b
Explanation: Differential amplifier is one which will reject any common mode signal that appears simultaneously at both amplifier input terminals and amplifies only the voltage difference that appears across its input terminals. Most of the amplifiers used for measuring bioelectric signals are of the differential type. AC amplifiers have a limited frequency response and are, therefore, used only for special medical applications such as electrocardiograph machine.
2. Which amplifier has a limited frequency response?
a) differential amplifier
b) dc amplifiers
c) ac coupled amplifiers
d) carrier amplifiers
Answer: b
Explanation: AC amplifiers have a limited frequency response and are, therefore, used only for special medical applications such as electrocardiograph machine. For electrocardiograms, an ac amplifier with sensitivity, giving 0.5 mV/cm, and a frequency response up to 1 kHz and an input impedance of 2 to 5 MW is used. For such applications as retinography, EEG and EMG, more sensitive ac amplifiers are required, giving a chart sensitivity of say 50 mV/cm with a high input impedance of over 10 MW.
3. ______________ are used with transducers which require an external source of excitation.
a) carrier amplifiers
b) dc amplifiers
c) ac coupled amplifiers
d) differential amplifier
Answer: a
Explanation: Carrier amplifiers are used with transducers which require an external source of excitation. They are characterized by high gain, negligible drift, extremely low noise and the ability to operate with resistive, inductive or capacitive type transducers. They essentially contain a carrier oscillator, a bridge balance and calibration circuit, a high gain ac amplifier, a phase-sensitive detector and a dc output amplifier.
4. DC amplifiers are employed with _______ feedback type.
a) positive
b) negative
c) depends on the application
d) can be any positive or negative does’t matter
Answer: b
Explanation: DC amplifiers are generally of the negative feedback type. They are used for medium gain applications down to about 1 mV signal levels for full scale. They are not practical for very low level applications because of dc drift and poor common-mode rejection capabilities.
5. DC amplifiers are mostly used for very low level applications because they offer very less dc drift and high common mode rejection capabilities.
a) True
b) False
Answer: b
Explanation: DC amplifiers are not practical for very low level applications because of dc drift and poor common-mode rejection capabilities. They are usually employed as pen drive amplifiers in direct writing recorders. They are used for medium gain applications down to about 1 mV signal levels for full scale.
6. Chopper stabilized dc amplifiers are complex amplifiers having ________ amplifiers incorporated in the module.
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: Chopper stabilized dc amplifiers are used for low level but preferably wideband applications such as oscilloscopes, tape recorders and light beam oscilloscope recorders. These are complex amplifiers having three amplifiers incorporated in the module. This includes an ac amplifier for signals above about 20 Hz, a dc chopper input amplifier for signals from about 20 Hz down to dc plus wideband feedback stabilized dc amplifier.
7. Which of the following amplifier is employed with resistive transducers which require an external source of excitation?
a) differential amplifier
b) ac coupled amplifier
c) carrier amplifier
d) dc bridge amplifier
Answer: d
Explanation: DC bridge amplifiersare employed with resistive transducers which require an external source of excitation. Essentially, the amplifier comprises of a stable dc excitation source, a bridge balance and calibration unit, a high gain differential dc amplifier and a dc output amplifier. They can be used as conventional dc high gain amplifiers and offer operating simplicity and high frequency response.
8. Chopper input dc amplifiersare preferred for low level inputs to instrumentation systems because of their high sensitivity, negligible drift and excellent common mode rejection capability.
a) True
b) False
Answer: a
Explanation: True. Chopper input dc amplifiersare preferred for low level inputs to instrumentation systems because of their high sensitivity, negligible drift and excellent common mode rejection capability. Their high frequency response is limited to about one half of the input chopper frequency.
This set of Biomedical Instrumentation Interview Questions and Answers for Experienced people focuses on “Sources of Noise in Low Level Measurements”.
1. Bio potential amplifiers have ____________ input terminals.
a) 3
b) 4
c) 5
d) 6
Answer: a
Explanation: Bio potential has three input terminals. Out of the three one is arranges at the reference potential. The other two are live terminals. Bio potential amplifiers are also known as differential amplifiers. The differential amplifier is employed when it is necessary to measure the voltage difference between two points, both of them varying in amplitude at different rates and in different patterns.
2. The ability of the amplifier to reject common voltages on its two input leads is known as ________
a) common mode rejection rate
b) coupled mode rejection rate
c) common mode rejection ratio
d) coupled mode rejection ratio
Answer: c
Explanation: The ability of the amplifier to reject common voltages on its two input leads is known as common-mode rejection. It is specified as the ratio of common-mode input to differential input to elicit the same response. It is abbreviated as CMRR .
3. CMRR is measured in ____________
a) V/s
b) dB
c) dB/s
d) dB/ms
Answer: b
Explanation: CMRR is an important specification referred to the differential amplifier and is normally expressed as decibels. The ability of the amplifier to reject common voltages on its two input leads is known as common-mode rejection. It is specified as the ratio of common-mode input to differential input to elicit the same response.
4. CMRR of the preamplifiers should be as high as possible.
a) True
b) False
Answer: a
Explanation: CMRR of the preamplifiers should be as high as possible so that only the wanted signals find a way through the amplifier and all unwanted signals get rejected in the preamplifier stage. The ability of the amplifier to reject these common voltages on its two input leads is known as common-mode rejection and is specified as the ratio of common-mode input to differential input to elicit the same response. CMRR is an important specification referred to the differential amplifier and is normally expressed as decibels.
5. The common mode rejection for most op-amps is typically between __________
a) 10-50dB
b) 20-40dB
c) 60-90dB
d) 100-120dB
Answer: c
Explanation: The common mode rejection for most op-amps is typically between 60 dB and 90 dB. This may not be sufficient to reject common mode noise generally encountered in biomedical measurements. Also, the input impedance is not very high to handle signals from high impedance sources.
6. The output of differential gain is given by _________
a) *
b) *
c) *
d) *
Answer: a
Explanation: The output of differential gain is given by *. gain is given by . The input resistances of but the inputs are the same.
7. In order to be able to minimize the effects of changes occurring in the electrode impedances, it is necessary to employ a preamplifier having a high input impedance.
a) True
b) False
Answer: a
Explanation: True. In order to be able to minimize the effects of changes occurring in the electrode impedances, it is necessary to employ a preamplifier having a high input impedance. It has been found that a low value of input impedance gives rise to considerable distortion of the recordings.
8. The impedance of the input should be ________ in order to obtain high CMRR in the differential amplifier.
a) low
b) High
c) Does not matter
d) Very low
Answer: b
Explanation: This shows that high input impedance is very necessary in order to obtain a high CMRR. Also, the electrode skin resistance should be low and as nearly equal as possible. In order to be able to minimize the effects of changes occurring in the electrode impedances, it is necessary to employ a preamplifier having a high input impedance.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Biomedical Signal Analysis and Processing Techniques”.
1. Which of the following statement is true for an instrumentational amplifier?
a) the input resistance of both the inputs is very high and does not change as the gain is varied
b) the input resistance of both the inputs is very low and does not change as the gain is varied
c) the input resistance of both the inputs is very high and does change as the gain is varied
d) the input resistance of both the inputs is very low and does change as the gain is varied
Answer: a
Explanation: The input resistance of both the inputs is very high and does not change as the gain is varied in and instrumentational amplifier. Voltage gain from differential input to single ended output, is set by one resistor. V0 does not depend on common-mode voltage, but only on their difference.
2. Which of the following is not the property of the instrumentational amplifier?
a) Extremely high input impedance
b) Low bias and offset currents
c) High slew rate
d) Very low CMRR
Answer: d
Explanation: Instrumentational amplifiers have very high CMRR. The instrumentation amplifier offers the following advantages for its applications in the biomedical field. Some of them are like extremely high input impedance, low bias and offset currents, high slew rate.
3. CMRR is measured in ___________
a) v/s
b) dB
c) dB/s
d) dB/ms
Answer: b
Explanation: CMRR is an important specification referred to the differential amplifier and is normally expressed as decibels. The ability of the amplifier to reject common voltages on its two input leads is known as common-mode rejection. It is specified as the ratio of common-mode input to differential input to elicit the same response.
4. The carrier amplifier consists of an oscillator and a capacitance coupled amplifier.
a) True
b) False
Answer: a
Explanation: The carrier amplifier consists of an oscillator and a capacitance coupled amplifier. The oscillator is used to energize the transducer with an alternating carrier voltage. The transducers, which require ac excitation, are those whose impedance is not purely resistive.
5. Electromagnetic coupling cannot be reduced by ___________
a) shielding
b) wire twisting
c) multiple grounding
d) common grounding
Answer: c
Explanation: Having multiple grounds in a single circuit increases the electromagnetic coupling effect by producing ground loop which may generate so much noise that it may completely obscure the useful signal. Thus, the electromagnetic coupling is reduced by shielding, wire twisting and proper grounding which provide a balanced signal pair with satisfactory noise rejection characteristics.
6. Which on the following is not a type of isolation amplifier?
a) capactively coupled isolation amplifiers
b) optically isolated isolation amplifiers
c) resistive coupled isolation amplifiers
d) transformer type isolation amplifiers
Answer: c
Explanation: There is nothing such as the resistive coupled isolation amplifiers. All the other three types are in common use, though the transformer isolation amplifier is more popular. Opto-coupled amplifier uses a minimum number of components and is cost effective, followed by the transformer coupled amplifier. The capacitor coupled amplifier is the most expensive.
7. The isolation includes different supply voltage sources and different grounds on each side of the isolation barrier.
a) True
b) False
Answer: a
Explanation: The isolation includes different supply voltage sources and different grounds on each side of the isolation barrier. Three methods are used in the design of isolation amplifiers: transformer isolation optical isolation capacitive isolation. Isolation amplifiers are commonly used for providing protection against leakage currents.
8. _________ are commonly used for providing protection against leakage currents.
a) Isolation amplifiers
b) Differential amplifiers
c) Instrumentational amplifiers
d) Inverting amplifiers
Answer: a
Explanation: Isolation amplifiers are commonly used for providing protection against leakage currents. They break the ohmic continuity of electric signals between the input and output of the amplifier. The isolation includes different supply voltage sources and different grounds on each side of the isolation barrier.
This set of Basic Biomedical Instrumentation Questions and Answers focuses on “The Main Amplifier and Driver Stage”.
1. The term ___________ is used when referring to the frequency content of a signal.
a) angular momentum
b) spectrum
c) scope
d) bandwidth
Answer: b
Explanation: The term spectrum is used when referring to the frequency content of a signal. The basic motivation for developing frequency analysis tools is to provide a mathematical and pictorial representation for the frequency components that are contained in any given signal. Most biomedical signals of practical interest can be decomposed into a sum of sinusoidal signal components.
2. The process of obtaining the spectrum of a given signal using the basic mathematical tools is known as _______________
a) time domain analysis
b) mathematical analysis
c) spectral analysis
d) pseudo analysis
Answer: c
Explanation: The process of obtaining the spectrum of a given signal using the basic mathematical tools is known as frequency or spectral analysis. The term spectrum is used when referring to the frequency content of a signal. Most biomedical signals of practical interest can be decomposed into a sum of sinusoidal signal components.
3. Most biomedical signals of practical interest can be decomposed into a sum of sinusoidal signal components. For the class of periodic signals, such a decomposition is called a _______ series.
a) fourier
b) discontinuous
c) continuous
d) frequency
Answer: a
Explanation: It is called a Fourier series. The term spectrum is used when referring to the frequency content of a signal. The process of obtaining the spectrum of a given signal using the basic mathematical tools is known as a frequency or spectral analysis.
4. Most biomedical signals of practical interest can be decomposed into a sum of sinusoidal signal components. For the class of finite energy signals, the decomposition is called the ____________
a) Fourier series
b) Fourier transform
c) Laplace transform
d) Laplace series
Answer: b
Explanation: For the class of finite energy signals, the decomposition is called the Fourier transform. For the class of periodic signals, such decomposition is called a Fourier series. The process of obtaining the spectrum of a given signal using the basic mathematical tools is known as a frequency or spectral analysis.
5. The ratio of response to a stimulus is called the transfer function.
a) True
b) False
Answer: a
Explanation: The ratio of response to a stimulus is called the transfer function.
H = R/S
The process of obtaining the spectrum of a given signal using the basic mathematical tools is known as a frequency or spectral analysis.
6. Each component in the FFT series can then be represented as A cos + iB sin where ______________
a) A = The phase angle of the component
b) f = An FFT coefficient
c) t = temperature
d) w = Angular frequency of the component
Answer: d
Explanation: w = Angular frequency of the component is the correct answer. Other all are the incorrect explanation of the variables. A = An FFT coefficient
f = The phase angle of the component and t = time.
7. Which of the following transform is best suited for spatial filtering, edge detection, feature extraction, data compression, pattern recognition, speech recognition, image compression and texture analysis?
a) wavelet transform
b) laplace transform
c) fourier transform
d) short time fourier transform
Answer: a
Explanation: The wavelet transform has very good time resolution at high frequencies and good frequency resolution at low frequencies. In biomedical engineering, wavelet transform have been widely used in many research areas including spatial filtering, edge detection, feature extraction, data compression, pattern recognition, speech recognition, image compression and texture analysis. Wavelets are a relatively new signal processing method. A wavelet transform is almost always implemented as a bank of filters that decompose a signal into multiple signal bands. It separates and retains the signal features in one or a few of these bands.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Writing System”.
1. For faithful reproduction of the input signal linearity over the required range of signal, amplitudes must be satisfied by the individual parts of the system.
a) True
b) False
Answer: a
Explanation: For faithful reproduction of the input signal, three basic conditions must be satisfied by the individual parts of the system. These requirements are linearity over the required range of signal amplitudes and an adequate passband for the frequencies involved without producing any phase shift between the input and recorded signal.
2. CRO stands for _______
a) Common Ray Oscilloscope
b) Cathode Ray Oscilloscope
c) Cathode Ray Oscillator
d) Common Ray Oscillator
Answer: b
Explanation: Cathode ray oscilloscopes are widely used for the display of waveforms encountered in the medical field. These waveforms can be recorded from the CRO screen by running a photographic film through a recording camera fixed in front of the screen. Recorders are either of the single channel type or of the type which record several channels simultaneously.
3. Which of the following is not a passive transducer?
a) Strain gauge
b) Ultrasonic transducer
c) IR sensor
d) Doppler effect transducer
Answer: a
Explanation: Strain gauge transducer is an active transducer. Its working principle is based on a change in resistance. Ultrasonic transducers need power to operate. So do the IR sensors and doppler effect transducers.
4. _____________ refers to the degree of repeatability of a measurant.
a) accuracy
b) precision
c) resolution
d) sensitivity.
Answer: b
Explanation: Precision refers to the degree of repeatability of a measurant. Accuracy describes the algebraic difference between the indicated value and the true or theoretical value of the measurand. Resolution is the ability of the transducer or sensor to see small differences in reading.
5. ____________ filter amplifies signals below a certain frequency.
a) band stop filter
b) high pass filter
c) band pass filter
d) low pass filter
Answer: d
Explanation: Low pass filter amplifies signals below a certain frequency. Band pass filter amplifies frequencies with in a certain band. Band stop filter amplifies all the frequencies except those in a certain band. High pass filter amplifies signal above a certain frequency.
6. Which of the following filter amplifies frequencies with a certain band?
a) band pass filter
b) band stop filter
c) low pass filter
d) high pass filter
Answer: a
Explanation: Band pass filter amplifies frequencies within a certain band. Band stop filter amplifies all the frequencies except those in a certain band. High pass filter amplifies signal above a certain frequency. Low pass filter amplifies signals below a certain frequency.
7. AAMI stands for ____________________
a) American Association of Medical Instrumentation
b) Association for the Advancement of Medical Instrumentation
c) Association of American Medical Instrumentation
d) American Association of Measurement Instruments
Answer: b
Explanation: Association for the Advancement of Medical Instrumentation, USA is an association for propelling the advancement, and protected and powerful utilization of restorative innovation established in 1965 by Robert D. Corridor, Jr. what’s more, Robert J. Allen, President and Vice President individually of Tech/Reps, Inc. AAMI is an intentional association, and in spite of the fact that its suggested practices and gauges once in a while reverberate other social insurance rules, consistency with these models isn’t really required by administrative associations that review medicinal services offices.
8. A wavelet transform is almost always implemented as a bank of filters that decompose a signal into multiple signal bands.
a) True
b) False
Answer: a
Explanation: It is true. A wavelet transform is almost always implemented as a bank of filters that decompose a signal into multiple signal bands. Wavelets are a relatively new signal processing method. Thus, one of the biggest advantages of using the wavelet transform is that signal features can be easily extracted. In many cases, a wavelet transform outperforms the conventional FFT when it comes to feature extraction and noise reduction. predictable, and software simulations can exactly reflect product performance.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Direct Writing Recorders”.
1. How many kidneys does a human have?
a) one
b) two
c) three
d) four
Answer: b
Explanation: The human body has two kidneys which lie in the back of the abdominal cavity just below the diaphragm, one on each side of the vertebral column. Each kidney consists of about a million individual units, all similar in structure and function. The main function of the kidneys is to form urine out of blood plasma.
2. The removal of waste products from blood plasma is performed by ___________
a) kidney
b) liver
c) heart
d) lungs
Answer: a
Explanation: The main function of the kidneys is to form urine out of blood plasma, which basically consists of two processes: the removal of waste products from blood plasma, and the regulation of the composition of blood plasma. The human body has two kidneys which lie in the back of the abdominal cavity just below the diaphragm, one on each side of the vertebral column.
3. The regulation of the composition of blood plasma is done by which of the following organ?
a) skin
b) heart
c) kidney
d) lung
Answer: c
Explanation: The human body has two kidneys which lie in the back of the abdominal cavity just below the diaphragm, one on each side of the vertebral column. The main function of the kidneys is to form urine out of blood plasma, which basically consists of two processes: the removal of waste products from blood plasma, and the regulation of the composition of blood plasma.
4. Each kidney consists of about a million individual units, all similar in structure and function. These tiny units are called __________
a) nerves
b) neurons
c) capillaries
d) nephrons
Answer: d
Explanation: Each kidney consists of about a million individual units, all similar in structure and function. These tiny units are called nephrons. A nephron is composed of two parts—a cluster of capillary loops called the glomerulus and a tubule.
5. Which of the following is the correct anatomical position of the kidney?
a) front of the abdominal cavity just below the diaphragm
b) back of the abdominal cavity just below the diaphragm
c) back of the abdominal cavity just above the diaphragm
d) front of the abdominal cavity just above the diaphragm
Answer: b
Explanation: The human body has two kidneys which lie in the back of the abdominal cavity just below the diaphragm, one on each side of the vertebral column. Each kidney consists of about a million individual units, all similar in structure and function. These tiny units are called nephrons.
6. Each kidney consists _______ number of nephrons.
a) thousands
b) millions
c) billions
d) trillions
Answer: b
Explanation: Each kidney consists of millions number of nephrons. A nephron is composed of two parts—a cluster of capillary loops called the glomerulus and a tubule. The tubule runs a tortuous course and ultimately drains via a collecting duct into the funnel-shaped expansion of the upper end of the ureter, i.e. the tube which conveys urine from the kidney to the bladder.
7. The kidneys work only on plasma.
a) True
b) False
Answer: a
Explanation: The kidneys work only on plasma. The erythrocytes supply oxygen to the kidneys but serve no other function in urine formation. Each substance in plasma is handled in a characteristic manner by the nephron, involving particular combinations of filtration, reabsorption and secretion.
8. The ___________ carry blood at very high pressure from the aorta into the glomerular capillary.
a) renal arteries
b) russal arteries
c) pulmonary arteries
d) fenal arteries
Answer: a
Explanation: The renal arteries carry blood at very high pressure from the aorta into the glomerular capillary tuft. The blood pressure within the glomerular capillaries is 70–90 mm of mercury. The blood flow through the capillary tuft is controlled by the state of contraction of the muscle of the arteriole leading to the tuft.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “The Inkjet Recorders”.
1. The total amount of glomerular filtrate is about ____________ per day.
a) 180 liters
b) 18 liters
c) 18 ml
d) 180 ml
Answer: a
Explanation: The total amount of glomerular filtrate is about 180 litres per day, whereas the amount of urine formed from it is only 1–1.5l. This means that very large amounts of water, and other substances, are re-absorbed by the kidney tubules.
2. The amount of urine formed by an average kidney in one day is ________
a) 10-10.5 L
b) 10-15 ml
c) 1-1.5 L
d) 5 L
Answer: c
Explanation: The amount of urine formed by an average kidney in one day is 1-1.5 L. The total amount of glomerular filtrate is about 180 litres per day. Very large amounts of water and other substances are re-absorbed by the kidney tubules.
3. Which hormone of the pituitary gland helps to automatically reabsorb water from the kidney?
a) Anti-diuretic hormone
b) Diuretic hormone
c) Pro-diuretic hormone
d) Pseudo-diuretic hormone
Answer: c
Explanation: The re-absorption is partly an automatic process because the absorption of water is accurately controlled by the anti-diuretic hormone of the pituitary gland, in relation to the body’s need for water. The absorption of electrolytes such as sodium and potassium is partly controlled by the supra-renal gland and the concentration of others, like chloride and bicarbonate, is related to the acid-base balance.
4. The total blood flow through the kidneys is about _____________
a) 120 ml/min
b) 1200 ml/min
c) 200 ml/min
d) 10 ml/min
Answer: b
Explanation: The total blood flow through the kidneys is about 1200 ml/min. The absorption of electrolytes such as sodium and potassium is partly controlled by the supra-renal gland and the concentration of others, like chloride and bicarbonate, is related to the acid-base balance. Some of the re-absorption from the glomerular filtrate is also a passive, automatic process of diffusion depending upon pressure gradients.
5. The total extra-cellular fluid amounts to about _________
a) 1 litres
b) 15 milli-litres
c) 15 litres
d) 150 litres
Answer: c
Explanation: The total extra-cellular fluid amounts to about 15 litres. Some of the re-absorption from the glomerular filtrate is also a passive, automatic process of diffusion depending upon pressure gradients. The total blood flow through the kidneys is about 1200 ml/min.
6. Kidneys has no role maintaining the acid-base balance.
a) True
b) False
Answer: b
Explanation: It is false. Kidney plays an important role in maintaining the acid-base balance. The water and electrolyte content of the blood plasma and, therefore, indirectly of the extra-cellular fluid are closely controlled by the kidneys. The blood plasma and the extra-cellular fluid are in equilibrium with each other and, therefore, an amount of blood equivalent to all the extra-cellular fluid can pass through the kidneys once every 15 minutes.
7. The symptoms and signs of profound renal malfunction are known as uremia.
a) True
b) False
Answer: a
Explanation: The symptoms and signs of profound renal malfunction are known as uremia, meaning urine in the blood. Since most urinary contents are water-soluble, they reach high concentrations in blood and result in deranged body parts and their physiology.
8. Chronic renal failure results in changes in the body fluids which occur due to a _____________
a) progressive increase in the number of functioning nephrons
b) progressive decrease in the number of functioning nephrons
c) progressive decrease in the number of functioning neurons
d) progressive increase in the number of functioning neurons
Answer: c
Explanation: Chronic renal failure results in changes in the body fluids which occur due to a progressive decrease in the number of functioning nephrons. With the decrease in functional nephrons, the clearance of urea, creatinine and other metabolic waste products will decrease proportionally. In consequence, the plasma concentrations of these substances will rise.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Potentiometric Recorder”.
1. Which of the following statement is correct?
a) movement of waste product molecules from the dialysate to the blood results in cleaning of the blood
b) movement of waste product molecules from the blood to the dialysate results in cleaning of the blood
c) movement of waste product molecules from the blood to the dialysate results in impuring of the blood
d) movement of waste product molecules from the dialysate to the blood results in cleaning of the blood
Answer: b
Explanation: Movement of waste product molecules from the blood to the dialysate results in cleaning of the blood. The dialysate fluid is free of waste product molecules and, therefore, those in the blood would tend to distribute themselves evenly throughout the blood and the dialysate. All other options are completely wrong.
2. A positive pressure is applied to the blood compartment or a negative pressure established in the dialysate compartment. This process in dialyses is called ______________
a) nano filtration
b) mega filtration
c) micro filtration
d) ultra filtration
Answer: d
Explanation: The volume of body fluid cannot be controlled by dialysis. Instead, ultra-filtration across the membrane is employed. For this, a positive pressure is applied to the blood compartment or a negative pressure established in the dialysate compartment. Either way, fluid—both water and electrolytes—will move from the blood compartment to the dialysate, which is subsequently discarded.
3. Electrode paste ______________
a) increases contact impedance
b) equates contact impedance
c) reduces contact impedance
d) absorbs contact impedance
Answer: c
Explanation: In order to obtain a clearly established contact an electrolyte or electrode paste is usually employed as an interface between the electrode and the surface of the source of the event. It is placed between the skin and the electrode. It helps to get better signal acquisition.
4. Heart wall is made up of __________ layers.
a) 2
b) 4
c) 3
d) 7
Answer: c
Explanation: Heart wall is made up of three layers. First pericardium which is the outer layer of the heart. Second is the myocardium which is the middle layer of the hear and finally endocardium which is the inner layer of the heart wall.
5. Uremia is the clinical state resulting from _____________
a) renal failure
b) liver failure
c) kidney failure
d) lung failure
Answer: a
Explanation: Uremia is the clinical state resulting from renal failure. The signs and symptoms of uremia are extremely diverse and frequently appear to point to a disease of other organs. Uremia affects every organ of the body as certain substances that accumulate in uremia are clearly toxic.
6. Dialysis takes place across a membrane of cellophane.
a) True
b) False
Answer: a
Explanation: It is true. The dialysate is an electrolyte solution of suitable composition and the dialysis takes place across a membrane of cellophane. The return of the dialyzed blood is by another plastic tube to an appropriate vein.
7. Blood pressure in the glomerular capillaries is in the range of?
a) 17-19 mmHg
b) 7-9 mmHg
c) 170-190 mmHg
d) 70-90 mmHg
Answer: d
Explanation: The blood pressure within the glomerular capillaries is 70–90 mm of mercury. The blood flow through the capillary tuft is controlled by the state of contraction of the muscle of the arteriole leading to the tuft. The renal arteries carry blood at very high pressure from the aorta into the glomerular capillary tuft.
8. The glomerular filtrate consists of blood plasma with proteins.
a) True
b) False
Answer: b
Explanation: It is false. The glomerular filtrate consists of blood plasma without proteins. The fluid pressure within the tuft forces some of the fluid part of the blood, by filtration, through the thin walls of the capillaries into the glomerulus and on into the tubule of the nephron.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Digital Recorders”.
1. The removal of waste products during dialysis is ___________
a) inversely proportional to the concentration gradient across the membrane
b) proportional to the concentration gradient across the membrane
c) proportional to the flow rate across the membrane
d) inversely proportional to the flow rate across the membrane
Answer: b
Explanation: The removal of waste products during dialysis is proportional to the concentration gradient across the membrane. In order to effect the maximum gradient, the concentration of waste products in the dialysate should be maintained at zero. This is achieved in most currently employed machines by using the dialysate only once and then discarding it.
2. Counter-current flow through the artificial kidney is used so that the dialysate enters the kidney at the blood exit-end. Where the blood concentration of waste products is at the lowest level?
a) lowest level
b) very high level
c) high level
d) medium level
Answer: a
Explanation: Counter-current flow through the artificial kidney is used so that the dialysate enters the kidney at the blood exit-end where blood concentration of waste products is at the lowest level. The removal of waste products during dialysis is proportional to the concentration gradient across the membrane. In order to effect the maximum gradient, the concentration of waste products in the dialysate should be maintained at zero.
3. Parallel flow dialyzer has a low internal resistance. Because of this blood pump is required.
a) True
b) False
Answer: b
Explanation: Parallel flow dialyzer has a low internal resistance which allows adequate blood flow through the dialyzer with the patient’s arterial blood pressure, eliminating the need for a blood pump. The dialyzing surface area of a parallel flow dialyzer is about 1 sq m. At a blood flow rate of 200 ml/min and a dialysate flow of 500 ml/min, the urea and creatinine clearance is about 80 and 64 ml/min.
4. KIIL dialyzer is a type of _________
a) coil hemodialyzer
b) hollow fiber dialyzer
c) series flow dialyzer
d) parallel flow dialyzer
Answer: b
Explanation: The KIIL dialyzer has earlier been the most commonly used form of parallel flow dialyzer. It consists of three polypropylene boards with dialyzing membranes laid between them. The boards are held firmly with a frame on the top and bottom and are fastened by a series of bolts on the side.
5. The KIIL dialyzer is not disposable.
a) True
b) False
Answer: a
Explanation: It is true. The KIIL dialyzer is not disposable. It needs to be cleaned and re-built after each dialysis operation. With this type of dialyzer, a single-pass body temperature dialysate passes through the dialyzer once before going to the drain to obtain higher operational efficiency and to minimize bacterial infection.
6. The volume of blood within the dialyzer is known as __________
a) secondary volume
b) quarterly volume
c) priming volume
d) residual volume
Answer: c
Explanation: The volume of blood within the dialyzer is known as priming volume. It is desirable that this should be minimal. Priming volume of present day dialyzers ranges from 75 to 200 ml, depending on the membrane area geometry and operating conditions.
7. The ideal membrane should possess __________
a) low permeability to water
b) high permeability to water
c) medium permeability to water
d) high permeability to waste
Answer: b
Explanation: The ideal membrane should possess high permeability to water, organic metabolites and ions, and the capability of retaining plasma proteins. The membrane should be of sufficient wet strength to resist tearing or bursting and non-toxic to blood and all body cells.
8. Which of the following is the commonly used membrane for hemodialysis?
a) Cupraphan
b) Cotton
c) Cellulose
d) calcium
Answer: a
Explanation: Cupraphan is the commonly used membrane for haemodialysis. It is a membrane consisting of natural cellulose and is considered puncture-proof, and of high tenacity and elasticity. During haemodialysis, different substances of varying molecular weight are to be removed.
9. The delta wave in EEG ranges from _________
a) 0.5-4Hz
b) 4-8Hz
c) 8-13Hz
d) 13-22Hz
Answer: a
Explanation: The delta wave in EEG ranges from 0.5-4Hz. The theta wave in EEG ranges from 4-8Hz. The alpha wave in EEG ranges from 8-13Hz and beta from 13-22Hz.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Video Printers”.
1. Any disturbance in the heart’s normal rhythmic contraction is called?
a) Heart stroke
b) Cardiac arrest
c) Arrhythmias
d) Premature contraction
Answer: c
Explanation: Any disturbance in the heart’s normal rhythmic contraction is called an arrhythmias or cardiac dysrhythmia. In this arrhythmias heart can’t beat in a regular rhythm. In arrhythmia heart-rate will be higher than normal rate or will be less than the normal rate.
2. Which diagnostic statement is based on ECG wave shapes that attempt to describe the state of the working muscle masses?
a) Rhythm statements
b) Morphological statements
c) Morphological-Rhythm statements
d) Rhythm-Morphological statements
Answer: b
Explanation: Morphological statement-primarily based on ECG wave shapes that attempt to describe the state of the working muscle masses. The other type of diagnostic statement is Rhythm statement. These both diagnostic statements are observed from the ECG records.
3. Rhythm statements concerned with the site and rate of the cardiac pacemaker and the propagation of impulses through the conduction system.
a) True
b) False
Answer: a
Explanation: Rhythm statements concerned with the site and rate of the cardiac pacemaker and the propagation of impulses through the conduction system is true because the other type of the diagnostic statements is Morphological statements and it is primarily based on ECG wave shapes that attempt to describe the state of the working muscle masses.
4. Which wave from ECG waveforms becomes widened when the self-triggering impulse does not arrive through the AV node?
a) P wave
b) QRS wave
c) ST wave
d) T wave
Answer: b
Explanation: Sometimes irritation occurs in the ventricles, the self-triggering impulse does not arrive through the node and thus travels a different and slower path in spreading over the ventricles. The QRS wave then becomes widened and is classified as a ventricular ectopic beat.
5. When the self-triggering impulse does not arrive at the AV node and travels a different and slower path over the ventricles, the QRS becomes widened and is classified as ___________
a) Ectopic beat
b) Ventricular-ectopic beat
c) Ventricular beat
d) Atrio-ventricular beat
Answer: b
Explanation: Sometimes irritation occurs in the ventricles, the self-triggering impulse does not arrive through the node and thus travels a different and slower path in spreading over the ventricles. The QRS wave then becomes widened, and is classified as a ventricular ectopic beat. This ectopic beat is classified from ventricles so it is called as a ventricular ectopic beat.
6. An ectopic beat, which starts in an abnormal location in the heart and is often premature, therefore also called _______
a) Pre ventricular contraction
b) Premature ventricular beat
c) Pre ventricular beat
d) Premature ventricular contraction
Answer: d
Explanation: An ectopic beat is a beat, which starts in an abnormal location in the heart and is often premature, therefore also called premature ventricular contraction , i.e. it occurs sooner than the next expected beat.
7. When the heartbeat is slower than the normal rate of the heart, this type of arrhythmias called _______
a) Bradycardia
b) Tachycardia
c) Arterial contraction
d) Ventricular contraction
Answer: a
Explanation: There are 2 types of arrhythmias, i) Bradycardia-when the heart-rate is to slow, ii)Tachycardia-when the heart-rate is to fast. Here the answer is Bradycardia because heart rate is less than 60.
8. Which of the following are resuscitation techniques?
a) Cepstrum coefficient
b) Prophylactic therapy
c) Transthoracic defibrillation
d) Dynamic time warping
Answer: d
Explanation: The necessity for early detection of the arrhythmias led to the establishment of coronary care units in hospitals for the intensive monitoring and treatment of such patients. The attempt in these units was to effectively carry out resuscitation techniques such as cardiac massage and transthoracic defibrillation.
9. If heart rate is x, then which value of x is known as tachycardia?
a) x < 60
b) x > 60
c) 60 < x < 100
d) x > 100
Answer: d
Explanation: There are 2 types of arrhythmias,i)Bradycardia-when the heartrate is to slow, ii)Tachycardia-when the heartrate is to fast.Here the answer is Bradycardia because,heart rate is less than 60.
10. Photo-diodes work in ___________
a) forward biased
b) reverse biased
c) independent of forward and reverse biasing
d) any configuration
Answer: b
Explanation: The photodiode is a P-N junction semiconductor diode. It always operated in the reversed biased condition. The light is always focused through a glass lens on the junction of the photo diode.
11. Parallel flow dialyzer has a low internal resistance. Because of this blood pump is required.
a) True
b) False
Answer: b
Explanation: Parallel flow dialyzer has a low internal resistance which allows adequate blood flow through the dialyzer with the patient’s arterial blood pressure, eliminating the need for a blood pump. The dialyzing surface area of a parallel flow dialyzer is about 1 sq m. At a blood flow rate of 200 ml/min and a dialysate flow of 500 ml/min, the urea and creatinine clearance is about 80 and 64 ml/min.
12. CMRR is measured in _______________
a) V/s
b) dB
c) dB/s
d) dB/ms
Answer: b
Explanation: CMRR is an important specification referred to the differential amplifier and is normally expressed as decibels. The ability of the amplifier to reject common voltages on its two input leads is known as common-mode rejection. It is specified as the ratio of common-mode input to differential input to elicit the same response.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Electrocardiography”.
1. The frequency range of ECG is ____________
a) 0.05-150 HZ
b) 500-1500 Hz
c) 5-500 kHz
d) 0.5-150 MHz
Answer: a
Explanation: The diagnostically useful frequency range is usually accepted as 0.05 to 150 Hz. Although the electric field generated by the heart can be best characterized by vector quantities, it is generally convenient to directly measure only scalar quantities, i.e. a voltage difference of mV order between the given points of the body.
2. Which of the following amplifier circulatory is employed to reduce the hum noise generated by the power supply in the ECG circuit?
a) band pass filters
b) high pass filters
c) notch filters
d) low pass filters
Answer: c
Explanation: A notch filter is employed to suppress the hum noise generated by the power supply in the ECG circuit. CMRR of the order of 100–120 dB with 5 kW unbalance in the leads is a desirable feature of ECG machines. The instability of the baseline, originating from the changes of the contact impedance, demands the application of the automatic baseline stabilizing circuit.
3. The branch of medicine that deals with the provision and use of artificial devices such as splints and braces is _________
a) prosthetics
b) orthotics
c) laproscopic
d) augmentative communication
Answer: c
Explanation: The branch of medicine that deals with the provision and use of artificial devices such as splints and braces are orthotics. A modality-specific appliance that aids the performance of a function or movement by augmenting or assisting the residual capabilities of that function or movement. An orthopaedic brace is an orthosis.
4. The sensitivity of an electrocardiograph is typically set at 10 mm/mV.
a) True
b) False
Answer: a
Explanation: It is true. The sensitivity of an electrocardiograph is typically set at 10 mm/mV. For routine work, the paper recording speed is 25 mm/s. Amplitude measurements are made vertically in millivolts. Time measurements and heart rate measurements are made horizontally on the electrocardiogram.
5. The volume of blood within the dialyzer is known as ___________
a) secondary volume
b) quarterly volume
c) priming volume
d) residual volume
Answer: c
Explanation: The volume of blood within the dialyzer is known as priming volume. It is desirable that this should be minimal. Priming volume of present day dialyzers ranges from 75 to 200 ml, depending on the membrane area geometry and operating conditions.
6. The ideal membrane should possess ___________ to water.
a) low permeability to water
b) high permeability to water
c) medium permeability to water
d) high permeability to waste
Answer: b
Explanation: The ideal membrane should possess high permeability to water, organic metabolites and ions, and the capability of retaining plasma proteins. The membrane should be of sufficient wet strength to resist tearing or bursting and non-toxic to blood and all body cells.
7. To achieve optimum performance and to enable the relationship of change in resistance with the volume of the cell to hold good, it is recommended that the ratio of the aperture length to the diameter of the aperture should be __________
a) 75:1
b) 0.75:100
c) 0.75:1
d) 0.5:10
Answer: c
Explanation: To achieve optimum performance and to enable the relationship of change in resistance with volume of the cell to hold good, it is recommended that the ratio of the aperture length to the diameter of the aperture should be 0.75:1, i.e. for an orifice of 100 m diameter the length should be 75 m. The instrument based on the Coulter principle works most satisfactorily when the average diameter of the particles ranges between 2 to 40% of the diameter of the measuring hole.
8. The blood is a poor conductor of electricity.
a) True
b) False
Answer: a
Explanation: It is true. Blood is a poor conductor of electricity. This principle is used in Coulter counters to count the number of RBCs in the blood.
9. In floating electrodes metal electrode does not make direct contact with the skin.
a) True
b) False
Answer: a
Explanation: In a floating electrode, the metal electrode does not make direct contact with the skin. The electrode consists of a light weighted metalled screen or plate held away from the subject by a flat washer which is connected to the skin. Floating electrodes can be recharged, i.e. the jelly in the electrodes can be replenished if desired.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Vectorcardiography ”.
1. Which gas saturation is of great importance in clinical practice?
a) oxygen
b) carbon dioxide
c) hydrogen
d) nitrogen
Answer: a
Explanation: In clinical practice, the percentage of oxygen saturation in the blood is of great importance. This saturation being a bio-constant is an indication of the performance of the most important cardio-respiratory functions. It is maintained at a fairly constant value to within a few percents in a healthy organism.
2. Liquid part of blood is __________
a) Platelets
b) Red Blood Cells
c) White Blood Cells
d) Plasma
Answer: d
Explanation: The plasma is a very poor carrier of oxygen. At the pressures available, only 0.3 ml of oxygen can dissolve in 100 ml of plasma, which is quite insufficient for the needs of the body.
3. What does red blood cells contain for combining with a large volume of oxygen?
a) Proteins
b) Haemoglobin
c) Lipids
d) Platelets
Answer: b
Explanation: The red blood cells contain haemoglobin which can combine with a large volume of oxygen so quickly that in the lungs it may become 97% saturated forming a compound called oxyhaemoglobin.
