300+ TOP Electronics & Instrumentation MCQs and Answers Pdf Quiz

ELECTRONICS & INSTRUMENTATION Objective Questions and Answers pdf free Download :-

1. Self generating type transducers are ___________ transducers.
a) Active
b) Passive
c) Secondary
d) Inverse
Answer: (a)

2. The transducers that converts the input signal into the output signal, which is a discrete function of time is known as ___________ transducer.
a) Active
b) Analog
c) Digital
d) Pulse
Answer: (c)

3. A transducer that converts measurand into the form of pulse is called
a) Active transducer
b) Analog transducer
c) Digital transducer
d) Pulse transducer
Answer: (d)

4. Which of the following is a digital transducer?
a) Strain gauge
b) Encoder
c) Thermistor
d) LVDT
Answer: (b)

5. Strain gauge, LVDT and thermocouple are examples of
a) Active transducers
b) Passive transducers
c) Analog transducers
d) Primary transducers
Answer: (c)

6. An inverse transducer is a device which converts
a) An electrical quantity into a non electrical quantity
b) Electrical quantity into mechanical quantity
c) Electrical energy into thermal energy
d) Electrical energy into light energy
Answer: (a)

7. A strain gauge is a passive transducer and is employed for converting
a) Mechanical displacement into a change of resistance
b) Pressure into a change of resistance
c) Force into a displacement
d) Pressure into displacement
Answer: (a)

8. Resolution of a transducer depends on
a) Material of wire
b) Length of wire
c) Diameter of wire
d) Excitation voltage
Answer: (c)

9. The sensitivity factor of strain gauge is normally of the order of
a) 1 to 1.5
b) 1.5 to 2.0
c) 0.5 to 1.0
d) 5 to 10
Answer: (b)

10. In wire wound strain gauges, the change in resistance is due to
a) Change in diameter of the wire
b) Change in length of the wire
c) Change in both length and diameter
d) Change in resistivity
Answer: (c)

11. Bonded wire strain gauges are
a) Exclusively used for construction of transducers
b) Exclusively used for stress analysis
c) Used for both stress analysis and construction of transducer
d) Pressure measurement
Answer: (c)

12. Certain type of materials generates an electrostatic charge or voltage when mechanical force is applied across them. Such materials are called
a) Piezo-electric
b) Photo-electric
c) Thermo-electric
d) Photo-resistive
Answer: (a)

13. Quartz and Rochelle salt belongs to ___________ of piezo-electric materials
a) Natural group
b) Synthetic group
c) Natural or Synthetic group
d) Fiber group
Answer: (a)

14. Which of the following are piezo electric substances?
1. Barium titanate
2. Lead titanate
3. Lead Zirconate
4. Cadmium and sulphate
a) 1,2 and 4
b) 1,3and4
c) 1,2and 3
d) 2,3and 4
Answer: (c)

15. Piezo-electric transducers are
a) Passive transducers
b) Inverse transducers
c) Digital transducers
d) Pulse transducers
Answer: (b)

16. Piezo – electric transducers work when we apply _____________ to it.
a) Mechanical force
b) Vibrations
c) Illuminations
d) Heat
Answer: (d)

17. Piezo electric crystal can produce an emf
a) When external mechanical force is applied to i
b) When radiant energy stimulates the crystal
c) When external magnetic field is applied
d) When the junction of two such crystals are heated
Answer: (a)

18. The draw backs of strain gauges are
S1: Low fatigue life
S2: They are expensive, brittle and sensitive to temperature
S3: Poor linearity
a) S1 and S2
b) S2 and S3
c) S1 and S3
d) S1 only
Answer: (b)

19. LVDT windings are wound on
a) Steel sheets
b) Aluminium
c) Ferrite
d) Copper
Answer: (c)

20. The size of air cored transducers in comparison to the iron core parts is
a) Smaller
b) Larger
c) Same
d) Unpredictable
Answer: (b)

21. The principle of operation of LVDT is based on the variation of
a) Self inductance
b) Mutual inductance
c) Reluctance
d) Permanence
Answer: (b)

22. LVDT is an/a ___________ transducer
a) Magneto-strict ion
b) Inductive
c) Resistive
d) Eddy current
Answer: (d)

23. Which of the following can be measured with the help of piezo electric crystal?
a) Force
b) Velocity
c) Sound
d) Pressure
Answer: (a)

24. S1: Transducer is a device which converts physical into electrical quantity
S2: Transducer is also called as sensor.
a) S1 is true & S2 is false
b) S2 is true & S1 is false
c) Both S1 & S2 are true
d) Both S1 & S2 are false
Ans (b)

27. In a LVDT, the two secondary voltages
a) Are independent of the core position
b) Vary unequally depending on the core position
c) Vary equally depending on the core position
d) Are always in phase quadrature
Answer: (b)

28. Capacitive transducers are normally employed for___________ measurements
a) Static
b) Dynamic
c) Transient
d) Both static and dynamic
Answer: (b)

