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Multiple choice question for engineering

Set 1

1. On increasing the chloride deposit the Ag-AgCl electrode ______________
a) increases impedance
b) reduces impedance
c) has no effect on impedance
d) cannot be determined

View Answer

Answer: a [Reason:] Studies have shown that impedance of 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

View Answer

Answer: b [Reason:] 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 he 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

View Answer

Answer: d [Reason:] 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. 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

View Answer

Answer: b [Reason:] Association for the Advancement of Medical Instrumentation, USA is an association for propelling the advancement and powerful utilization of restorative innovation established in 1965 by Robert D. Corridor. 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, consistence with these models isn’t really required by administrative associations that review medicinal services offices.

5. Electrocardiography was invented by ___________
a) Willem Einthoven
b) Robert Koch
c) Werner Forssmann
d) Gertrude B.Elion

View Answer

Answer: a [Reason:] Willem Einthoven a Dutch physician and physiologist. He invented the first Electrocardiogram (ECG or ECG) in 1903. He received the Nobel Prize for Medicine in 1924 for it.

6. MRI stands for ____________
a) Mechanical Resonance Imaging
b) Magnetic Resonance Imaging
c) Mutually Related Imaging
d) Magnetic Resultant Imaging

View Answer

Answer: b [Reason:] 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. A MR mirrors the spine using a magnet crossing the body to excite hydrogen atoms.

7. The interior of the neuron is at a potential of about _____mV relative to the exterior.
a) -70
b) +70
c) -170
d) +170

View Answer

Answer: a [Reason:] 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.

8. Tricuspid valve is also called _______________
a) Left Atrio-ventricular valve
b) Right Atrio-ventricular valve
c) Pulmonary valve
d) Cardiac valve

View Answer

Answer: b [Reason:] 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 right atrium.

9. From instruments point of view, heart is a ______ system
a) pneumatic
b) electric
c) electronic
d) hydraulic

View Answer

Answer: d [Reason:] Heart pumps blood. It is analogous to water. Thus heart can be considered as a hydraulic system.

10. The basic functional unit of nervous system is ____________
a) nerves
b) axon
c) neuron
d) dendrite

View Answer

Answer: c [Reason:] The basic functional unit of nervous system is 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.

Set 2

1. Bio potential amplifiers have ____ input terminals
a) 3
b) 4
c) 5
d) 6

View Answer

Answer: a [Reason:] Bio potential have 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

View Answer

Answer: c [Reason:] 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 (Common-mode rejection ratio).

3. CMRR is measured in ____________
a) V/s
b) dB
c) dB/s
d) dB/ms

View Answer

Answer: b [Reason:] 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. 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

View Answer

Answer: b [Reason:] 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. CMRR of the preamplifiers should be as high as possible.
a) True
b) False

View Answer

Answer: a [Reason:] 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.

6. The common mode rejection for most op-amps is typically between _____
a) 10-50dB
b) 20-40dB
c) 60-90dB
d) 100-120dB

View Answer

Answer: c [Reason:] 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.

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

View Answer

Answer: d [Reason:] 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. The output of differential gain is given by _________
a) (difference of the two input voltage)*(feedback resistance/input resistance)
b) (sum of the two input voltage)*(feedback resistance/input resistance)
c) (difference of the two input voltage)*(input resistance/feedback resistance)
d) (sum of the two input voltage)*(input resistance/feedback resistance)

View Answer

Answer: a [Reason:] The output of differential gain is given by (difference of the two input voltage)*(feedback resistance/input resistance). gain is given by (feedback resistance/input resistance). The input resistances of but the inputs are same.

9. 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

View Answer

Answer: a [Reason:] 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 a considerable distortion of the recordings.

10. The impedance of the input should be ________ in order to obtain high CMRR in differential amplifier.
a) low
b) High
c) Does not matter
d) Very low

View Answer

Answer: b [Reason:] This shows that a 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.

Set 3

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

View Answer

Answer: a [Reason:] 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

View Answer

Answer: c [Reason:] 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 are 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

View Answer

Answer: d [Reason:] 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

View Answer

Answer: c [Reason:] 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 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

View Answer

Answer: d [Reason:] 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

View Answer

Answer: a [Reason:] 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 the which principle?
a) electro-physiological
b) electrochemical
c) physio-chemical
d) chemical

View Answer

Answer: b [Reason:] 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

View Answer

Answer: a [Reason:] 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 (H2O2) is also produced in some amount.

9. Home blood glucose measurement devices measure the glucose level through non-invasive method.
a) True
b) False

View Answer

Answer: b [Reason:] 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

View Answer

Answer: a [Reason:] 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.

Set 4

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

View Answer

Answer: b [Reason:] 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

View Answer

Answer: a [Reason:] 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. Which of the following is not a passive transducer?
a) Strain gauge
b) Ultrasonic transducer
c) IR sensor
d) Doppler effect transducer

View Answer

Answer: a [Reason:] 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. _____________ refers to the degree of repeatability of a measurant.
a) accuracy
b) precision
c) resolution
d) sensitivity.

View Answer

Answer: b [Reason:] 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. 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

View Answer

Answer: c [Reason:] 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.

6. 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

View Answer

Answer: d [Reason:] 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.

7. Unwanted signal at the output due either to internal sources or to interference is called ________
a) offset
b) noise
c) drift
d) threshold

View Answer

Answer: b [Reason:] 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.

8. The ability of the sensor to see small differences in reading is called ______
a) resolution
b) drift
c) offset
d) linearity

View Answer

Answer: a [Reason:] The ability of the sensor to see small differences in reading is called 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.

9. Change is signal over long period of time is called _______
a) noise
b) offset
c) hysteresis
d) drift

View Answer

Answer: d [Reason:] 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.

10. Linearity of transducer is ___________
a) Closeness of transducer’s calibration curve to a special curved line within a given percentage of full scale output.
b) Closeness of transducer’s calibration curve to a special straight line within a given percentage of full scale output.
c) Closeness of transducer’s calibration curve to a special straight line within a given percentage of half scale output.
d) Closeness of transducer’s calibration curve to a special curved within a given percentage of half scale output.

View Answer

Answer: b [Reason:] Linearity of transducer is closeness of 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.

Set 5

1. The material used in limb surface electrode is ___________
a) german silver
b) copper
c) gold
d) platinum

View Answer

Answer: a [Reason:] 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

View Answer

Answer: c [Reason:] 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

View Answer

Answer: a [Reason:] 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

View Answer

Answer: b [Reason:] 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

View Answer

Answer: d [Reason:] 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

View Answer

Answer: a [Reason:] Located in the top right atrium near the entry of the vena cava, are a group of cells known as the sino-atrial node (SA 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. 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

View Answer

Answer: c [Reason:] 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

View Answer

Answer: b [Reason:] 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

View Answer

Answer: d [Reason:] Smart pad is a system that displays a 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

View Answer

Answer: b [Reason:] 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 (shape) 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.