4. How much quantity of oxygen bound with haemoglobin in the normal arterial blood?
a) 20.3ml %
b) 21.5ml %
c) 19.4ml %
d) 20.1ml %
Answer: c
Explanation: The total quantity of oxygen bound with haemoglobin in the normal arterial blood is approximately 19.4 ml percent at a pO2 of 95 mmHg. On passing through the tissue capillaries this amount is reduced to 14.4 ml percent at a pO2 of 40 mmHg.
5. When blood is withdrawn from the subject under anaerobic conditions and measurement for oxygen saturation is made at a later time in the laboratory, the procedure is referred to as _________ oximetry.
a) in vitro
b) in vivo
c) transmission
d) reflection
Answer: a
Explanation: When blood is withdrawn from the subject under anaerobic conditions and measurement for oxygen saturation is made at a later time in the laboratory, the procedure is referred to as in vitro oximetry.
6. For discrete blood samples, a spectrophotometric measurement of oxygen saturation can be made by which method?
a) in vitro
b) in vivo
c) transmission
d) cannot be determined
Answer: c
Explanation: For discrete blood samples, a spectrophotometric measurement of oxygen saturation can be made by either a transmission method or a reflection method.
7. Which principle is used by ear oximeter usually?
a) in vivo
b) transmission
c) reflection
d) in vitro
Answer: b
Explanation: Ear oximeters usually make use of the transmission principle to measure arterial oxygen saturation. In this case, the pinna of the ear acts as a cuvette. Blood in the ear must be made similar to arterial blood in composition.
8. Blood in _________ must be made similar to arterial Blood in composition.
a) heart
b) brain
c) ear
d) eyes
Answer: c
Explanation: Blood in the ear must be made similar to arterial blood in composition. This is done by increasing the flow through the ear without appreciably increasing the metabolism. Maximum vasodilatation is achieved by keeping the ear warm.
9. By keeping the ear warm, maximum vasodilatation is achieved.
a) True
b) False
Answer: a
Explanation: Yes, maximum vasodilatation is achieved by keeping the ear warm. It takes about 5 or 10 min for the ear to become fully dilated after the ear unit has been put up in place and the lamp turned on.
10. What is time taken for the ear to become fully dilated after ear unit has been placed?
a) 5-10 min
b) 10-15 min
c) 15-20 min
d) 20-25 min
Answer: a
Explanation: Maximum vasodilatation is achieved by keeping the ear warm. It takes about 5 or 10 min for the ear to become fully dilated after the ear unit has been put up in place and the lamp turned on.
11. Merrick and Hayes describe details of a _________ oximeter which enables the measurement of oxygen saturation of blood.
a) Pulse
b) Ear
c) Skin Reflactance
d) Intravascular
Answer: b
Explanation: Merrick and Hayes describe details of an ear oximeter which enables the measurement of oxygen saturation of the blood. This measurement is independent of a wide range of encountered variables and is made without involving patients in any calibration or standardization procedure.
12. This technique involves measuring the optical transmittance of the ear at how many wavelengths?
a) 12
b) 6
c) 8
d) 10
Answer: c
Explanation: In brief, the technique involves measuring the optical transmittance of the ear at 8 wavelengths in the 650 to 1050 nm range. A 2.5 m long flexible fibre ear probe connects the patient to the instrument.
13. Ear probe which connects the patient to instrument is ___________ m long.
a) 1.5
b) 2.0
c) 2.5
d) 3.0
Answer: c
Explanation: A 2.5 m long flexible fibre ear probe connects the patient to the instrument. The ear probe can be either held in position for discrete measurements or can be conveniently mounted to a headband for continuous display.
14. Ear oximeter instrument is based on Beer-Lambert law.
a) True
b) False
Answer: a
Explanation: The instrument is based on the Beer-Lambert law. However, it is assumed that the optical absorbers act independently and additively and that the effects of light scattering by the ear tissue can be minimized by a proper source and detector geometry.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Phonocardiography ”.
1. An arrhythmia monitor is basically a ______
a) Sophisticated monitoring system
b) Sophisticated alarm system
c) Patient monitoring system
d) ECG interpretation system
Answer: b
Explanation: An arrhythmia monitor is basically a sophisticated alarm system. It is not an ECG interpretation system. It constantly scans ECG rhythm patterns and issues alarms to events that may be premonitory or life threatening.
2. In arrhythmia monitoring system, it gives alarm light signals whenever the prematured or widened ectopic beats exist up to the rate of ___________
a) 6/min to 10/min
b) 6/min to 12/min
c) 6/min or 10/min
d) 6/min or 12/min
Answer: d
Explanation: In arrhythmia monitoring instrument, it gives alarm light signals whenever the prematured or widened ectopic beat exist up to the rate of 6/min or 12/min.It is one of the operating sequences of the arrhythmia monitoring instrument.
3. In automated arrhythmia monitoring system, which task is performed after the Ventricular fibrillation detection?
a) Rhythm definition
b) Beat labeling
c) Atrial fibrillation detection
d) Noise detection
Answer: a
Explanation: In automated arrhythmia monitoring system, Rhythm definition is performed after the Ventricular fibrillation detection. Rhythm definition is also performed after the beat labeling and atrial fibrillation detection in automated arrhythmia monitoring and analysis system.
4. In signal conditioning, ECG signal is amplified, filtered with 0.05-100 Hz for monitoring purposes and 1-40 Hz for diagnostic purposes.
a) True
b) False
Answer: b
Explanation: ECG signal is amplified and filtered with 0.05-100 Hz for diagnostic purposes and 1-40 Hz for monitoring purposes in signal conditioning.
5. Which analog-to-digital converter is used in the digitization of ECG signal in signal conditioning?
a) 16 bit
b) 12 bit
c) 32 bit
d) 64 bit
Answer: b
Explanation: In signal conditioning, ECG signal is amplified, filtered and digitized using an 8 or 12 bit analog-to-digital converter with a typical sampling rate of 250 Hz.
6. By using a _________ rather than a _________ the amplitude of low frequency noise as well as the low frequency components of the ECG will be reduced without affecting the QRS.
a) High-pass filter, Band-pass filter
b) Low-pass filter, Band-pass filter
c) Band-pass filter, Low-pass filter
d) Band-pass filter, High-pass filter
Answer: c
Explanation: The maximum of the QRS energy spectrum is in the vicinity of 10 Hz, the filter is designed to have a bandwidth of about 15 Hz with a centre frequency of 10-12 Hz. By using a bandpass filter rather than a low-pass filter, the amplitude of low frequency noise as well as the low frequency components of the ECG will be reduced without affecting the QRS.
7. The steep, large amplitude variation of the QRS complex is the obvious characteristics to use and this is the function of the R wave detector.
a) True
b) False
Answer: a
Explanation: Arrhythmia monitors require reliable R wave detectors as a prerequisite for subsequent analysis. The steep, large amplitude variation of the QRS complex is the obvious characteristics to use and this is the function of the R wave detector.
8. In the process of the ECG waveform, the detection filter removes _______ and _______
a) Baseline wander, motion noise
b) Muscle artifact, motion noise
c) Low frequency noise, motion noise
d) Baseline wander, muscle artifact
Answer: c
Explanation: The ECG waveform is processed by two digital filters: a detection filter and a classification filter. The detection filter removes low frequency noise and muscle artifact. P waves and T waves are diminished.
9. How many steps are there in QRS detection?
a) Three steps
b) Two steps
c) Four steps
d) One step
Answer: b
Explanation: QRS detection is now almost universally performed digitally in a two-step process. The ECG is first preprocessed to enhance the QRS complex while suppressing noise, artifact and non-QRS portions of the ECG. The output of the preprocessor stage is subjected to a decision rule that confirms the detection of QRS if the processor output exceeds a threshold.
10. _________ is based on analyzing the shape of the QRS complexes and separating beats into groups or clusters.
a) Timing classification
b) Morphology characterization
c) Beat labeling
d) Noise detection
Answer: b
Explanation: Morphology characterization is based on analyzing the shape of the QRS complexes and separating beats into groups or clusters of similar morphology. Most algorithms for real time arrhythmia analysis maintain no more than 10-20 clusters at a time, order to limit the amount of computation needed to assign a QRS complex to a cluster.
11. When will be R-R interval declared premature?
a) If it is greater than 85% of the predicted interval
b) If it is less than 85% of the predicted interval
c) If it is greater than 75% of the predicted interval
d) If it is less than 75% of the predicted interval
Answer: b
Explanation: In timing classification, the observed R-R interval is compared to an estimate of the expected R-R interval. An R-R interval will be declared premature if it is less than 85% of the predicted interval. Similarly, an R-R interval is long if it is greater than 110% of the predicted value.
12. Which is the final stage in arrhythmia analysis?
a) Beat labeling
b) Alarms
c) Rhythm labeling
d) Summary statistics
Answer: c
Explanation: Rhythm labeling is the final stage in arrhythmia analysis. It is based on defined sequences of QRS complexes. The analysis systems are heavily oriented towards detecting ventricular arrhythmias, particularly single PVCs.
13. Ventricular Fibrillation is detected by _________
a) Shape of the QRS complexes
b) Difference of the R-R interval
c) Timing sequence of QRS complexes
d) Frequency domain analysis
Answer: d
Explanation: Ventricular fibrillation is usually detected by frequency domain analysis. The system is characterized as a narrow-band, low frequency signal with energy concentrated in a band around 5-6 Hz. It can be distinguished from noise by appropriately designing band-pass filters.
14. Which techniques are used in a new algorithm proposed by Jen and Hwang to obtain the long term ECG signal feature and extract the meaningful information hiding in the QRS complex?
a) Cepstrum time warping and Dynamic coefficient
b) Cepstrum coefficient and Dynamic time warping
c) QRS detection and Dynamic coefficient
d) QRS detection and Cepstrum time warping
Answer: b
Explanation: Jen and Hwang proposed a new algorithm using cepstrum coefficient and the dynamic time warping techniques to obtain the long term ECG signal feature and extract the meaningful information hiding in the QRS complex. This algorithm may also be used for arrhythmia detection by simply checking the difference of R-R wave intervals through signal feature extraction comparison for a certain period of time.
15. What is the sampling rate of the analog-to-digital converter in digitizing of ECG signal in signal conditioning?
a) 250 Hz
b) 215 Hz
c) 40-100 Hz
d) 200-215 Hz
Answer: a
Explanation: In signal conditioning, ECG signal is amplified, filtered and digitized using an 8 or 12-bit analog-to-digital converter with a typical sampling rate of 250 Hz.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Digital Stethoscope”.
1. Blood in ___________ must be made similar to arterial Blood in composition.
a) heart
b) brain
c) ear
d) eyes
Answer: c
Explanation: Blood in the ear must be made similar to arterial blood in composition. This is done by increasing the flow through the ear without appreciably increasing the metabolism. Maximum vasodilatation is achieved by keeping the ear warm.
2. By keeping the ear warm, maximum vasodilatation is achieved.
a) True
b) False
Answer: a
Explanation: Yes, maximum vasodilatation is achieved by keeping the ear warm. It takes about 5 or 10 min for the ear to become fully dilated after the ear unit has been put up in place and the lamp turned on.
3. Merrick and Hayes describe details of a __________ oximeter which enables the measurement of oxygen saturation of the blood.
a) Pulse
b) Ear
c) Skin Reflectance
d) Intravascular
Answer: b
Explanation: Merrick and Hayes describe details of an ear oximeter which enables the measurement of oxygen saturation of blood. This measurement is independent of a wide range of encountered variables and is made without involving patients in any calibration or standardization procedure.
4. Ear probe which connects the patient to instrument is __________ m long.
a) 1.5
b) 2.0
c) 2.5
d) 3.0
Answer: c
Explanation: A 2.5 m long flexible fibre ear probe connects the patient to the instrument. The ear probe can be either held in position for discrete measurements or can be conveniently mounted to a headband for continuous display.
5. Ear oximeter instrument is based on Beer- Lambert law.
a) True
b) False
Answer: a
Explanation: The instrument is based on the Beer-Lambert law. However, it is assumed that the optical absorbers act independently and additively and that the effects of light scattering by the ear tissue can be minimized by a proper source and detector geometry.
6. The percentage of functional haemoglobin combined with oxygen is expressed as ______
a) *100
b) *100
c) *100
d) *100
Answer: a
Explanation: The instrument is designed to measure the percentage of functional hemoglobin combined with oxygen. This can be expressed as:
biomedical-instrumentation-questions-answers-digital-stethoscope-q9
where CO is the concentration of oxyhemoglobin and CR is the concentration of deoxyhemoglobin.
7. What is used as a light source in ear oximeter?
a) Mercury-vapor lamp
b) Sodium-vapor lamp
c) Tungsten-iodine lamp
d) Sulfur lamp
Answer: c
Explanation: The light source is a tungsten-iodine lamp that has a high output in the spectrum of interest. A lens system collimates the light beam and directs it through thin-film interference filters that provide wavelength selection.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Electroencephalograph ”.
1. Pulse oximetry is used to measure the oxygen level in blood & heart rate.
a) True
b) False
Answer: a
Explanation: Pulse oximetry is a technology used to measure the oxygen level in your blood and your heart rate. A finger pulse oximeter is equipped with technology to rapidly detect changes in your blood oxygen level.
2. How many wavelengths are used by Pulse Oximeter?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: Pulse oximetry is based on the concept that arterial oxygen saturation determinations can be made using two wavelengths, provided the measurements are made on the pulsatile part of the waveform.
3. Light passing through finger will be adsorbed by ___________
Skin Pigments
Tissue
Arteries
Veins
a) &
b) &
c) &
d) &
Answer: c
Explanation: The two wavelengths assume that only two absorbers are present; namely oxyhaemoglobin and reduced haemoglobin .Light passing through the ear or finger will be absorbed by skin pigments, tissue, cartilage, bone, arterial blood, venous blood.
4. How is the blood flow in arteries and arterioles?
a) plug
b) laminar
c) parabolic
d) pulsatile
Answer: d
Explanation: Most of the absorbances are fixed and do not change with time. Even blood in the capillaries and veins under steady state metabolic circumstances is constant in composition and flow, at least over short periods of time.Only the blood flow in the arteries and arterioles is pulsatile.
5. Law obeyed by Pulse Oximeter is _______
a) Lambert-Bouguer law
b) Beer ‘s law
c) Beer-Lambert law
d) Lamber-Bouguer, Beer’s and Beer-Lambert Law
Answer: d
Explanation: Light passing through the ear or finger will be absorbed by skin pigments, tissue, cartilage, bone, arterial blood, venous blood. The absorbances are additive and obey the Beer-Lambert law. Beer-Lambert is combination of Lambert-Bouguer and Beer’s Law.
6. Which oximeter probe is in the picture?
biomedical-instrumentation-questions-answers-electroencephalograph-eeg-q6
a) Ear
b) Pulse
c) Skin Reflectance
d) Intravascular
Answer: b
Explanation: Components of pulse oximeter Probe.
7. How many LED’s are used in Pulse oximeter probe?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: This has two LEDs , one that transmits infrared light at a wavelength of approximately 940 nm and the other transmitting light at approximately 660 nm.
8. Oxygen saturation is estimated by _________
a) ratio of pulse-added red absorbance at 660 nm to the pulse-added infrared absorbances at 940 nm
b) ratio of pulse-added red absorbance at 940 nm to the pulse-added infrared absorbances at 660 nm
c) ratio of pulse-added red absorbance at 330 nm to the pulse-added infrared absorbances at 940 nm
d) ratio of pulse-added red absorbance at 940 nm to the pulse-added infrared absorbances at 330 nm
Answer: a
Explanation: Oxygen saturation is estimated from the ratio of pulse-added red absorbance at 660 nm to the pulse-added infrared absorbances at 940 nm.
9. What gets affected by lower saturation?
a) blood flow
b) translucency
c) accuracy
d) low atmospheric pressure
Answer: c
Explanation: An accuracy of 1% or better has been reported for the saturation range of above 80% for most transmission type pulse oximeters. Usually, the accuracy is less at lower saturation because of non-linear effects of absorption.
10. What factors has no significant influence on the measurement?
a) skin pigmentation
b) thickness
c) tissue
d) skin pigmentation, thickness and tissue
Answer: d
Explanation: The instrument can be empirically calibrated. Subject variability has no significant influence on the measurement.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Electromyograph ”.
1. Which of the following instrument is used to measure the oxygen saturation level of blood in localized areas of oxygen?
a) Ear Oximeter
b) Pulse Oximeter
c) Skin reflectance Oximeter
d) Intravascular Oximeter
Answer: c
Explanation: For the measurement of oxygen saturation level of blood in localized areas of oxygen deprived tissues on the limbs, head and torso, a skin reflectance oximeter can be employed.
2. Skin Reflectance oximeter depends on monitoring backscattered lights in how many wavelengths?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: The instrument basically depends on monitoring backscattered light from living tissue in two wavelengths. The backscattered light data is then used for the in vivo determination of the blood’s relative oxygen saturation.
3. Who brought out the difficulties in the extraction of useful information from backscattered light intensity from human tissue?
a) Cohen and Wadsworth
b) Cohen and Logini
c) Cohen
d) Logini
Answer: a
Explanation: Cohen and Wadsworth bring out the difficulties in the extraction of useful information from backscattered light intensity from human tissue. There are vast variations of tissue construction and optical properties among various subjects and in different locations on the same subject.
4. Who considered “Human tissues are composed of parallel semi-infinite layers of homogenous materials”.
a) Cohen and Wadsworth
b) Cohen and Logini
c) Cohen
d) Wadsworth
Answer: b
Explanation: Cohen and Longini suggested a theoretical solution to some of these problems. They considered human tissues to be composed of parallel semi-infinite layers of homogeneous materials.
5. Who has poorer signal-to-noise ratio?
a) Transmission Pulse Oximeter
b) Reflection Pulse Oximeter
c) Ear Oximeter
d) Pulse Oximeter
Answer: b
Explanation: However, in comparison to transmission, the reflection pulse oximeter has poorer signal-to noiseratio. Mendelson et al utilized multiple photodiodes around the light source to enhance signal level.
6. What was utilized around the light source to enhance the signal?
a) Photodiodes
b) Optical Shied
c) Ceramic Substrate
d) Red and infrared LED’s
Answer: a
Explanation: However, in comparison to transmission, the reflection pulse oximeter has poorer signal-to noise ratio. Mendelson et al utilized multiple photodiodes around the light source to enhance signal level.
7. What are used as light source in Skin Reflectance Oximeter?
a) Photodiode
b) Red and infrared LED’s
c) Flashtube
d) Arc Lamp
Answer: b
Explanation: A pair of red and infrared light emitting diodes are used for the light source, with peak emission wavelengths of 665 nm and 935 nm . The reflected light from the skin at these two wavelengths is detected by a silicon diode.
8. The reflected light from the skin at wavelengths of 665nm and 935nm is detected by ______________
a) Photo diode
b) Laser diode
c) Silicon diode
d) Zener diode
Answer: c
Explanation: A pair of red and infrared light emitting diodes are used for the light source, with peak emission wavelengths of 665 nm and 935 nm . The reflected light from the skin at these two wavelengths is detected by a silicon diode.
9. The detected signals are processed in the form of photo – plethysmographs to determine ___________
a) SiO 2
b) SO 2
c) CO 2
d) TiO 2
Answer: b
Explanation: A pair of red and infrared light emitting diodes is used for the light source, with peak emission wavelengths of 665 nm and 935 nm . The reflected light from the skin at these two wavelengths is detected by a silicon diode. These detected signals are processed in the form of photo-plethysmographs to determine So 2 .
10. What is incorporated in sensor to warm the tissue so as to increase local blood flow?
a) heater
b) heating plate
c) thermostat
d) thermometer
Answer: a
Explanation: A heater was incorporated in the sensor to warm the tissue so as to increase local blood flow. Excellent correlation in comparison with the transmission oximeter has been shown from the calf and thigh.
This set of Biomedical Instrumentation test focuses on “Other Biomedical Recorders”.
1. How much blood is present in an average adult?
a) 10-12 L
b) 2-3 L
c) 5-6 L
d) 20-25 L
Answer: c
Explanation: In an average adult about 5-6 L of blood is present. Blood consists of corpuscles suspended in a fluid called plasma in the proportion of 45 parts of corpuscles to 55 parts of plasma. The percentage of cells in the blood is called the haematocrit value or packed cell volume .
2. What is the blood percentage of total body weight?
a) 5-10 %
b) 20-30 %
c) 2-3 %
d) 10-15 %
Answer: a
Explanation: The blood constitutes 5–10% of the total body weight and in the average adult, it amounts to 5–6 l. Blood consists of corpuscles suspended in a fluid called plasma in the proportion of 45 parts of corpuscles to 55 parts of plasma. The percentage of cells in the blood is called the haematocrit value or packed cell volume .
3. Blood consists of corpuscles suspended in a fluid called plasma in the proportion of 45 parts of ____________ to 55 parts of _____________
a) Plasma, corpuscles
b) Corpuscles, plasma
c) Protoplasma, cytozomes
d) Cytozomes, protoplasma
Answer: b
Explanation: Blood consists of corpuscles suspended in a fluid called plasma in the proportion of 45 parts of corpuscles to 55 parts of plasma. The percentage of cells in the blood is called the haematocrit value or packed cell volume . The majority of the corpuscles in the blood are red blood cells , others being white blood cells and platelets .
4. The percentage of cells in the blood is called _____________
a) haematocrit value
b) packet corpuscles value
c) packed haematocrit value
d) corpuscles value
Answer: a
Explanation: The percentage of cells in the blood is called the haematocrit value or packed cell volume . The majority of the corpuscles in the blood are red blood cells , others being white blood cells and platelets .
5. Which of the following blood constituent is in the form of a bi-concave disc?
a) lymphocytes
b) leucocutes
c) neutrophils
d) erythrocytes
Answer: d
Explanation: Red blood cells have the form of a bi-concave disc with a mean diameter of about 7.5 m and thickness of about 1.7 m. The mean surface area of the cell is about 134mm 2 . There are about 5.5 million of them in every cubic millimetre of blood in men and nearly 5 million in women.
6. Diameter of erythrocytes is in the range of ___________
a) nano meters
b) micro meters
c) pico meters
d) femto meters
Answer: b
Explanation: Mean diameter of about 7.5 m and a thickness of about 1.7 m. The mean surface area of the cell is about 134mm2. There are about 5.5 million of them in every cubic millimetre of blood in men and nearly 5 million in women.
7. In the whole body, there are about 25 billion erythrocytes and they are constantly being destroyed and replaced at a rate of about 9000 million per hour.
a) True
b) False
Answer: a
Explanation: It is true. In the whole body, there are about 25 billion erythrocytes and they are constantly being destroyed and replaced at a rate of about 9000 million per hour. There are about 5.5 million of them in every cubic millimetre of blood in men and nearly 5 million in women.
8. The normal red cell lasts approximately how many days before it is destroyed?
a) 240
b) 10
c) 12
d) 120
Answer: d
Explanation: The normal red cell lasts approximately 120 days before it is destroyed. There are about 5.5 million of them in every cubic millimetre of blood in men and nearly 5 million in women. In the whole body, there are about 25 billion erythrocytes and they are constantly being destroyed and replaced at a rate of about 9000 million per hour.
9. The erythrocytes have a nucleus.
a) True
b) False
Answer: b
Explanation: The erythrocytes have no nucleus. They are responsible for carrying oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs. In the whole body, there are about 25 billion erythrocytes and they are constantly being destroyed and replaced at a rate of about 9000 million per hour.
10. Anaemia is reduction/increase _________
a) in the carbon dioxide carrying capacity of blood
b) in the oxygen carrying capacity of blood
c) in the oxygen carrying capacity of blood
d) in the carbon dioxide carrying capacity of blood
Answer: b
Explanation: Anaemia is a reduction in the oxygen carrying capacity of the blood. It can develop from a change in the number, volume or Hb concentration of erythrocytes, caused by bone marrow dysfunction resulting in the poor production rate of RBCs. Since these changes are specific, the measurement of packed cell volume , the number of RBCs and the haemoglobin are very important.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Biofeedback Instrumentation”.
1. What is the shape of Leucocytes?
a) Cubic
b) Cuboid
c) Spherical
d) Hollow
Answer: c
Explanation: Leucocytes are spherical cells having a nucleus. There are normally 5000–10,000 white cells per cubic mm of blood but their number varies during the day. They live for seven to fourteen days and there is a rapid turn over, with constant destruction and replacement.
2. Life span of leucocytes is _____________
a) 3 – 4 weeks
b) 7 – 14 days
c) 9 – 10 months
d) 7 – 14 years
Answer: b
Explanation: They live for seven to fourteen days and there is a rapid turn over, with constant destruction and replacement. Leucocytes form the defence mechanism of the body against infection. They are of two main types: the neutrophils and the lymphocytes. Leucocytes are spherical cells having a nucleus.
3. Leucocytes form the defence mechanism of the body against infection.
a) True
b) False
Answer: a
Explanation: Leucocytes form the defence mechanism of the body against infection. They are of two main types: the neutrophils and the lymphocytes. Neutrophils ingest bacteria and lymphocytes are concerned with immunological response. The number and proportion of these types of leucocytes may vary widely in response to various disease conditions.
4. Neutrophills are concerned __________ and lymphocytes are concerned with __________
a) ingestion of bacteria, immunological responses
b) production of bacteria, electrical responses
c) electrical responses, production of bacteria
d) immunological responses, ingestion of bacteria
Answer: a
Explanation: Neutrophils ingest bacteria and lymphocytes are concerned with immunological response. The number and proportion of these types of leucocytes may vary widely in response to various disease conditions. For thus reason, it is important to know the total leucocyte count.
5. Neutrophils are smaller than the red cells.
a) True
b) False
Answer: b
Explanation: It is false. Neutrophils are nearly twice as big as the red cells. They contain both a nucleus divided into several lobes and granules in their protoplasm. Lymphocytes are of the same size as the red cells but contain a large density staining nucleus and no granules.
6. Which of the following option is correct in terms of size?
a) Monocytes > Neutrophils > RBC > lymphocytes
b) Monocytes > Neutrophils > RBC >= lymphocytes
c) Monocytes < Neutrophils < RBC < lymphocytes
d) Monocytes =< Neutrophils < RBC < lymphocytes
Answer: b
Explanation: Monocytes are twice as big as neutrophils. Neutrophils are twice as big as the RBC. The lymphotocytes are of almost of the same size of the RBC of smaller.
7. _________ is the ratio of the integrated platelet volume to the platelet count and is expressed in femolitres.
a) Mean Platelet Volume
b) Platelet Distribution Width
c) Red Cell Distribution Width
d) Mean Cell Haemoglobin Concentration
Answer: a
Explanation: Mean Platelet Volume is the ratio of the integrated platelet volume to the platelet count and is expressed in femolitres. Red Cell Distribution Width is a numerical expression of the width of the size distribution of red cells. Platelet Distribution Width is related to the size range covered by those platelets lying between the sixteenth and eighty fourth percentile.
8. Normal mean red cell volume is _____________
a) 6 ± 10 f/l
b) 16 ± 10 f/l
c) 86 ± 10 f/l
d) 56 ± 10 f/l
Answer: c
Explanation: Normal mean red cell volume is 86 ± 10 f/l. In diseased conditions, it may fall to 50 f/l or rise upto 150 f/l. 1f/l = 10–15. 1 litre of blood contains 0.45 litres of red cells and if there are 5 ¥ 1012 red cells per litre.
9. Normal mean cell haemoglobin is 29.5 ± 2.5 pg.
a) True
b) False
Answer: a
Explanation: It is true. Normal mean cell haemoglobin is 29.5 ± 2.5 pg. In diseased conditions it may rise to 50 pg or fall to 15 pg.
10. The percentage of the total specimen volume occupied by the platelets is called ____________
a) Platelet Distribution Width
b) Red Cell Distribution Width
c) Plateletcrit
d) Mean Platelet Volume
Answer: c
Explanation: The percentage of the total specimen volume occupied by the platelets is called. Mean Platelet Volume is the ratio of the integrated platelet volume to the platelet count and is expressed in femolitres. Red Cell Distribution Width is a numerical expression of the width of the size distribution of red cells.
11. What is used in modern instrument for intravascular oximetry?
a) photodiode
b) red and infrared LED’s
c) optical fibre
d) phototransistor
Answer: c
Explanation: For intravascular oximetry, modern instruments make use of optical fibres to guide the light signal inside the vessel and the reflected light from the red blood cells back to the light detector.
12. For estimating SO2, usually reflectance at ________ wavelengths are used.
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: For estimating SO 2 , usually the reflectance at two wavelengths, one in the red and the other in the near infrared regions, are used.
13. How many wavelengths are utilized by currently available oximeters?
a) More than 2
b) Less than 2
c) Equal to 2
d) Cannot be determined
Answer: a
Explanation: For estimating SO 2 , usually the reflectance at two wavelengths, one in the red and the other in the near infrared regions, are used. Currently available fiber-optic oximeters utilize more than two wavelengths to adjust for haematocrit variation.
14. What is used to measure mix venous saturation?
a) Ear Oximeter
b) Pulse Oximeter
c) Skin Reflectance Oximeter
d) Intravascular Oximeter
Answer: d
Explanation: Intravasacular oximeters are normally used to measure mixed venous saturation, from which the status of the circulatory system can be deduced. Mixed venous saturation varies in reflecting the changes of oxygen saturation, cardiac output, haematocrit or haemoglobin content and oxygen consumption.
15. The RDW index is expressed by which of the following equation?
a) [ Percentile Volume / Percentile Volume] X 100 X K
b) [ Percentile Volume / Percentile Volume] X 100 X K
c) [ Percentile Volume / Percentile Volume] X 100 X K
d) [ Percentile Volume / Percentile Volume] X 100 X K
Answer: a
Explanation: The RDW index is expressed by the following equation [ Percentile Volume / Percentile Volume] X 100 X K. It is a numerical expression of the width of the size distribution of red cells. It is derived by analog computation. The total erythrocyte count is scanned by a continuously variable thresholding circuit. The upper threshold is moved progressively lower from a level equivalent to 360 femolitres until 20 percent of all erythrocytes present have a size above a certain value.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “System Concepts”.
1. Which of the following instrument records the electrical activity of the heart?
a) VCG
b) PCG
c) ECG
d) EEG
Answer: c
Explanation: The electrocardiograph is an instrument, which records the electrical activity of the heart. Electrical signals from the heart characteristically precede the normal mechanical function and monitoring of these signals has great clinical significance.
2. Electrocardiography are used in catheterization laboratories, coronary care units and for routine diagnostic applications in cardiology.
a) True
b) False
Answer: a
Explanation: True, electrocardiographs are used in catheterization laboratories, coronary care units and for routine diagnostic applications in cardiology.
3. Who provides valuable information about a wide range of cardiac disorders?
a) VCG
b) ECG
c) PCG
d) EEG
Answer: b
Explanation: ECG provides valuable information about a wide range of cardiac disorders such as the presence of an inactive part or an enlargement of the heart muscle.
4. What is diagnostically useful frequency range?
a) 0.025 to 0.05 Hz
b) 0.05 to 150 Hz
c) 150 to 200 Hz
d) 0.05 to 150 MHz
Answer: b
Explanation: Although the electric field generated by the heart can be best characterized by vector quantities, it is generally convenient to directly measure only scalar quantities, i.e. a voltage difference of mV order between the given points of the body. The diagnostically useful frequency range is usually accepted as 0.05 to 150 Hz .
5. Which machines CMRR is of order of 100-120 dB?
a) VCG
b) PCG
c) EEG
d) ECG
Answer: d
Explanation: CMRR of the order of 100–120 dB with 5 kW unbalance in the leads is a desirable feature of ECG machines. In addition to this, under specially adverse circumstances, it becomes necessary to include a notch filter tuned to 50 Hz to reject hum due to power mains.
6. How many paper speeds are necessary for ECG recording?
a) One
b) Minimum two
c) Can be any
d) Max two
Answer: b
Explanation: The instability of the baseline, originating from the changes of the contact impedance, demands the application of the automatic baseline stabilizing circuit. A minimum of two paper speeds is necessary for ECG recording.
7. Where are potentials picked up by patient electrodes taken to?
a) Lead Selector switch
b) Preamp
c) Power Amplifier
d) Instrumentational amplifier
Answer: a
Explanation: The potentials picked up by the patient electrodes are taken to the lead selector switch. In the lead selector, the electrodes are selected two by two according to the lead program.
8. How lead selector selects electrodes?
a) one by one
b) two by two
c) three by three
d) four by four
Answer: b
Explanation: The potentials picked up by the patient electrodes are taken to the lead selector switch. In the lead selector, the electrodes are selected two by two according to the lead program.
9. The amplified output signal is picked up single-ended from preamp and is given to the _________
a) Power Amplifier
b) Lead Selector
c) Pen Motor
d) Paper motor
Answer: a
Explanation: The preamplifier is usually a three or four stage differential amplifier having a sufficiently large negative current feedback, from the end stage to the first stage, which gives a stabilizing effect. The amplified output signal is picked up single-ended and is given to the power amplifier. The power amplifier is generally of the push-pull differentical type.
10. Why is preamplifier used?
a) For Amplification
b) For Stabilizing effect
c) For Reducing effect
d) For Modifying effects
Answer: b
Explanation: The preamplifier is usually a three or four stage differential amplifier having a sufficiently large negative current feedback, from the end stage to the first stage, which gives a stabilizing effect.
11. ‘Stand by’ mode of operation is generally provided in which instrument?
a) VCG
b) PCG
c) ECG
d) EMG
Answer: c
Explanation: A‘stand by’ mode of operation is generally provided on the electrocardiograph. In this mode, the stylus moves in response to input signals, but the paper is stationary. This mode allows the operator to adjust the gain and baseline position controls without wasting paper.
12. ________ are made horizontally on electrocardiogram.
a) Time Measurements
b) Heart Rate Measurements
c) Time Measurements and Heart Rate Measurements
d) Not fixed and can be any thing
Answer: c
Explanation: Electrocardiograms are almost invariably recorded on graph paper with horizontal and vertical lines at 1 mm intervals with a thicker line at 5 mm intervals. Time measurements and heart rate measurements are made horizontally on the electrocardiogram.
13. What is paper recording speed for routine work?
a) 10 mm/s
b) 15 mm/s
c) 20 mm/s
d) 25 mm/s
Answer: c
Explanation: Electrocardiograms are almost invariably recorded on graph paper with horizontal and vertical lines at 1 mm intervals with a thicker line at 5 mm intervals. Time measurements and heart rate measurements are made horizontally on the electrocardiogram.
14. What measurements are made vertically on electrocardiogram?
a) Time Measurements
b) Heart Rate Measurements
c) Amplitude Measurements
d) Time Measurements and Heart Rate Measurements
Answer: c
Explanation: Electrocardiograms are almost invariably recorded on graph paper with horizontal and vertical lines at 1 mm intervals with a thicker line at 5 mm intervals. Time measurements and heart rate measurements are made horizontally on the electrocardiogram. Amplitude measurements are made vertically in millivolts.The sensitivity of an electrocardiograph is typically set at 10 mm/mV.
15. What is sensitivity of an electrocardiograph?
a) 10 mm/mV
b) 15 mm/mV
c) 20 mm/mV
d) 25 mm/mV
Answer: a
Explanation: Electrocardiograms are almost invariably recorded on graph paper with horizontal and vertical lines at 1 mm intervals with a thicker line at 5 mm intervals. Time measurements and heart rate measurements are made horizontally on the electrocardiogram. Amplitude measurements are made vertically in millivolts. The sensitivity of an electrocardiograph is typically set at 10 mm/mV.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Cardiac Monitor”.
1. Interruption or interference with normal physiological and developmental processes or structures is called _________
a) Functional Limitation
b) Pathophysiology
c) Societal Limitation
d) Modality-Specific
Answer: b
Explanation: Interruption or interference with normal physiological and developmental processes or structures is called Pathophysiology. Modality-Specific is a task that is specific to a single sense or movement pattern. Functional limitation is a restriction or lack of ability to perform an action in the manner or within the range consistent with the purpose of an organ or organ system.
2. For rehabilitation engineering perspective a task that is specific to a single sense or movement pattern is called ___________
a) Functional Limitation
b) Societal Limitation
c) Modality-Specific
d) Pathophysiology
Answer: c
Explanation: A task that is specific to a single sense or movement pattern is called Modality- Specific. Interruption or interference with normal physiological and developmental processes or structures is called Pathophysiology. Functional limitation is a restriction or lack of ability to perform an action in the manner or within the range consistent with the purpose of an organ or organ system.
3. An artificial limb, a sensory substitution system, or an augmentative communication aid is prosthetic devices __________
a) therapeutic device
b) diagnostics device
c) orthosis device
d) prosthetic device
Answer: d
Explanation: An appliance that substitutes for the loss of a particular function, generally by involving a different modality as an input and/or output channel. An artificial limb, a sensory substitution system, or an augmentative communication aid is prosthetic devices.
4. Aesthetics of appearance is called ____________
a) orthosis
b) cosmesis
c) lymphosis
d) homeostasis
Answer: b
Explanation: Aesthetics of appearance is called cosmesis. Orthosis is a modality-specific appliance that aids the performance of a function or movement by augmenting or assisting the residual capabilities of that function or movement.
5. Filter that amplifies frequency above certain value is called ___________
a) low pass filter
b) high pass filter
c) band pass filter
d) band stop filter
Answer: b
Explanation: High pass filter amplifies signal above a certain frequency. Low pass filter amplifies signals below a certain frequency. Band pass filter amplifies frequencies within a certain band. Band stop filter amplifies all the frequencies except those in a certain band.
6. Transcutaneous means ________
a) passing to the skin
b) passing to the bones
c) passing to the heart
d) passing to the lungs
Answer: a
Explanation: Transcutaneous means passing to the skin. This term generally used with the type of surgical instrument to be used. It is also used to describe the interaction of rehabilitation devices.
7. Which of the following is not a soft tissue?
a) ligament
b) bone
c) tendons
d) skin
Answer: b
Explanation: Hard tissue, mineralized tissue, and calcified tissue are often used as synonyms for bone when describing the structure and properties of bone or tooth. Biological soft tissues are nonlinear, anisotropic, fibrous composites, and a detailed description of their behavior is the subject of active research. One can separate these tissues based on their mode of loading: cartilage is generally loaded in compression; tendons and ligaments are loaded in tension, and muscles generate active tension.
8. Blood vessels are _______
a) soft tissue
b) hard tissue
c) connective and hard tissue
d) connective and soft tissue
Answer: d
Explanation: Connective and soft tissue says blood is soft and connective tissue. Soft tissues include tendon, ligament, blood vessels etc. Hard tissues include bones.
9. Bones serve as a reservoir for calcium and phosphorus, essential minerals for various cellular activities which happen throughout the human body.
a) True
b) False
Answer: a
Explanation: True. Bones serve as a reservoir for calcium and phosphorus, essential minerals for various cellular activities that occurs throughout the body. The composition of bone depends on a large number of factors: the species, which bone, the location from which the sample is taken, and the age, sex, and type of bone tissue, for example, woven, cancellous, cortical.
10. Bones are non – living tissues.
a) True
b) False
Answer: b
Explanation: It is false. Bones are living tissues. They keep growing. They also are responsible for the production of blood cells and act a mineral reservoir in the body. They also play the role of protection of internal soft organs like the brain is protected by the skull and lungs and heart by the rib cage.
This set of Biomedical Instrumentation Quiz focuses on “Bedside Patient Monitoring System”.
1. A model of the normal QRS complex, called ___________
a) ECG model
b) QRS model
c) Template
d) Detection model
Answer: c
Explanation: A popular approach in the detection of arrhythmias is based on template matching. A model of the normal QRS complex, called a template, is derived from the ECG complex of a patient under normal circumstances.