29. Match the following
1. EEG A. Diagnostic tool for heart alignment
2. ECG B. Diagnostic tool for brain alignment
3. Sphygmo-manometer C. Instrument used for measuring blood pressure
4. Stethoscope D. instrument used to hear pulse/heart beat
a) 1- B, 2 – A, 3 – C, 4 – D
b) 1 – B, 2 – A, 3 – D, 4 – C
c) 1- C, 2 – A, 3 – B, 4 – D
d) 1 – A, 2 – B, 3 – C, 4 – D
Answer: (a)

30. Pick the correct statement regarding functions of a transducer
S1: Sense the magnitude, change in & / or frequency of same measurand
S2: To provide electrical output that furnishes accurate, quantitative data about the measurand
a) S1 is true & S2 is false
b) S2 is true & S1 is false
c) Both S1 & S2 are true
d) Both S1 & S2 are false
Answer: (c)

31. The transducers which requires an external power and their output is a measure of some variation such as resistance, inductance, capacitance etc., are called as
a) Active transducer
b) Primary sensor
c) Passive transducer
d) Self generating transducer
Answer: (c)

32. The principle of operation of variable resistance transducer is
a) Deformation leads to change in resistance
b) Displacement of a contact slider on a resistance
c) Coupling of two coils changes with displacement
d) Movement of magnetic field produces variation in resistance of material
Answer: (b)

33. The application of LVDT is
a) Joint motion
b) Finger movement
c) Limb movement
d) Heart wall motion
Answer: (c)

34. Venturi is associated with
a) Venous blood pressure
b) Digital plethysmography
c) Dialysate flow in artificial kidney
d) Blood flow in heart lung machine
Answer: (d)

35. Pressure transducer for measuring blood pressure is
a) Strain gauge transducer only
b) Strain gauge or capacitive transducer
c) Resistive transducer
d) Fiber optic transducer
Answer: (b)

36. The change in resistance of a metal wire owing to strain is due to
S1: Change in dimension of wire expressed by factor (1-2µ)
S2: Change in resistance ??
a) S1 is true & S2 is false
b) S2 is true & S1 is false
c) Both S1 & S2 are true
d) Both S1 & S2 are false
Answer: (b)

37. In foil strain gauge the thickness of foil varies from
a) 2.5 micron to 6 micron
b) 25 micron (or) less
c) 25 micron to 60 micron
d) 2.5 micron to 5 micron
Answer: (a)

38. Photo conductive cell consists of a thin film of
a) Quartz
b) Lithium sulphate
c) Barium titanate
d) Selenium
Answer: (d)

39. S1: In multimode fiber optics, intensity modulating schemes can be employed.
S2: Schemes using polarizing techniques need birefringent fiber.
a) S1 is true and S2 is false
b) Both S1 and S2 are true
c) S1 is false and S2 is true
d) Both S1 and S2 are false
ans (b)

40. Test electrode is also known as
a) Indicator electrode
b) Reference electrode
c) Second electrode
d) Primary electrode
Answer: (a)

41. Most commonly used indicator electrode is
a) Calomel electrode
b) Silver electrode
c) Silver – Silver chloride electrode
d) Glass electrode
Answer: (d)

42. _____________ is the example of photo emissive cell
a) LDR
b) Photo diode
c) Photo transistor
d) Photo multiplier
Answer: (a)

43. pH value of venous blood is
a) 7.30
b) 7.40
c) 7.35
d) 7.45
Answer: (c)

44. Silver chloride electrode is used as a reference electrode due to its
a) Large half cell potential
b) Stable half cell potential
c) Stable resting potential
d) Stable action potential
Answer: (b)

45. The capacitance microphone is used for the detection of
a) Heart rate
b) Blood flow
c) Heart sound
d) Foot pressure
Answer: (c)

46. In a graded index fiber, the total reflected light takes a ___________
a) Straight line path
b) Parabolic path
c) Elliptical path
d) Circular path
Ans (b)

47. ____________ fiber is used in interferometric instruments.
a) Monomode
b) Multimode
c) Birefringent
d) Coated
Ans (a)

48. Fiber optic sensor can be used to sense _________
a) Displacement
b) Power
c) Current
d) Resistance
Ans (a)

49. Photo multiplier consists of
a) 1 Photo emissive cathode & 2 dynodes
b) 2 Photo emissive cathodes & 2 dynodes
c) 2 Photo emissive cathodes & 1 dynode
d) 1 Photo emissive cathode & 1 dynode
Answer: (a)

50. The resistance of LDR ________________ when exposed to radiant energy.
a) Remains unaltered
b) Increases
c) Reaches maximum
d) Decreases
Answer: (d)

ELECTRONICS & INSTRUMENTATION OBJECTIVE QUESTIONS :-

1. The decibel is a measure of
a) Current
b) Voltage
c) Power
d) Power level

Answer: (d)

2. Power gain in decibels is equal to voltage gain in decibels only when
a) Input impedance is equal to output impedance
b) Output impedance is zero
c) Never
d) Input impedance is zero