2. Who gave the ST/AR algorithm in 1999?
a) Hewlett Packard
b) Jen and Hwang
c) Clynes
d) Cox and Nolle
Answer: a
Explanation: The ST/AR algorithm from Hewlett Packard is a multi lead ECG algorithm designed for both arrhythmias and ST segment monitoring.
3. In order to detect the QRS, the detection threshold is kept as ________ to prevent the detection of T waves or baseline noise as QRS complexes during a complete heart block or asystole.
a) 0.15 V
b) 0.015 mV
c) 0.015 mV
d) 0.00015 V
Answer: d
Explanation: In order to detect the QRS, the detection threshold is kept as 0.15 mV to prevent the detection of T waves or baseline noise as QRS complexes during a complete heart block or asystole. For optimal performance and to prevent false alarms, the lead selected for monitoring should have adequate amplitude.
4. The contribution from each ECG lead to the QRS detection signal is proportional to its measured quality based on the waveform amplitude, and the amount of muscle and baseline noise.
a) True
b) False
Answer: a
Explanation: The contribution from each ECG lead to the QRS detection signal is proportional to its measured quality based on the waveform amplitude, and the amount of muscle and baseline noise. The weighting factors are updated every 200 ms to allow for a quick adaption to signal quality changes.
5. What is the value of the refractory period from the previously identified QRS complex?
a) 200 ms
b) 198 ms
c) 192 ms
d) 215 ms
Answer: c
Explanation: The QRs detector checks the QRS detection signal for the presence of the peak of an R wave. Search begins after an absolute refractory period from the previously identified QRS complex. The value used for the refractory period is 192 ms. This helps to prevent a T wave from being identified as an R wave.
6. The area of the P wave is ______ wide and ends ______ before the R wave peak.
a) 120 ms, 200 ms
b) 200 ms, 120 ms
c) 100 ms, 215 ms
d) 215 ms, 100 ms
Answer: b
Explanation: After a QRS complex is identified, a search is made on each lead independently in the area prior to the R wave to determine if there is an associated P wave. This area is 200 ms wide and ends 120 ms before the R wave peak.
7. If the height of the P wave is X, then the height of the R wave is _____
a) X/32
b) 32/X
c) X/16
d) 32X
Answer: d
Explanation: To be accepted as a P wave, it must be at least 1/32 of the R wave height and the P-R interval must be close to the average P-R interval.
So, P=R/32
If P=X then, X = R/32
R = 32X.
8. Which wave detection is used to differentiate between a Sinus Rhythm and a Supraventricular Rhythm?
a) P wave
b) QRS complex
c) T wave
d) R wave
Answer: a
Explanation: P wave detection is used to differentiate between a Sinus Rhythm and a Supraventricular Rhythm.
9. In the Beat Labeling, if the signal quality is not good, the algorithm assigns the label ______ and ______
a) Supraventricular premature, inoperative
b) Inoperative, artifact
c) Artifact, Supraventricular premature
d) Ventricular ectopic, inoperative
Answer: b
Explanation: Beat Labeling means that the algorithm assigns the complex one of the following labels: normal N, supraventricular premature S, ventricular ectopic V, paced P, questionable ?, and learning L. If the signal quality is not good, the algorithm assigns the label “inoperative I” and “artifact A”.
10. If a flutter or sinusoidal wave-form persists for more than __________ seconds in any ECG channel, then the monitor alarms for ventricular fibrillation.
a) 8 sec
b) 2 sec
c) 4 sec
d) 12 sec
Answer: c
Explanation: A separate detector continuously examines the ECG signal for ventricular fibrillation. If a flutter or sinusoidal wave-form persists for more than 4 seconds in an ECG channel, then the monitor alarms for ventricular fibrillation.
11. The heart rate is computed by averaging the most recent _________________
a) 12 P waves
b) 12 R-R intervals
c) 12 QRS complex
d) 12 R waves
Answer: b
Explanation: Normally, the heart rate is computed by averaging the most recent 12 R-R intervals. This average gives a stable estimate of the heart rate even when the rhythm is irregular.
12. Friesen compared _______ of nine types of QRS detection algorithms.
a) QRS complex sensitivity
b) Noise sensitivity
c) Motion artifact
d) Muscle artifact
Answer: b
Explanation: Friesen compared noise sensitivity of nine types of QRS detection algorithms. He established that an algorithm using a digital filter had the best performance for the composite noise corrupted data.
13. The frequency of the sinusoid and the filter leakage fraction, these two criteria are used for ____________
a) Detection of arrhythmias
b) Detection of QRS complex
c) Detection of Ventricular fibrillation
d) Detection of Heart-rate
Answer: c
Explanation: The detection of ventricular fibrillation is based on two criteria:
i) The frequency of the sinusoid
ii) The filter leakage fraction.
14. For an ideal sinusoid, the filter leakage fraction will be _____
a) 1
b) 0
c) Infinity
d) Undefined
Answer: b
Explanation: For an ideal sinusoid, the filter leakage fraction will be zero. As the ventricular fibrillation waveform is not an ideal sinusoid, a higher leakage fraction is used as the threshold for detection of this condition.
15. For how much time period, the weighting factors are updated to allow for quick adaptation to signal quality changes?
a) Every 192 ms
b) Every 16 ms
c) Every 215 ms
d) Every 200 ms
Answer: d
Explanation: The contribution from each ECG lead to the QRS detection signal is proportional to its measured quality based on the waveform amplitude, and the amount of muscle and baseline noise. The weighting factors are updated every 200 ms to allow for a quick adaption to signal quality changes.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Central Monitors”.
1. Which one of the following is not the category of ECG compression techniques?
a) Transformation domain
b) Parameter Extraction
c) Frequency domain
d) Time domain
Answer: c
Explanation: Several ECG compression techniques have been proposed in the last few decades. These techniques can be classified into three major categories: i) Time domain ii) Transformation domain iii) Parameter Extraction.
2. The scan-along polygonal approximation and the amplitude zone time epoch coding are the examples of the __________ category of ECG compression techniques.
a) Transformation domain
b) Time domain
c) Parameter extraction
d) Frequency domain
Answer: b
Explanation: In the time domain category, the compression technique is applied directly to the samples of the ECG signal in the time domain to remove redundant information. Examples include the scan-along polygonal approximation and the amplitude zone time epoch coding.
3. Which of the following techniques are not included in the transformation domain category?
a) Wavelet transform
b) Discrete cosine transform
c) Fourier descriptors
d) Combine discrete cosine and Fourier transform
Answer: d
Explanation: In the transformation domain category, ECG samples are transformed to another domain. Examples include Fourier descriptors, discrete cosine transform, wavelet transform and combine discrete cosine and wavelet transform.
4. Who suggests a new discrete wavelet transform for compressing ECG signals with minimum loss of diagnostic information?
a) Alshamali
b) Friesen
c) Al-Ajlouni
d) Cox and Nolle
Answer: c
Explanation: Various Wavelet-based ECG compression techniques have been found to give lower distortion for the same compression ratios. A new discrete wavelet transform has been suggested by Al-Ajlouni for compression ECG signals with minimum loss of diagnostic information.
5. Full form of AZTEC _______________
a) Amplitude Zone Tech Epoch Coding
b) Amplitude Zone Time Epoch Coding
c) Arrhythmia Zone Tech Epoch Coding
d) Arrhythmia Zone Time Epoch Coding
Answer: b
Explanation: Cox and Nolle suggested AZTEC a pre-processing program for real-time ECG rhythm analysis at an approximate data reduction rate of 10:1.
6. AZTEC contains digital logic, which is able to detect?
a) Baseline wander
b) QRS complex
c) R-R interval
d) Motion artifact
Answer: a
Explanation: AZTEC contains digital logic, which is able to detect base line wander. Also, the sum of absolute values of all slopes is used for noise detection, but sudden bursts of muscle artifact or an excursion from baseline are distinguishable from an ECG wave only if the condition persists.
7. A signal of poor quality that cannot be processed is called chaotic.
a) True
b) False
Answer: a
Explanation: The module runs once every second, depending upon the quality of the signal. If the signal is ‘chaotic’ or ‘noisy’ , no processing is carried out.
8. In the detection of the waveform of ECG signal, a wave is considered as a T wave if _______
a) It occurs within a 120 ms interval
b) Its peak occurred within 1/6th the R-R interval
c) It occurs within a 200 ms interval
d) Its peak occurred within 1/3rd the R wave height
Answer: c
Explanation: AT wave following a QRS is also searched. A wave is considered as a T wave if it occurs within a 200 ms interval, its peak occurred within 1/3rd the R–R interval +80 ms or within 240 ms whichever is greater, following the preceding R wave, and its height is half the height of a normal R wave.
9. The four measurements of QRS and a fifth measurement called ________ based on height, duration and offset to those of the patient’s normal QRS are compared.
a) QRS polarity
b) R-to-R interval
c) Wiggle
d) Distance D
Answer: d
Explanation: The four measurements of QRS and a fifth measurement called ‘distance D’ based on height, duration and offset to those of the patient’s normal QRS are compared. Beats are classified on the basis of their deviation from the normal and maybe definitely normal, probably normal, probably PVC or definitely PVC.
10. Cox and Nolle suggested AZTEC – pre-processing program for real time ECG rhythm analysis at an approximate data reduction rate of _______________
a) 1:10
b) 10:1
c) 1:20
d) 20:1
Answer: b
Explanation: Cox and Nolle suggested AZTEC a pre-processing program for real time ECG rhythm analysis at an approximate data reduction rate of 10:1.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Measurement of Heart Rate”.
1. Which of the following instrument is used for recording the electrical activity of the brain?
a) ECG
b) EMG
c) PCG
d) EEG
Answer: d
Explanation: Electroencephalograph is an instrument for recording the electrical activity of the brain, by suitably placing surface electrodes on the scalp. EEG, describing the general function of the brain activity, is the superimposed wave of neuron potentials operating in a non-synchronized manner in the physical sense.
2. EEG electrodes are larger in size than ECG electrodes.
a) True
b) False
Answer: b
Explanation: Several types of electrodes may be used to record EEG. These include: Peel and Stick electrodes, Silver plated cup electrodes and Needle electrodes. EEG electrodes are smaller in size than ECG electrodes.
3. _______ is the superimposed wave of neuron potentials operating in a non-synchrronized manner in a physical sense.
a) VCG
b) ECG
c) EEG
d) PCG
Answer: c
Explanation: Electroencephalograph is an instrument for recording the electrical activity of the brain, by suitably placing surface electrodes on the scalp. EEG, describing the general function of the brain activity, is the superimposed wave of neuron potentials operating in a non-synchronized manner in the physical sense.
4. Which of the following is material is used to improve electrical contact?
a) Silver Tungsten
b) Electrode jelly
c) Silver Graphite
d) Copper Tungsten
Answer: b
Explanation: Electrode jelly or paste is used to improve the electrical contact. If the electrodes are intended to be used under the skin of the scalp, needle electrodes are used. They offer the advantage of reducing movement artefacts.
5. Whose electrodes give high skin impedance as compared to ECG?
a) VCG
b) PCG
c) EMG
d) EEG
Answer: d
Explanation: EEG electrodes give high skin contact impedance as compared to ECG electrodes. Good electrode impedance should be generally below 5 kilohms. The impedance between a pair of electrodes must also be balanced or the difference between them should be less than 2 kilohms.
6. What are generally designed to have a very high value of input impedance to take care of high electrode impedance?
a) Montages
b) Electrodes
c) Preamplifiers
d) Filters
Answer: c
Explanation: Good electrode impedance should be generally below 5 kilohms. Impedance between a pair of electrodes must also be balanced or the difference between them should be less than 2 kilohms. EEG preamplifiers are generally designed to have a very high value of input impedance to take care of high electrode impedance.
7. Voltage difference between an active electrode on the scalp with respect to reference electrode at ear lobe or any other part of body is known as ___________ recording.
a) Monopolar
b) Bipolar
c) Unipolar
d) Nonpolar
Answer: a
Explanation: EEG may be recorded by picking up the voltage difference between an active electrode on the scalp with respect to a reference electrode on the ear lobe or any other part of the body. This type of recording is called ‘monopolar’ recording.
8. How is bipolar recording done?
a) Omni channel EEG
b) Multi channel EEG
c) Uni Channel EEG
d) Non Channel EEG
Answer: b
Explanation: ‘bipolar’ recording is more popular wherein the voltage difference between two scalp electrodes is recorded. Such recordings are done with multi-channel electroencephalographs.
9. EEG signals picked up by surface electrodes are usually small as compared to ECG.
a) True
b) False
Answer: a
Explanation: Yes, EEG signals picked up by the surface electrodes are usually small as compared with the ECG signals. They may be several hundred microvolts, but 50 microvolts peak-to-peak is the most typical.
10. A pattern of electrodes on the head and the channels they are connected to are __________
a) Amplifiers
b) Oscilloscope
c) Montage
d) Wires
Answer: c
Explanation: A pattern of electrodes on the head and the channels they are connected to is called a montage. Montages are always symmetrical. The reference electrode is generally placed on a nonactive site such as the forehead or earlobe.
11. Where is the reference electrode placed?
a) nasal
b) cervical
c) forehead
d) facial
Answer: c
Explanation: A pattern of electrodes on the head and the channels they are connected to is called a montage. Montages are always symmetrical. The reference electrode is generally placed on a nonactive site such as the forehead or earlobe.
12. What is the typical value of the calibration signal?
a) 10 uV/cm
b) 30 uV/cm
c) 50 uV/cm
d) 70 uV/cm
Answer: c
Explanation: A calibrating signal is used for controlling and documenting the sensitivity of the amplifier channels. This supplies a voltage step of adequate amplitude to the input of the channels. A typical value of the calibration signal is 50 uV/cm.
13. Preamplifiers used in electroencephalograph have high gain and low noise characteristics.
a) True
b) False
Answer: a
Explanation: Yes, preamplifier used in electroencephalographs must have high gain and low noise characteristics because the EEG potentials are small in amplitude. In addition, the amplifier must have very high common-mode rejection to minimize stray interference signals from power lines and other electrical equipment.
14. EEG machines have notch filter sharply tuned at _______ Hz as to eliminate mains frequency interference.
a) 10
b) 30
c) 50
d) 70
Answer: c
Explanation: EEG machines have a notch filter sharply tuned at 50 Hz so as to eliminate mains frequency interference. These however have the undesirable property of ‘ringing’ i.e. they produce a damped oscillatory response to a square wave calibration waveform or a muscle potential. The use of notch filters should preferably be restricted to exceptional circumstances when all other methods of eliminating interference have been found to be ineffective.
15. What is the typical frequency range of standard EEG machines?
a) 0.025 to 0.05 Hz
b) 0.05 to 0.1 Hz
c) 0.1 to 70 Hz
d) 70 to 140 Hz
Answer: c
Explanation: The typical frequency range of standard EEG machines is from 0.1 Hz to 70 Hz, though newer machines allow the detection and filtering of frequencies up to several hundred Hertz. This may be of importance in some intracranial recordings.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Measurement of Temperature”.
1. Which of the following is the technique of analyzing the electrical activity of the heart by obtaining ECG’s?
a) VCG
b) EEG
c) EMG
d) PCG
Answer: a
Explanation: Vectorcardiography is the technique of analyzing the electrical activity of the heart by obtaining ECG’s along three axes at right angles to one another and displaying any two of these ECGs as a vector display on an X-Y oscilloscope.
2. Vectorcardiogram displays the electrical events in __________ perpendicular axes.
a) one
b) two
c) three
d) four
Answer: b
Explanation: In contrast, the electrocardiogram which displays the electrical potential in any one single axis, the vectorcardiogram displays the same electrical events simultaneously in two perpendicular axes.
3. ___________ is a vectorial representation of the distribution of electric potentials generated by heart.
a) EEG
b) ECG
c) PCG
d) VCG
Answer: d
Explanation: In contrast, the electrocardiogram which displays the electrical potential in any one single axis, the vectorcardiogram displays the same electrical events simultaneously in two perpendicular axes. This gives a vectorial representation of the distribution of electrical potentials generated by the heart and produces loop type patterns on the CRT screen.
4. How many loops each vectorcardiogram exhibits?
a) one
b) two
c) three
d) four
Answer: c
Explanation: The major information that it provides is the direction of depolarization and repolarization of the atria and the ventricles. Each vectorcardiogram exhibits three loops, showing the vector orientation of the P wave, the QRSaxis and the T wave.
5. Which of the following instrument is used for recording the sounds connected with the pumping action of the heart?
a) ECG
b) VCG
c) PCG
d) EEG
Answer: c
Explanation: The phonocardiograph is an instrument used for recording the sounds connected with the pumping action of the heart. These sounds provide an indication of the heart rate and its rhythmicity. They also give useful information regarding the effectiveness of blood pumping and valve action.
6. Which instrument is used for clinical detection of heart sounds?
a) Stethoscope
b) Endoscope
c) Anoscope
d) Proctoscope
Answer: a
Explanation: Heart sounds are diagnostically useful. Sounds produced by healthy hearts are remarkably identical and abnormal sounds always corelate to specific physical abnormalities. From the beginning till today, the principal instrument used for the clinical detection of heart sounds is the acoustical stethoscope.
7. Who provides a recording of waveforms of heart sounds?
a) Electrocardiograph
b) Vectorcardiograph
c) Phonocardiograph
d) Electromyograph
Answer: c
Explanation: The phonocardiographs provide a recording of the waveforms of the heart sounds. These waveforms are diagnostically more important and revealing than the sounds themselves.
8. What is the frequency range of sound generated from the closure of the mitral and tricuspid valve?
a) 0 to 30 Hz
b) 30 to 100 Hz
c) 100 to 1000 Hz
d) above 1000 Hz
Answer: b
Explanation: The closure of the mitral and tricuspid valve contributes largely to the first sound. The frequencies of these sounds are generally in the range of 30 to 100 Hz and the duration is between 50 to 100 ms.
9. Which of the following microphone is used for recording phonocardiograms?
a) Contact Microphone
b) Shotgun Microphone
c) Handheld Microphone
d) Lapel Microphone
Answer: a
Explanation: Two types of microphones are commonly in use for recording phonocardiograms. They are the contact microphone and the air coupled microphone. They are further categorized into crystal type or dynamic type based on their principle of operation.
10. What is the frequency range of sound produced at the closure of aortic and pulmonic valves?
a) less than 0 Hz
b) 0 to 30 Hz
c) 30 to 100 Hz
d) above 100 Hz
Answer: d
Explanation: The second sound is higher in pitch than the first, with frequencies above 100 Hz and the duration between 25 to 50 ms. This sound is produced by the slight back flow of blood into the heart before the valves close and then by the closure of the valves in the arteries leading out of the ventricles. This means that it occurs at the closure of aortic and the pulmonic valves.
11. What is the thickness of the new acoustic sensor?
a) 0.25 mm
b) 0.5 mm
c) 1.0 mm
d) 1.5 mm
Answer: c
Explanation: A new acoustic sensor, which enhances the audibility of heart sounds and enables recording of quantitative acoustic spectral data is described by Kassal et al, 1994. This device is a polymer based adherent differential-output sensor, which is only 1.0 mm thick.
12. Who described the new acoustic sensor?
a) Golden et al
b) Rijn et al
c) Levkov et al
d) Kassal et al
Answer: d
Explanation: A new acoustic sensor, which enhances the audibility of heart sounds and enables recording of quantitative acoustic spectral data is described by Kassal et al, 1994. This device is a polymer based adherent differential-output sensor, which is only 1.0 mm thick.
13. Acoustic sensor principal sensing component is made up of which polymer?
a) PEO
b) PET
c) PVDF
d) PS
Answer: c
Explanation: Its principle sensing components is PVDF , which is a piezo-electric polymer. It produces charges of equal magnitude and opposite polarity on opposite surfaces when a mechanical strain is imposed on the material.
14. What is the frequency range of amplifier used for a phonocardiograph?
a) less than 0 Hz
b) 0 to 20 Hz
c) 20 to 2000 Hz
d) above 2000 Hz
Answer: c
Explanation: The amplifier used for a phonocardiograph has wide bandwidth with a frequency range of about 20 to 2000 Hz. Filters permit selection of suitable frequency bands, so that particular heart sound frequencies can be recorded.
15. PCG amplifiers usually have gain compensation circuits to increase the amplification of high frequency signals, which are usually of low intensity.
a) True
b) False
Answer: a
Explanation: Yes, PCG amplifiers usually have gain compensation circuits to increase the amplification of high frequency signals, which are usually of low intensity. The frequencies at the higher end of the range are of particular significance in research applications.
This set of Biomedical Instrumentation Questions and Answers for Entrance exams focuses on “Measurement of Respiration Rate”.
1. Which of the following instrument is used for recording the electrical activity of the muscles?
a) ECG
b) EMG
c) PCG
d) EEG
Answer: b
Explanation: Electromyograph is an instrument used for recording the electrical activity of the muscles to determine whether the muscle is contracting or not; or for displaying on the CRO and loudspeaker the action potentials spontaneously present in a muscle or those induced by voluntary contractions as a means of detecting the nature and location of motor unit lesions; or for recording the electrical activity evoked in a muscle by the stimulation of its nerve.
2. EMG is recorded by using surface electrodes.
a) True
b) False
Answer: a
Explanation: EMG is usually recorded by using surface electrodes because the surface electrodes may be disposable, adhesive types or the ones which can be used repeatedly.
3. Whose measurements are important for myoelectric control of prosthetic devices?
a) VCG
b) ECG
c) EEG
d) EMG
Answer: d
Explanation: EMG measurements are also important for the myoelectric control of prosthetic devices . This use involves picking up EMG signals from the muscles at the terminated nerve endings of the remaining limb and using the signals to activate a mechanical arm. This is the most demanding requirement from an EMG since it depends on the working of the prosthetic device.
4. What is used to display EMG waveforms?
a) Cathode Ray Oscilloscope
b) Analog storage Oscilloscope
c) Digital Oscilloscope
d) Dual-beam Oscilloscope
Answer: a
Explanation: The Cathode Ray oscilloscope displays EMG waveforms. Electromyograph is an instrument used for recording the electrical activity of the muscles to determine whether the muscle is contracting or not; or for displaying on the CRO.
5. The amplitude of EMG signals depend upon which of the following factor?
a) Respiration
b) Position of electrode
c) Blood Resistivity
d) Ventricular Volume
Answer: b
Explanation: The amplitude of the EMG signals depends upon various factors, e.g. the type and placement of electrodes used and the degree of muscular exertions. The needle electrode in contact with a single muscle fibre will pick up spike type voltages whereas a surface electrode picks up many overlapping spikes and therefore produces an average voltage effect.
6. What is the typical range of EMG signals?
a) 0.025 to 0.050 mV
b) 0.050 to 0.1 mV
c) 0.1 to 0.5 mV
d) 0.5 to 1 mV
Answer: c
Explanation: A typical EMG signal ranges from 0.1 to 0.5 mV. They may contain frequency components extending up to 10 kHz.Such high frequency signals cannot be recorded on the conventional pen recorders and therefore, they are usually displayed on the CRT screen.
7. EMG instrument contain frequency component extending up to ____________ Khz.
a) 1
b) 5
c) 10
d) 15
Answer: c
Explanation: A typical EMG signal ranges from 0.1 to 0.5 mV. They may contain frequency components extending up to 10 kHz.Such high frequency signals cannot be recorded on the conventional pen recorders and therefore, they are usually displayed on the CRT screen.
8. What is included in the system to facilitate playback and study of EMG sound waveforms at a later convenient time?
a) Preamplifier
b) Oscilloscope
c) Tape Recorder
d) Ground Electrode
Answer: c
Explanation: The tape recorder is included in the system to facilitate playback and study of the EMG sound waveforms at a later convenient time. The waveform can also be photographed from the CRT screen by using a synchronized camera.
9. What is necessary for providing a common reference for measurement?
a) active electrode
b) ground electrode
c) tape recorder
d) oscilloscope
Answer: b
Explanation: A ground electrode is necessary for providing a common reference for measurement. These electrodes pick up the potentials produced by the contracting muscle fibres. The signal can then be amplified and displayed on the screen of a cathode ray tube. It is also applied to an audio amplifier connected to a loudspeaker.
10. Which of the following interpreter can diagnose various muscular disorders by listening to the sounds produced when the muscle potentials are fed to loudspeaker?
a) EEG
b) ECG
c) VCG
d) EMG
Answer: d
Explanation: A trained EMG interpreter can diagnose various muscular disorders by listening to the sounds produced when the muscle potentials are fed to the loudspeaker.
11. What is the diameter of silver electrodes in the amplifier circuit of Johnson et al?
a) 2 mm
b) 4 mm
c) 6 mm
d) 10 mm
Answer: c
Explanation: Johnson et al designed a miniature amplifier circuit fully encapsulated in epoxy resin with two small silver electrodes of 6 mm diameter, exposed flush with the base of the module. The electrode is attached to the skin using adhesive tape.
12. What should be CMRR of preamplifier upto 5 Khz?
a) 10 dB
b) 30 dB
c) 90 dB
d) greater than 90 dB
Answer: d
Explanation: The common-mode rejection should be greater than 90 dB up to 5 kHz. A calibrating square wave signal of 100 mV at a frequency of 100 Hz is usually available. The main amplifier has controls for gain adjustment from 5 mV/div to 10 mV/div for selecting the sensitivity most appropriate to the incoming signal from the patient.
13. Modern EMG machines are PC based.
a) True
b) False
Answer: a
Explanation: Modern EMG machines are PC based available both in the console as well as laptop models as they provide full colour waveform display, automatic cursors for marking and making measurements and a keyboard for access to convenient and important test controls. The system usually incorporates facilities for recording of the EMG and evoked potentials.
14. EMG instrument is useful for making study of ___________
a) cardiovascular function
b) neuromuscular function
c) nervous function
d) Immune function
Answer: b
Explanation: The instrument is useful for making a study of several aspects of neuromuscular function, neuromuscular condition, extent of nerve lesion, reflex responses, etc.
15. Which of the following instrument is used for making a study of reflex responses?
a) EEG
b) ECG
c) VCG
d) EMG
Answer: d
Explanation: The instrument is useful for making a study of several aspects of neuromuscular function, neuromuscular condition, the extent of nerve lesion, reflex responses, etc.
This set of Biomedical Instrumentation MCQs focuses on “Catheterization Laboratory Instrumentation”.
1. Which of the following instrument is used for recording the chest-wall movements over the apex of heart?
a) Apexcardiograph
b) Ballistocardiograph
c) Electro-oculograph
d) Electro-retinograph
Answer: a
Explanation: An apexcardiograph records the chest-wall movements over the apex of the heart. These movements are in the form of vibrations having a frequency range of 0.1 to about 20 Hz.
2. The transducer required for recording these movements in apexcardiograph is similar to the electrocardiograph.
a) True
b) False
Answer: b
Explanation: False, The transducer required for recording these movements in apexcardiograph is similar to that employed for a phonocardiograph but which has a frequency response much below the audio range. It can be an aircoupled microphone or a contact microphone. They are further categorized into crystal type or dynamic type based on their principle of operation. The crystal microphone contains a wafer of piezo-electric material, which generates potentials when subjected to mechanical stresses due to heart sounds. The dynamic type microphone consists of a moving coil having a fixed magnetic core inside it. The coil moves with the heart sounds and produces a voltage because of its interaction with the magnetic flux.
3. Which of the following instrument is used for recording the movements imparted to the body with each beat of the heart cycle?
a) Apexcardiograph
b) Ballistocardiograph
c) Electro-oculograph
d) Electro-retinograph
Answer: b
Explanation: A ballistocardiograph is a machine that records the movement imparted to the body with each beat of the heart cycle. These movements occur during the ventricular contraction of the heart muscle when the blood is ejected with sufficient force.
4. What is mounted on the table to convert the movements into corresponding electrical signals in BCG?
a) Oscilloscope
b) Sensing device
c) Pramplifier
d) Tape recorder
Answer: b
Explanation: In BCG, the patient is made to lie on a table top which is spring suspended or otherwise mounted to respond to very slight movements along the head axis. Sensing devices are mounted on the table to convert these movements into corresponding electrical signals. The sensors usually are piezo-electric crystals, resistive elements or permanent magnets, moving with respect to fixed coils.
5. ________________ is the recording of the bio-potentials generated by the movement of eye ball.
a) Apexcardiography
b) Electro-oculography
c) Electro-retinography
d) Ballistocardiography
Answer: b
Explanation: Electro-oculography is the recording of the bio-potentials generated by the movement of the eyeball. The EOG potentials are picked up by small surface electrodes placed on the skin near the eye.
6. What is used to pick EOG potentials?
a) Oscilloscope
b) Tape Recorder
c) Surface Electrodes
d) Preamplifier
Answer: c
Explanation: Electro-oculography is the recording of the bio-potentials generated by the movement of the eyeball. The EOG potentials are picked up by small surface electrodes placed on the skin near the eye.
7. What is the frequency range of Chest-wall movements?
a) 0.025 to 0.05 Hz
b) 0.05 to 0.1 Hz
c) 0.1 to 20 Hz
d) 20 to 100 Hz
Answer: c
Explanation: An apexcardiograph records the chest-wall movements over the apex of the heart. These movements are in the form of vibrations having a frequency range of 0.1 to about 20 Hz.
8. Which of the following instrument is used for recording the change in potential when light falls on the eye?
a) Apexcardiography
b) Ballistocardiography
c) Electro-oculography
d) Electro-retinography
Answer: d
Explanation: It is found that an electrical potential exists between the cornea and the back of the eye. This potential changes when the eye is illuminated. The process of recording the change in potential when light falls on the eye is called electroretinography.
9. One of the electrode is mounted on the contact lens and the other is placed to the skin adjacent to the outer cornea of the eye.
a) True
b) False
Answer: a
Explanation: True, ERG potentials can be recorded with a pair of electrodes. One of the electrodes is mounted on a contact lens and is in direct contact with the cornea and the other electrode is placed on the skin adjacent to the outer corner of the eye as it is found that an electrical potential exists between the cornea and the back of the eye. This potential changes when the eye is illuminated. A reference electrode may be placed on the forehead.
10. Which of the following is useful in the diagnosis of the enlargement of the heart chambers and some type of valvular disorders?
a) Apexcardiograph
b) Ballistocardiograph
c) Electro-oculograph
d) Electro-retinograph
Answer: a
Explanation: The apexcardiograph has limited applications. It is, however, useful in the diagnosis of the enlargement of the heart chambers and some type of valvular disorders.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Cardiac Arrhythmias”.
1. _____________ is common engineering term and refers to its function to control a process.
a) Open-loop
b) Feedback
c) Reaction
d) Closed-loop
Answer: b
Explanation: Feedback is a common engineering term and refers to its function to control a process. When this concept is applied to biological processes within the body, it is known as biofeedback. Biofeedback is a means for gaining control of the body processes to create a specially required psychological state so as to increase relaxation, relieve pain and develop healthier and more comfortable life patterns.
2. Biofeedback training is an educational process for learning body skills.
a) True
b) False
Answer: a
Explanation: True, Biofeedback training is an educational process for learning specialized mind/body skills as through practice, one learns to recognize physiological responses and to control them rather than having them control us. The objective of biofeedback training is to gain self-regulatory skills which help to adjust the activity in various systems to optimal levels.
3. Which of the following instrument is used for measuring the average activity of sweat glands?
a) EOG
b) ECG
c) GSR
d) PCG
Answer: c
Explanation: Electrodermal activity is measured in two ways: BSR and GSR is a measure of the average activity of the sweat glands and is a measure of the phasic activity of these glands.
4. BSR gives _____________
a) activity of sweat glands
b) baseline value of skin resistance
c) activity of endrocine glands
d) baseline value of breathing
Answer: b
Explanation: BSR and GSR is a measure of the average activity of the sweat glands and is a measure of the phasic activity of these glands. BSR gives the baseline value of the skin resistance where as GSR is due to the activity of the sweat glands.
5. GSR gives ________________
a) activity of sweat glands
b) baseline value of skin resistance
c) activity of endrocine glands
d) baseline value of breathing
Answer: a
Explanation: BSR and GSR is a measure of the average activity of the sweat glands and is a measure of the phasic activity of these glands. BSR gives the baseline value of the skin resistance where as GSR is due to the activity of the sweat glands.
6. At which place GSR is measured?
a) palms of hand
b) nose
c) eye
d) teeth
Answer: a
Explanation: BSR gives the baseline value of the skin resistance where as GSR is due to the activity of the sweat glands. The GSR is measured most conveniently at the palms of the hand, where the body has the highest concentration of sweat glands. The measurement is made using a dc current source.
7. What is used to measure and record BSR and GSR?
a) Tape recorder
b) Amplifier
c) Silver-Silver electrode
d) Piezoelectric device
Answer: c
Explanation: The GSR is measured most conveniently at the palms of the hand, where the body has the highest concentration of sweat glands. The measurement is made using a dc current source. Silver-silver electrodes are used to measure and record the BSR and GSR.
8. The BSR output is connected to RC network with time constant of _________________ seconds.
a) 1 to 3
b) 3 to 5
c) 5 to 7
d) 7 to 9
Answer: b
Explanation: Silver-silver electrodes are used to measure and record the BSR and GSR. The BSR output is connected to an RC network with a time constant of 3 to 5 seconds which enables the measurement of GSR as a change of the skin resistance.
9. Biofeedback instrumentation for the measurement of EMG, temperature and pulse/heart rate.
a) True
b) False
Answer: a
Explanation: True, Biofeedback instrumentation for the measurement of EMG, temperature and pulse/heart rate as it is not different from other instruments used for the measurement of physiological variables. Transducers and amplifiers are employed to measure the variable that is to be controlled by the feedback process.
10. What is employed to measure the variable that is to be controlled by the feedback process?
a) Transducers
b) Sensing device
c) Tape recorder
d) Piezo-electric device
Answer: a
Explanation: Biofeedback instrumentation for the measurement of EMG, temperature and pulse/heart rate is not different from other instruments used for the measurement of physiological variables. Transducers and amplifiers are employed to measure the variable that is to be controlled by the feedback process.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Arrhythmias Monitor”.
1. Which is the most important physiological parameter monitored in the intensive care unit?
a) temperature
b) heart rate
c) blood pressure
d) skin color
Answer: b
Explanation: The most important physiological parameters monitored in the intensive care unit are the heart rate and the morphology or shape of the electrical waveform produced by the heart. This is done to observe the presence of arrhythmias or to detect changes in the heart rate that might be indicative of a serious condition.
2. Which of the following instrument is used for monitoring patients with cardiac problems?
a) Cardiac Monitor
b) Central Monitor
c) Bedside Patient Monitor
d) Blood Pressure Monitor
Answer: a
Explanation: A Cardiac monitor is specifically useful for monitoring patients with cardiac problems and the special areas in the hospitals where they are generally used are known as cardiac care units or coronary care units . These instruments are also called ‘Cardioscopes’.
3. Which of the following instrument is also known as Cardioscopes?
a) Central Monitor
b) Bedside Patient Monitor
c) Cardiac Monitor
d) Blood Pressure Monitor
Answer: c
Explanation: A Cardiac monitor is specifically useful for monitoring patients with cardiac problems and the special areas in the hospitals where they are generally used are known as cardiac care units or coronary care units . These instruments are also called ‘Cardioscopes’.
4. Disposable type pregelled electrodes to pick up ____________ signal in cardiac monitor.
a) EOG
b) EMG
c) ECG
d) PCG
Answer: c
Explanation: A Cardiac monitor is specifically useful for monitoring patients with cardiac problems and the special areas in the hospitals where they are generally used are known as cardiac care units or coronary care units . These instruments are also called ‘Cardioscopes’ and comprise of disposable type pregelled electrodes to pick up ECG signal. Amplifier and a cathode ray tube for the amplification and display the ECG which enable direct observation of the ECG waveform.
5. What is used for amplification of signal in cardiac monitor?
a) Piezoelectric device
b) Transducer
c) Amplifier
d) Tape recorder
Answer: c
Explanation: ‘Cardioscopes’ and comprise of disposable type pregelled electrodes to pick up ECG signal. Amplifier and a cathode ray tube for the amplification and display the ECG which enable direct observation of the ECG waveform.
6. _____________ is used to display ECG which enable direct observation of the ECG waveform.
a) Amplifier
b) Transducer
c) Tape Recorder
d) Cathode ray tube
Answer: d
Explanation: ‘Cardioscopes’ and comprise of disposable type pregelled electrodes to pick up ECG signal. Amplifier and a cathode ray tube for the amplification and display the ECG which enable direct observation of the ECG waveform.
7. A cardioscope differ in one important aspects as compared to the conventional instrument.
a) True
b) False
Answer: b
Explanation: False, Cardioscope differ in two important aspects as compared to the conventional instrument. These are slower sweep speeds and a long persistence screen. The slow sweep speed necessitates the use of a long persistence screen so as to enable a convenient observation of the waveform.
8. The slow sweep is an outcome of the low frequency character of ________________ signal.
a) EMG
b) EOG
c) ECG
d) PCG
Answer: c
Explanation: The slow sweep is an outcome of the low frequency character of the ECG signal. The slow sweep speed necessitates the use of a long persistence screen so as to enable a convenient observation of the waveform. Without a long persistence screen, one can only see a moving dot of light instead of a continuous trace.
9. What is total sweep time for a 13-cm screen?
a) 0 to 0.5 s
b) 0.5 to 2 s
c) 2 to 2.5 s
d) 2.5 to 5 s
Answer: d
Explanation: Without a long persistence screen, one can only see a moving dot of light instead of a continuous trace. Typically for a 13-cm screen, total sweep time is usually kept as 2.5 or 5 s. In this way, one can observe at least four heart beats in a single sweep period.
10. How many heart beat one can observe in a single sweep period?
a) 1
b) 2
c) 3
d) 4
Answer: d
Explanation: Without a long persistence screen, one can only see a moving dot of light instead of a continuous trace. Typically for a 13-cm screen, total sweep time is usually kept as 2.5 or 5 s. In this way, one can observe at least four heart beats in a single sweep period.
11. What indicate average heart rate with audible beep?
a) disposable electrodes
b) heart rate meter
c) amplifier
d) cathode ray tube
Answer: b
Explanation: ‘Cardioscopes’ and comprise of disposable type pregelled electrodes to pick up ECG signal. Amplifier and a cathode ray tube for the amplification and display the ECG which enable direct observation of the ECG waveform.A heart rate meter to indicate average heart rate with audible beep or flashing light or both with each beat.
12. What is diameter of CRT used in small cardioscopes?
a) 1”
b) 3”
c) 5”
d) 7”
Answer: c
Explanation: Small cardioscopes using 3” diameter cathode ray tubes are mounted on anaesthesia trollies. These are called “Anaesthesia monitors”. These monitors are use by the anaesthetist for continuous monitoring of the ECG of anaesthetized patients.
13. An alarm system is used to produce signal in event of abnormalities occurring in heart rate.
a) True
b) False
Answer: a
Explanation: ‘Cardioscopes’ and comprise of disposable type pregelled electrodes to pick up ECG signal. Amplifier and a cathode ray tube for the amplification and display the ECG which enable direct observation of the ECG waveform.An alarm system to produce signal in the event of abnormalities occurring in the heart rate.
14. What is range of RF signals generated by Electrosurgery machine?
a) 0 to 0.4 MHz
b) 0.4 to 5 MHz
c) 5 to 6.5 MHz
d) 6.5 to 10 MHz
Answer: b
Explanation: Electrosurgery machines generate RF signals within a range of 0.4 to 5 MHz with peak-to-peak amplitudes of 100 to 1000 V, pulse modulated at rates from 1.5 to 25 kHz for coagulating or 120 Hz for cutting. Cardiac monitors are often used in operation theatres, where the RF is applied through a pointed scalpel at the point of incision and the return path for the current is through a wide area electrode on the opposite side of the patient’s body.
15. Which of the following storage device is used for storing digital information in memory monitors?
a) Hard disk
b) Magnetic Tape
c) RAM
d) DVD
Answer: c
Explanation: Two basic types of storage devices are used to store digital information in memory monitors: shift registers and random access memories. Both of them are equally good for this application. The other important component of memory monitors is the analog-to-digital converter.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “QRS Detection Techniques”.
1. ______ is used to determine the physical performance characteristics of a cardiac patient.
a) Data compression techniques
b) Stress test electrocardiography
c) Stress amplitude ECG
d) QRS detection techniques
Answer: b
Explanation: Stress test or exercise electrocardiography is used when the diagnosis of coronary arterial disease is suspected or to determine the physical performance characteristics of a cardiac patient. The test involves the recording of the electrocardiogram during dynamic or occasionally isometric exercise.
2. Which of the following are devices used for testing physical fitness?
a) Treadmill and sphygmomanometer
b) Ergometer and sphygmomanometer
c) Treadmill and Ergometer
d) Sphygmomanometer and Event recorders
Answer: c
Explanation: Both the treadmill and ergometer can be used as stand-alone devices for testing physical fitness. Advanced ergometers and treadmills can store and display activity data, transfer it to a PC and download patient data from PC.
3. Which of the following is the type of exercise protocols used in treadmill tests?
a) The Balke-Bruce Protocol
b) The Bruce-Ware Protocol
c) The Balke-Ware Protocol
d) The Balke Protocol
Answer: c
Explanation: There are two basic kinds of exercise protocols used in treadmill tests: i) The Balke-Ware Protocol and ii) The Bruce Protocol. Both protocols are satisfactory for most clinical purposes. However, they may have to be modified to suit the condition of the individual being subjected to exercise testing.
4. In the Balke-Ware Protocol, how much speed it uses with progressive increments in the load every 2 minutes?
a) 3.3 km/hour
b) 3.3 km to 5.3 km /hour
c) 3.3 miles to 5.3 miles /hour
d) 3.3 miles/hour
Answer: d
Explanation: In the Balke-Ware Protocol, it uses a constant speed of 3.3 miles/hour , with progressive increments in the load every 2 minutes. This is achieved by increasing the grade or incline of the motor-driven treadmill.
5. ______ is a blood pressure measuring instrument.
a) Sphygmomanometer
b) Ergometer
c) Treadmill
d) Holtemanometer
Answer: a
Explanation: Sphygmomanometer, an instrument for measuring blood pressure, typically consisting of an inflatable rubber cuff which is applied to the arm and connected to a column of mercury next to a graduated scale, enabling the determination of systolic and diastolic blood pressure by increasing and gradually releasing the pressure in the cuff.
6. In the ST segment measurement _________ is either between the P and Q waves or in front of the P wave.
a) J point
b) Isoelectric baseline
c) ST measurement point
d) ST value
Answer: b
Explanation: The current standard for determining the ST segment measurement is by measuring the voltage difference between the value at a point 60-80 ms after the J point and the isoelectric baseline. The isoelectric baseline is either between the P and Q waves or in front of the P-wave .
7. _________ is a signal of low amplitude and low frequency content.
a) QRS complex
b) R-R interval
c) ST segment
d) T-P interval
Answer: c
Explanation: The ST segment is a signal of low amplitude and low-frequency content. Therefore, a sampling rate of 250 samples /s is adequate. To ensure that the ST segment can be measured accurately, the incoming ECG signals must have a low-end bandwidth of 0.05 Hz.
8. In the ST segment measurement, what is the bandwidth of the ST filter which is used to remove unwanted baseline noise?
a) 0.05 Hz
b) 0.67 Hz
c) 0.5 Hz
d) 0.067 Hz
Answer: b
Explanation: To ensure that the ST segment can be measured accurately, the incoming ECG signals must have a low-end bandwidth of 0.05 Hz. A special ST filter with a higher low-end bandwidth of 0.67 Hz is used to further remove unwanted baseline noise.
9. ________compare various algorithms employed for processing stress ECG signals.
a) Friesen
b) Jen and Hwang
c) Clynes
d) Alfonso
Answer: d
Explanation: Alfonso compares various algorithms employed for processing stress ECG signals. It may be observed that the exercise test when applied in an appropriate manner and interpreted by an experienced cardiologist is a very useful tool in the functional assessment of normal and abnormal cardiovascular physiology.
10. At an interval of _______ the Bruce Protocol uses simultaneous increments in both speed and treadmill grade.
a) 250 sec
b) 120 sec
c) 160 sec
d) 198 sec
Answer: c
Explanation: At an interval of 3 minutes the Bruce Protocol uses simultaneous increments in both speed and treadmill grade. Typically during a Bruce Protocol, Heart Rate and Rating of Perceived Exertion are taken every minute and Blood Pressure is taken at the end of each stage .
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Data Compression Techniques”.
1. The instrument which carries out a continuous and simultaneous recording of the instantaneous foetal heart rate and labour activity is called ____________
a) Ergometer
b) Cardiotocograph
c) Cardiotocometer
d) Cardiotonometer
Answer: b
Explanation: Cardiotocography is a technical means of recording the fetal heartbeat and the uterine contractions during pregnancy. The machine used to perform the monitoring is called a cardiotocograph, more commonly known as an electronic fetal monitor.
2. In the cardiotocograph, the sensitivity of _______ of recording chart allows adequate reading of the recorder FHR.
a) 30 bpm / cm
b) 10 bpm / cm
c) 20 bpm / cm
d) 15 bpm / cm
Answer: c
Explanation: Normally, an accuracy of measurement of foetal heart rate may be 2-3% for classification for responses. Sensitivity of 20 bpm /cm of the recording chart allows adequate reading of the recorder FHR. Labour activity and FHR traces are usually recorded simultaneously on the same time scale.
3. What is the chart speed in cardiotocograph to provide sufficient resolution of the stimulus-response relationship?
a) 1-2 cm / sec
b) 2-3 cm / min
c) 1-2 cm / min
d) 2-3 cm / sec
Answer: c
Explanation: Normally, accuracy of measurement of foetal heart rate may be 2-3% for classification for responses. Sensitivity of 20 bpm /cm of the recording chart allows adequate reading of the recorder FHR. Labour activity and FHR traces are usually recorded simultaneously on the same time scale. Chart speed of 1-2 cm/min is adequate to provide sufficient resolution of the stimulus-response relationship.
4. Which of the following is not an indirect method of foetal heart rate in cordiotocography monitoring?
a) Foetal ECG with scalp electrode
b) Foetal phonocardiogram
c) Abdominal foetal electrocardiogram
d) Ultrasound techniques
Answer: a
Explanation: The following methods are commonly employed in most of the cardiotocographic monitoring during labour: I) Indirect method: Abdominal foetal electrocardiogram, foetal phonocardiogram, ultrasound techniques II) Direct method: Foetal ECG with scalp electrode .
5. Which of the following is a direct technique of uterine contraction in cardiotocographic monitoring?
a) Tocodynamometry
b) Intrauterine pressure measurement
c) Phonocardiometry
d) Ultrasound technique
Answer: b
Explanation: The following techniques are commonly used in uterine contraction in most of the cardiotocographic monitoring: I) Indirect method: Tocodynamometry II) Direct method: Intrauterine pressure measurement .
6. What is the range of instantaneous “beat-to-beat” rate which is displayed on a calibrated linear scale?
a) 200-220 bpm
b) 150-210 bpm
c) 50-200 bpm
d) 50-210 bpm
Answer: d
Explanation: Instantaneous “beat-to-beat” rate is displayed on a calibrated linear scale or digitally displayed with a range from 50 to 210 bpm. A two channel chart recorder is incorporated in instruments used for monitoring labour activity.
7. One channel records FHR on a calibrated chart in beats per minute while the other channel is used for recording uterine contractions calibrated _______
a) 50-210 mmHg
b) 0-210 mmHg
c) 0-100 mmHg
d) 0-50 mmHg
Answer: c
Explanation: A two channel chart recorder is incorporated in instruments used for monitoring labour activity. One channel records FHR on a calibrated chart in beats per minute while the other channel is used for recording uterine contractions calibrated 0-100 mmHg. The record is printed on thermo-sensitive z-fold paper using a high-resolution thermal matrix printer.
8. The intrauterine pressure can reach values of _______ or more during the expulsion period.
a) 150 mmHg
b) 200 mmHg
c) 220 mmHg
d) 250 mmHg
Answer: a
Explanation: During labour, the uterus muscle starts contraction of increasing intensity in a bid to expel out the child. The intrauterine pressure can reach values of 150 mmHg or more during the expulsion period. However, a normal patient in spontaneous active labour will demonstrate uterine contractions occurring at intervals of three to five minutes, with a duration of 30 to 70 s and a peak intensity of 50 to 75 mmHg.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Exercise Stress Testing”.
1. FHR yields important information about the status of ________
a) fats
b) eye
c) fibrous joint
d) foetus
Answer: d
Explanation: The obstetrician is faced with the problem of having very few parameters available on which to base a diagnosis of foetal well-being or distress. In most cases, the condition of the foetus is assessed by studying the blood flow in the foetal heart and its heart rate. The foetal heart rate yields important information about the status of the foetus, and therefore, has become a widely studied parameter in maternity cases.
2. Foetal Heart sounds are listened by digital stethoscope.
a) True
b) False
Answer: b
Explanation: False, Foetal heart rate monitoring in the labour ward has generally been carried out on an intermittent basis. It has been traditional to listen to the foetal heart sounds at intervals of up to every 15 minutes. This is done by using the Pinard stethoscope.
3. To listen to the foetal heart sounds at intervals of up to every _______ minutes is tradition.
a) 5
b) 10
c) 15
d) 20
Answer: c
Explanation: Foetal heart rate monitoring in the labour ward has generally been carried out on an intermittent basis. It has been traditional to listen to the foetal heart sounds at intervals of up to every 15 minutes. This is done by using the Pinard stethoscope.
4. How is the assessment of the condition of foetus can be made during labour?
a) activity of sweat glands
b) baseline value of skin resistance
c) by foetal heart action
d) baseline value of breathing
Answer: c
Explanation: An assessment of the condition of the foetus can be made during labour from the foetal heart action. Simultaneously, recording beat-to-beat foetal heart rate and uterine activity provides basic information for assessing the compensatory potential of the foetal circulatory system.
5. Which of the following instrument carries out a continuous and simultaneous recording of the instantaneous foetal heart rate and labour activity?
a) Electrocardiograph
b) Cardiotocograph
c) Electromyograph
d) Vectorcardiograph
Answer: b
Explanation: The instrument which carries out a continuous and simultaneous recording of the instantaneous foetal heart rate and labour activity is called cardiotocograph. In addition to detecting long-term bradycardia or tachycardia, this instrument helps in the evaluation of foetal heart rate response of the undisturbed circulatory system and response stimulated by uterine contractions.
6. Sensitivity of _______ bpm/cm of the recording chart allows adequate reading of the recorded FHR.
a) 5
b) 10
c) 15
d) 20
Answer: d
Explanation: Cardiotocographs are designed to measure and record foetal heart rate on a beat-to-beat basis rather than on an average basis. Normally, accuracy of measurement may be 2–3% for the classification of responses. The sensitivity of 20 bpm/cm of the recording chart allows adequate reading of the recorded FHR.
7. What is the used in Tocodynamometry to sense changes in uterine tension transmitted to abdominal skin surface?
a) U-Manometer
b) Barometer
c) Tocotonometer
d) Picometer
Answer: c
Explanation: Tocodynamometry is an indirect method to measure uterine contraction in cardiotographic monitoring during labour in which tocotonometer is used to sense changes in uterine tension transmitted to abdominal skin surface.
8. Which of the following is a direct method for measuring foetal heart rate?
a) Abdominal foetal electrocardiogram
b) Foetal phonocardiogram
c) Ultrasound technique
d) Foetal ECG with scalp electrode
Answer: d
Explanation: Abdominal foetal electrocardiogram, foetal phonocardiogram and Ultrasound technique are indirect methods of measuring foetal heart rate where as Foetal ECG with scalp electrode is a direct method as in it spiral, clip or suction electrode is attached to the presenting part of foetus.
9. Cardiotocographs are designed to measure and record foetal heart rate on an average basis.
a) True
b) False
Answer: b
Explanation: False, Cardiotocographs are designed to measure and record foetal heart rate on a beat-to-beat basis rather than on an average basis. Normally, accuracy of measurement may be 2–3% for the classification of responses.
10. What is the accuracy of measurement for the classification of responses?
a) 1-2%
b) 2-3%
c) 3-4%
d) 4-5%
Answer: b
Explanation: Cardiotocographs are designed to measure and record foetal heart rate on a beat-to-beat basis rather than on an average basis. Normally, accuracy of measurement may be 2–3% for the classification of responses.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Ambulatory Monitoring Instruments”.
1. Where are the electrodes placed for recording foetal electrocardiogram?
a) heart
b) abdomen
c) brain
d) veins
Answer: b
Explanation: Foetal electrocardiogram is recorded by suitably placing the electrodes on the mother’s abdomen and recording the combined maternal and foetal ECG. The maximum amplitude of FECG recorded during pregnancy is about 100 to 300 mV. This magnitude is much smaller than in the typical adult ECG which is about 1 mV in the standard lead connection.
2. What is the maximum amplitude of FECG recorded during pregnancy?
a) 100 to 300 mV
b) 300 to 500 mV
c) 500 to 700 mV
d) 700 to 900 mV
Answer: a
Explanation: Foetal electrocardiogram is recorded by suitably placing the electrodes on the mother’s abdomen and recording the combined maternal and foetal ECG. The maximum amplitude of FECG recorded during pregnancy is about 100 to 300 mV. This magnitude is much smaller than in the typical adult ECG which is about 1 mV in the standard lead connection.
3. The foetus heart rate is approximately _______ time/s of normal adult foetal heart rate.
a) one
b) two
c) three
d) four
Answer: b
Explanation: The foetal heart rate is computed from the foetal ECG by appropriately shaping the foetal QRS wave. The foetus heart rate is approximately twice that of the normal adult ranging approximately from 110 to 180 bpm. The main problem in processing the foetal heart signals is the poor SNR.
4. Which of the following is periodic noise source in the foetal ECG signal from the maternal abdomen?
a) Amplifier input noise
b) Maternal Muscle noise
c) Fluctuations in electrode polarization potential
d) Maternal ECG
Answer: d
Explanation: The major sources of noise in the foetal ECG signal recorded from the maternal abdomen are amplifier input noise, maternal muscle noise , fluctuations in electrode polarization potential, and maternal ECG. For practical purposes, the first three of these sources can be considered as random whereas the maternal ECG is a periodic noise source.
5. What is the magnitude of ECG for a typical adult in the standard lead connection?
a) 1 mV
b) 2 mV
c) 3 mV
d) 4 mV
Answer: a
Explanation: Foetal electrocardiogram is recorded by suitably placing the electrodes on the mother’s abdomen and recording the combined maternal and foetal ECG. The maximum amplitude of FECG recorded during pregnancy is about 100 to 300 mV. This magnitude is much smaller than in the typical adult ECG which is about 1 mV in the standard lead connection.
6. Which of the following technique is used to measure foetal heart rate?
a) ECG
b) FECG
c) PCG
d) VCG
Answer: b
Explanation: Abdominal FECG processing circuit is used for computing foetal heart rate. After proper placement of the electrodes, the signals are amplified in a preamplifier which provides a very high input impedance and high sensitivity and good common mode rejection ratio .
7. What is the CMRR of Foetal electrocardiogram?
a) 0-150 dB
b) 0- 130 dB
c) 0-120 dB
d) 0-200 dB
Answer: c
Explanation: Abdominal FECG processing circuit is used for computing foetal heart rate. After proper placement of the electrodes, the signals are amplified in a preamplifier which provides a very high input impedance and high sensitivity and good common mode rejection ratio .
8. What is responsible for most of the common-mode interfering signal?
a) Preamplifier
b) Notch Filter
c) Power Line Hum
d) Band Pass Filter
Answer: c
Explanation: A sizable common-mode signal manages to pass through the input amplifier, a circumstance to be expected whenever electrodes spaced a few centimetres apart are attached to the human body in a hospital environment. Power line hum is responsible for most of the common-mode interfering signal. This is suppressed by a notch filter following the input amplifier.
9. What is present in the processing circuit for signal separation?
a) Preamplifier
b) Power Line Hum
c) Notch Filter
d) Band Pass Filter
Answer: d
Explanation: The signal path then splits into two channels: the maternal ECG channel or Mchannel and the foetal or F channel. Since the frequency spectrum of the foetal ECG differs somewhat from the maternal ECG, some initial signal separation is achieved by using the appropriate bandpass filtering in each channel.
10. The F channel has a _______ ms pulse generator that is triggered by the foetal ECG.
a) 5
b) 10
c) 20
d) 30
Answer: d
Explanation: The F channel has a 30 ms pulse generator that is triggered by the foetal ECG. It is inhibited, however, by the blanking pulse from the M channel, so it will not generate a pulse in response to the maternal ECG signal feeding through to the F channel.
11. Foetal ECG signal detected via electrodes placed on mother’s abdomen is complex and requires accertion of maternal signals for obtaining FHR.
a) True
b) False
Answer: b
Explanation: False, Foetal ECG signal detected via electrodes placed on the mother’s abdomen is complex and requires attenuation of maternal signals for obtaining FHR. Also, due to the overlapping of the foetal ECG with the maternal ECG, about 20% to 50% of the expected pulses may be missing.
12. AECG technique fails in those rare cases where the amniotic fluid fails to provide adequate electrical coupling from foetus to mother.
a) True
b) False
Answer: a
Explanation: Clinical trials have shown that the AECG technique is usually effective in most cases except in those rare cases where the amniotic fluid fails to provide adequate electrical coupling from foetus to mother. However, during labour, the uterine and abdominal wall electromyogram signals tend to obliterate the FECG signal, making FHR counting quite difficult. At present, the abdominal FECG, therefore, does not seem to offer a practical reliable means of FHR monitoring during labour and delivery.
13. What is delay time to establish a missing foetal trigger pulse by substitution logic?
a) 150 ms
b) 200 ms
c) 250 ms
d) 270 ms
Answer: d
Explanation: The substitution logic requires a delay time to establish a missing foetal trigger pulse. On the one hand, this delay has to be longer than the maximum permissible change in heart period and on the other hand, it has to be shorter than the shortest period duration . It is thus kept as 270 ms.
14. What is the range of FHR measurement due to substitution logic?
a) 0-200 bpm
b) 40-240 bpm
c) 20-220 bpm
d) 60-260 bpm
Answer: b
Explanation: The substitution logic requires a delay time to establish a missing foetal trigger pulse. It is thus kept as 270 ms. The range of FHR measurement is limited to 40–240 bpm because of the substitution logic. Thereafter, the output of logic circuits goes to standard heart rate computing circuits.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Cardiotocograph”.
1. Ambulatory monitoring of ECG is called ____________
a) Event Cardiography
b) Holter Cardiography
c) Real-Time Cardiography
d) Implantable Cardiography
Answer: b
Explanation: Ambulatory monitoring of ECG is called ‘Holter Cardiography’, after Dr. Norman Holter who introduced this concept in 1962. A Holter monitor is a type of ambulatory electrocardiography device, a portable device for cardiac monitoring for at least 24 hours .
2. Which of the following type of systems are not available for ambulatory ECG monitoring?
a) Holter monitors
b) Event Recorders
c) Time Recorders
d) Implantable Loop Recorders
Answer: c
Explanation: Currently, the following four types of systems are available for ambulatory ECG monitoring: I) Holter Monitors II) Event Recorders III) Real-Time Continuous Cardiac Monitoring System IV) Implantable Loop Recorders.
3. The current state of Holter technology uses small recorders, which size is about _______
a) 75 x 20 x 90 cm
b) 75 x 95 x 20 cm
c) 75 x 20 x 95 mm
d) 75 x 95 x 20 mm
Answer: d
Explanation: The current state of Holter technology uses small recorders with flashcard technology to record and store data from 2 to 3 ECG leads attached to the patient’s chest and collected continuously over 24 to 48 hours.
4. Who provides an excellent review of ambulatory cardiac event recorders?
a) Handelsman
b) Benz
c) Alfonso
d) Friesen
Answer: b
Explanation: An excellent review of ambulatory cardiac event recorders is provided by Benz in 1999. The major advantage of these devices compared with a traditional Holter monitor is that they are small, allow ECG monitoring for longer time periods, and can provide nearly real time data analysis when the patient transmits a recording in proximity to the symptomatic event.
5. The monitor automatically transmits recorded data transtelephonically to a central monitoring station for subsequent analysis when an arrhythmia is detected by an arrhythmia algorithm.
a) True
b) False
Answer: a
Explanation: In Real-Time Continuous Cardiac Monitoring Systems, the monitor is equipped with software that analyzes the rhythm data continuously and automatically. The monitor automatically transmits recorded data transtelephonically to a central monitoring station for subsequent analysis when an arrhythmia is detected by an arrhythmia algorithm.
6. In the data recording, the normal speed of sub miniature tape recorder is ___________
a) 3 cm/s
b) 2 cm/s
c) 3 mm/s
d) 2 mm/s
Answer: d
Explanation: In data recording, the core of the modern ambulatory monitoring system is a multichannel sub-miniature tape recorder running normally at a speed of 2 mm/s. At this speed, a C-120 entertainment cassette will run for 24 hours.
7. In data recorders, during replay, the tape is run at ________ to achieve rapid manual or automatic scanning of ambulatory records.
a) 80 times of recording speed
b) 70 times of recording speed
c) 60 times of recording speed
d) 50 times of recording speed
Answer: c
Explanation: In data recorders, during replay, the tape is run at 120 mm/s to achieve rapid manual or automatic scanning of ambulatory records. The tape recorders used for this purpose have some special features as compared to the usually available entertainment tape recorders.
8. Which of the following is not an arrhythmic condition?
a) Cardiographic beat
b) Bradycardia
c) Dropped beat
d) Ectopic beat
Answer: a
Explanation: The analyzer part in automatic scanning of ambulatory records look for four arrhythmic conditions. These are bradycardia, tachycardia, dropped beat and premature beat. A threshold control is associated with each of these and when the appropriate threshold is exceeded, an alarm condition is generated.
9. Which CPU has an overall system control responsibility?
a) Control
b) Acquisition
c) Control and timing
d) Acquisition and display
Answer: c
Explanation: The control and timing CPU has an overall system control responsibility. It also handles individuals functions such as keyboard and direct writer interface, tape deck control, timing data processing, and arrhythmia count totalizing via a high speed interrupt system.
10. Full form of P-FCB is ________
a) Planar-Functional Circuit Board
b) Planar-Fashionable Circuit Branch
c) Planar-Functional Circuit Board
d) Planar-Fashionable Circuit Board
Answer: d
Explanation: The full form of F-PCB is Planar-Fashionable Circuit Board. Sometimes in Holter monitoring, the patient needs typically 6 to 10 wires worn around the body throughout the day. To overcome these problems, a wearable electrocardiogram acquisition system implemented with planar-fashionable circuit board -based shirt is explained by Yoo.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Methods of Monitoring Foetal Heart Rate – 1”.
1. Which system may include lenses, mirrors, slits, diaphragm etc?
a) Radiant system
b) Optical system
c) Cardiac system
d) Photo system
Answer: b
Explanation: An optical system for producing a parallel beam of filtered light for passage through an absorption cell . The system may include lenses, mirrors, slits, diaphragm, etc. A detecting system for the measurement of unabsorbed radiant energy, which could be the human eye, a barrier-layer cell, phototube or photo-multiplier tube.
2. What is the most common and convenient source of light?
a) Xenon-mercury arc
b) Hydrogen discharge lamp
c) Neon-xenon arc
d) Tungsten lamp
Answer: d
Explanation: The most common and convenient source of light is the tungsten lamp. This lamp consists of a tungsten filament enclosed in a glass envelope. It is cheap, intense and reliable. A major portion of the energy emitted by a tungsten lamp is in the visible region and only about 15 to 20% is in the infrared region.
3. In the radiation source, for work in the ultraviolet region, a _______ is used.
a) Tungsten lamp
b) Xenon-mercury arc
c) Deuterium discharge lamp
d) Hydrogen arc
Answer: c
Explanation: For work in the ultraviolet region, a hydrogen or deuterium discharge lamp is used. In these lamps, the envelope material of the lamp puts a limit on the smallest wavelength which can be transmitted.
4. What are the wavelengths of quartz and fused silica respectively in a hydrogen discharge lamp?
a) 200 nm, 185 nm
b) 200 nm, 145 nm
c) 185 nm, 200 nm
d) 145 nm, 200 nm
Answer: a
Explanation: In these lamps, the envelope material of the lamp puts a limit on the smallest wavelength which can be transmitted. For example, quartz is suitable only up to 200 nm and fused silica up to 185 nm. The radiation from the discharge lamps is concentrated into narrow wavelength regions of emission lines. Practically, there is no emission beyond 400 nm in these lamps.
5. Modern instruments use ________ light source in calorimeters and spectrophotmetry.
a) Xenon-mercury lamp
b) Tungsten-halogen lamp
c) Mercury arc
d) Deuterium discharge lamp
Answer: b
Explanation: Modern instruments use a tungsten-halogen light source, which has a higher intensity output than the normal tungsten lamp in the change over the region of 320–380 nm used in colorimetry and spectrophotometry. It also has a larger life and does not suffer from the blackening of the bulb glass envelope.
6. The absorption type optical filter usually consists of coloured glasses, gelatin etc. and solutions of the coloured substances.
a) True
b) False
Answer: a
Explanation: The absorption type optical filter usually consists of colour media: colour glasses, coloured films , and solutions of the coloured substances. This type of filter has a wide spectral bandwidth, which may be 40 to 50 m in width at one-half the maximum transmittance.
7. Which of the following is the dielectric?
a) MgF3
b) ZnF2
c) ZnS
d) ZnF3
Answer: c
Explanation: Interference filters usually consist of two semi-transparent layers of silver, deposited on glass by evaporation in a vacuum and separated by a layer of dielectric . In this arrangement, the semi-transparent layers are held very close.
8. The transmittance of interference filters varies between ________ % with a spectral bandwidth of 10 to 15 nm.
a) 15 to 20 %
b) 20 to 60 %
c) 10 to 20 %
d) 15 to 60 %
Answer: d
Explanation: Interference filters allow a much narrower band of wavelengths to pass and are similar to monochromators in selectivity. They are simpler and less expensive. However, as the selectivity increases, the transmittance decreases. The transmittance of these filters varies between 15 to 60 percent with a spectral bandwidth of 10 to 15 nm.
9. The expression relating the wavelength of the radiation and the angle at which it is reflected is given by _________
a) ml = 2d sin q, where l= lambda
b) m = 2d sin q
c) ml = d sin q, where l= lambda
d) m = d sin q
Answer: a
Explanation: The expression relating the wavelength of the radiation and the angle at which it is reflected is given by
ml = 2d sin q, where l= lambda.
where d is the distance separating the grooves and is known as the grating constant and m is the order of interference.
When m = 1, the spectrum is known as first order and with m = 2, the spectrum is known as second order.
10. _______ are optical systems, which provide better isolation of spectral energy than the optical filters.
a) Spectromators
b) Monochromators
c) Tocochromators
d) Baromators
Answer: b
Explanation: Monochromators are optical systems, which provide better isolation of spectral energy than the optical filters, and are therefore preferred where it is required to isolate narrow bands of radiant energy. Monochromators usually incorporate a small glass of quartz prism or a diffraction grating system as the dispersing media.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Methods of Monitoring Foetal Heart Rate – 2”.
1. The energy must be reflected and returned through a single 30° prism, so that it passes through the prism in both directions is called __________
a) Cornu mounting
b) Mono mounting
c) Littrow mounting
d) Trio mounting
Answer: c
Explanation: Quartz shows the property of double refraction. Therefore, two pieces of quartz, one right-handed and one left handed are taken and cemented back-to-back in the construction of 60° prism , or the energy must be reflected and returned through a single 30° prism, so that it passes through the prism in both directions .
2. Most modern instruments now use a _______ as a dispersing element in the monochromator.
a) Prism monochromators
b) Holographic gratings
c) Diffraction gratings
d) Replica gratings
Answer: c
Explanation: Most modern instruments now use a diffraction grating as a dispersing element in the monochromator, as prisms in general have a poorer stray light performance and require complex precision cams to give a linear wavelength scale. Replica gratings can even be produced more cheaply than prisms and require only a simple sine bar mechanism for the wavelength scale.
3. A typical reflection grating may have 1200 grooves/mm, which means the grooves are spaced at about _______ intervals.
a) 800 nm
b) 600 nm
c) 860 nm
d) 680 nm
Answer: a
Explanation: A typical reflection grating may have 1200 grooves/mm, which means the grooves are spaced at about 800 nm intervals. The grating may have a width of 20 mm or more, giving a total of at least 24,000 grooves.
4. What is reproduced from a master holographic grating by moulding its grooves onto a resin surface or silica substrate?
a) Diffraction grating
b) Replica grating
c) Silicate glasses
d) Fused silica
Answer: b
Explanation: Holographic gratings used in commercial spectrophotometers are either original master gratings produced directly by an interferometer or are replica gratings. Replica gratings are reproduced from a master holographic grating by moulding its grooves onto a resin surface on a glass or silica substrate.
5. What is the utilization wavelength limit for quartz?
a) 300 nm
b) 350 nm
c) 180 nm
d) 210 nm
Answer: d
Explanation: Normally, the absorbance of any material should be less than 0.2 at the wavelength of use. Below 300 nm, quartz or fused silica is utilized. The limit for quartz is 210 nm.
6. Which material is used to reduce the reflections from glass surfaces?
a) Manganese Flouride
b) Magnesium oxide
c) Magnesium Flouride
d) Manganese oxide
Answer: c
Explanation: Reflections from glass surfaces are reduced by coating these with magnesium fluoride, which is one-quarter wavelength in optical thickness. With this, scattering effects are also greatly reduced.
7. With the use of _______ chromatic aberrations and other imperfections of the lenses are minimized.
a) Lenses
b) Mirrors
c) Slits
d) Diaphragm
Answer: b
Explanation: To minimize light losses, lenses are sometimes replaced by front-surfaced mirrors to focus or collimate light beam in absorption instruments. Mirrors are aluminized on their front surfaces. With the use of mirrors, chromatic aberrations and other imperfections of the lenses are minimized.
8. _______ are often used for splitting the beam.
a) Multilayer coated lenses
b) Silvered films
c) Silicate glasses
d) Half-silvered mirrors
Answer: d
Explanation: The two beams must retain the spectral properties of the incident beam. Half-silvered mirrors are often used for splitting the beam. However, they absorb some of the light in the thin metallic coating. Beam splitting can also be achieved by using a prismatic mirror or stack of thin horizontal glass plates, silvered on their edges and alternatively oriented to the incident beam.
9. The sample holder is generally inserted somewhere in the interval between the ______and _______
a) Silvered film and multi-layered coating
b) The light source and the detector
c) The light source and silvered film
d) Silvered film and the detector
Answer: b
Explanation: Gases may be contained in cells which are sealed or stoppered to make them air-tight. The sample holder is generally inserted somewhere in the interval between the light source and the detector. For the majority of analyses, a 10 mm path-length rectangular cell is usually satisfactory.
10. In sample holders, for such applications, a 50 cm path-length with about a ________ volume cell is employed.
a) 0.3 ml
b) 3 liters
c) 0.3 liters
d) 3 ml
Answer: c
Explanation: Studies of dilute or weakly-absorbing liquid samples, or of samples where trace components must be detected, require a cell with a long path-length. For such applications, a 50 cm path-length with about a 300 ml volume cell is employed.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Monitoring Labour Activity”.
1. Which section of the clinical laboratory deals with determinations of the number and characteristics of the constituents of the blood, particularly the blood cells?
a) Chemistry
b) Haematology
c) Microbiology
d) Sample collection
Answer: b
Explanation: There are three different areas within the clinical laboratory set up. These are:
• Chemistry section deals with the analysis of blood, urine, cerebrospinal fluid and other fluids to determine the quantity of various important substances they contain. Most of the electronic instruments in the clinical laboratory are available in this section.
• Haematology section deals with the determinations of the number and characteristics of the constituents of the blood, particularly the blood cells.
• Microbiology section in which studies are performed on various body tissues and fluids to determine the presence of pathological micro-organisms.
2. What is the percentage of blood plasma and the blood cells respectively in blood volume?
a) 60, 40
b) 40, 60
c) 70, 30
d) 30, 70
Answer: a
Explanation: The liquid part of the blood—the blood plasma, and the formed elements—the blood cells are analyzed during a chemical examination. The blood plasma accounts for about 60% of the blood volume and the blood cells occupy the other 40%. The plasma is obtained by centrifuging a blood sample.
3. The plasma is a viscous, light yellow liquid, i.e. almost clear in the fasting stage.
a) True
b) False
Answer: a
Explanation: The plasma is obtained by centrifuging a blood sample. During centrifugation, the heavy blood cells get packed at the bottom of the centrifuge tube and the plasma can thus be separated. The plasma is a viscous, light yellow liquid, i.e. almost clear in the fasting stage.
4. Which of the following method is based on the absorption of electromagnetic radiation in the visible, ultraviolet and infrared ranges?
a) Cardiotocography
b) Ultrasonic therapy
c) Spectrophotometry
d) Diathermy
Answer: c
Explanation: Spectrophotometry is the most important of all the instrumental methods of analysis in clinical chemistry. This method is based on the absorption of electromagnetic radiation in the visible, ultraviolet and infrared ranges.
5. Which of the following waves have short wave-length?
a) Microwave
b) Radio wave
c) Gamma rays
d) IR waves
Answer: c
Explanation: Electromagnetic spectrum ranges from very short wavelengths to very long wavelengths . The range of wavelength of gamma rays and X-rays is 10 -4 to 10 nm. The range of wavelengths of microwaves and radio-waves is 10 6 to 10 9 nm.
6. The method based on the absorption of radiation of a substance is known as?
a) Absorption photometry
b) Spectrophotometry
c) Absorption tocometry
d) Absorption spectrophotoscopy
Answer: d
Explanation: Electronic transitions correspond to the ultraviolet and visible regions, vibrational transitions to the near infrared and infrared regions and rotational transitions to the infrared and far-infrared regions. The method based on the absorption of radiation of a substance is known as Absorption Spectroscopy.
7. What is the range of visible light of electromagnetic spectrum?
a) 380 to 780 mm
b) 780 to 1080 nm
c) 380 to 780 nm
d) 380 to 1080 nm
Answer: c
Explanation: The region in the electromagnetic spectrum which is normally used in spectroscopic work is very limited. Visible light represents only a very small portion of the electromagnetic spectrum and generally covers a range from 380 to 780 nm. The ultraviolet region extends from 185 mm to the visible.
8. The ratio of the radiant power transmitted by a sample to the radiant power incident on the sample is known as ______
a) Absorbance
b) Transmittance
c) Optical density
d) Photometric concentration
Answer: b
Explanation: Let us suppose, Po is the incident radiant energy and P is the energy which is transmitted. The ratio of the radiant power transmitted by a sample to the radiant power incident on the sample is known as the transmittance.
Transmittance = P/Po
9. If absorbance is plotted graphically against concentration, the graph is _________
a) Parabola
b) Increasing
c) Straight line
d) Decreasing
Answer: c
Explanation: If absorbance is plotted graphically against concentration, a straight line is obtained. A graph derived from the transmittance data will not be a straight line unless transmittance is plotted on the log axis of a semi-log paper.
10. Which of the following is not a source of radiant energy?
a) Tungsten-mercury lamp
b) Tungsten lamp
c) Xenon-mercury arc
d) Deuterium discharge lamp
Answer: a
Explanation: Radiant just means energy that can move from one place to another without a medium to carry it. A source of radiant energy, which may be a tungsten lamp, a xenon-mercury arc, hydrogen or deuterium discharge lamp, etc.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Recording System”.
1. How are foetal heart sounds picked up from the maternal abdomen?
a) Piezoelectric device
b) Sensitive Microphone
c) Crystal microphone
d) Dynamic microphone
Answer: b
Explanation: Foetal heart sounds can be picked up from the maternal abdomen by a sensitive microphone. The heart sounds in the form of mechanical vibrations have to pass through tissue structure and the signals picked up are rather weak because of distance effects and the small size of foetal heart valves.
2. Crystal microphone is used for picking _______ signals.
a) cardiac
b) brain
c) phono
d) muscles
Answer: c
Explanation: To pick up the heart sounds, it is essential that the transducer is properly placed and its impedance carefully matched. A crystal microphone is used for picking up phono signals. The phono transducer signals are amplified by a low noise preamplifier and fed to a bandpass filter which rejects all frequencies outside the 70 to 110 Hz range.
3. Bandpass filter used in foetal phonocardiogram rejects all frequencies outside the ________ Hz range.
a) 0-40
b) 40-80
c) 70-110
d) 110-150
Answer: c
Explanation: To pick up the heart sounds, it is essential that the transducer be properly placed and its impedance carefully matched. A crystal microphone is used for picking up phono signals. The phono transducer signals are amplified by a low noise preamplifier and fed to a bandpass filter which rejects all frequencies outside the 70 to 110 Hz range.
4. The preamplifier is incorporated in the transducer housing to maximize interference signals being picked up.
a) True
b) False
Answer: b
Explanation: The preamplifier is incorporated in the transducer housing to minimize interference signals being picked up. Much of the random noise is eliminated during this process and the record on paper after this stage is called foetal phonocardiograph.
5. How many sounds are produced from the normal foetal heart action?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: From the normal foetal heart action, generally two sounds are produced corresponding to the contraction and relaxation of the heart muscles. These two bursts of heart sounds are mixed up with unwanted signals which may succeed in passing through the filters.
6. What is the fixed pulse width of the pulse after process of one-shot circuit?
a) 110 ms
b) 170 ms
c) 230 ms
d) 280 ms
Answer: c
Explanation: After peak detection, the processed pulses operate a one-shot circuit which gives a fixed pulse width of 230 ms. The output of one-shot triggers a variable pulse width multi-vibrator which adds and gives either 43 or 116 ms time depending on the heart rate. The pulse width at the output will be either 230 + 43 = 273 ms or 230 + 116 = 346 ms.
7. What is used to detect heart frequency in foetal phonocardiograph?
a) 230 ms one shot
b) 400 ms one shot
c) 20 ms one shot
d) 440 ms one shot
Answer: b
Explanation: To detect the heart frequency, the 400 ms one-shot is used. If the period duration is greater than 400 ms, the one-shot will deliver a pulse. The negative slope of this pulse is used to trigger the 20 ms one-shot. These 20 ms pulses are integrated by the integrator and the output of this integrator is compared with a fixed voltage -V.
8. If the period duration is lesser than 400 ms, the one-shot will deliver a pulse.
a) True
b) False
Answer: b
Explanation: False, to detect the heart frequency, the 400 ms one-shot is used. If the period duration is greater than 400 ms, the one-shot will deliver a pulse. The negative slope of this pulse is used to trigger the 20 ms one-shot. These 20 ms pulses are integrated by the integrator and the output of this integrator is compared with a fixed voltage -V.
9. What is used to delay the change in the time constant in foetal phonocardiograph?
a) Preamplifier
b) Notch Filter
c) Integrator
d) Band Pass Filter
Answer: c
Explanation: The integrator is used to delay the change in the time constant and to make sure that a change of on-time takes place only if several heart beats with the longer period duration are present.
10. No output pulse will occur when the period between two pulses is less than _____ ms.
a) 230
b) 20
c) 400
d) 440
Answer: c
Explanation: No output pulse will occur if the period between two pulses is less than 400 ms. The 20 ms pulses are, therefore, not generated and the integrator discharges slowly from the negative output voltage to a positive output voltage. If the output of the integrator is less negative than-V, the output of the comparator will become negative.
11. Ultrasound provides basically clearer signal than does phonocardiography.
a) True
b) False
Answer: b
Explanation: False, Phonocardiography provides a basically cleaner signal than does ultrasound, thus allowing a greater chance of detecting a smooth baseline FHR. Unfortunately, phonocardiography is more susceptible to artefacts introduced from ambient noise, patient movement or other intra-abdominal sounds.
12. Which of the following instrument makes use of the Doppler shift principle?
a) Abdominal Foetal Electrocardiogram
b) Foetal Phonocardiogram
c) Foetus blood flow detector
d) Foetal ECG with scalp electrode
Answer: c
Explanation: An important clinical instrument for obstetric applications which makes use of the Doppler shift principle is the foetus blood flow detector. The technique is extended to derive an integrated rate of the foetus heart from blood flow signals and to display it on a suitable display system.
13. Which technique is used to derive an integrated rate of the foetus heart from blood flow signals and to display it on a suitable display system?
a) Abdominal Foetal Electrocardiogram
b) Foetal Phonocardiogram
c) Ultrasound
d) Foetal ECG with scalp electrode
Answer: c
Explanation: An important clinical instrument for obstetric applications which makes use of the Doppler shift principle is the foetus blood flow detector. The ultrasound technique is extended to derive an integrated rate of the foetus heart from blood flow signals and to display it on a suitable display system.
14. What is ultrasonic frequency employed for obstetric studies?
a) 0.5 to 1 MHz
b) 1 to 1.5 MHz
c) 1.5 to 2 MHz
d) 2 to 2.5 MHz
Answer: d
Explanation: For obstetric studies, ultrasonic frequency of about 2 to 2.5 MHz is usually employed, whereas in the study of blood flow in arteries and superficial blood vessels frequencies around 5–10 MHz are preferred. The level of ultrasonic energy transmitted into the body is generally kept between 10–15 mW/cm 2 .
15. What is range of ultrasonic energy transmitted into the body?
a) 0-5 mW/cm 2
b) 5-10 mW/cm 2
c) 10-15 mW/cm 2
d) 15-20 mW/cm 2
Answer: c
Explanation: For obstetric studies, ultrasonic frequency of about 2 to 2.5 MHz is usually employed, whereas in the study of blood flow in arteries and superficial blood vessels frequencies around 5–10 MHz are preferred. The level of ultrasonic energy transmitted into the body is generally kept between 10–15 mW/cm 2 .
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Oximeters”.
1. Blood flow detectors based on Doppler shift start detecting foetal pulses as early as in which week of pregnancy?
a) tenth
b) eleventh
c) twelfth
d) ninth
Answer: b
Explanation: Blood flow detectors based on ultrasonic Doppler shift can detect foetal pulse as early as the tenth week of pregnancy and in nearly all cases by the twelfth week. At about 20 weeks it is possible to detect multiple pregnancies especially if two instruments are used together and the pulse rates compared. Intrauterine death of the foetus can also be diagnosed.
2. When it is possible to detect multiple pregnancies?
a) 10th week
b) 12th week
c) 15th week
d) 20th week
Answer: d
Explanation: Blood flow detectors based on ultrasonic Doppler shift can detect foetal pulse as early as the tenth week of pregnancy and in nearly all cases by the twelfth week. At about 20 weeks it is possible to detect multiple pregnancies especially if two instruments are used together and the pulse rates compared. Intrauterine death of the foetus can also be diagnosed.
3. Which of the following is the most reliable method for detecting FHR pattern?
a) Abdominal foetal electrocardiogram
b) Foetal phonocardiogram
c) Ultrasound technique
d) Foetal ECG with scalp electrode
Answer: c
Explanation: We can hear the signal through a loudspeaker with a scarce chance of failing to recognize any beat, but a simple electronic circuit may fail to trigger from this signal. Still, the ultrasound Doppler shift method is more practical and easy to use during labour. It is currently the most reliable method for detecting the FHR pattern that is interpretable.
4. Signal processing for FHR determination can be based either on detecting the foetal heart valve motion or on detecting the heart wall motion in Abdominal foetal electrocardiogram technique.
a) True
b) False
Answer: b
Explanation: False, Signal processing for FHR determination can be based either on detecting the foetal heart valve motion or on detecting the heart wall motion in Ultrasound technique as The heart valve motion detection technique is based on the distinct ultrasound frequency shift produced by the fast opening and closing of the heart valves. The technique, however, requires that the ultrasound beam must be directed against the relatively small heart valves involving a longer search period and frequent repositioning of the transducer. Therefore, it is not preferred for continuous monitoring applications.
5. What is maximum ultrasound intensity of narrow beam transducer?
a) 15 mW/cm 2
b) 20 mW/cm 2
c) 25 mW/cm 2
d) 30 mW/cm 2
Answer: c
Explanation: The narrow beam transducer uses a single ultrasound transmitter/receiver piezo-electric crystal pair. The maximum ultrasound intensity is generally kept below 25 mW/cm 2 . The typical transducer diameter is 25 mm. The narrow beam transducer is very sensitive and produces a good trigger signal for instantaneous heart rate determination.
6. What is the diameter of a narrow beam transducer?
a) 15 mm
b) 20 mm
c) 25 mm
d) 30 mm
Answer: c
Explanation: The narrow beam transducer uses a single ultrasound transmitter/receiver piezo-electric crystal pair. The maximum ultrasound intensity is generally kept below 25 mW/cm2. The typical transducer diameter is 25 mm. The narrow beam transducer is very sensitive and produces a good trigger signal for instantaneous heart rate determination.
7. What is used to detect foetal heart movements in broad beam transducer?
a) Quartz crystal
b) Piezo electric crystal
c) Topaz crystal
d) Berlinite crystal
Answer: b
Explanation: The broad beam transducers are available in many configurations. The transducers comprise a number of piezo-electric crystals mounted in such a way as to be able to detect foetal heart movements over a wider area.
8. The narrow beam transducer is very sensitive and produces a good trigger signal for instantaneous heart rate determination.
a) True
b) False
Answer: a
Explanation: True, The narrow beam transducer is very sensitive and produces a good trigger signal for instantaneous heart rate determination because it takes time to detect a good signal and, therefore, frequent transducer repositioning is necessary.
9. Which of the following transducer is used to detect foetal heart movements over a wider area?
a) piezo-electric
b) ultrasonic
c) array
d) pressure
Answer: a
Explanation: The broad beam transducers are available in many configurations. The transducers comprise a number of piezo-electric crystals mounted in such a way as to be able to detect foetal heart movements over a wider area.
10. Which transducer is arranged in the shape of a clover leaf so that it provides a large area of illumination?
a) piezo-electric
b) ultrasonic
c) array
d) pressure
Answer: b
Explanation: The ultrasonic transducer is arranged in the shape of a clover-leaf so that it provides a large area of ultrasonic illumination which allows the monitoring considerable lateral and descending foetal motion before requiring repositioning. The transducer housing is flexible to permit it to follow the contour of the abdomen regardless of shape changes with contractions.
11. The array transducer housing is flexible to permit it to follow the contour of the abdomen regardless of shape changes with contractions.
a) True
b) False
Answer: b
Explanation: False, the ultrasonic transducer is arranged in the shape of a clover-leaf so that it provides a large area of ultrasonic illumination which allows the monitoring considerable lateral and descending foetal motion before requiring repositioning. The ultrasonic transducer housing is flexible to permit it to follow the contour of the abdomen regardless of shape changes with contractions.
12. At what angle divergent beam is transmitted by a crystal in array transducer?
a) 10°
b) 20°
c) 30°
d) 40°
Answer: d
Explanation: An alternative arrangement is the array transducer which has one transmitter and six peripheral ceramic receiving crystals. The transmitting crystal emits a 40° divergent beam so that at 10 cm from the skin surface the beam covers an area of approximately 10 cm diameter.
13. The transmitting crystal emits 40° divergent beam so that the beam covers an area of approximately _____ cm diameter.
a) 10
b) 20
c) 30
d) 40
Answer: a
Explanation: An alternative arrangement is the array transducer which has one transmitter and six peripheral ceramic receiving crystals. The transmitting crystal emits a 40° divergent beam so that at 10 cm from the skin surface the beam covers an area of approximately 10 cm diameter.
14. What is the diameter of an array transducer?
a) 2
b) 4
c) 6
d) 8
Answer: c
Explanation: The transmitting crystal emits a 40° divergent beam so that at 10 cm from the skin surface the beam covers an area of approximately 10 cm diameter. This construction ensures continuous recording of the foetal heart activity without the need to reposition the transducer which is otherwise necessitated due to normal foetal movement. The transducer has a diameter of 6 cm and can be held in place either by a simple buckle or a stretch belt.
15. The array transducer can be held in place by a simple buckle.
a) True
b) False
Answer: a
Explanation: True, the transmitting crystal emits a 40° divergent beam so that at 10 cm from the skin surface the beam covers an area of approximately 10 cm diameter. This construction ensures continuous recording of the foetal heart activity without the need to reposition the transducer which is otherwise necessitated due to normal foetal movement. The transducer has a diameter of 6 cm and can be held in place either by a simple buckle or a stretch belt.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Ear Oximeter”.
1. What is intrauterine pressure during the expulsion period?
a) 130 mm Hg
b) 140 mm Hg
c) 150 mm Hg
d) 160 mm Hg
Answer: c
Explanation: During labour, the uterus muscle starts contractions of increasing intensity in a bid to expel out the child. The intrauterine pressure can reach values of 150 mmHg or more during the expulsion period. However, a normal patient in spontaneous active labour will demonstrate uterine contractions occurring at intervals of three to five minutes, with a duration of 30 to 70 s and a peak intensity of 50 to 75 mmHg.
2. What is the interval of uterine contractions in a normal patient in spontaneous active labour?
a) 1 to 3 minutes
b) 3 to 5 minutes
c) 5 to 7 minutes
d) 7 to 9 minutes
Answer: c
Explanation: During labour, the uterus muscle starts contractions of increasing intensity in a bid to expel out the child. The intrauterine pressure can reach values of 150 mmHg or more during the expulsion period. However, a normal patient in spontaneous active labour will demonstrate uterine contractions occurring at intervals of three to five minutes, with a duration of 30 to 70 s and a peak intensity of 50 to 75 mmHg.
3. What is the duration of uterine contractions in a normal patient in spontaneous active labour?
a) 0 to 30 s
b) 30 to 70 s
c) 80 to 100 s
d) 110 to 150 s
Answer: b
Explanation: During labour, the uterus muscle starts contractions of increasing intensity in a bid to expel out the child. The intrauterine pressure can reach values of 150 mmHg or more during the expulsion period. However, a normal patient in spontaneous active labour will demonstrate uterine contractions occurring at intervals of three to five minutes, with a duration of 30 to 70 s and a peak intensity of 50 to 75 mmHg.
4. The toco-transducers are temperature sensitive.
a) True
b) False
Answer: b
Explanation: False, the toco-transducers are location sensitive. They should be placed over the fundus where there is maximum motion with the contractions. The toco-tonometer transducer cannot be used in the same place as the foetal heart rate detector, thus the patient must have two transducers on her abdomen.
5. What is the peak intensity of uterine contractions in a normal patient in spontaneous active labour?
a) 0 to 35 mm Hg
b) 50 to 75 mm Hg
c) 90 to 120 mm Hg
d) 120 to 150 mm Hg
Answer: b
Explanation: During labour, the uterus muscle starts contractions of increasing intensity in a bid to expel out the child. The intrauterine pressure can reach values of 150 mmHg or more during the expulsion period. However, a normal patient in spontaneous active labour will demonstrate uterine contractions occurring at intervals of three to five minutes, with a duration of 30 to 70 s and a peak intensity of 50 to 75 mmHg.
6. What are labour-activity transducers?
a) temperature transducer
b) ultrasonic transducer
c) pressure transducer
d) piezoelectric transducer
Answer: c
Explanation: The labour-activity transducers are pressure transducers that drive circuits for obtaining an electrical indication of pressure by conventional means. The pressure channel on the recorder is provided with a positioning control. This is done because the baseline is affected by the static pressure on the transducer that results from the tension on the belt holding the transducer in place.
7. What is used to convert the movement of transducer due to an increase of tension in uterus into an electric signal?
a) AC Amplifier
b) Strain guage
c) Synchronous detector
d) piezoelectric crystal
Answer: b
Explanation: The transducer carries a protruding tip which is pressed to the mother’s abdomen with a light force to ensure an effective coupling. The protruding surface of the transducer is displaced as the tension in the uterus increases. This movement is converted into an electrical signal by a strain gauge in the transducer housing. The abdominal transducer provides a reliable indication of the occurrence frequency, duration and relative intensity of the contraction.
8. The narrow beam transducer permits the operator to position the baseline on the zero-level line of recording chart.
a) True
b) False
Answer: b
Explanation: False, the labour-activity transducers are pressure transducers that drive circuits for obtaining an electrical indication of pressure by conventional means. The pressure channel on the recorder is provided with a positioning control. This is done because the baseline is affected by the static pressure on the transducer that results from the tension on the belt holding the transducer in place. The control permits the operator to position the baseline on the zero-level line of the recording chart.
9. In external toco-tonometry, movement of _____ may be superimposed on labour activity.
a) heart
b) eye
c) foetus
d) muscle
Answer: c
Explanation: In external toco-tonometry, movement of the foetus may be superimposed on the labour activity curve. Stress imposed on the foetal circulatory system by the uterine contractions, foetal movements or other factors are seen in the response of the foetal heart to these stimuli and are studied in the correct time relationship.
10. What is measured in the internal method using fluid-filled catheter?
a) IUP
b) ECG
c) IUC
d) EMG
Answer: a
Explanation: The internal method measures intra-uterine pressure via a fluid-filled catheter. The catheter is inserted into the uterus through a guide after the rupture of the foetal membranes. After allowing free flow of amniotic fluid to ensure correct placement, the distal end of the catheter is usually attached to a pressure transducer of the type used for cardiac studies.
11. What is the range of Instantaneous beat to beat rate digitally displayed?
a) 0 to 50 bpm
b) 50 to 210 bpm
c) 210 to 350 bpm
d) 350 to 410 bpm
Answer: b
Explanation: Instantaneous “beat-to-beat” rate is displayed on a calibrated linear scale or digitally displayed with a range from 50 to 210 bpm. A two-channel chart recorder is incorporated in instruments used for monitoring labour activity. One channel records FHR on a calibrated chart in beats per minute while the other channel is used for recording uterine contractions calibrated 0-100 mmHg.
12. A _______ channel chart recorder is incorporated in instruments used for monitoring labour activity.
a) one
b) two
c) three
d) four
Answer: b
Explanation: Instantaneous “beat-to-beat” rate is displayed on a calibrated linear scale or digitally displayed with a range from 50 to 210 bpm. A two-channel chart recorder is incorporated in instruments used for monitoring labour activity. One channel records FHR on a calibrated chart in beats per minute while the other channel is used for recording uterine contractions calibrated 0-100 mmHg.
13. What is the standard chart speed?
a) 2 cm/min
b) 3 cm/min
c) 4 cm/min
d) 5 cm/min
Answer: a
Explanation: A two-channel chart recorder is incorporated in instruments used for monitoring labour activity. One channel records FHR on a calibrated chart in beats per minute while the other channel is used for recording uterine contractions calibrated 0-100 mmHg. The standard chart speed is usually 1 or 2 cm/min.
14. In two-channel chart recorder, FHR is recorded on a calibrated chart in ________
a) cm/min
b) m/min
c) beats/min
d) pulses/min
Answer: c
Explanation: A two-channel chart recorder is incorporated in instruments used for monitoring labour activity. One channel records FHR on a calibrated chart in beats per minute while the other channel is used for recording uterine contractions calibrated 0-100 mmHg. The standard chart speed is usually 1 or 2 cm/min.
15. Uterine contractions are calibrated in range of ______ in two-channel chart recorder.
a) 0-100 mm Hg
b) 100-200 mm Hg
c) 200-300 mm Hg
d) 300-400 mm Hg
Answer: a
Explanation: A two-channel chart recorder is incorporated in instruments used for monitoring labour activity. One channel records FHR on a calibrated chart in beats per minute while the other channel is used for recording uterine contractions calibrated 0-100 mmHg. The standard chart speed is usually 1 or 2 cm/min.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Pulse Oximeter”.
1. _____ is non-invasive method allowing the monitoring of the saturation of a patient’s hemoglobin.
a) Ear Oximetry
b) Pulse Oximetry
c) Skin-Reflectance Oximetry
d) Intravascular Oximetry
Answer: b
Explanation: Pulse oximetry is a non-invasive method allowing the monitoring of the saturation of a patient’s hemoglobin. A pulse oximeter shows the percentage of arterial hemoglobin in the oxyhemoglobin and hemoglobin . These observations:
A = -logT = log I0/I =ɛDC.
2. A = log I0/I,where I0 is_____
a) Incident light Intensity
b) Transmitted light Intensity
c) Extinction coefficient
d) Concentration
Answer: a
Explanation: A pulse oximeter shows the percentage of arterial hemoglobin in the oxyhemoglobin and hemoglobin . This observation A = -logT = log I0/I = ɛDC where Io and I are incident and transmitted light intensities, e is the extinction coefficient, D is the depth of the absorbing layer and C is concentration.
3. A = ɛDC, where ɛ is _______
a) Incident light Intensity
b) Transmitted light Intensity
c) Extinction coefficient
d) Concentration
Answer: c
Explanation: A pulse oximeter shows the percentage of arterial hemoglobin in the oxyhemoglobin and hemoglobin . This observation A = -logT = log I0/I = ɛDC where Io and I are incident and transmitted light intensities, e is the extinction coefficient, D is the depth of the absorbing layer and C is concentration.
4. A pulse oximeter shows the percentage of venous hemoglobin in the oxyhemoglobin and hemoglobin .
a) True
b) False
Answer: b
Explanation: False, pulse oximetry is a non-invasive method allowing the monitoring of the saturation of a patient’s hemoglobin. A pulse oximeter shows the percentage of arterial hemoglobin in the oxyhemoglobin and hemoglobin . These observations:
A = -logT = log I0/I =ɛDC.
5. What is used as a photodetector in pulse oximetry?
a) Phototransistor
b) Solar cell
c) Photodiode
d) Photographic plates
Answer: c
Explanation: Pulse oximetry is a particularly convenient noninvasive measurement method. Typically it utilizes a pair of small light-emitting diodes facing a photodiode through a translucent part of the patient’s body, usually a fingertip or an earlobe. One LED is red, with a wavelength of 660 nm, and the other is infrared, 905, 910, or 940 nm.
6. What is the wavelength of the red LED in pulse oximetry?
a) 660 nm
b) 740 nm
c) 905 nm
d) 950 nm
Answer: a
Explanation: Pulse oximetry is a particularly convenient noninvasive measurement method. Typically it utilizes a pair of small light-emitting diodes facing a photodiode through a translucent part of the patient’s body, usually a fingertip or an earlobe. One LED is red, with a wavelength of 660 nm, and the other is infrared, 905, 910, or 940 nm.
7. What is the wavelength of infrared LED in pulse oximetry?
a) 660 nm
b) 740 nm
c) 905 nm
d) 950 nm
Answer: c
Explanation: Pulse oximetry is a particularly convenient noninvasive measurement method. Typically it utilizes a pair of small light-emitting diodes facing a photodiode through a translucent part of the patient’s body, usually a fingertip or an earlobe. One LED is red, with a wavelength of 660 nm, and the other is infrared, 905, 910, or 940 nm.
8. A pulse oximeter is useful in any setting where a patients oxygenation is unstable.
a) True
b) False
Answer: a
Explanation: True, pulse oximeter is useful in any setting where a patient’s oxygenation is unstable, including intensive care, operating, recovery, emergency and hospital ward settings, pilots in unpressurized aircraft, for assessment of any patient’s oxygenation, and determining the effectiveness of or need for supplemental oxygen.
9. Portable pulse oximeters are useful for ______ whose oxygen levels may decrease at high altitude.
a) Athlete
b) Swimmer
c) Mountain climber
d) Fisher
Answer: c
Explanation: Portable pulse oximeter is also useful for mountain climbers and athletes whose oxygen levels may decrease at high altitudes or with exercise. Some portable pulse oximeters employ software that charts a patient’s blood oxygen and pulse, serving as a reminder to check blood oxygen levels.
10. ______ is very useful for patients having respiratory or cardiac problems because of their simplicity of use and the ability to provide continuous and immediate oxygen saturation levels.
a) Pulse Oximeter
b) Ear Oximeter
c) Skin Reflactance Oximeter
d) Intravascular Oximeter
Answer: a
Explanation: Because of their simplicity of use and the ability to provide continuous and immediate oxygen saturation values, pulse oximeters are of critical importance in emergency medicine and are also very useful for patients with respiratory or cardiac problems, especially COPD, or for diagnosis of some sleep disorders such as apnea and hypopnea.
This set of Biomedical Instrumentation Questions and Answers for Aptitude test focuses on “Skin Reflectance Oximeters”.
1. Which module consists of a pair of Perspex plates?
a) The dialyzer module
b) The recorder module
c) The sampling module
d) Heating bath module
Answer: a
Explanation: In analytical chemistry, it is often necessary to remove protein cells to obtain an interference-free analysis. This is accomplished by dialysis in the auto-analyzer. The dialyzer module consists of a pair of perspex plates, the mating surfaces of which are mirror grooved in a continuous channel, which goes in towards the centre, on itself and returns to the outside.
2. The part of the automated system that shown in the figure is ____________
biomedical-instrumentation-questions-answers-aptitude-test-q2
a) Dialyzer
b) Pump
c) Recorder
d) Sampler
Answer: d
Explanation: The automated system consists of a group of modular instruments interconnected together by a manifold system and electrical systems. The sample to be analyzed is introduced into a stream of diluting liquid flowing in the narrow bore of a flexible plastic tube. The stages of the analytical reaction are completed by the successive combination of other flowing streams of liquids with the sample stream, by means of suitably shaped glass functions.
3. In the sampling unit, when it is in its earlier form consisted of a circular turntable carrying around its rim 40 disposable __________ of 2 ml capacity.
a) Polyvinyl cups
b) Polythene cups
c) Polyester cups
d) Polystyrene cups
Answer: d
Explanation: The unit in its earlier form consisted of a circular turntable carrying around its rim 40 disposable polystyrene cups of 2 ml capacity. The sample plate carrying these cups rotates at a predetermined speed. The movement of the turntable is synchronized with the movements of a sampling crook.
4. What is the ratio of the sampling time to wash time?
a) 1:2
b) 3:1
c) 2:1
d) 1:3
Answer: c
Explanation: Between each sampling, the crook enters a receptacle of water or other suitable wash fluid, to reduce cross-contamination of one sample with another. The ratio of sampling time to wash time is normally 2:1.
5. Which of the following is not the part of the manifold?
a) Transmission tubing
b) Pump tubes
c) Platter
d) Plastic tubes
Answer: d
Explanation: A manifold mainly consists of a platter, pump tubes, coils, transmission tubing, fittings and connections. A separate manifold is required for each determination and the change can be effected within a few minutes. The pump tubing and the connected coils are placed on a manifold platter, which keeps them in proper order for each test.
6. Which of the following is not the type of tubing?
a) Acidflex tubing
b) Glass tubing
c) Polypropylene tubing
d) Tygon
Answer: c
Explanation: Several other tubes are required to introduce reagents and to transport the specimen from one module to another. There are five types of such tubings. They are of varying sizes and are to be selected according to the requirements. These are standard transmission tubing , solvaflex tubing, acidflex tubing, polyethylene tubing and glass tubing.
7. There are two types of coils employed in the system, which are ____
a) Tygon coils and mixing coils
b) Mixing coils and tubing coils
c) Delay coils and tygon coils
d) Mixing coils and delay coils
Answer: d
Explanation: Two types of coils are employed in the system—mixing coils and delay coils. Coils are glass spirals of critical dimensions, in which the mixing liquids are inverted several times, so that complete mixing can result. Mixing coils are used to mix the sample and/or reagents. Delay coils are employed when a specimen must be delayed for the completion of a chemical reaction before reaching the colorimeter.
8. In phasing, if the cholesterol stream arrives at Y time, albumin must arrive at ______
a) Y + 5 s
b) Y + 10 s
c) Y + 15 s
d) Y + 20 s
Answer: c
Explanation: With 12 tests to be recorded on each sample and a sampling rate of 60 samples per hour, it follows that 5 s are allowed to record each steady state plateau. The reaction streams in the 12 channels and up to four blank channels must, therefore, be phased to arrive at the colorimeter in waves 5 s apart. For example, if the cholesterol stream arrives at X time, calcium must arrive at X + 5 s, total protein at X + 10 s, albumin at X + 15 s, etc.
9. Which coils are used to permit the channels to enter the calorimeter in the proper sequence?
a) Mixing coils
b) Delay coils
c) Solvaflex coils
d) Phasing coils
Answer: d
Explanation: In order to ensure a proper sequencing for the presentation of results, a number of devices have been provided to make this adjustment an extremely simple operation. Phasing coils are used to permit the channels to enter the colorimeter in the proper sequence.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Intravascular Oximeters”.
1. What is the amount of blood in the average adult?
a) 5-10 liters
b) 10-15 liters
c) 5-6 liters
d) 5-15 liters
Answer: c
Explanation: The blood constitutes 5–10% of the total body weight and in the average adult, it amounts to 5–6 l. Blood consists of corpuscles suspended in a fluid called plasma in the proportion of 45 parts of corpuscles to 55 parts of plasma.
2. Which of the following is not the type of blood cell?
a) Erythrocytes
b) Thrombocytes
c) Leukocytes
d) Eosinocytes
Answer: d
Explanation: The percentage of cells in the blood is called the haematocrit value or packed cell volume . The majority of the corpuscles in the blood are red blood cells , others being white blood cells and platelets .
3. Which of the following is the Red Blood Cells?
a) Erythrocytes
b) Leukocytes
c) Basophils
d) Monocytes
Answer: a
Explanation: Erythrocytes : Red blood cells have the form of a bi-concave disc with a mean diameter of about 7.5 m and thickness of about 1.7 m. The mean surface area of the cell is about 134mm2. There are about 5.5 million of them in every cubic millimetre of blood in men and nearly 5 million in women.
4. The normal red cell lasts approximately ______ before it is destroyed.
a) 90 days
b) 210 days
c) 120 days
d) 60 days
Answer: c
Explanation: In the whole body, there are about 25 billion erythrocytes and they are constantly being destroyed and replaced at a rate of about 9000 million per hour. The normal red cell lasts approximately 120 days before it is destroyed.
5. Who is responsible for carrying oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs?
a) Basophils
b) Eosinophils
c) RBC
d) Thrombocytes
Answer: c
Explanation: The erythrocytes have no nucleus. They are responsible for carrying oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs. Anaemia can develop from a change in the number, volume or Hb concentration of erythrocytes, caused by bone marrow dysfunction resulting in the poor production rate of RBCs.
6. The main two types of leukocytes are ____________
a) The neutrophils and the thrombophils
b) The lymphocytes and the neutrophils
c) The neutrophils and the monophils
d) The lymphocytes and the monophils
Answer: b
Explanation: Leucocytes form the defence mechanism of the body against infection. They are of two main types: the neutrophils and the lymphocytes. Neutrophils ingest bacteria and lymphocytes are concerned with an immunological response.
7. ______ play an important role in the blood coagulation process.
a) Platelets
b) Leukocytes
c) RBC
d) Neutrophils
Answer: a
Explanation: Platelets are usually tiny, round, oblong or irregularly shaped cells of the blood with an average diameter of approximately 2 m. They play an important role in the blood coagulation process. There are usually 250,000–750,000 platelets in every cubic mm of blood.
8. Which of the following is not the method of cell counting?
a) Microscopic method
b) Electrical conductivity method
c) Automatic optical method
d) Electroscopic method
Answer: d
Explanation: There are three methods of cell counting: i) Microscopic method, ii) Automatic optical method, iii) Electrical conductivity method.
9. What is the difference of measuring accuracy between microscopic counting and electronic counters?
a) + or – 20 %
b) + or – 17%
c) + or – 3%
d) + or – 23%
Answer: b
Explanation: Agoston and Zillich compared the results of microscopic counting with those made by electronic counters. It may be observed that instead of the + 0r – 20% measuring accuracy in microscopic counting, the electronic counters can provide an accuracy of + or – 3%.
10. What is the ratio of a sample of red blood cells in dilute blood?
a) 500:1
b) 50000:1
c) 1:500
d) 1:50000
Answer: d
Explanation: The method is based on collecting scattered light from the blood cells and converting them into electrical pulses for counting. A sample of dilute blood is taken in a glass container. It is drawn through a counting chamber in which the blood stream is reduced in cross-section by a concentric high velocity liquid sheath.
11. The instrument of an optical method of counting cells, that require about _____ of blood sample.
a) 100 ml
b) 1 liter
c) 1 ml
d) 10 ml
Answer: c
Explanation: Instruments based on optical technique take about 30 s for completing the count. An accuracy of 2% is attainable. The instruments require about 1 ml of the blood sample.
12. 1 f/l = ____
a) 10 18
b) 10 15
c) 10 -18
d) 10 -15
Answer: d
Explanation: f/l = Femolitres
1f/l = 10 -15 .
13. _______ will be calculated if the value of PCV and Hb per deciliters are known.
a) MCV
b) MCHC
c) MCH
d) PCT
Answer: b
Explanation: It can be calculated if PCV and Hb per dl are known. For example, if PCV is 0.45 and there are 15 g Hb per dl of blood, then
MCHC = g/dl
= 33.3 g/dl.
14. PDW index is related to the size range covered by those platelets lying between _______ and _______ percentile.
a) 20th and 84th percentile
b) 16th and 20th percentile
c) 16th and 84th percentile
d) 20th and 80th percentile
Answer: c
Explanation: Platelet Distribution Width : This index is related to the size range covered by those platelets lying between the sixteenth and eighty fourth percentile. This is the conventional geometric standard deviation of the mean platelet size and is derived from the distribution curve based on the data in a 64-channel pulse height analyzer.
15. Instruments based on the automatic optical technique take about _____ for completing the count blood cells.
a) 30 sec
b) 120 sec
c) 60 sec
d) 90 sec
Answer: a
Explanation: Instruments based on this automatic optical technique take about 30 s for completing the count. An accuracy of 2% is attainable. The instruments require about 1 ml of the blood sample.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Mechanism of Hearing”.
1. The tympanic membrane separates the ear canal from the _____________
a) upper ear cavity
b) lower ear cavity
c) middle ear cavity
d) inner ear cavity
Answer: c
Explanation: The tympanic membrane separates the ear canal from the middle ear cavity. The pinna scatters acoustic waves so that some of the scattered energy enters the auditory canal and pushes against the tympanic membrane during a wave of compression. The distance membrane moves is a function of the force and velocity with which the air molecules strike it and is, therefore, related to the loudness of sound.
2. The middle ear is exposed to atmospheric pressure only through the _______
a) eustachian tube
b) tympanic membrane
c) pinna
d) auditory nerve
Answer: a
Explanation: The middle ear is exposed to atmospheric pressure only through the eustachian tube, which connects it to the pharynx and nose or mouth. The sound energy from the tympanic membrane is transmitted through the cavity of the middle ear, to the receptor cells in the inner ear, which are surrounded by fluid. The tympanic membrane separates the ear canal from the middle ear cavity.
3. The major function of the middle ear is ____________
a) to transfer movements of the air in the outer ear to the cochlea
b) to transfer movements of the air in the outer ear to the auditory nerves
c) to transfer movements of the air in the outer ear to the tympanic membrane
d) to transfer movements of the air in the outer ear to the fluid-filled chambers of the inner ear
Answer: d
Explanation: Thus, the major function of the middle ear is to transfer movements of the air in the outer ear to the fluid-filled chambers of the inner ear. A chain of three small, middle ear bones couple the tympanic membrane to a membrane covered opening, called the oval window. The total force on the oval window is the same as that on the tympanic membrane.
4. The human ear responses to vibrations ranging from ___________
a) 20KHz – 20MHz
b) 2KHz – 20MHz
c) 20Hz – 20KHz
d) 2Hz – 2KHz
Answer: c
Explanation: The human ear responds to vibrations ranging from 20 to 20,000 Hz. The waves of speech and many other common sounds are not of single frequency but are complex waves made up of several frequencies of vibration. The number of sound frequencies in addition to the fundamental tone, i.e. the degree of purity of the sound wave is related to the quality or timbre of the sound. The human ear can in fact, distinguish some 400,000 different sounds.
5. Name the bone that rests upon the lower end of the cochlea and passes the vibrations directly into the fluid within.
a) malleus
b) stapes
c) incus
d) hammer
Answer: b
Explanation: One of the bones, called the stapes, rests upon the lower end of the cochlea and passes the vibrations directly into the fluid within. A chain of three small, middle ear bones couple the tympanic membrane to a membrane covered opening, called the oval window. The total force on the oval window is the same as that on the tympanic membrane.
6. Air conduction, by definition, is the transmission of sound through the external and middle ear to the internal ear.
a) True
b) False
Answer: a
Explanation: It is true. Air conduction, by definition, is the transmission of sound through the external and middle ear to the internal ear. Bone conduction, on the other hand, refers to the transmission of sound to the internal ear mediated by mechanical vibration of the cranial bones and soft tissues. Clinical observation has shown that hard-of-hearing patients with middle ear disease usually have normal hearing by bone conduction, whereas patients with inner ear involvement have decreased or diminished bone-conduction.
7. The hearing threshold is an invariable fixed intensity above which sound is always heard and below which sound is never heard.
a) True
b) False
Answer: a
Explanation: It is False. The hearing threshold is not an invariable fixed intensity above which sound is always heard and below which sound is never heard. In fact, the sensitivity of the auditory mechanism is found to vary with interactions between certain physiological, psychological and physical factors. Therefore, the threshold may be regarded as an intensity range within which sound stimuli at or near the statistically determined threshold may or may not be perceived.
8. Unit of sound intensity ________
a) joules per sq. cm
b) watt per sq. cm
c) joules per cm
d) watt per cm
Answer: b
Explanation: Sound intensity may be defined as the amount of energy flow per unit time through a unit area perpendicular to the direction of energy flow. It is expressed as watts per square centimetre. However, the common receivers of sound are microphones, which do not measure sound intensity directly.
9. Sound intensity is proportional to the _________ of sound pressure.
a) cube
b) square
c) inverse square
d) inverse square root
Answer: b
Explanation: Sound intensity is proportional to the square of sound pressure. Sound pressure, for a given sinusoidal event, is related linearly to both amplitude and frequency. Sound intensity may be defined as the amount of energy flow per unit time through a unit area perpendicular to the direction of energy flow.
10. Decibel expresses the logarithm of the ratio between two sound _________
a) intensities
b) powers
c) pressures
d) intensities, powers and pressures
Answer: d
Explanation: Decibel expresses the logarithm of the ratio between two sound intensities, powers or sound pressures. The convenient unit for making such comparisons and to express the sound intensity and sound pressure data for all practical purposes is the decibel . The dB is 1/10 of a larger unit, the bell, named after Alexander Graham Bell.
11. What is the unit of dB?
a) watts per sq cm
b) dyne per sq cm
c) unit less
d) watts per cm
Answer: c
Explanation: Since dB is merely a ratio, it is a dimensionless entity. Decibel expresses the logarithm of the ratio between two sound intensities, powers or sound pressures. Use of decibels as units for comparison of intensities help to avoid all mathematical calculations except algebraic addition or subtraction of small numbers. The transmission efficiency of any medium like air, a hearing aid or an amplifier is usually expressed in dB as a gain when the output is greater and as a loss, if less.
12. If I1 and I2 are two intensities in watts per square centimetre, then the number of decibels with which they are related can be expressed as _________
a) N = 10 log I1/I2
b) N = 10 log I2/I1
c) N = -10 log I1/I2
d) N = log I1/I2
Answer: a
Explanation: If I1 and I2 are two intensities in watts per square centimetre, then the number of decibels with which they are related can be expressed as N = 10 log I1/I2. Attenuation is commonly expressed in negative dB numbers whereas amplification is given in positive dB numbers. Use of decibels as units for comparison of intensities help to avoid all mathematical calculations except algebraic addition or subtraction of small numbers. The transmission efficiency of any medium like air, a hearing aid or an amplifier is usually expressed in dB as a gain when the output is greater and as a loss, if less.
13. __________ is specialized equipment, which is used for the identification of hearing the loss in individuals.
a) gaugemeter
b) tachometer
c) manometer
d) audiometer
Answer: d
Explanation: An audiometer is specialized equipment, which is used for the identification of hearing the loss in individuals, and the quantitative determination of the degree and nature of such a loss. Both frequency and output are adjustable over the audio range. The instrument is also provided with a calibrated noise source and bone-conductor vibrator. It is essentially an oscillator driving a pair of headphones and is calibrated in terms of frequency and acoustic output.
14. Which threshold of hearing is measured by a pure-tone audiometer?
a) air-conduction thresholds of hearing
b) bone-conduction thresholds of hearing
c) speech reception thresholds for diagnostic purposes
d) air-conduction and bone-conduction thresholds of hearing
Answer: d
Explanation: A pure-tone audiometer is used primarily to obtain air-conduction and bone-conduction thresholds of hearing. Audiometers may be divided into two main groups on the basis of the type of stimulus they provide to elicit an auditory response: pure-tone audiometers and speech audiometers. These thresholds are helpful in the diagnosis of hearing loss.
15. Speech audiometers are normally used to determine ______________
a) speech reception thresholds for diagnostic purposes
b) air-conduction and bone-conduction thresholds of hearing
c) bone-conduction thresholds of hearing
d) air-conduction thresholds of hearing
Answer: a
Explanation: Speech audiometers are normally used to determine speech reception thresholds for diagnostic purposes and to assess and evaluate the performance of hearing aids. A pure-tone audiometer is used primarily to obtain air-conduction and bone-conduction thresholds of hearing. These thresholds are helpful in the diagnosis of hearing loss. Pure-tone screening tests are employed extensively in industrial and school hearing conservation programmes.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Measurement of Hearing”.
1. Pure-tone audiometers usually generate test tones in octave steps from ___________
a) 125 to 800 Hz
b) 125 to 8000 Hz
c) 25 to 8000 Hz
d) 15 to 800 Hz
Answer: b
Explanation: Pure-tone audiometers usually generate test tones in octave steps from 125 to 8000 Hz, the signal intensity ranging from –10 dB to +100 dB. Pure-tone audiometry is used in routine tests and, therefore, it is the most widely used technique for determining hearing loss. Pure-tone audiometry has several advantages, which makes it specifically suitable for making threshold sensitivity measurements. A pure-tone is the simplest type of auditory stimulus. It can be specified accurately in terms of frequency and intensity.
2. Speech audiometry normally allows measurements to be made within the frequency range of _____
a) 300–3000 Hz
b) 30–300 Hz
c) 300–3000 KHz
d) 3–30K Hz
Answer: a
Explanation: Speech audiometry normally allows measurements to be made within the frequency range of 300–3000 Hz. Pure-tone audiometers usually generate test tones in octave steps from 125 to 8000 Hz, the signal intensity ranging from –10 dB to +100 dB. Some patients may have impaired high frequency response due to high intensity level occupational noise at 4000 or 6000 Hz.
3. The signal intensity of Pure-tone audiometers ranging from ______
a) 10 dB to +100 dB
b) –10 dB to -100 dB
c) –10 dB to +100 dB
d) –10 dB to +10 dB
Answer: c
Explanation: Pure-tone audiometers usually generate test tones in octave steps from 125 to 8000 Hz, the signal intensity ranging from –10 dB to +100 dB. A wave in the air, which involves only one frequency of vibration, is known as pure-tone. Pure-tone audiometry is used in routine tests and, therefore, it is the most widely used technique for determining hearing loss. Pure-tone audiometry has several advantages, which makes it specifically suitable for making threshold sensitivity measurements.
4. The frequency range of pure-tone audiometer is more than that of speech audiometer.
a) True
b) False
Answer: a
Explanation: It is True. The frequency range of pure-tone audiometer is more than that of speech audiometer. Pure-tone audiometers usually generate test tones in octave steps from 125 to 8000 Hz, the signal intensity ranging from –10 dB to +100 dB. Speech audiometry normally allows measurements to be made within the frequency range of 300–3000 Hz. Pure-tone audiometry has several advantages, which makes it specifically suitable for making threshold sensitivity measurements.
5. ___________ amplifier circulatory is employed to reduce the hum noise generated by the power supply in the ECG circuit.
a) low pass filters
b) high pass filters
c) band pass filters
d) notch filters
Answer: d
Explanation: CMRR of the order of 100–120 dB with 5 kW unbalance in the leads is a desirable feature of ECG machines. A notch filter is employed to suppress the hum noise generated by the power supply in the ECG circuit.The instability of the baseline, originating from the changes of the contact impedance, demands the application of the automatic baseline stabilizing circuit.
6. The unit of sensitivity of an electrocardiograph is ________
a) m/mV
b) mm/V
c) mm/mV
d) m/V
Answer: c
Explanation: The unit of the sensitivity of an electrocardiograph is mm/mV. The sensitivity of an electrocardiograph is typically set at 10 mm/mV. Time measurements and heart rate measurements are made horizontally on the electrocardiogram. For routine work, the paper recording speed is 25 mm/s.
7. The volume of blood outside the dialyzer is known as priming volume.
a) True
b) False
Answer: b
Explanation: False, The volume of blood within the dialyzer is known as priming volume. It is desirable that this should be minimal. Priming volume of present day dialyzers ranges from 75 to 200 ml, depending on the membrane area geometry and operating conditions.
8. The range of CMRR of Foetal electrocardiogram is ______________
a) 0-120 dB
b) 0-200 dB
c) 0-150 dB
d) 0- 130 dB
Answer: a
Explanation: The range of CMRR of Foetal electrocardiogram is 0-120 dB. After proper placement of the electrodes, the signals are amplified in a preamplifier which provides a very high input impedance and a high sensitivity and good common mode rejection ratio . Abdominal FECG processing circuit is used for computing foetal heart rate.
9. Power Line Hum is responsible for most of common-mode interfering signal.
a) True
b) False
Answer: a
Explanation: It is True. Power Line Hum is responsible for most of common-mode interfering signal. This is suppressed by a notch filter following the input amplifier. A sizable common-mode signal manages to pass through the input amplifier, a circumstance to be expected whenever electrodes spaced a few centimetres apart are attached to the human body in a hospital environment.
10. What is the role of Cupraphan in haemodialysis?
a) used to check conductivity of dialyzer
b) used as membrane
c) used to check blood leakage
d) not at all used
Answer: b
Explanation: Cupraphan is the commonly used membrane for haemodialysis. During haemodialysis, different substances of varying molecular weight are to be removed. It is a membrane consisting of natural cellulose and is considered puncture-proof, and of high tenacity and elasticity.
11. Which of the following is the property of instrumentational amplifier?
a) Extremely low input impedance
b) High bias and offset currents
c) Low slew rate
d) Very high CMRR
Answer: d
Explanation: Instrumentational amplifiers have very high CMRR. Instrumentational amplifiers have extremely high input impedance. Instrumentational amplifiers have low bias and offset currents. Instrumentational amplifiers have high slew rate.
12. Foetal ECG signal detected via electrodes placed on mother’s abdomen is complex and requires attenuation of maternal signals for obtaining FHR.
a) True
b) False
Answer: a
Explanation: It is True. Foetal ECG signal detected via electrodes placed on the mother’s abdomen is complex and requires attenuation of maternal signals for obtaining FHR. Also, due to the overlapping of the foetal ECG with the maternal ECG, about 20% to 50% of the expected pulses may be missing.
13. The blood is a good conductor of electricity.
a) True
b) False
Answer: b
Explanation: It is False. The blood is not a good conductor of electricity. Blood is a poor conductor of electricity. This principle is used in Coulter counters to count the number of RBCs in the blood.
14. The range of FHR measurement due to substitution logic is between __________ bpm.
a) 20-220
b) 60-260
c) 40-240
d) 0-200
Answer: c
Explanation: The range of FHR measurement due to substitution logic is between 40-240 bpm. The range of FHR measurement is limited to 40–240 bpm because of the substitution logic. Thereafter, the output of logic circuits go to standard heart rate computing circuits. The substitution logic requires a delay time to establish a missing foetal trigger pulse. It is thus kept as 270 ms.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Biotelemetry”.
1. Leucocytes are in the shape of ________
a) sphere
b) cube
c) hollow
d) cuboid
Answer: a
Explanation: Leucocytes are in the shape of a sphere. Leucocytes have a nucleus. They live for seven to fourteen days and there is a rapid turn over, with constant destruction and replacement. There are normally 5000–10,000 white cells per cubic mm of blood but their number varies during the day.
2. What should be the frequency response of the amplifiers that are used for the amplification purpose of the input signal in medical devices?
a) high frequency response
b) low frequency response
c) frequency response has no role to play in it
d) average frequency response
Answer: b
Explanation: The response should be down to less than one hertz which is a very frequent requirement. The bioelectric signals in medical science contain components of extremely low frequency. Thus the amplifiers must also have a low frequency response.
3. Leucocytes are not responsible for the formation of the defence mechanism of the body that fights against infection.
a) True
b) False
Answer: b
Explanation: It is False. Leucocytes form the defence mechanism of the body against infection. The number and proportion of these types of leucocytes may vary widely in response to various disease conditions. They are of two main types: the neutrophils and the lymphocytes. Neutrophils ingest bacteria and lymphocytes are concerned with immunological response.
4. To achieve the ______________ required for medical applications, the amplifier must have large values of coupling capacitance.
a) random frequency response
b) high frequency response
c) average frequency response
d) low frequency response
Answer: d
Explanation: In all RC-coupled amplifiers, low frequency response is limited by the reluctance of the coupling capacitors. The response should be down to less than one hertz which is a very frequent requirement. To achieve the low frequency response required for medical applications, the amplifier must have large values of coupling capacitance.
5. Neutrophils are bigger than the red cells.
a) True
b) False
Answer: a
Explanation: It is True. Neutrophils are nearly twice as big as the red cells.Lymphocytes are of the same size as the red cells but contain a large density staining nucleus and no granules. Neutrophils contain both a nucleus divided into several lobes and granules in their protoplasm.
6. High pass filter amplifies frequency _____________
a) above certain value
b) below certain value
c) above and below certain value
d) at certain value
Answer: a
Explanation: High pass filter amplifies signal above a certain frequency. Band pass filter amplifies frequencies with in a certain band. Band stop filter amplifies all the frequencies except those in a certain band. Low pass filter amplifies signals below a certain frequency.
7. Mean Platelet Volume is the ratio of the ___________ and is expressed in femolitres.
a) integrated platelet volume to the platelet count
b) integrated platelet volume to the WBC count
c) integrated RBC volume to the platelet count
d) integrated platelet volume to the RBC count
Answer: a
Explanation: Mean Platelet Volume is the ratio of the integrated platelet volume to the platelet count and is expressed in femolitres. Platelet Distribution Width is related to the size range covered by those platelets lying between the sixteenth and eighty fourth percentile. Red Cell Distribution Width is a numerical expression of the width of the size distribution of red cells.
8. Unit of Mean Platelet Volume is expressed in?
a) millilitres
b) femolitres
c) picolitres
d) decilitres
Answer: c
Explanation: Unit of Mean Platelet Volume is expressed in femolitres. 1f/l = 10–15 . 1 litre of blood contains 0.45 litres of red cells. Mean Platelet Volume is the ratio of the integrated platelet volume to the platelet count and is expressed in femolitres.
9. Low pass filter amplifies signals below a certain frequency.
a) True
b) False
Answer: a
Explanation: It is true. Low pass filter amplifies signals below a certain frequency. Band stop filter amplifies all the frequencies except those in a certain band. High pass filter amplifies signal above a certain frequency. Band pass filter amplifies frequencies within a certain band.
10. _______ is the percentage of the total specimen volume occupied by the platelets.
a) Mean Platelet Volume
b) Plateletcrit
c) Red Cell Distribution Width
d) Platelet Distribution Width
Answer: b
Explanation: Plateletcrit is the percentage of the total specimen volume occupied by the platelets. Red Cell Distribution Width is a numerical expression of the width of the size distribution of red cells. Mean Platelet Volume is the ratio of the integrated platelet volume to the platelet count and is expressed in femolitres.
11. Modern instrument use ________ for intravascular oximetry?
a) photodiode
b) red and infrared LED’s
c) optical fibre
d) phototransistor
Answer: c
Explanation: For intravascular oximetry, modern instruments make use of optical fibres to guide the light signal inside the vessel and the reflected light from the red blood cells back to the light detector.
12. Optical fiber sensors are immune to electromagnetic disturbances.
a) True
b) False
Answer: a
Explanation: It is True. Optical fiber sensors are electrically passive and consequently immune to electromagnetic disturbances. They can be miniaturized and are most suitable for telemetry applications. They are geometrically flexible and corrosion resistant.
13. Currently available oximeters utilize __________ wavelengths.
a) Equal to 2
b) Cannot be determined
c) Less than 2
d) More than 2
Answer: d
Explanation: Currently available fiber-optic oximeters utilize more than two wavelengths to adjust for haematocrit variation. For estimating SO 2 , usually the reflectance at two wavelengths, one in the red and the other in the near infrared regions, are used.
14. Mix venous saturation is measured by __________
a) Ear Oximeter
b) Intravascular Oximeter
c) Skin Reflectance Oximeter
d) Pulse Oximeter
Answer: b
Explanation: Mixed venous saturation varies in reflecting the changes of oxygen saturation, cardiac output, haematocrit or haemoglobin content and oxygen consumption. Intravasacular oximeters are normally used to measure mixed venous saturation, from which the status of the circulatory system can be deduced.
15. Which of the following is correct expression for RDW index?
a) [(20 th – 80 th ) Percentile Volume / (20 th – 80 th ) Percentile Volume] X 100 X K
b) [(20 th – 80 th ) Percentile Volume / (20 th + 80 th ) Percentile Volume] X 100 X K
c) [(20 th + 80 th ) Percentile Volume / (20 th – 80 th ) Percentile Volume] X 100 X K
d) [(20 th + 80 th ) Percentile Volume / (20 th + 80 th ) Percentile Volume] X 100 X K
Answer: b
Explanation: The total erythrocyte count is scanned by a continuously variable thresholding circuit. The RDW index is expressed by the following equation [(20 th – 80 th ) Percentile Volume / (20 th + 80 th ) Percentile Volume ] X 100 X K. It is a numerical expression of the width of the size distribution of red cells. It is derived by analog computation. The upper threshold is moved progressively lower from a level equivalent to 360 femolitres until 20 per cent of all erythrocytes present have a size above a certain value.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Single Channel Telemetry System”.
1. ___________ system may include lenses, mirrors, slits, diaphragm etc.
a) Photo system
b) Radiant system
c) Cardiac system
d) Optical system
Answer: d
Explanation: A detecting system for the measurement of unabsorbed radiant energy, which could be the human eye, a barrier-layer cell, phototube or photo-multiplier tube. An optical system for producing a parallel beam of filtered light for passage through an absorption cell . The system may include lenses, mirrors, slits, diaphragm, etc.
2. __________ is not the property of instrumentational amplifier.
a) Extremely high input impedance
b) Very low CMRR
c) Low bias and offset currents
d) High slew rate
Answer: b
Explanation: Instrumentational amplifiers have very high CMRR. The instrumentation amplifier offers the following advantages for its applications in the biomedical field. Some of them are like extremely high input impedance, low bias and offset currents, high slew rate.
3. Which of the following feedback type is employed with DC amplifiers?
a) negative
b) can be any positive or negative doesn’t matter
c) depends on the application
d) positive
Answer: a
Explanation: DC amplifiers are generally of the negative feedback type. They are used for medium gain applications down to about 1 mV signal levels for full scale. They are not practical for very low level applications because of dc drift and poor common-mode rejection capabilities.
4. The CMRR is expressed in _____________
a) V/s
b) dB/ms
c) dB/s
d) dB
Answer: d
Explanation: The ability of the amplifier to reject common voltages on its two input leads is known as common-mode rejection. It is specified as the ratio of common-mode input to differential input to elicit the same response. CMRR is an important specification referred to the differential amplifier and is normally expressed as decibels.
5. An oscillator and a capacitance coupled amplifier are present in a carrier amplifier.
a) True
b) False
Answer: a
Explanation: It is True. The transducers, which require ac excitation, are those whose impedance is not purely resistive. The carrier amplifier consists of an oscillator and a capacitance coupled amplifier. The oscillator is used to energize the transducer with an alternating carrier voltage.
6. Reduction in electromagnetic coupling is achieved by _____
a) shielding
b) common grounding
c) multiple grounding
d) wire twisting
Answer: c
Explanation: Electromagnetic coupling is reduced by shielding, wire twisting and proper grounding which provide a balanced signal pair with satisfactory noise rejection characteristics. Having multiple grounds in a single circuit increases the electromagnetic coupling effect by producing ground loop which may generate so much noise that it may completely obscure the useful signal.
7. ________________ is employed with resistive transducers which require an external source of excitation?
a) dc bridge amplifier
b) ac coupled amplifier
c) carrier amplifier
d) differential amplifier
Answer: a
Explanation: Essentially, the amplifier comprises a stable dc excitation source, a bridge balance and calibration unit, a high gain differential dc amplifier and a dc output amplifier. DC bridge amplifiers are employed with resistive transducers which require an external source of excitation. They can be used as conventional dc high gain amplifiers and offer operating simplicity and high frequency response.
8. From the options given below select the one which is not a type of isolation amplifier?
a) transformer type isolation amplifiers
b) resistive coupled isolation amplifiers
c) optically isolated isolation amplifiers
d) capactively coupled isolation amplifiers
Answer: b
Explanation: Opto-coupled amplifier uses a minimum number of components and is cost effective, followed by the transformer coupled amplifier. The capacitor coupled amplifier is the most expensive. There is nothing such as the resistive coupled isolation amplifiers. All the other three types are in common use, though the transformer isolation amplifier is more popular.
9. The isolation includes common supply voltage sources and common grounds on each side of the isolation barrier.
a) True
b) False
Answer: b
Explanation: It is False. Three methods are used in the design of isolation amplifiers: transformer isolation optical isolation capacitive isolation. Isolation amplifiers are commonly used for providing protection against leakage currents. The isolation includes different supply voltage sources and different grounds on each side of the isolation barrier.
10. Which of the following amplifier is commonly used for providing protection against leakage currents?
a) Isolation amplifiers
b) Instrumentational amplifiers
c) Inverting amplifiers
d) Differential amplifiers
Answer: a
Explanation: Isolation amplifiers are commonly used for providing protection against leakage currents. They break the ohmic continuity of electric signals between the input and output of the amplifier. The isolation includes different supply voltage sources and different grounds on each side of the isolation barrier.
This set of Biomedical Instrumentation online test focuses on “Multi-Channel Wireless Telemetry System”.
1. _________ instrument is used for recording the electrical activity of the muscles.
a) ECG
b) EMG
c) PCG
d) EEG
Answer: b
Explanation: Electromyograph is an instrument used for recording the electrical activity of the muscles to determine whether the muscle is contracting or not; or for displaying on the CRO and loudspeaker the action potentials spontaneously present in a muscle or those induced by voluntary contractions as a means of detecting the nature and location of motor unit lesions; or for recording the electrical activity evoked in a muscle by the stimulation of its nerve.
2. EMG cannot be recorded by using surface electrodes.
a) True
b) False
Answer: b
Explanation: It is False. EMG is usually recorded by using surface electrodes because the surface electrodes may be disposable, adhesive types or the ones which can be used repeatedly.
3. Which of the following signal is used to myoelectric prosthetic devices?
a) EEG
b) EMG
c) ECG
d) VCG
Answer: b
Explanation: EMG measurements are also important for the myoelectric control of prosthetic devices . This is the most demanding requirement from an EMG since on it depends on the working of the prosthetic device. This use involves picking up EMG signals from the muscles at the terminated nerve endings of the remaining limb and using the signals to activate a mechanical arm.
4. _________ is the most common and convenient source of light.
a) Neon-xenon arc
b) Xenon-mercury arc
c) Tungsten lamp
d) Hydrogen discharge lamp
Answer: c
Explanation: The most common and convenient source of light is the tungsten lamp. This lamp consists of a tungsten filament enclosed in a glass envelope. It is cheap, intense and reliable. A major portion of the energy emitted by a tungsten lamp is in the visible region and only about 15 to 20% is in the infrared region.
5. Which of the following factor determines the amplitude of EMG signal?
a) Respiration
b) Ventricular Volume
c) Blood Resistivity
d) Position of electrode
Answer: d
Explanation: The amplitude of the EMG signals depends upon various factors, e.g. the type and placement of electrodes used and the degree of muscular exertions. The needle electrode in contact with a single muscle fibre will pick up spike type voltages whereas a surface electrode picks up many overlapping spikes and therefore produces an average voltage effect.
6. EMG signals range from ______________
a) 0.1 to 0.5 mV
b) 0.050 to 0.1 mV
c) 0.5 to 1 mV
d) 0.025 to 0.050 mV
Answer: a
Explanation: A typical EMG signal ranges from 0.1 to 0.5 mV. They may contain frequency components extending up to 10 kHz.Such high frequency signals cannot be recorded on the conventional pen recorders and therefore, they are usually displayed on the CRT screen.
7. Modern day calorimeters and spectrophotmetry instruments use ________ light source.
a) Tungsten-halogen lamp
b) Xenon-mercury lamp
c) Deuterium discharge lamp
d) Mercury arc
Answer: d
Explanation: Modern instruments use a tungsten-halogen light source, which has a higher intensity output than the normal tungsten lamp in the change over a region of 320–380 nm used in colorimetry and spectrophotometry. It also has a larger life and does not suffer from blackening of the bulb glass envelope.
8. Which of the following from the options is included in the system to facilitate playback and study of EMG sound waveforms at a later convenient time?
a) Tape Recorder
b) Preamplifier
c) Oscilloscope
d) Ground Electrode
Answer: a
Explanation: The waveform can also be photographed from the CRT screen by using a synchronized camera. The tape recorder is included in the system to facilitate playback and study of the EMG sound waveforms at a later convenient time.
9. ____________ is necessary for providing a common reference for measurement?
a) active electrode
b) ground electrode
c) tape recorder
d) oscilloscope
Answer: b
Explanation: A ground electrode is necessary for providing a common reference for measurement. The signal can then be amplified and displayed on the screen of a cathode ray tube. It is also applied to an audio amplifier connected to a loudspeaker. These electrodes pick up the potentials produced by the contracting muscle fibres.
10. Which among the following are optical systems, which provide better isolation of spectral energy than the pptical filters.
a) Spectromators
b) Monochromators
c) Baromators
d) Tocochromators
Answer: b
Explanation: Monochromators are optical systems, which provide better isolation of spectral energy than the optical filters, and are therefore preferred where it is required to isolate narrow bands of radiant energy. Monochromators usually incorporate a small glass of quartz prism or a diffraction grating system as the dispersing media.
11. _______________ is not an arrhythmic condition.
a) Cardiographic beat
b) Bradycardia
c) Ectopic beat
d) Dropped beat
Answer: a
Explanation: These are bradycardia, tachycardia, dropped beat and premature beat. The analyzer part in automatic scanning of ambulatory records looks for four arrhythmic conditions. A threshold control is associated with each of these and when the appropriate threshold is exceeded, an alarm condition is generated.
12. CMRR of preamplifier upto 5 Khz should be _____________
a) 10 dB
b) greater than 90 dB
c) less than 90 dB
d) 30 dB
Answer: b
Explanation: The common-mode rejection should be greater than 90 dB up to 5 kHz. The main amplifier has controls for gain adjustment from 5 mV/div to 10 mV/div for selecting the sensitivity most appropriate to the incoming signal from the patient. A calibrating square wave signal of 100 mV at a frequency of 100 Hz is usually available.
13. Holter Cardiography is ambulatory monitoring of ECG signal.
a) True
b) False
Answer: a
Explanation: Modern EMG machines are PC based available both in a console as well as laptop models as they provide full colour waveform display, automatic cursors for marking and making measurements and a keyboard for access to convenient and important test controls. Ambulatory monitoring of ECG is called ‘Holter Cardiography’, after Dr. Norman Holter who introduced this concept in 1962. A Holter monitor is a type of ambulatory electrocardiography device, a portable device for cardiac monitoring for at least 24 hours .
14. _____________ provides an excellent review of ambulatory cardiac event recorders.
a) Alfonso
b) Benz
c) Handelsman
d) Friesen
Answer: b
Explanation: An excellent review of ambulatory cardiac event recorders is provided by Benz in 1999. The major advantage of these devices compared with a traditional Holter monitor is that they are small, allow ECG monitoring for longer time periods, and can provide nearly real time data analysis when the patient transmits a recording in proximity to the symptomatic event.
15. ________ CPU has overall system control responsibility.
a) Control
b) Acquisition
c) Control and timing
d) Acquisition and display
Answer: c
Explanation: It also handles individuals functions such as keyboard and direct writer interface, tape deck control, timing data processing, and arrhythmia count totalizing via a high speed interrupt system. The control and timing CPU has an overall system control responsibility.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Multi-Patient Telemetry”.
1. _____________ instrument is used for recording the electrical activity of the brain.
a) ECG
b) PCG
c) EEG
d) EMG
Answer: c
Explanation: EEG, describing the general function of the brain activity, is the superimposed wave of neuron potentials operating in a non-synchronized manner in the physical sense. Electroencephalograph is an instrument for recording the electrical activity of the brain, by suitably placing surface electrodes on the scalp.
2. EEG electrodes are smaller in size than ECG electrodes.
a) True
b) False
Answer: a
Explanation: EEG electrodes are smaller in size than ECG electrodes. Several types of electrodes may be used to record EEG. These include: Peel and Stick electrodes, Silver plated cup electrodes and Needle electrodes.
3. Which of the following is the superimposed wave of neuron potentials operating in a non-synchronized manner in a physical sense?
a) EEG
b) ECG
c) VCG
d) PCG
Answer: a
Explanation: Electroencephalograph is an instrument for recording the electrical activity of the brain, by suitably placing surface electrodes on the scalp. EEG, describing the general function of the brain activity, is the superimposed wave of neuron potentials operating in a non-synchronized manner in the physical sense.
4. ______________ material is used to improve electrical contact in electrodes with the skin.
a) Silver Tungsten
b) Copper Tungsten
c) Electrode jelly
d) Silver Graphite
Answer: c
Explanation: If the electrodes are intended to be used under the skin of the scalp, needle electrodes are used. Electrode jelly or paste is used to improve the electrical contact. They offer the advantage of reducing movement artefacts.
5. Which among the following electrode gives high skin impedance as compared to ECG?
a) VCG
b) EEG
c) EMG
d) PCG
Answer: b
Explanation: EEG electrodes give high skin contact impedance as compared to ECG electrodes. Good electrode impedance should be generally below 5 kilohms. Impedance between a pair of electrodes must also be balanced or the difference between them should be less than 2 kilohms.
6. Which of the following component is generally designed to have a very high value of input impedance to take care of high electrode impedance?
a) Montages
b) Filters
c) Electrodes
d) Preamplifiers
Answer: c
Explanation: EEG preamplifiers are generally designed to have a very high value of input impedance to take care of high electrode impedance. Good electrode impedance should be generally below 5 kilohms. Impedance between a pair of electrodes must also be balanced or the difference between them should be less than 2 kilohms.
7. What is the recording called in which voltage difference between an active electrode on scalp with respect to reference electrode at ear lobe or any other part of the body is recorded?
a) Unipolar
b) Bipolar
c) Monopolar
d) Nonpolar
Answer: c
Explanation: This type of recording is called ‘monopolar’ recording. EEG may be recorded by picking up the voltage difference between an active electrode on the scalp with respect to a reference electrode on the ear lobe or any other part of the body.
8. Which of the following is employed for a bipolar recording done?
a) Uni Channel EEG
b) Omni channel EEG
c) Non Channel EEG
d) Multi channel EEG
Answer: d
Explanation: Such recordings are done with multi-channel electroencephalographs. ‘bipolar’ recording is more popular wherein the voltage difference between two scalp electrodes is recorded.
9. EEG signals picked up by surface electrodes are usually larger as compared to ECG.
a) True
b) False
Answer: b
Explanation: They may be several hundred microvolts, but 50 microvolts peak-to-peak is the most typical. Yes, EEG signals picked up by the surface electrodes are usually small as compared with the ECG signals.
10. A pattern of electrodes on the head and the channels they are connected to is called a montage. Montages are always ___________
a) inverse
b) random
c) symmetrical
d) asymmetrical
Answer: c
Explanation: Montages are always symmetrical. A pattern of electrodes on the head and the channels they are connected to is called a montage. The reference electrode is generally placed on a nonactive site such as the forehead or earlobe.
11. Reference electrode for recording EEG is placed on __________
a) forehead
b) cervical
c) nasal
d) facial
Answer: a
Explanation: The reference electrode is generally placed on a nonactive site such as the forehead or earlobe. A pattern of electrodes on the head and the channels they are connected to is called a montage. Montages are always symmetrical.
12. The typical value of calibration signal is ________
a) 10 uV/cm
b) 70 uV/cm
c) 50 uV/cm
d) 30 uV/cm
Answer: c
Explanation: A typical value of the calibration signal is 50 uV/cm. A calibrating signal is used for controlling and documenting the sensitivity of the amplifier channels. This supplies a voltage step of adequate amplitude to the input of the channels.
13. Preamplifiers used in electroencephalograph have low gain and high noise characteristics for EEG.
a) True
b) False
Answer: b
Explanation: It is False. Preamplifier used in electroencephalographs must have high gain and low noise characteristics because the EEG potentials are small in amplitude. In addition, the amplifier must have a very high common-mode rejection to minimize stray interference signals from power lines and other electrical equipments.
14. At what frequency is the notch filter in EEG machines sharply tuned to eliminate mains frequency interference?
a) 60
b) 90
c) 10
d) 70
Answer: a
Explanation: EEG machines have a notch filter sharply tuned at 60 Hz so as to eliminate mains frequency interference. The use of notch filters should preferably be restricted to exceptional circumstances when all other methods of eliminating interference have been found to be ineffective. These however have the undesirable property of ‘ringing’ i.e. they produce a damped oscillatory response to a square wave calibration waveform or a muscle potential.
15. ______________ is typical frequency range of standard EEG machines.
a) 70 to 140 Hz
b) 0.1 to 70 Hz
c) 0.05 to 0.1 Hz
d) 0.025 to 0.05 Hz
Answer: b
Explanation: The typical frequency range of standard EEG machines is from 0.1 Hz to 70 Hz, though newer machines allow the detection and filtering of frequencies up to several hundred Hertz. This may be of importance in some intracranial recordings.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Implantable Telemetry Systems”.
1. ______________ is not a piezo-electric material.
a) quartz
b) rochelle salt
c) aluminium
d) barium titanate
Answer: a
Explanation: Quartz is the most stable natural crystal with high mechanical and thermal stability and has volume resistivity higher than 10^4 ohm-cm and small internal electric loss. Barium titanate ceramic is a ferroelectric crystal and has small voltage output. Aluminium is not a piezo-electric material.
2. Which of the following is the correction option in relation to piezo-electricity?
a) sound electricity
b) pressure electricity
c) temperature electricity
d) photo electricity
Answer: b
Explanation: Piezo-electricity is pressure electricity. The piezo electric effect is a property of natural crystalline substance to develop electric potential along a crystallographic axis in response to the movement of charge as a result of mechanical deformation.
3. Mechanical deformation occurs in the piezo-electric material on applying electricity.
a) True
b) False
Answer: a
Explanation: It is True. The piezo electric effect is a property of a natural crystalline substance to develop electric potential along a crystallographic axis in response to the movement of charge as a result of mechanical deformation. On applying electricity to the piezo-electric material mechanical deformation occurs in the material.
4. ________________ material employed for making diaphragm to measure pressure.
a) zirconate titanate
b) barium titanate
c) tourmaline
d) phosphor bronze
Answer: d
Explanation: The motion of the diaphragm is measured in terms of electric signals. Tourmaline, barium titanate and zirconate titanate are piezo electric materials. Phosphor bronze is used to make diaphragm to measure pressure.
5. Which of the following is the principle behind strain gauge?
a) variable contact area
b) variable inductance
c) variable capacitance
d) variable resistance
Answer: d
Explanation: The principle behind strain gaude is the variable resistance. A linear relation exists between the deformation and electrical resistance of a suitable selected gauge over a specified range. The transducer is based upon the changed in resistance of a wire produced due to small mechanical displacement.
6. Electricity is generated by a piezo-electric crystal on applying pressure to it.
a) True
b) False
Answer: a
Explanation: It is True. On applying pressure to piezo-electric crystal, electricity is generated. The piezo electric effect is a property of a natural crystalline substance to develop electric potential along a crystallographic axis in response to the movement of charge as a result of mechanical deformation. Thus, piezo-electricity is pressure electricity.
7. ________________ is used to describe the figure of merit which determines the overall behaviour of the wire under stress.
a) gauge resistance
b) elastic factor
c) gauge factor
d) elastic modulus
Answer: c
Explanation: Gauge factor gives information on the expected resistance change or output signal at maximum permissible elongation. The gauge factor determines to a large extent the sensitivity of the wire when it is made into a practical strain gauge. The figure of merit which describes the overall behaviour of the wire under stress is determined from the gauge factor of the wire.
8. Which of the following is the correct definition for Gauge factor?
a) *
b) *
c) *
d) *
Answer: d
Explanation: Gauge factor is defined as *. Gauge factor gives information on the expected resistance change or output signal at maximum permissible elongation. The gauge factor determines to a large extent the sensitivity of the wire when it is made into a practical strain gauge.
9. Which lead method is employed to compensate for temperature variation in the leads?
a) three
b) eight
c) six
d) two
Answer: c
Explanation: The third lead is in series with the power supply and is therefore independent of bridge balance. Compensation for temperature variation in the leads can be provided by using three lead methods. In this method, two of the leads are in the adjacent legs of the bridge which cancels their resistance changes and does not disturb the bridge balance.
10. Which of the following parameter is measured by strain gauge?
a) temperature
b) displacement
c) height
d) pressure
Answer: d
Explanation: Strain gauge is used to measure pressure. There are two types of strain gauges. Bounded strain gauge and unbounded strain gauge. Its working principle is a change in resistance. Mostly used to measure the arterial and venous blood pressure in the body.
This set of Biomedical Instrumentation Problems focuses on “Biotelemetry Application on Wimax Networks”.
1. ________________ records the electrical activity of heart.
a) ECG
b) PCG
c) VCG
d) EEG
Answer: a
Explanation: Electrical signals from the heart characteristically precede the normal mechanical function and monitoring of these signals has great clinical significance.The electrocardiograph is an instrument, which records the electrical activity of the heart.
2. Which of the following material used in limb surface electrode?
a) german silver
b) platinum
c) gold
d) copper
Answer: a
Explanation: The most common type of electrode most routinely used for recording ECG are rectangular or circular surface limb electrodes. They are applied to the surface of the body with electrode jelly. The material used in them are German silver, nickel silver or nickel plated steel.
3. Which of the following reason is responsible for the Welsh cup electrodes to record the electrical signal of the heart?
a) low contact impedance
b) zero contact impedance
c) high contact impedance
d) negligible contact impedance
Answer: c
Explanation: It has a high contact impedance as only the rim of the electrode is in contact with the skin. Welsh cup electrodes or suction electrodes is a metallic cup shaped electrode which is used for recording ECG from various positions from the chest. It is commonly used to record the unipolar chest leads.
4. Among the following, which has CMRR is of an order of 100-120 dB?
a) VCG
b) ECG
c) PCG
d) EEG
Answer: b
Explanation: CMRR of the order of 100–120 dB with 5 kW unbalance in the leads is a desirable feature of ECG machines. In addition to this, under specially adverse circumstances, it becomes necessary to include a notch filter tuned to 50 Hz to reject hum due to power mains.
5. In floating electrodes metal electrode make direct contact with the skin.
a) True
b) False
Answer: b
Explanation: The electrode consists of a light weighted metalled screen or plate held away from the subject by a flat washer which is connected to the skin. In floating electrode the metal electrode does not make direct contact with the skin. Floating electrodes can be recharged, i.e. the jelly in the electrodes can be replenished if desired.
6. __________ is considered to be the primary pacemaker of the heart.
a) bundle of his
b) sino-atrial node
c) purkinje fibres
d) atrio-ventricular node
Answer: b
Explanation: Located in the top right atrium near the entry of the vena cava, are a group of cells known as the sion-atrial node that initiates the heart activity. Because of this is also considered as the primary pacemaker of the heart. The SA node is 25 to 30 mm in length and 2 to 5 mm in thickness.
7. Which is the correct location of Atrio ventricular node?
a) upper part of the heart wall between the two atrial
b) lower part of the heart wall above the two atrial
c) upper part of the heart wall above the two atrial
d) lower part of the heart wall between the two atrial
Answer: d
Explanation: The AV node delays the spread of excitation for about 0.12s, due to the presence of a fibrous barrier of non-excitable cells that effectively prevent its propagation from continuing beyond the limits of stria. The AV node is located in the lower part of the wall between the two atria.
8. Which of the following option is correct regarding the Buffer Amplifier?
a) low impedance signals to high impedance signals
b) high impedance signals to low impedance signals
c) ac impedance signals to dc impedance signals
d) dc impedance signals to ac impedance signals
Answer: b
Explanation: A buffer amplifies is essentially an impedance converter, that converts high impedance signals to low impedance signals. Noise is typically generated from motion artefacts and power line interference. A common solution used to suppress noise in dry electrode signals is a buffer amplifier.
9. Preamplifier is used ________
a) For Amplification
b) For Stabilizing effect
c) For Modifying effects
d) For Reducing effect
Answer: b
Explanation: The preamplifier is usually a three or four stage differential amplifier having a sufficiently large negative current feedback, from the end stage to the first stage, which gives a stabilizing effect.
10. ______________ is a wireless ECG acquiring system.
a) limb electrodes
b) smart pad
c) pasteless electrodes
d) pregelled disposable electrodes
Answer: b
Explanation: The system automatically selects three electrodes from an array of Cu/Ni fabric based electrodes patterned on a thin pad on which the patient lies. The smart pad is a system that displays a patients electrocardiogram signals without adhesive pads, wires or active intervention from a clinician. The selected electrodes are used to provide a differential 3 lead measurement of the patient’s ECG, which is then transmitted wirelessly and displayed on a laptop computer.
11. What is made horizontally on electrocardiogram?
a) time measurements and heart rate measurements
b) only heart Rate Measurements
c) only time Measurements
d) not fixed and can be any thing
Answer: a
Explanation: Time measurements and heart rate measurements are made horizontally on the electrocardiogram. Electrocardiograms are almost invariably recorded on graph paper with horizontal and vertical lines at 1 mm intervals with a thicker line at 5 mm intervals.
12. _____________ is paper recording speed for routine work.
a) 10 mm/s
b) 20 mm/s
c) 25 mm/s
d) 15 mm/s
Answer: b
Explanation: Time measurements and heart rate measurements are made horizontally on the electrocardiogram. Electrocardiograms are almost invariably recorded on graph paper with horizontal and vertical lines at 1 mm intervals with a thicker line at 5 mm intervals.
13._______________ is measured on the vertical axis of electrocardiogram.
a) Time Measurements and Heart Rate Measurements
b) Amplitude Measurements
c) Time Measurements
d) Heart Rate Measurements
Answer: c
Explanation: Time measurements and heart rate measurements are made horizontally on the electrocardiogram. Electrocardiograms are almost invariably recorded on graph paper with horizontal and vertical lines at 1 mm intervals with a thicker line at 5 mm intervals. Amplitude measurements are made vertically in millivolts. The sensitivity of an electrocardiograph is typically set at 10 mm/mV.
14. Which of the following option is correct regarding the sensitivity of an electrocardiograph?
a) 10 mm/mV
b) 15 mm/mV
c) 20 mm/mV
d) 25 mm/mV
Answer: a
Explanation: Time measurements and heart rate measurements are made horizontally on the electrocardiogram. Electrocardiograms are almost invariably recorded on graph paper with horizontal and vertical lines at 1 mm intervals with a thicker line at 5 mm intervals. Amplitude measurements are made vertically in millivolts. The sensitivity of an electrocardiograph is typically set at 10 mm/mV.
This set of Biomedical Instrumentation online quiz focuses on “Transmission of Analog Physiological Signals Over Telephone”.
1. What is the principle behind Doppler velocimetry working?
a) amplitude measurement of fiber optic sensor
b) frequency measurement of fiber optic sensor
c) time shift measurement of fiber optic sensor
d) phase measurement of fiber optic sensor
Answer: b
Explanation: Doppler velocimetry works on the principle of frequency measurement of fiber optic sensor. The moving red blood cells scatter the light and produce a Doppler frequency shift because of their movement. In this method, light from a laser, normally helium/neon, is sent via a fibre onto the skin surface.
2. Which of the following is the principle behind Fluoroptic temperature sensors working?
a) optical fiber
b) thermistor
c) thermocouple
d) rtd
Answer: a
Explanation: They contain a rare earth phosphor which is illuminated by a white light along a short length of large core optical fibre. Fluoroptic temperature sensors work on the principle of optical fiber sensors. The light excites the phosphor which emits a number of lines. By using filters, two of these lines at 540 and 630 nm are selected, and the ratio of their intensities is a single valued function of the temperature of the phosphor.
3. Monopolar needle electrode has a coating of______________ material over the stainless steel wires which are bare only at the tips.
a) carbon
b) calcium
c) teflon
d) sodium
Answer: c
Explanation: The wire is bare only at the tip. The monopolar needle electrode consists of a teflon coated stainless steel wire. It is found that after the needle has been used a number of times, the teflon coating will recede, increasing the tip area. The needle should be discarded when this happens.
4. Which of the following sensor is used for Endoscopic imaging?
a) thermal sensors
b) optic fiber sensors
c) chemical sensors
d) pressure sensors
Answer: b
Explanation: Optical fibre sensors are non-electrical and hence are free from electrical interference usually associated with electronically based sensors. Optic sensors are used for endoscopic imaging. They are suitable for telemetry applications as the bulk of the instrumentation can be at a reasonable distance from the patient.
5. Which of the following component converts biochemical events into measurable signals?
a) amplifier
b) opamp
c) rectifier
d) transducer
Answer: d
Explanation: Transducers convert biochemical events into measurable signals. They provide the means for detecting the biochemical changes inside the body. Particularly biosensors are employed for this purpose.
6. Which of the following is used to determine the biological response of the biosensor?
a) artificial membrane
b) chemical membrane
c) physio-chemical membrane
d) biocatalytic membrane
Answer: d
Explanation: The biocatalytic membrane accomplishes the conversion of reactant to product. The product of the reaction diffuses to the transducer. The biological response of the biosensor is determined by biocatalytic membrane. This then causes the electrical response.
7. What is the working principle behind Home blood glucose sensor?
a) electro-physiological
b) electrochemical
c) chemical
d) physio-chemical
Answer: b
Explanation: Home blood glucose detection sensor works on the principle of electrochemical. The biosensor in this instrument relies upon enzymes that recognize and catalyze reactions of glucose with the generation of redox – active species that are detected electrochemically.
8. ____________ is a wireless ECG acquiring system.
a) pregelled disposable electrodes
b) smart pad
c) pasteless electrodes
d) limb electrodes
Answer: b
Explanation: Smart pad is a system that displays patients electrocardiogram signals without adhesive pads, wires or active intervention from a clinician. The selected electrodes are used to provide a differential 3 lead measurement of the patient’s ECG, which is then transmitted wirelessly and displayed on a laptop computer. The system automatically selects three electrodes from an array of Cu/Ni fabric based electrodes patterned on a thin pad on which the patient lies.
9. Home blood glucose measurement devices measure the glucose level through an invasive method.
a) True
b) False
Answer: a
Explanation: There is a small needle at the tip of the machine that pierces the skin to take a blood sample. Home blood glucose measurement devices measure the glucose level through invasive method. This blood is then undergoes electrochemical reactions and the glucose level is determined.
10. Blood glucose level measurement device uses a biosensor works on the principle of _____________
a) electromechanical
b) electrochemical
c) electrothermal
d) electroresistive
Answer: b
Explanation: The biosensor in this instrument relies upon enzymes that recognise and catalyze reactions of glucose with the generation of redox – active species that are detected electrochemically. Home blood glucose detection sensor works on the principle of electrochemical.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Essential Parameters for Telemedicine”.
1. Which of the following option is the correct full form of CRO?
a) Common Ray Oscilloscope
b) Common Ray Oscillator
c) Cathode Ray Oscillator
d) Cathode Ray Oscilloscope
Answer: d
Explanation: Cathode ray oscilloscopes are widely used for the display of waveforms encountered in the medical field. These waveforms can be recorded from the CRO screen by running a photographic film through a recording camera fixed in front of the screen. Recorders are either of the single channel type or of the type which record several channels simultaneously.
2. __________has the widest range of temperature measurement.
a) RTD
b) Mercury thermometer
c) Thermocouple
d) Thermistor
Answer: c
Explanation: Thermocouple has the widest range of temperature measurement from -184*C to +2300*C. RTD has a range of -200*C to +850*C. Thermistor has a range of 0*C to 100*C whereas conventional mercury thermometers range is -37*C to +356*C.
3. The junction at a lower temperature in thermocouple is termed as measuring junction.
a) True
b) False
Answer: b
Explanation: The junction at a higher temperature in thermocouple is termed as measuring junction. The junction at a lower temperature in the thermocouple is called the reference temperature. The cold junction is usually kept at 0*C.
4. Select the correct option from below for the particular description of arrangement. When two wires of different material are joined together at either end, forming two junctions which are maintained at different temperature, a thermo-motive force is generated causing a current to flow around the circuit.
a) thermocouple
b) thermalpair
c) thermistor
d) thermostat
Answer: a
Explanation: The junction at a higher temperature in thermocouple is termed as measuring junction. This arrangement is called thermocouple. The junction at a lower temperature in the thermocouple is called the reference temperature.
5. What force is generated when two wires of different material are joined together at either end, forming two junctions which are maintained at a different temperature?
a) chemical reactive
b) electro-motive
c) thermo-motive
d) mechanical
Answer: c
Explanation: When two wires of different material are joined together at either ends, forming two junctions which are maintained at a different temperature, a thermo-motive force is generated causing a current to flow around the circuit. This arrangement is called a thermocouple. The junction at a lower temperature in the thermocouple is called the reference temperature. The junction at a higher temperature in thermocouple is termed as measuring junction.
6. The junction at a higher temperature in the thermocouple called is measuring junction.
a) True
b) False
Answer: a
Explanation: The junction at a lower temperature in the thermocouple is called the reference temperature. The cold junction is usually kept at 0*C. The junction at a higher temperature in thermocouple is termed as measuring junction.
7. What is the temperature at which the lower junction in thermocouple is maintained?
a) 0 K
b) 273 K
c) -327 K
d) -273 K
Answer: b
Explanation: The lower temperature junction in thermocouple is maintained at 273 K . The junction at lower temperature in the thermocouple is called the reference temperature. The junction at a higher temperature in thermocouple is termed as measuring junction.
8. Which is the correct formula for the resistance Rt of a metallic conductor at any temperature t?
a) Rt = Roɑ
b) Rt = Roɑ
c) Rt = Roɑ
d) Rt = Roɑ
Answer: c
Explanation: The resistance Rt of a metallic conductor at any temperature t is given by Rt = Roɑ. Ro is the resistance at 0*C. ɑ is a temperature coefficient of resistivity.
9. The full form of RTD is _________________
a) resistive thermal detector
b) resistance temperature detector
c) resistance temperature device
d) reluctance thermal device
Answer: b
Explanation: It is a passive sensor and requires current excitation to produce an output voltage. RTD has very low temperature coefficient.RTD stands for Resistance Temperature Device. Voltage drop across RTD is much larger than the thermocouple output voltage.
10. Which of the following quantity is measured by Thermister?
a) pressure
b) displacement
c) temperature
d) height
Answer: c
Explanation: Thermistors are the oxides of certain metals like manganese, cobalt and nickel which have large negative temperature coefficient, i.e. resistance decreases with increase in temperature. A thermistor is used to measure temperature. It is a temperature transducer. With a change in temperature its resistance changes. Thus its working principle is variable resistance.
This set of Biomedical Instrumentation Assessment Questions and Answers focuses on “Delivery Models in Telemedicine”.
1. ___________ is the interruption or interference with normal physiological and developmental processes or structures.
a) Pathophysiology
b) Societal Limitation
c) Functional Limitation
d) Modality-Specific
Answer: a
Explanation: Modality-Specific is a task that is specific to a single sense or movement pattern. Interruption or interference with normal physiological and developmental processes or structures is called Pathophysiology. A functional limitation is a restriction or lack of ability to perform an action in the manner or within the range consistent with the purpose of an organ or organ system.
2. A task that is specific to a single sense or movement pattern is called _________ in a rehabilitation engineering perspective.
a) Functional Limitation
b) Modality-Specific
c) Societal Limitation
d) Pathophysiology
Answer: b
Explanation: Interruption or interference with normal physiological and developmental processes or structures is called Pathophysiology. A task that is specific to a single sense or movement pattern is called Modality- Specific. A functional limitation is a restriction or lack of ability to perform an action in the manner or within the range consistent with the purpose of an organ or organ system.
3. _______________ is not a passive transducer.
a) Doppler effect transducer
b) IR sensor
c) Strain gauge
d) Ultrasonic transducer
Answer: c
Explanation: Strain gauge transducer is an active transducer. Its working principle is based on change in resistance. Ultrasonic transducers need power to operate. So do the IR sensors and doppler effect transducers.
4. _________ is called the Aesthetics of appearance.
a) lymphosis
b) cosmesis
c) orthosis
d) homeostasis
Answer: b
Explanation: Orthosis is a modality-specific appliance that aids the performance of a function or movement by augmenting or assisting the residual capabilities of that function or movement. Aesthetics of appearance is called cosmesis.
5. Which of the following filter is used to amplify frequency above a certain value?
a) band stop filter
b) low pass filter
c) band pass filter
d) high pass filter
Answer: d
Explanation: Low pass filter amplifies signals below a certain frequency. High pass filter amplifies signal above a certain frequency. Band pass filter amplifies frequencies within a certain band. Band stop filter amplifies all the frequencies except those in a certain band.
6. From the options given below, select the one that best describes: Transcutaneous.
a) passing to the heart
b) passing to the bones
c) passing to the skin
d) passing to the lungs
Answer: c
Explanation: This term generally used with the type of surgical instrument to be used. It is also used to describe the interaction of rehabilitation devices. Transcutaneous means passing to the skin.
7. _____________ is not a soft tissue.
a) ligament
b) bone
c) tendons
d) skin
Answer: b
Explanation: Biological soft tissues are nonlinear, anisotropic, fibrous composites, and a detailed description of their behavior is the subject of active research. Hard tissue, mineralized tissue, and calcified tissue are often used as synonyms for bone when describing the structure and properties of bone or tooth. One can separate these tissues based on their mode of loading: cartilage is generally loaded in compression; tendons and ligaments are loaded in tension, and muscles generate active tension.
8. Which is the correct characteristic of Blood vessels?
a) Soft tissue
b) Connective and soft tissue
c) Connective and hard tissue
d) Hard tissue
Answer: d
Explanation: Hard tissue is correct which says blood is soft and connective tissue. Soft tissues include tendon, ligament, blood vessels etc. Hard tissues include bones.
9. Muscles are the reservoir for calcium and phosphorus, essential minerals for various cellular activities which happen throughout the human body.
a) True
b) False
Answer: b
Explanation: It is False. Muscles are not the reservoir for calcium and phosphorus, essential minerals for various cellular activities which happen throughout the human body. Bones serve as a reservoir for calcium and phosphorus, essential minerals for various cellular activities that occur throughout the body. The composition of bone depends on a large number of factors: the species, which bone, the location from which the sample is taken, and the age, sex, and type of bone tissue, for example, woven, cancellous, cortical.
10. Bones are living tissues.
a) True
b) False
Answer: a
Explanation: It is True. Bones are living tissues. hey also are responsible for the production of blood cells and act a mineral reservoir in the body. They keep growing. They also play the role of protection of internal soft organs like the brain is protected by skull and lungs and heart by the rib cage.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Telemedicine System”.
1. _______________ will reject any common mode signal that appears simultaneously at both amplifier input terminal.
a) ac coupled amplifiers
b) dc amplifiers
c) carrier amplifiers
d) differential amplifiers
Answer: d
Explanation: Most of the amplifiers used for measuring bioelectric signals are of the differential type. A differential amplifier is one which will reject any common mode signal that appears simultaneously at both amplifier input terminals and amplifies only the voltage difference that appears across its input terminals. AC amplifiers have a limited frequency response and are, therefore, used only for special medical applications such as electrocardiograph machine.
2. The amplifier from the following that has a limited frequency response is _________
a) dc amplifiers
b) differential amplifier
c) ac coupled amplifiers
d) carrier amplifiers
Answer: a
Explanation: AC amplifiers have a limited frequency response and are, therefore, used only for special medical applications such as electrocardiograph machine. For electrocardiograms, an ac amplifier with sensitivity, giving 0.5 mV/cm, and frequency response up to 1 kHz and an input impedance of 2 to 5 MW is used. For such applications as retinography, EEG and EMG, more sensitive ac amplifiers are required, giving a chart sensitivity of say 50 mV/cm with a high input impedance of over 10 MW.
3. Which of the following amplifiers are used with transducers which require an external source of excitation?
a) ac coupled amplifiers
b) dc amplifiers
c) carrier amplifiers
d) differential amplifier
Answer: c
Explanation: Carrier amplifiers are used with transducers which require an external source of excitation. They essentially contain a carrier oscillator, a bridge balance and calibration circuit, a high gain ac amplifier, a phase-sensitive detector and a dc output amplifier. They are characterized by high gain, negligible drift, extremely low noise and the ability to operate with resistive, inductive or capacitive type transducers.
4. Which feedback system is employed in DC amplifiers?
a) Can be any positive or negative doesn’t matter
b) Negative
c) Depends on the application
d) Positive
Answer: b
Explanation: DC amplifiers are generally of the negative feedback type. They are not practical for very low level applications because of dc drift and poor common-mode rejection capabilities. They are used for medium gain applications down to about 1 mV signal levels for full scale.
5. Digital filters are not sensitive to temperature as compared with analog filters.
a) True
b) False
Answer: a
Explanation: It is True. Digital filters are insensitive to temperature as compared with analog filters. They are also insensitive to ageing, voltage drift and external interference as compared to analog filters. Their response is completely reproducible and predictable, and software simulations can exactly reflect product performance.
6. The number of amplifiers incorporated in the module of a Chopper stabilized dc amplifiers are ___________
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: Chopper stabilized dc amplifiers are used for low level but preferably wideband applications such as oscilloscopes, tape recorders and light beam oscilloscope recorders. This includes an ac amplifier for signals above about 20 Hz, a dc chopper input amplifier for signals from about 20 Hz down to dc plus wideband feedback stabilized dc amplifier. These are complex amplifiers having three amplifiers incorporated in the module.
7. _____________ is employed with resistive transducers which require an external source of excitation.
a) differential amplifier
b) dc bridge amplifier
c) carrier amplifier
d) ac coupled amplifier
Answer: b
Explanation: Essentially, the amplifier comprises a stable dc excitation source, a bridge balance and calibration unit, a high gain differential dc amplifier and a dc output amplifier. DC bridge amplifiers are employed with resistive transducers which require an external source of excitation. They can be used as conventional dc high gain amplifiers and offer operating simplicity and high-frequency response.
8. Which of the following IC is a variable negative voltage regulator?
a) 7912
b) 7905
c) LM337
d) LM317
Answer: c
Explanation: LM337 is a variable negative voltage regulator IC. It is capable of drawing current up to 1.5A and voltage range from – ideally. LM317 is a variable positive voltage regulator IC. 7905 and 7912 are fixed voltage regulator IC that give output voltage as -5V and -12V respectively.
9. Chopper input dc amplifiers are preferred for high level inputs to instrumentation systems because of their high sensitivity, negligible drift and excellent common mode rejection capability.
a) True
b) False
Answer: b
Explanation: It is False. Chopper input dc amplifiers are preferred for low level inputs to instrumentation systems because of their high sensitivity, negligible drift and excellent common mode rejection capability. Their high frequency response is limited to about one half of the input chopper frequency.
10. The amplifier configuration must contain _____________ to achieve the low frequency response for medical applications?
a) higher resistance
b) lower resistance
c) lower capacitance
d) higher capacitance
Answer: d
Explanation: To achieve the low frequency response required for medical applications, the amplifier must have large values of coupling capacitance. The response should be down to less than one hertz which is a very frequent requirement. In all RC-coupled amplifiers, low frequency response is limited by the reluctance of the coupling capacitors.
This set of Biomedical Instrumentation Question Bank focuses on “Clinical Data Interchange/Exchange Standards”.
1. What is an arrhythmia monitor?
a) Patient monitoring system
b) Sophisticated alarm system
c) Sophisticated monitoring system
d) ECG interpretation system
Answer: b
Explanation: An arrhythmia monitor is basically a sophisticated alarm system. It is not an ECG interpretation system. It constantly scans ECG rhythm patterns and issues alarms to events that may be premonitory or life threatening.
2. Which task is performed after the Ventricular fibrillation detection in automated arrhythmia monitoring system?
a) Noise detection
b) Beat labeling
c) Atrial fibrillation detection
d) Rhythm definition
Answer: d
Explanation: In automated arrhythmia monitoring system, Rhythm definition is performed after the Ventricular fibrillation detection. Rhythm definition is also performed after the beat labeling and atrial fibrillation detection in automated arrhythmia monitoring and analysis system.
3. In arrhythmia monitoring system, it gives alarm light signals whenever the prematured or widened ectopic beats exist up to the rate of __________
a) 6/min to 10/min
b) 6/min to 12/min
c) 6/min or 10/min
d) 6/min or 12/min
Answer: d
Explanation: In the arrhythmia monitoring instrument, it gives alarm light signals whenever the prematured or widened ectopic beat exist up to the rate of 6/min or 12/min.It is one of the operating sequences of the arrhythmia monitoring instrument.
4. ECG signal is amplified and filtered with 0.05-100 Hz for diagnostic purposes and 1-40 Hz for monitoring purposes in signal conditioning.
a) True
b) False
Answer: a
Explanation: It is True. ECG signal is amplified and filtered with 0.05-100 Hz for diagnostic purposes and 1-40 Hz for monitoring purposes in signal conditioning.
5. _________ resolution analog-to-digital converter is used in digitization of ECG signal in signal conditioning.
a) 16 bit
b) 12 bit
c) 32 bit
d) 64 bit
Answer: b
Explanation: In signal conditioning, ECG signal is amplified, filtered and digitized using an 8- or 12- bit analog-to-digital converter with a typical sampling rate of 250 Hz.
6. A disturbance in the heart’s normal rhythmic contraction is called ____________
a) Heart stroke
b) Cardiac arrest
c) Arrhythmias
d) Premature contraction
Answer: c
Explanation: Any disturbance in the heart’s normal rhythmic contraction is called an arrhythmias or cardiac dysrhythmia. In this arrhythmias heart can’t beat in a regular rhythm. In arrhythmia heart-rate will be higher than normal rate or will be less than the normal rate.
7. The steep, large amplitude variation of the QRS complex is the obvious characteristics to use and this is the function of the Q wave detector.
a) True
b) False
Answer: b
Explanation: It is False. Arrhythmia monitors require reliable R wave detectors as a prerequisite for subsequent analysis. The steep, large amplitude variation of the QRS complex is the obvious characteristics to use and this is the function of the R wave detector.
8. Which of the following two elements are removed by the detection filter in the process of the ECG waveform?
a) Low frequency noise, motion noise
b) Muscle artifact, motion noise
c) Baseline wander, motion noise
d) Baseline wander, muscle artifact
Answer: a
Explanation: The detection filter removes low frequency noise and muscle artifact. The ECG waveform is processed by two digital filters: a detection filter and a classification filter. P waves and T waves are diminished.
9. The number of steps involved in the detection of QRS complex is ______
a) One step
b) Two steps
c) Three steps
d) Four steps
Answer: b
Explanation: The ECG is first preprocessed to enhance the QRS complex while suppressing noise, artifact and non-QRS portions of the ECG. QRS detection is now almost universally performed digitally in a two-step process. The output of the preprocessor stage is subjected to a decision rule that confirms detection of QRS if the processor output exceeds a threshold.
10. Which of the following is based on analyzing the shape of the QRS complexes and separating beats into groups or clusters?
a) Morphology characterization
b) Noise detection
c) Beat labeling
d) Timing classification
Answer: a
Explanation: Morphology characterization is based on analyzing the shape of the QRS complexes and separating beats into groups or clusters of similar morphology. Most algorithms for real time arrhythmia analysis maintain no more than 10-20 clusters at a time, order to limit the amount of computation needed to assign a QRS complex to a cluster.
11. What is the condition in which the R-R interval is declared premature?
a) If it is less than 75% of the predicted interval
b) If it is greater than 75% of the predicted interval
c) If it is less than 85% of the predicted interval
d) If it is greater than 85% of the predicted interval
Answer: c
Explanation: In timing classification, the observed R-R interval is compared to an estimate of the expected R-R interval. An R-R interval will be declared premature if it is less than 85% of the predicted interval. Similarly, an R-R interval is long if it is greater than 110% of the predicted value.
12. ___________ is the final stage in arrhythmia analysis.
a) Summary statistics
b) Alarms
c) Rhythm labeling
d) Beat labeling
Answer: c
Explanation: It is based on defined sequences of QRS complexes. Rhythm labeling is the final stage in arrhythmia analysis. The analysis systems are heavily oriented towards detecting ventricular arrhythmias, particularly single PVCs.
13. ______________ techniques are used in a new algorithm proposed by Jen and Hwang to obtain the long term ECG signal feature and extract the meaningful information hiding in the QRS complex.
a) Cepstrum time warping and Dynamic coefficient
b) Cepstrum coefficient and Dynamic time warping
c) QRS detection and Dynamic coefficient
d) QRS detection and Cepstrum time warping
Answer: b
Explanation: This algorithm may also be used for arrhythmia detection by simply checking the difference of R-R wave intervals through signal feature extraction comparison for a certain period of time. Jen and Hwang proposed a new algorithm using cepstrum coefficient and the dynamic time warping techniques to obtain the long term ECG signal feature and extract the meaningful information hiding in the QRS complex.
14. Which of the following is used to detect Ventricular Fibrillation?
a) Shape of the QRS complexes
b) Frequency domain analysis
c) Timing sequence of QRS complexes
d) Difference of the R-R interval
Answer: b
Explanation: Ventricular fibrillation is usually detected by frequency domain analysis. It can be distinguished from noise by appropriately designing band-pass filters. The system is characterized as a narrow-band, low frequency signal with energy concentrated in a band around 5-6 Hz.
15. ____________ is the sampling rate of analog-to-digital converter in digitizing of ECG signal in signal conditioning.
a) 200-215 Hz
b) 215 Hz
c) 40-100 Hz
d) 250 Hz
Answer: d
Explanation: In signal conditioning, ECG signal is amplified, filtered and digitized using an 8- or 12-bit analog-to-digital converter with a typical sampling rate of 250 Hz.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Transmission of Still Images”.
1. The minimum input of physical parameter that will create a detectable out change. This is the definition of which of the following parameter?
a) threshold
b) span
c) sensitivity
d) precision
Answer: c
Explanation: The sensitivity of the sensor is defined as the slope of the output characteristic curve. In simple words The minimum input of physical parameter that will create a detectable out change is called sensitivity. Total operating range of the transducer is called its span.
2. What is the total operating range of the transducer is called?
a) offset
b) threshold
c) span
d) drift
Answer: c
Explanation: The total operating range of the transducer is called the span of the transducer. Offset is the output that will exist when it should be zero. Drift is basically the change in a signal over a long period of time.
3. Hysteresis is changed in output with the same value of the input.
a) True
b) False
Answer: a
Explanation: Hysteresis is observed when the input/output characteristics for a transducer are different for increasing inputs than for decreasing outputs. Hysteresis is changed in output with the same value of input but with a different history of input variation. It results when some of the energy applied for increasing inputs is not recovered when the input decreases.
4. What is the region called in which the output does not change with an increase in input?
a) saturation
b) threshold
c) offset
d) input range
Answer: a
Explanation: The region in which the output does not change with an increase in input is called saturation. The threshold of the transducer is the smallest change in measurant that will result in a measurable change in the transducer output. Offset is the output that will exist when it should be zero.
5. Which of the following characteristic is defined for the material: Ability of the sensor to repeat a measurement when put back in the same environment.
a) saturation
b) conformance
c) threshold
d) repeatability
Answer: d
Explanation: Ability of the sensor to repeat a measurement when put back in the same environment is called repeatability. The threshold of the transducer is the smallest change in measurant that will result in a measurable change in the transducer output. The region in which the output does not change with an increase in input is called saturation.
6. ___________ is called the closeness of a calibration curve to a specified curve for an inherently non linear transducer.
a) saturation
b) linearity
c) conformance
d) hysteresis
Answer: c
Explanation: Hysteresis is changed in output with the same value of input but with a different history of input variation. Conformance indicates the closeness of a calibration curve to a specified curve for an inherently non linear transducer. The region in which the output does not change with an increase in input is called saturation.
7. The range between the max and min values is applied parameter which can be measured is called ____________
a) repeatability
b) span
c) output range
d) input range
Answer: b
Explanation: Ability of the sensor to repeat a measurement when put back in the same environment is called repeatability. Input range is the range between the max and min values is applied parameter which can be measured. The total operating range of the transducer is called span of the transducer.
8. ___________ is not a static property.
a) repeatability
b) frequency response
c) hysteresis
d) saturation
Answer: b
Explanation: Frequency response is the change of transfer function with frequency, both in magnitude and in phase. It is a dynamic property. The region in which the output does not change with an increase in the input is called saturation. Ability of the sensor to repeat a measurement when put back in the same environment is called repeatability.
9. Time for the sensor to reach a stable output once it is turned on. This is the definition of ________________
a) settling time
b) span
c) frequency response
d) response time
Answer: a
Explanation: Frequency response is the change of transfer function with frequency, both in magnitude and in phase. Settling time is the time for the sensor to reach a stable output once it is turned on. The total operating range of the transducer is called the span of the transducer.
10. _______________ is not a dynamic property.
a) frequency response
b) response time
c) settling time
d) saturation
Answer: d
Explanation: Settling time is the time for the sensor to reach a stable output once it is turned on. The region in which the output does not change with an increase in the input is called saturation. It is a static property of the transducer. Frequency response is the change of transfer function with frequency, both in magnitude and in phase.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Transmission of Video Images”.
1. Blood cell counters, operating on the principle of conductivity change, which occurs each time a cell passes through an orifice, are generally known as ________________
a) optical method
b) electrical conductivity
c) coulter Counter
d) microscopic method
Answer: c
Explanation: Blood cell counters, operating on the principle of conductivity change, which occurs each time a cell passes through an orifice, are generally known as Coulter Counters. The method was patented by Coulter in 1956 and it forms the basis of several particle counting instruments manufactured by a number of firms throughout the world.
2. Which electrode is placed inside the orifice tube, in coulter counter?
a) Metal electrode
b) Platinum electrode
c) Silicon electrode
d) Magnesium electrode
Answer: b
Explanation: In a coulter counter, a platinum electrode is placed inside the orifice tube and a second electrode is submerged into the beaker containing the cell dilution, creating an electrical circuit between the two electrodes.
3. Which of the following information is not provided by the Coulter Counter?
a) Relative cell size distribution
b) Settings of the threshold level control
c) Relative cell size
d) Mean cell volume
Answer: d
Explanation: The Coulter counters are usually provided with an oscilloscope monitor to display the pulse information, which has passed through the amplifier, and acts as a visible check on the counting process indicating instantaneously any malfunctions such as a blocked orifice. In particular, it provides information regarding relative cell size, relative cell size distribution, settings of the threshold level control, and means to check the performance of the instrument for the reliability of counts.
4. In Coulter counter, for such an aperture, a length of about ______ and flow rate of ______ ml/s would be optimum.
a) 100 u, 0.04
b) 200 u, 0.02
c) 100 u, 0.02
d) 200 u, 0.04
Answer: d
Explanation: Taylor suggests that an aperture diameter of 100 m would be generally useful. For such an aperture, a length of about 200 μ and flow rate of 0.04 ml/s would be optimum. The aperture can be made using ruby watch jewels bonded to a glass surface.
5. Typically, an aperture of 100 m diameter and 200 m length, separating two solutions of sulphate buffered saline, has a resistance of about 25 kW and capacitance of 120 pF.
a) True
b) False
Answer: b
Explanation: Typically, an aperture of 100 u diameter and 200 m length, separating two solutions of phosphate buffered saline, has a resistance of about 25 kW and capacitance of 120 pF.
6. The required bandwidth of the preamplifier used in cell counter must be?
a) 70 kHz
b) 120 kHz
c) 70 Hz
d) 120 Hz
Answer: a
Explanation: The electronic circuit must have upper frequency response greater than 70 kHz. The preamplifier used in cell counters must be of very low noise preferably having noise voltage less than 2 nA at the required bandwidth of 70 kHz.
7. Which following is not constant for the calibration factor in Coulter counter?
a) Electrolyte resistivity
b) Amplifier gain setting
c) Given aperture size
d) Setting of the threshold level control
Answer: d
Explanation: The calibration factor is constant for given aperture size, electrolyte resistivity and amplifier gain setting. It is used for the conversion of threshold settings to particle volumes or their cube roots to equivalent spherical diameters.
8. What is the diameter of Ragweed pollen?
a) 6 micron
b) 19 micron
c) 14 micron
d) 15 micron
Answer: b
Explanation: Ragweed pollen and polystyrene latex particles seem to meet these requirements. Of the two, polystyrene latex is preferred for calibration purposes . The particles when used seldom plug the orifice. These can be conveniently obtained in the range of 5 million particles per cubic mm.
9. Which of the following is not the provide by multi-parameter coulter counter?
a) Mean cell volume
b) Red cell count
c) Mean cell hemoglobin volume
d) White cell count
Answer: c
Explanation: It provides the universally accepted profile of white cell count, red cell count, mean cell volume, haemotocrit, mean cell haemoglobin concentration, mean cell haemoglobin and haemoglobin. Besides this, the following five parameters are presented: platelet count, red cell distribution width, mean platelet volume, plateletcrit, and platelet distribution width.
10. The diameter of the polystyrene latex particles are ______________________
a) 6 micron
b) 6-20 micron
c) 20 micron
d) 6-14 micron
Answer: d
Explanation: Ragweed pollen and polystyrene latex particles seem to meet these requirements. Of the two, polystyrene latex is preferred for calibration purposes . The particles when used seldom plug the orifice. These can be conveniently obtained in the range of 5 million particles per cubic mm.
11. In multi-parameter coulter counter, what is the time taken by 1 ml of blood to obtain all parameters?
a) 34 sec
b) 45 sec
c) 34-50 sec
d) 34-45 sec
Answer: c
Explanation: All the directly measured parameters are measured in triplicate and the average results are displayed. All the 14 parameters are obtained from 1 ml of whole blood in 34–50 s depending on the number of platelets present.
12. What occurs when two or more particles are present in the sensing zone at the same time?
a) Calibration
b) Troubleshooting
c) Delay in results
d) Coincidence error
Answer: d
Explanation: Coincidence error occurs when two or more particles are present in the sensing zone at the same time. This will result in the instrument detecting fewer particles that are actually present. This will also result in the instrument adding the pulses together to produce a single much longer pulse.
13. Model ____________ automatically compensates for the loss of pulses during coincidence error.
a) 4008 S Coulter counter
b) S plus Coulter counter
c) A plus Coulter counter
d) 4008 A Coulter counter
Answer: b
Explanation: As the instrument detects fewer pulses than are actually present, to render the total count accurate, it is necessary to add on the pulses that have been ‘lost’ due to coincidence. The rate at which this happens has been mathematically determined. Model S-plus Coulter counter automatically compensates for this loss.
14. Under a total count of _______ pulses, primary coincidence is negligible and can be ignored.
a) 5000
b) 1000
c) 8000
d) 10000
Answer: d
Explanation: With some instruments, a correction chart is available to allow the correct number to be determined. Under a total count of 10,000 pulses, primary coincidence is negligible and can be ignored.
15. Coulter counters have a serious drawback linked with the mercury manometer arrangement.
a) True
b) False
Answer: a
Explanation: Coulter counters have a serious drawback linked with the mercury manometer arrangement. The surface of the mercury gets dirty as a consequence of which the contact bordering the volume becomes uncertain, which may make the measured values uncertain.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Transmission of Digital Audio”.
1. The instrument picoscale primarily counting for?
a) MCH
b) MCV
c) PBC
d) PCT
Answer: c
Explanation: Based on the same principle of detecting a change in conductivity in the presence of a cell in the orifice of a measuring tube, there is another cell counting instrument known by the name Picoscale. This instrument does not make use of a mercury manometer for fixing the volume thus eliminating the problems associated with its use. This instrument is primarily meant for counting RBC, WBC and PBC and is manufactured by MEDICOR, Budapest.
2. In picoscale, the number of particles N in a unit volume is determined from the relation if H stands for a factor of dilution, L is scaling factor of the counter, V is measured volume and E is result display on the digital display.
a) N = HL/VE
b) N = H/LVE
c) N = HV/LE
d) N = HLV/E
Answer: d
Explanation: One great advantage of this instrument is that the clogging of the capillary is greatly eliminated by applying a bi-directional flow during the measurement procedure. The number of particles N in a unit volume is determined from the relation,
N = HLV/E
where
H = factor of dilution
I = scaling factor of the counter
V = measured volume
E = result displayed on the digital display.
3. For white cells, the diameter of capillaries are?
a) 58 micrometer
b) 72 micrometer
c) 116 micrometer
d) 102 micrometer
Answer: d
Explanation: The capillary diameter for red cell count is 72 um and the dilution factor is 63,000. For white cells, the diameter is 102 um, and the dilution factor is 630. For platelet count, the diameter of the capillary is 72 um and a dilution of 6300 is used.
4. What is the dilution factor of platelet count?
a) 63000
b) 630
c) 6300
d) 63
Answer: c
Explanation: The capillary diameter for red cell count is 72 um and the dilution factor is 63,000. For white cells, the diameter is 102 um, and the dilution factor is 630. For platelet count, the diameter of the capillary is 72 um and a dilution of 6300 is used.
5. Which of the following is not the error of the electronic counter?
a) Settling error
b) Coincidence error
c) Concentration error
d) Dilution errors
Answer: c
Explanation: There are a number of errors that may occur in the electronic cell counting technique. Briefly, these errors are categorized as follows:
Aperture Clogging, Uncertainty of Discriminator Threshold, Coincidence Error, Settling Error, Statistical Error, Error in Sample Volume, Error due to Temperature Variation, Biological Factors, Dilution Errors, Error due to External Disturbances.
6. In the settling error, if the readings are taken within 4–5 min., the settling error is?
a) Less than 1%
b) Less than 10%
c) More than 1%
d) Equals 1%
Answer: a
Explanation: Settling Error: This error arises due to the settling of the particles in the solution, with the result that the measurements show a decreasing tendency with time. If the readings are taken within 4–5 min., the settling error is less than 1%.
7. To obtain the statistical error, the instrument reading should be multiplied by the scaling factor of the counter.
a) True
b) False
Answer: a
Explanation: Assuming Gaussian distribution, the mean statistical error means that 67% of tests fall into the interval with 33% of the measurements greater than that. To obtain the statistical error, the instrument reading should be multiplied by the scaling factor of the counter. This will yield the value of n.
8. Miller describes a differential white blood cell classifier based upon a ______ approach.
a) A four-colour flying spot-scanner
b) A four-colour flying-scanner
c) A three-colour flying spot-scanner
d) A three-colour flying-scanner
Answer: c
Explanation: Miller describes a differential white blood cell classifier based upon a three-colour flying spot-scanner approach. It utilizes recognition parameters based on the principle of geometrical probability functions, which are generated at high speed in a dedicated computer.
9. The system is built around a Zeiss microscope with two______ eyepieces and a _____ oil immersion objective and with computer controlled focusing.
a) 40 x, 10 x
b) 10 x, 40 x
c) 15 x, 40 x
d) 15 x, 10 x
Answer: c
Explanation: The system uses a conventional microscope with automatic focus and stage motion. The system is built around a Zeiss microscope with two 15 x eyepieces and a 40 x oil immersion objective and with computer controlled focusing. A television monitor displays the data and shows the relative position of the cells in each field.
10. Which of the following is not determined by the cell identification system?
a) Lymphocytes
b) Basophils
c) Monocytes
d) Erythrocytes
Answer: d
Explanation: The system is capable of determining segmented neutrophils, bands, eosinophils, basophils, lymphocytes, and monocytes, as well as abnormal cells such as atypical lymphocytes, blasts, nucleated red cells, and immature granulocytes. In addition, the system carries out the red cell morphology, evaluating size, shape, and colour, counts the reticulocytes, estimates the platelet count and plots a distribution of red cell diameters.
11. There are two types of coils employed in the system, which are ______________
a) Tygon coils and mixing coils
b) Mixing coils and tubing coils
c) Delay coils and tygon coils
d) Mixing coils and delay coils
Answer: d
Explanation: Two types of coils are employed in the system—mixing coils and delay coils. Coils are glass spirals of critical dimensions, in which the mixing liquids are inverted several times, so that complete mixing can result. Mixing coils are used to mix the sample and/or reagents. Delay coils are employed when a specimen must be delayed for the completion of a chemical reaction before reaching the colorimeter.
12. What is used to check the wavelength calibration of a spectrometer?
a) Absorption filter
b) Helium oxide filter
c) Homium oxide filter
d) Helium dioxide filter
Answer: c
Explanation: Wavelength calibration of a spectrophotometer can be checked by using a holmium oxide filter as a wavelength standard. Holmium oxide glass has a number of sharp absorption bands, which occur at precisely known wavelengths in the visible and ultraviolet regions of the spectrum.
13. In diff-3 system, counts and differentiates _______ important categories of red blood cells.
a) Three
b) Seven
c) Four
d) Two
Answer: b
Explanation: The system electronically examines conventional microscope blood smear slides and employs optical pattern recognition techniques to achieve the following:
Counts and differentiates seven important categories of red blood cells ; three based on size, two on colour, one on shape and one covering red cells with nuclei .
14. The system is designed to analyze standard slides at a_______ slides per hour rate.
a) 30 to 35
b) 20 to 30
c) 40 to 50
d) 35 to 40
Answer: d
Explanation: The system is designed to analyze standard slides at a 35 to 40 slides per hour rate. The actual analysis task takes only 90 s. In fact, the system largely duplicates mechanically and opto-electronically, the manual procedures followed while examining blood smears with a microscope.
15. What enables the system to transfer cell pattern recognition information into differential results in an image processor?
a) A flying spot-scanner
b) A three-colour flying spot-scanner
c) Golay logic processor
d) Golay linear processor
Answer: c
Explanation: Image Processor: The system uses two computers. The second computer is a special purpose pattern recognition computer, the Golay Logic Processor , which enables the system to transform cell pattern recognition information into differential results. Golay logic enables the system to ‘see’ a cell in much the same way as a technologist does.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Cyber Medicine”.
1. In which type of electromagnetic flowmeter, the probe magnet is energized with sine wave?
a) Sine wave electromagnetic flowmeter
b) Square wave electromagnetic flowmeter
c) Sawtooth wave electromagnetic flowmeter
d) Impulse wave electromagnetic flowmeter
Answer: a
Explanation: In a sine wave flowmeter, the probe magnet is energized with a sine wave and consequently the induced voltage will also be sinusoidal in nature. The major problem encountered with the sinusoidal type of magnetic field is that the blood vessel and the fluid contained in it act as the secondary coil of a transformer when the probe magnet is excited.
2. In which type of electromagnetic blood flowmeter, the energizing voltage is given to magnet is a square wave?
a) Sine wave electromagnetic flowmeter
b) Square wave electromagnetic flowmeter
c) Sawtooth wave electromagnetic flowmeter
d) Impulse wave electromagnetic flowmeter
Answer: b
Explanation: This differs from a sine wave flowmeter in that the energizing voltage given to the magnet is a square wave and therefore, the induced voltage is also a square wave. The square wave flowmeter has less stringent requirements of phase stability than the sine wave type as it can suppress the quadrature voltages relatively easily.
3. The preamplifier used in square wave blood flowmeter has a CMRR of _______ dB.
a) 96
b) 100
c) 106
d) 110
Answer: c
Explanation: The preamplifier used by Goodman ) has a CMRR of 106 dB with a common mode input impedance of 150 MW. The preamplifier gain is of the order of 1000. The preamplifier also must incorporate the facility for ‘probe balance’ by which signals in phase with the magnet current can be selected to balance background voltages in phase with flow voltages.
4. What is the common mode input impedance of preamplifier used in square wave blood flowmeter?
a) 110 MW
b) 130 MW
c) 150 MW
d) 180 MW
Answer: c
Explanation: The preamplifier used by Goodman ) has a CMRR of 106 dB with a common mode input impedance of 150 MW. The preamplifier gain is of the order of 1000. The preamplifier also must incorporate the facility for ‘probe balance’ by which signals in phase with the magnet current can be selected to balance background voltages in phase with flow voltages. A calibrating signal of 30 mV amplitude can be connected to the preamplifier with an input selector switch.
5. A calibrating signal of _____ mV amplitude can be connected to preamplifier with an input selector switch.
a) 10
b) 20
c) 30
d) 40
Answer: c
Explanation: The preamplifier used by Goodman ) has a CMRR of 106 dB with a common mode input impedance of 150 MW. The preamplifier gain is of the order of 1000. The preamplifier also must incorporate the facility for ‘probe balance’ by which signals in phase with the magnet current can be selected to balance background voltages in phase with flow voltages. A calibrating signal of 30 mV amplitude can be connected to the preamplifier with an input selector switch.
6. What is used to recover the signal, which is analogue of the flow rate being measured?
a) Low-pass filter
b) Phase sensitive detector
c) Gating Circuit
d) Bandpass filter
Answer: b
Explanation: A phase sensitive detector is used to recover the signal, which is an analogue of the flow rate being measured. This type of demodulator not only offers maximum signal-to-noise ratio but also helps in the rejection of interfering voltages at frequencies well below the carrier frequency.
7. The major problem encountered with the sinusoidal type of magnetic field is that the blood vessel and the fluid contained in it act as the primary coil of a transformer when the probe magnet is excited.
a) True
b) False
Answer: b
Explanation: False, the major problem encountered with the sinusoidal type of magnetic field is that the blood vessel and the fluid contained in it act as the secondary coil of a transformer when the probe magnet is excited. As a result, in addition to the induced flow voltage, there is an induced artefact voltage generally referred to as ‘transformer voltage’.
8. _______ instruments are now available for the measurement of blood velocity, volume flow, flow direction, flow profile and to visualize the internal lumen of blood vessel.
a) Transit-time
b) Doppler-shift
c) Square wave
d) Sine wave
Answer: b
Explanation: For routine clinical measurements, the transcutaneous Doppler instrument has, by far, superseded the transit-time type. Therefore, most of the recent efforts have been concentrated on the development of Doppler-shift instruments, which are now available for the measurement of blood velocity, volume flow, flow direction, flow profile and to visualize the internal lumen of a blood vessel.
9. Which of the following is a non-invasive technique to measure blood velocity in a particular vessel from surface of the body?
a) Electromagnetic
b) Ultrasonic
c) NMR
d) Laser Doppler
Answer: b
Explanation: Ultrasonic is a non-invasive technique to measure blood velocity in a particular vessel from the surface of the body. It is based on the analysis of echo signals from the erythrocytes in the vascular structures. Because of the Doppler effect, the frequency of these echo signals changes relative to the frequency which the probe transmits.
10. Which of the following is a non invasive method for measurement of peripheral blood flow or blood flow in various organs?
a) Electromagnetic
b) Ultrasonic
c) NMR
d) Laser Doppler
Answer: c
Explanation: Nuclear magnetic resonance principle offers yet another non-invasive method for the measurement of peripheral blood flow or blood flow in various organs. The method pertains to a quantum mechanical phenomenon related to the magnetic energy levels of the nucleus of some elements and their isotopes.
11. The Angular frequency of precession is given by W=2pv=rBo,where Bo is _______
a) ratio of magnetic moment to angular momentum
b) density of steady magnetic field
c) frequency of radiation
d) length of coil
Answer: b
Explanation: The angular frequency of this precession is given by:
W = 2p v = r Bo
Where r is the ratio of the magnetic moment to the angular momentum and Bo is the density of the steady magnetic field and v is the frequency of radiation.
12. For blood flow measurement work, the behavior of the two hydrogen atoms of water is studied.
a) True
b) False
Answer: a
Explanation: True, for blood flow measurement work, behaviour of the two hydrogen atoms of water is studied, since blood is approximately 83% water. Due to the magnetic moment of the hydrogen atom, the nucleus behaves as a microminiature magnet which can be affected by externally applied magnetic fields.
13. The Angular frequency of precession is given by W=2pv=rBo, where r is ____________
a) ratio of magnetic moment to angular momentum
b) density of steady magnetic field
c) frequency of radiation
d) length of coil
Answer: a
Explanation: The angular frequency of this precession is given by:
W = 2p v = r Bo
Where r is the ratio of the magnetic moment to the angular momentum and Bo is the density of the steady magnetic field and v is the frequency of radiation.
14. The Angular frequency of precession is given by W=2pv=rBo, where v is _____________
a) ratio of magnetic moment to angular momentum
b) density of steady magnetic field
c) frequency of radiation
d) length of coil
Answer: c
Explanation: The angular frequency of this precession is given by:
W = 2p v = r Bo
Where r is the ratio of the magnetic moment to the angular momentum and Bo is the density of the steady magnetic field and v is the frequency of radiation.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Application of Telemedicine”.
1. Which of the following physiological parameter is most difficult to measure accurately?
a) Blood pressure
b) Blood Flow
c) Blood Volume
d) Skin color
Answer: b
Explanation: Blood flow is one of the most important physiological parameters and also one of the most difficult to measure accurately. This is because instruments for measuring the flow through blood vessels within the body have to meet certain stringent specifications; e.g. sensitivity and stability requirements depend upon the magnitude of flow, location and the diameter of the individual vessels.
2. Which of the following instrument is most commonly used for measurement of blood flow?
a) NMR Blood Flowmeter
b) Ultrasonic Blood Flowmeter
c) Electromagnetic Blood Flowmeter
d) Laser Doppler Blood Flowmeter
Answer: c
Explanation: The most commonly used instrument for the measurement of blood flow is of the electromagnetic type. With this type of instrument, blood flow can be measured in intact blood vessels without cannulation and under conditions which would otherwise be impossible. However, this method requires that the blood vessel be exposed so that the flow head or the measuring probe can be put across it.
3. Magnitude of voltage picked up is denoted as e = CHVd, where H is ___________
a) velocity of blood flow
b) strength of magnetic field
c) diameter of blood vessel
d) constant of proportionality
Answer: b
Explanation: The magnitude of the voltage picked up is directly proportional to the strength of the magnetic field, the diameter of the blood vessel and the velocity of blood flow, i.e. e = CHVd, where e = induced voltage, H = strength of the magnetic field, V = velocity of blood flow,d = diameter of the blood vessel and C = constant of proportionality.
4. Magnitude of voltage picked up is denoted as e = CHVd, where C is __________
a) velocity of blood flow
b) strength of magnetic field
c) diameter of blood vessel
d) constant of proportionality
Answer: c
Explanation: The magnitude of the voltage picked up is directly proportional to the strength of the magnetic field, the diameter of the blood vessel and the velocity of blood flow, i.e. e = CHVd, where e = induced voltage, H = strength of the magnetic field, V = velocity of blood flow, d = diameter of the blood vessel and C = constant of proportionality.
5. The induced emf is picked by point electrodes made from ______ in electromagnetic blood flowmeter.
a) copper
b) graphite
c) platinium
d) copper tungsten
Answer: c
Explanation: In actual practice, the electromagnetic flowmeter transducer is a tube of non-magnetic material to ensure that the magnetic flux does not bypass the flowing liquid and go into the walls of the tube. The tube is made of a conducting material and generally has an insulating lining to prevent short circuiting of the induced emf. The induced emf is picked up by point electrodes made from stainless steel or platinum.
6. What is the external diameter of flow heads?
a) 0.5 mm
b) 1 mm
c) 1.5 mm
d) 2 mm
Answer: b
Explanation: The flow head contains a slot through which the intact blood vessel can be inserted to make a snug fit. Several probes of different sizes must therefore accompany the flowmeter to match the full range of sizes of the blood vessels which have various diameters. It is naturally more difficult to construct flow heads suitable for use with very small blood vessels. However, flow heads having as small as 1 mm external diameter have been reported in the literature.
7. The operating principle underlying all electromagnetic type flowmeters is based upon Kirchoff’s law.
a) True
b) False
Answer: b
Explanation: False, The operating principle underlying all electromagnetic type flowmeters is based upon Faraday’s law of electromagnetic induction which states that when a conductor is moved at right angles through a magnetic field in a direction at right angles both to the magnetic field and its length, an emf is induced in the conductor. In the flowmeter, an electromagnetic assembly provides the magnetic field placed at right angles to the blood vessel in which the flow is to be measured.
8. The average flow velocity appears to be _______ cm/s in arteries.
a) 5 to 10
b) 10 to 12
c) 12 to 18
d) 20 to 25
Answer: d
Explanation: The flow-induced voltage of an electromagnetic flowmeter is, within certain limitations, proportional to the velocity of the flow. This velocity is the average across the flow stream with an axis symmetric velocity profile. The average flow velocity appears to be 20 to 25 cm/s in arteries and 10 to 12 cm/s in veins.
9. What is the average flow velocity in veins?
a) 5 to 10 cm/s
b) 10 to 12 cm/s
c) 12 to 18 cm/s
d) 20 to 25 cm/s
Answer: b
Explanation: The flow-induced voltage of an electromagnetic flowmeter is, within certain limitations, proportional to the velocity of the flow. This velocity is the average across the flow stream with an axis symmetric velocity profile. The average flow velocity appears to be 20 to 25 cm/s in arteries and 10 to 12 cm/s in veins.
10. What is velocity for the cardiovascular system taken for designing the probe?
a) 5 cm/s
b) 10 cm/s
c) 15 cm/s
d) 20 cm/s
Answer: c
Explanation: For designing the probe, velocity for the cardiovascular system is taken as 15 cm/s. For non-cannulated probes, a uniform magnetic field over the measuring area is so selected that it has a convenient shape and the smallest size .
11. Iron cored electromagnets are used in probes having a diameter between ______
a) 0.1 to 1 mm
b) 1 to 8.2 mm
c) 8.2 to 10 mm
d) 10 to 15 mm
Answer: b
Explanation: Iron cored electromagnets are used in probes having a diameter between 1 to 8.2 mm, and air cored electromagnets are used in diameters above 8.2 mm. Cannulated probes for extracorporeal use can have greater field strengths and magnet size as the constraint of small size is no longer present.
12. To protect probe from chemical attack, it must be encapsulated in silicon rubber.
a) True
b) False
Answer: a
Explanation: True, To protect the probe from chemical attack, it must be encapsulated in a biologically inert material having a high electrical and chemical resistance, e.g. silicone rubber. The probes can generally be sterilized by chemical means. Probe calibration is carried out in 0.9% saline during manufacture and each probe is given a calibration factor that is engraved on the connector.
13. The cable from the transducer to an instrument is sleeved with medical grade silicon rubber.
a) True
b) False
Answer: a
Explanation: True, the cable from the transducer to the instrument should comprise of a teflon insulated wire completely shielded with a tinned copper braid. The entire cable is sleeved with medical grade silicone rubber tubing and impregnated with silicone rubber to minimize leakage and electrical noise.
14. Air cored electromagnets are used in probes having a diameter _________
a) between 0.5 to 1 mm
b) between 1 to 2 mm
c) below 8.2 mm
d) above 8.2 mm
Answer: d
Explanation: Iron cored electromagnets are used in probes having a diameter between 1 to 8.2 mm, and air cored electromagnets are used in diameters above 8.2 mm. Cannulated probes for extracorporeal use can have greater field strengths and magnet size as the constraint of small size is no longer present.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “PACS ”.
1. Which of the following instrument is used to measure blood flow in the skin?
a) NMR Blood Flowmeter
b) Ultrasonic Blood Flowmeter
c) Electromagnetic Blood Flowmeter
d) Laser Doppler Blood Flowmeter
Answer: d
Explanation: A system utilizing the Doppler-shift of monochromatic laser light to measure blood flow in the skin is described by Watkins and Holloway . When a laser beam is directed towards the tissue under study, absorption and scattering take place. Radiation scattered in movable structures, such as red cells, is shifted in frequency due to the Doppler effect, while radiation scattered in nonmoving soft tissue is unshifted in frequency.
2. What is the effective radiation penetration depth in soft tissue?
a) 1 mm
b) 2 mm
c) 3 mm
d) 4 mm
Answer: a
Explanation: The effective radiation penetration depth is approximately 1 mm in soft tissue and scattering and absorption take place mostly in the papilla region and the underlying corium—two dermal layers containing the capillary network of the skin.
3. What is the power of laser light used in Laser Doppler Blood flowmeter?
a) 2 mW
b) 3 mW
c) 4 mW
d) 5 mW
Answer: d
Explanation: In principle, light from a low power He–Ne laser is coupled into a quartz fibre and transmitted to the skin. The light is reflected from both the non-moving tissues and moving red blood cells . The two beams are received by a plastic fibre and transmitted back to a photo-diode where optical heterodyning takes place.
4. Which laser is used in Laser doppler blood flowmeter?
a) Nd-YAG
b) Argon
c) He-Ne
d) CO 2
Answer: c
Explanation: In principle, light from a low power He–Ne laser is coupled into a quartz fibre and transmitted to the skin. The light is reflected from both the non-moving tissues and moving red blood cells . The two beams are received by a plastic fibre and transmitted back to a photo-diode where optical heterodyning takes place.
5. What is used to receive beams of light?
a) Plastic fibre
b) Photo diode
c) He-Ne Laser
d) CO 2 Laser
Answer: a
Explanation: In principle, light from a low power He–Ne laser is coupled into a quartz fibre and transmitted to the skin. The light is reflected from both the non-moving tissues and moving red blood cells . The two beams are received by a plastic fibre and transmitted back to a photo-diode where optical heterodyning takes place.
6. Where optical heterodyning takes place in Laser Doppler Blood Flowmeter?
a) Plastic fibre
b) Photo diode
c) He-Ne Laser
d) CO 2 Laser
Answer: b
Explanation: In principle, light from a low power He–Ne laser is coupled into a quartz fibre and transmitted to the skin. The light is reflected from both the non-moving tissues and moving red blood cells . The two beams are received by a plastic fibre and transmitted back to a photo-diode where optical heterodyning takes place.
7. The laser output is coupled into the fibre using a converging lens.
a) True
b) False
Answer: a
Explanation: True, The He–Ne laser operating at 632.8 nm wavelength is used. The laser output is coupled into the fibre using a converging lens, which results in an increased power density at the skin surface and thus enables the detection of flow in the more deeply seated veins and arteries.
8. What is the operating wavelength of He-Ne laser?
a) 610.8 nm
b) 622.6 nm
c) 632.8 nm
d) 650 nm
Answer: c
Explanation: The He–Ne laser operating at 632.8 nm wavelength is used. The laser output is coupled into the fibre using a converging lens, which results in an increased power density at the skin surface and thus enables the detection of flow in the more deeply seated veins and arteries.
9. What functions as a square law device and gives out current?
a) Plastic fibre
b) Photodetector
c) He-Ne Laser
d) CO 2 Laser
Answer: b
Explanation: The photodetector functions as a square law device and gives out current, which is proportional to the intensity of the incident light and, therefore, to the frequency of beating of the shifted and unshifted signals. The light falling on the photodetector is an optically mixed signal involving a Doppler-shifted signal back scattered from the moving red blood cells with the ‘reference’ signal reflected from the non-moving skin surface.
10. Which technique seems to offer several advantages like light reproducibility and sensitivity?
a) NMR
b) Laser Doppler
c) Electromagnetic
d) Ultrasonic
Answer: b
Explanation: Laser Doppler flowmetry is a non-invasive technique and seems to offer several advantages like light reproducibility and sensitivity. However, its disadvantages like poor selectivity, baseline instability and restriction in a site of measurement are still limiting factors in its successful clinical utilization.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Pulmonary Function Measurement”.
1. Most of the ________ processes result in chemical changes in the internal environment of the human body.
a) micromorphological
b) pathological
c) immunological
d) neuropschycological
Answer: b
Explanation: Most of the pathological processes result in chemical changes in the internal environment of the human body. These changes can generally be detected by the analysis of various samples taken from the body. The analysis not only helps in the diagnosis of various ailments but also in determining the progress of treatment and for making a prognosis.
2. Which section deals with the analysis of blood, urine, CSF and other fluids to determine the quantity of various important substance?
a) Chemistry
b) Haemotology
c) Microbiology
d) Blood Bank
Answer: a
Explanation: Chemistry: section deals with the analysis of blood, urine, cerebrospinal fluid and other fluids to determine the quantity of various important substances they contain. Most of the electronic instruments in the clinical laboratory are available in this section. Haematology: section deals with the determinations of the number and characteristics of the constituents of the blood, particularly the blood cells. Microbiology: section in which studies are performed on various body tissues and fluids to determine the presence of pathological micro-organisms.
3. Which section deals with the determinations of the number and characteristics of the constituents of the blood, particularly the blood cells?
a) Chemistry
b) Haemotology
c) Microbiology
d) Blood Bank
Answer: b
Explanation: Chemistry: section deals with the analysis of blood, urine, cerebrospinal fluid and other fluids to determine the quantity of various important substances they contain. Most of the electronic instruments in the clinical laboratory are available in this section. Haematology: section deals with the determinations of the number and characteristics of the constituents of the blood, particularly the blood cells. Microbiology: section in which studies are performed on various body tissues and fluids to determine the presence of pathological micro-organisms.
4. In which section studies are performed on various body tissues and fluids to determine the presence of pathological micro-organisms?
a) Chemistry
b) Haemotology
c) Microbiology
d) Blood Bank
Answer: c
Explanation: Chemistry: section deals with the analysis of blood, urine, cerebrospinal fluid and other fluids to determine the quantity of various important substances they contain. Most of the electronic instruments in the clinical laboratory are available in this section. Haematology: section deals with the determinations of the number and characteristics of the constituents of the blood, particularly the blood cells. Microbiology: section in which studies are performed on various body tissues and fluids to determine the presence of pathological micro-organisms.
5. Which of the following is the most common substance for analysis from the body?
a) CSF
b) Urine
c) Blood
d) Glucose
Answer: c
Explanation: The most common substance for analysis from the body is blood. This is because the blood carries out the most important function of transportation and many pathological processes manifest themselves as demonstrable changes in the blood.
6. _____ accounts for 60% of blood volume.
a) Blood cells
b) Water
c) Carbon Dioxide
d) Blood plasma
Answer: d
Explanation: The liquid part of the blood—the blood plasma, and the formed elements—the blood cells are analyzed during a chemical examination. The blood plasma accounts for about 60% of the blood volume and the blood cells occupy the other 40%. The plasma is obtained by centrifuging a blood sample.
7. The blood plasma gets separated by centrifugation.
a) True
b) False
Answer: a
Explanation: True, During centrifugation, the heavy blood cells get packed at the bottom of the centrifuge tube and the plasma can thus be separated. The plasma is a viscous, light yellow liquid, i.e. almost clear in the fasting stage.
8. _____ accounts for 40% of the blood volume.
a) Blood cells
b) Water
c) Carbon Dioxide
d) Blood plasma
Answer: a
Explanation: The liquid part of the blood—the blood plasma, and the formed elements—the blood cells are analyzed during a chemical examination. The blood plasma accounts for about 60% of the blood volume and the blood cells occupy the other 40%. The plasma is obtained by centrifuging a blood sample.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Spirometry”.
1. What is the pH range of extracellular fluid?
a) 7.25 to 730
b) 7.30 to 7.35
c) 7.35 to 7.45
d) 7.50 to 7.60
Answer: c
Explanation: The normal pH of the extracellular fluid lies in the range of 7.35 to 7.45, indicating that the body fluid is slightly alkaline. When the pH exceeds 7.45, the body is considered to be in a state of alkalosis. A body pH below 7.35 indicates acidosis. Both acidosis or alkalosis are disease conditions widely encountered in clinical medicine.
2. What is the pH of Arterial blood?
a) 7.25
b) 7.30
c) 7.35
d) 7.40
Answer: d
Explanation: Arterial blood has a pH of approximately 7.40. As venous blood acquires carbon dioxide, forms carbonic acid and hydrogen ions, the venous blood pH falls to approximately 7.36. This pH drop of 0.04 units occurs when the CO 2 enters the tissue capillaries. When CO 2 diffuses from the pulmonary capillaries into the alveoli, the blood pH rises 0.04 units to bring the normal arterial value of 7.40.
3. What is the pH range of intracellular fluid?
a) 7.0 to 7.2
b) 7.3 to 7.35
c) 7.35 to 7.45
d) 7.50 to 7.60
Answer: a
Explanation: When CO 2 diffuses from the pulmonary capillaries into the alveoli, the blood pH rises 0.04 units to bring the normal arterial value of 7.40. It is quite difficult to measure the pH of fluids inside the tissue cells, but from estimates based on CO 2 and ion concentration, intracellular pH probably ranges from 7.0 to 7.2.
4. What is E0 in given equation?
biomedical-instrumentation-questions-answers-spirometry-q4
a) induced emf
b) Faradays Constant
c) pH value deviation from 7
d) standard potential
Answer: d
Explanation: The potential of the glass electrode may be written by means of the Nernst
equation:
biomedical-instrumentation-questions-answers-spirometry-q4
where, Eo = standard potential R = gas constant T = absolute temperature F = Faraday constant DpH = pH value deviation from 7.The above relation shows that the emf developed in the electro-chemical pH cell is a linear function of DpH.
5. What is E in given equation?
biomedical-instrumentation-questions-answers-spirometry-q4
a) induced emf
b) Faradays Constant
c) pH value deviation from 7
d) standard potential
Answer: a
Explanation: The potential of the glass electrode may be written by means of the Nernst
equation:
biomedical-instrumentation-questions-answers-spirometry-q4
where, Eo = standard potential R = gas constant T = absolute temperature F = Faraday constant DpH = pH value deviation from 7. The above relation shows that the emf developed in the electro-chemical pH cell is a linear function of DpH.
6. With a 1°C change in temperature, the emf changes by ________ mV.
a) 0.1
b) 0.2
c) 0.5
d) 0.8
Answer: b
Explanation: The factor –2.3036 RTF is called the slope factor and is clearly dependent upon the solution temperature. With a 1°C change in temperature, the emf changes by 0.2 mV. It is also obvious that the measurement of pH is essentially a measurement of millivolt signals by special methods.
7. The venous blood pH falls to approximately 7.36.
a) True
b) False
Answer: a
Explanation: True, as venous blood acquires carbon dioxide, forms carbonic acid and hydrogen ions, the venous blood pH falls to approximately 7.36. This pH drop of 0.04 units occurs when the CO2 enters the tissue capillaries. When CO 2 diffuses from the pulmonary capillaries into the alveoli, the blood pH rises 0.04 units to bring the normal arterial value of 7.40.
8. How much amount of capillary blood is required by a micro-electrode for determination of pH?
a) 5 to 10 ml
b) 10 to 12 ml
c) 12 to 18 ml
d) 20 to 25 ml
Answer: d
Explanation: A micro-electrode for clinical applications requires only 20–25 ml of capillary blood for the determination of pH. The electrode is enclosed in a water jacket with circulating water at a constant temperature of 38°C. The water contains 1% NACI for shielding against static interference.
9. The micro-electrode is enclosed in a water jacket with circulating water at a constant temperature of ___________ °C for determination of pH.
a) 25
b) 34
c) 38
d) 42
Answer: c
Explanation: A micro-electrode for clinical applications requires only 20–25 ml of capillary blood for the determination of pH. The electrode is enclosed in a water jacket with circulating water at a constant temperature of 38°C. The water contains 1% NACI for shielding against static interference.
10. Internal Reference electrode is of _______
a) gold
b) silver
c) platinum
d) graphite
Answer: b
Explanation: The internal reference electrode is silver/silver chloride and the calomel reference electrode is connected to a small pool of saturated KCI, through a porous pin. Accuracy of 0.001 pH can be obtained with this electrode against a constant buffer.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Pneumotachometers”.
1. Which of the following component is used for selection of narrow band in spectrophotometer?
a) Optical system
b) Radiating source
c) Filtering Arrangement
d) Detecting system
Answer: c
Explanation: A source of radiant energy, which may he a tungsten lamp, a xenon-mercury arc, hydrogen or deuterium discharge lamp, etc. Filtering arrangement for the selection of a narrow band of radiant energy. It could be a single wavelength absorption filter, an interference filter, a prism or a diffraction grating.
2. Which of the following component is used to produce a parallel beam of filtered light for passage through an absorption cell in spectrophotometer?
a) Optical system
b) Radiating source
c) Filtering Arrangement
d) Detecting system
Answer: a
Explanation: An optical system for producing a parallel beam of filtered light for passage through an absorption cell . The system may include lenses, mirrors, slits, diaphragm, etc. A detecting system for the measurement of unabsorbed radiant energy, which could be the human eye, a barrier-layer cell, phototube or photo-multiplier tube.
3. What is used for the measurement of unabsorbed radiant energy in spectrophotometer?
a) Optical system
b) Radiating source
c) Filtering Arrangement
d) Detecting system
Answer: d
Explanation: An optical system for producing a parallel beam of filtered light for passage through an absorption cell . The system may include lenses, mirrors, slits, diaphragm, etc. A detecting system for the measurement of unabsorbed radiant energy, which could be the human eye, a barrier-layer cell, phototube or photo-multiplier tube.
4. Which of the following method uses only the human eye as a measuring instrument?
a) Telemetric
b) Colorimetric
c) Polarimetric
d) Calorimetric
Answer: b
Explanation: A colorimetric method in its simplest form uses only the human eye as a measuring instrument. This involves the comparison by visual means of the colour of an unknown solution, with the colour produced by a single standard or a series of standards. The comparison is made by obtaining a match between the colour of the unknown and that of a particular standard by comparison with a series of standards prepared in a similar manner, as the unknown.
5. Which of the following instrument isolates monochromatic radiation in a more efficient and versatile manner than colour filters in filter photometers?
a) Calorimeter
b) Colorimeter
c) Spectrophotometer
d) Polarimeter
Answer: c
Explanation: A spectrophotometer is an instrument which isolates monochromatic radiation in a more efficient and versatile manner than colour filters used in filter photometers. In these instruments, light from the source is made into a parallel beam and passed to a prism or diffraction grating, where light of different wavelengths is dispersed at different angles.
6. Which of the following detector is required in spectrophotometer?
a) Phototransistor
b) Photodiode
c) LDR
d) Photomultiplier
Answer: d
Explanation: The amount of light reaching the detector of a spectrophotometer is generally much smaller than that available for a colorimeter, because of the small spectral bandwidth. Therefore, a more sensitive detector is required. A photomultiplier or vacuum photocell is generally employed.
7. Spectrophotometer generally employs a 6V Xenon Arc Lamp, which emits radiation in a wavelength region of visible light.
a) True
b) False
Answer: b
Explanation: False, Spectrophotometers generally employ a 6 V tungsten lamp, which emits radiation in the wavelength region of visible light. Typically, it is 32 candle power. These lamps should preferably be operated at a potential of say 5.4 V when its useful life is estimated at 1200 h.
8. The recorder used with spectrophotometers has _____ wavelength scanning speeds.
a) one
b) two
c) three
d) four
Answer: d
Explanation: The recorder used with spectrophotometers have four wavelength scanning speeds and seven chart speeds . It has a sensitivity of 100 mV absorbance units or 100 mV/100% T.
9. The recorder used in spectrophotometers has ______ chart speeds.
a) three
b) five
c) seven
d) nine
Answer: c
Explanation: The recorder used with spectrophotometers have four wavelength scanning speeds and seven chart speeds . It has a sensitivity of 100 mV absorbance units or 100 mV/100% T.
10. Which component is used in spectrophotometer for control, Signal Processing, and Communication functions?
a) Detector
b) Microprocessor
c) Deuterium Lamp
d) Tungsten Lamp
Answer: b
Explanation: A microprocessor, in a spectrophotometer, could be used for the following functions: Control functions: Wavelength scanning, automatic light source selection, control of slit width, detector sensitivity, etc. Signal processing functions: Baseline correction, signal smoothing, calculation of % T, absorbance and concentration, derivative, etc. Communication functions: Keyboard entry, menu-driven operations, data presentation, warning display, communication with external systems, etc.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Measurement of Volume”.
1. Which of the following parameter would provide information about the nature of the material?
a) Number of photons
b) Frequencies of photons
c) Number of atom
d) Molecules of atom
Answer: b
Explanation: The study of the frequencies of the photons which are absorbed would thus provide information about the nature of the material. Also, the number of photons absorbed may provide information about the number of atoms or molecules of the material present in a particular state. It thus provides us with a method to have a qualitative and quantitative analysis of a substance.
2. Molecules posses _____________ types of internal energy.
a) one
b) two
c) three
d) four
Answer: c
Explanation: Molecules possess three types of internal energy—electronic, vibrational and rotational. When a molecule absorbs radiant energy, it can increase its internal energy in a variety of ways. The various molecular energy states are quantized and the amount of energy necessary to cause any change in any one of the above energy states would generally correspond to specific regions of the electromagnetic spectrum.
3. Electronic transitions corresponds to ___________ region.
a) near Infrared
b) infrared
c) gar Infrared
d) visible
Answer: d
Explanation: Electronic transitions correspond to the ultraviolet and visible regions, vibrational transitions to the near infrared and infrared regions and rotational transitions to the infrared and far-infrared regions. The method based on the absorption of radiation of a substance is known as Absorption Spectroscopy.
4. Vibrational transition corresponds to ____ region.
a) ultarviolet
b) infrared
c) far Infrared
d) visible
Answer: b
Explanation: Electronic transitions correspond to the ultraviolet and visible regions, vibrational transitions to the near infrared and infrared regions and rotational transitions to the infrared and far-infrared regions. The method based on the absorption of radiation of a substance is known as Absorption Spectroscopy.
5. Which of the following transition corresponds to the far-infrared region?
a) Electronic
b) Vibrational
c) Rotational
d) Mechanical
Answer: c
Explanation: Electronic transitions correspond to the ultraviolet and visible regions, vibrational transitions to the near infrared and infrared regions and rotational transitions to the infrared and far-infrared regions. The method based on the absorption of radiation of a substance is known as Absorption Spectroscopy.
6. Which method is based on the absorption of radiation of a substance?
a) Absorption Endoscopy
b) Absorption Spectroscopy
c) Absorption Arthroscopy
d) Absorption Colonoscopy
Answer: b
Explanation: Electronic transitions correspond to the ultraviolet and visible regions, vibrational transitions to the near infrared and infrared regions and rotational transitions to the infrared and far-infrared regions. The method based on the absorption of radiation of a substance is known as Absorption Spectroscopy.
7. Spectrometric methods are speedy and sensitive.
a) True
b) False
Answer: a
Explanation: True, the main advantages of spectrometric methods are speed, sensitivity to very small amounts of change and a relatively simple operational methodology. The time required for the actual measurement is very short and most of the analysis time, in fact, goes into the preparation of the samples.
8. Which of the following component is used to provide a sufficient intensity of light which is suitable for making measurement in Spectrophotometer?
a) Optical system
b) Radiating source
c) Filtering Arrangement
d) Detecting system
Answer: b
Explanation: The function of the radiation source is to provide a sufficient intensity of light which is suitable for making a measurement. The most common and convenient source of light is the tungsten lamp. This lamp consists of a tungsten filament enclosed in a glass envelope. It is cheap, intense and reliable. A major portion of the energy emitted by a tungsten lamp is in the visible region and only about 15 to 20% is in the infrared region.
9. Which of the following radiating source is most common and convenient for use in spectrophotometer?
a) Carbon Arc Lamp
b) Mercury-vapor Lamp
c) Tungsten Lamp
d) Xenon Arc Lamp
Answer: c
Explanation: The function of the radiation source is to provide a sufficient intensity of light which is suitable for making a measurement. The most common and convenient source of light is the tungsten lamp. This lamp consists of a tungsten filament enclosed in a glass envelope. It is cheap, intense and reliable. A major portion of the energy emitted by a tungsten lamp is in the visible region and only about 15 to 20% is in the infrared region.
10. Deuterium arc lamp provides emission of high intensity and adequate continuity in the _____ nm range.
a) 0-90
b) 90-180
c) 190-380
d) 390-650
Answer: c
Explanation: Deuterium arc lamp provides emission of high intensity and adequate continuity in the 190–380 nm range. A quartz or silica envelope is necessary not only to provide a heat shield but also to transmit the shorter wavelengths of the ultraviolet radiation. The limiting factor is normally the lower limit of atmospheric transmission at about 190 nm.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Pulmonary Function Analysers”.
1. The instrument which carries out a continuous and simultaneous recording of the instantaneous foetal heart rate and labour activity is called _________
a) Ergometer
b) Cardiotocograph
c) Cardiotocometer
d) Cardiotonometer
Answer: b
Explanation: Cardiotocography is a technical means of recording the fetal heartbeat and the uterine contractions during pregnancy. The machine used to perform the monitoring is called a cardiotocograph, more commonly known as an electronic fetal monitor.
2. ________ is not an indirect method of foetal heart rate in cordiotocography monitoring.
a) Foetal ECG with scalp electrode
b) Foetal phonocardiogram
c) Abdominal foetal electrocardiogram
d) Ultrasound techniques
Answer: a
Explanation: The following methods are commonly employed in most of the cardiotocographic monitoring during labour: I) Indirect method: Abdominal foetal electrocardiogram, foetal phonocardiogram, ultrasound techniques II) Direct method: Foetal ECG with scalp electrode .
3. _______ is a direct technique of uterine contraction in cardiotocographic monitoring.
a) Tocodynamometry
b) Intrauterine pressure measurement
c) Phonocardiometry
d) Ultrasound technique
Answer: b
Explanation: The following techniques are commonly used in uterine contraction in most of the cardiotocographic monitoring: I) Indirect method: Tocodynamometry II) Direct method: Intrauterine pressure measurement .
4. The galvanometer, which needs a frequency response of only 3 MHz, is positioned by a servo motor through a silent step-down belt drive.
a) True
b) False
Answer: b
Explanation: The galvanometer, which needs a frequency response of only 3 Hz, is positioned by a servo motor through a silent step-down belt drive. Recording sensitivity is 20 bpm/cm giving a basic resolution of 1 bpm for seeing small changes in the heart rate.
5. The intrauterine pressure can reach values of 150 mmHg or more during the expulsion period.
a) True
b) False
Answer: a
Explanation: True, because during labour, the uterus muscle starts contraction of increasing intensity in a bid to expel out the child. The intrauterine pressure can reach values of 150 mmHg or more during the expulsion period. However, a normal patient in spontaneous active labour will demonstrate uterine contractions occurring at intervals of three to five minutes, with a duration of 30 to 70 s and a peak intensity of 50 to 75 mmHg.
6. Which transducer cannot be used in the same place as the foetal heart rate detector, thus the patient must have two transducers on her abdomen?
a) Cardiotocometer
b) Toco-tonometer
c) LVDT
d) IUPC
Answer: b
Explanation: The toco-transducers are location sensitive. They should be placed over the fundus where there is maximum motion with the contractions. The toco-tonometer transducer cannot be used in the same place as the foetal heart rate detector, thus the patient must have two transducers on her abdomen.
7. Which is the most important of all instrumental methods of analysis in clinical chemistry?
a) Colorimetry
b) Spectrophotometry
c) Pneumotachometry
d) Oximetry
Answer: b
Explanation: Spectrophotometry is the most important of all the instrumental methods of analysis in clinical chemistry. This method is based on the absorption of electromagnetic radiation in the visible, ultraviolet and infrared ranges.
8. Which method of the following is based on the absorption of electromagnetic radiation in visible, ultraviolet and infrared ranges?
a) Colorimetry
b) Spectrophotometry
c) Pneumotachometry
d) Oximetry
Answer: b
Explanation: Spectrophotometry is the most important of all the instrumental methods of analysis in clinical chemistry. This method is based on the absorption of electromagnetic radiation in the visible, ultraviolet and infrared ranges.
This set of Biomedical Instrumentation Multiple Choice Questions & Answers focuses on “Respiratory Gas Analysers”.
1. The plasma is a viscous, light red liquid, i.e. almost clear in the fasting stage.
a) True
b) False
Answer: b
Explanation: False, because the plasma is obtained by centrifuging a blood sample. During centrifugation, the heavy blood cells get packed at the bottom of the centrifuge tube and the plasma can thus be separated. The plasma is a viscous, light yellow liquid, i.e. almost clear in the fasting stage.
2. __________ method is based on the absorption of electromagnetic radiation in the visible, ultraviolet and infrared ranges.
a) Cardiotocography
b) Ultrasonic therapy
c) Spectrophotometry
d) Diathermy
Answer: c
Explanation: Spectrophotometry is the most important of all the instrumental methods of analysis in clinical chemistry. This method is based on the absorption of electromagnetic radiation in the visible, ultraviolet and infrared ranges.
3. ________ waves have short wave-length.
a) Microwave
b) Radio wave
c) Gamma rays
d) IR waves
Answer: c
Explanation: Electromagnetic spectrum ranges from very short wavelengths to very long wavelengths . The range of wavelength of gamma rays and X-rays is 10-4 to 10 nm. The range of wavelengths of microwaves and radio-waves is 106 to 109 nm.
4. The method based on the absorption of radiation of a substance is known as ________
a) Absorption photometry
b) Spectrophotometry
c) Absorption tocometry
d) Absorption spectrophotoscopy
Answer: d
Explanation: Electronic transitions correspond to the ultraviolet and visible regions, vibrational transitions to the near infrared and infrared regions and rotational transitions to the infrared and far-infrared regions. The method based on the absorption of radiation of a substance is known as Absorption Spectroscopy.
5. The ratio of the radiant power transmitted by a sample to the radiant power incident on the sample is known as ________
a) Absorbance
b) Transmittance
c) Optical density
d) Photometric concentration
Answer: b
Explanation: Let us suppose, Po is the incident radiant energy and P is the energy which is transmitted. The ratio of the radiant power transmitted by a sample to the radiant power incident on the sample is known as the transmittance.
Transmittance = P/Po.
6. If absorbance is plotted graphically against concentration, the graph is _________
a) Parabola
b) Increasing
c) Straight line
d) Decreasing
Answer: c
Explanation: If absorbance is plotted graphically against concentration, a straight line is obtained. A graph derived from the transmittance data will not be a straight line unless transmittance is plotted on the log axis of a semi-log paper.
7. ________________ is not a source of radiant energy.
a) Tungsten-mercury lamp
b) Tungsten lamp
c) Xenon-mercury arc
d) Deuterium discharge lamp
Answer: a
Explanation: Radiant just means energy that can move from one place to another without a medium to carry it. A source of radiant energy, which may be a tungsten lamp, a xenon-mercury arc, hydrogen or deuterium discharge lamp, etc.
This set of Biomedical Instrumentation Questions and Answers for Campus interviews focuses on “Medical Diagnosis with Chemical Tests”.
1. Which of the following is not the electrolyte?
a) Bicarbonate
b) Potassium
c) Magnesium
d) Sodium
Answer: c
Explanation: For instance, the group of important anions and cations of the blood plasma like sodium, potassium, chloride and bicarbonate, which together with serum urea form a related set of tests— performed on patients with electrolyte disturbances.
2. The blood pressure within the glumerular capillaries is _________ of mercury.
a) 80 mm
b) 70-80 mm
c) 90 mm
d) 70-90 mm
Answer: d
Explanation: The renal arteries carry blood at very high pressure from the aorta into the glomerular capillary tuft. The blood pressure within the glomerular capillaries is 70–90 mm of mercury. The blood flow through the capillary tuft is controlled by the state of contraction of the muscle of the arteriole leading to the tuft.
3. In the sampling control, one complete rotation of the plate thus presents _______
a) 35 samples
b) 40 samples
c) 20 samples
d) 30 samples
Answer: b
Explanation: The plate rotates a distance sufficient to allow the tube, when it next moves down, to dip into the next cup. One complete rotation of the plate thus presents 40 samples. As the sample plate completes a cycle, a switch is operated, which stops the rotating action of the plate and the sampling action of the sample probe. The sampling rate can be adjusted to 20, 40 or 60 per hour.
4. In the sampler, the range of the sample size is from _______
a) 0.1 to 8.5 ml
b) 1 to 8.5 ml
c) 0.85 to 0.1 ml
d) 8.5 to 10 ml
Answer: a
Explanation: With this sampler, the sample size may range from 0.1 to 8.5 ml. It utilizes cups of sizes 0.5, 2, 3 and 10 ml. The sample plate is kept covered to prevent evaporation, which may sometimes lead to errors up to 5%. Sampling and washing periods are controlled by a programming cam.
5. Which cams are used in the earlier modules of auto-analyzers to initiate and control sample aspiration and wash cycles?
a) Electrical cams
b) Digital cams
c) Analog cams
d) Mechanical cams
Answer: d
Explanation: Mechanical cams were used in the earlier modules of auto-analyzers to initiate and control sample aspiration and wash cycles. Modern systems use electronic timers to do the same function. These timers provide greater flexibility in the control of the sample-to-wash ratios, which in turn allows flexibility in setting up parameters for analyses.
6. The function of the _________ is to continuously and simultaneously push fluids, air and gases through the analytical chain.
a) sampling unit
b) proportioning pump
c) manifold
d) dialyzer
Answer: b
Explanation: The function of the proportioning pump is to continuously and simultaneously push fluids, air and gases through the analytical chain. In fact, it is the heart of the automatic analysis system.
7. In the proportioning pump, two speed pump has a non-synchronous _____ rpm motor.
a) 10 rpm
b) 30 rpm
c) 45 rpm
d) 15 rpm
Answer: c
Explanation: Proportioning pumps are available either for single-speed or for two-speed operations. The single-speed pump has the capacitor synchronous gear head utilizing 10 rpm output shaft at 50 Hz. The two-speed pump has a non-synchronous 45 rpm motor.
8. ________ is not part of the manifold.
a) Transmission tubing
b) Pump tubes
c) Platter
d) Plastic tubes
Answer: d
Explanation: A manifold mainly consists of a platter, pump tubes, coils, transmission tubing, fittings and connections. A separate manifold is required for each determination and the change can be effected within a few minutes. The pump tubing and the connected coils are placed on a manifold platter, which keeps them in proper order for each test.