Answer: (a)

3. An ideal amplifier has
a) Noise figure of 0 db
b) Noise figure of more than 0 db
c) Noise factor of unity
d) Noise figure of less than 1 db
Answer: (c)

4. Fidelity represents
S1: Reproduction of signal
S2: Reproduction of phase relation
a) S1 and S2 are true
b) S1 and S2 are false
c) S1 false and S2 true
d) S1 true and S2 false
Answer: (d)

5. If the current gain of the amplifier is X, its voltage gain is Y, then its power gain will be
a) X/Y
b) X*Y
c) X+Y
d) X-Y

Answer: (b)

6. In an amplifier, the coupling capacitors are employed for
a) Limiting the bandwidth
b) Matching the impedance
c) Preventing of Dc mixing with input or output
d) Controlling the output

Answer: (c)

7. The amplifier which has no drift is called as
a) Differential amplifier
b) DC amplifier
c) Single ended amplifier
d) Chopper amplifier

Answer: (d)

8. The amplifier gain varies with frequency. This happens mainly due to
a) Miller effect
b) Presence of external and internal capacitance
c) Logarithmic increase in its output
d) Inter stage transformer

Answer: (b)

9. The outstanding characteristics of a D.C. amplifier is its
a) Ability to amplify Dc and low frequency signals
b) Temperature stability
c) Utmost economy
d) Avoidance of frequency sensitive components

Answer: (a)

10. Isolation amplifier actually operates on the principle of
a) Filtering
b) Attenuation
c) Clipping
d) Amplification
Answer: (b)

11. Isolation amplifiers are also called as
a) DC amplifier
b) Output amplifier
c) Inverting amplifier
d) Iso-amps

Answer: (d)

12. The improper response time of the amplifier in the biomedical recorders
a) Affects the gain of the amplifier
b) Delays the signals
c) Changes the shape of the waveform of the signal
d) Attenuates the signals

Answer: (c)

13. To reduce common mode interference during recording of bio signals one can use__________
a) Buffer amplifier
b) Differential amplifier
c) Single ended amplifier
d) Chopper amplifier

Answer: (b)

14. Resistively generated inference arises through incorrect __________________
a) Grounding
b) Current density at the electrodes
c) Supply voltage
d) Input impedance

Answer: (a)

15. CMRR is more in_______________
a) Single ended amplifier
b) Differential amplifier
c) Inverting operational amplifier
d) Chopper amplifier

Answer: (b)

16. For biomedical applications the mostly used amplifier is
a) Single ended amplifier
b) Differential amplifier
c) Inverting operational amplifier
d) Chopper amplifier
Answer: (b)

17. ___________ amplifier is used to drive the recorder.
a) Power amplifier
b) Pre amplifier
c) Operational amplifier
d) Differential amplifier

Answer: (a)

18. When a number of components are fabricated on same IC chip it is necessary to provide isolation between two different components for input interconnection is called __________
a) Input amplification
b) Input differentiation
c) Common mode rejection
d) Input isolation

Answer: (d)

19. A chopper amplifier
a) Converts AC signal from low frequency to high frequency
b) Converts DC signal from low frequency to high frequency
c) Converts AC signal from low frequency to DC high frequency
d) Converts DC signal from low frequency to high frequency

Answer: (b)

20. Power amplifier is provided with
S1: Cross over distortion compensation
S2: Offset control
a) S1 is true & S2 is false
b) S2 is true & S1 is false
c) Both S1 & S2 are true
d) Both S1 & S2 are false

Answer: (c)

21. Pre amplifier isolation in ECG circuit is to
a) Increase input impedance
b) Decrease input impedance
c) Increase output impedance
d) Decrease output impedance

Answer: (a)

22. Raising input impedance of pre amplifier reduces
a) Input current
b) Output current
c) Stray current
d) Grid current

Answer: (c)

23. Common mode rejection ratio is defined as ratio of
a) Common mode gain to differential mode gain
b) Differential mode gain to common mode gain
c) Common mode gain at input to differential mode gain at input
d) Common mode gain at output to differential mode gain at output

Answer: (b)

24. An electrometer amplifier has high input impedance of
a) 1010?
b) 105?
c) 1020?
d) 1015?

Answer: (d)

25. When the input of differential amplifier V1 = 0, then the differential amplifier is said to be operated in
a) Common mode
b) Differential mode
c) Non inverting mode
d) Inverting mode

Answer: (c)

26. When either one of the inputs to the differential amplifier is equal to zero then it is said to be operated in
a) Single ended mode
b) Differential mode
c) Non inverting mode
d) Inverting mode

Answer: (a)

27. The negative feed back in an amplifier
a) Reduces voltage gain
b) Increases the voltage gain
c) Increases the gain band width product
d) Reduces the input impedances

Answer: (a)

28. Feedback in an amplifier always helps in
a) Increasing its input impedance
b) Increasing its gain
c) Controlling its output
d) Stabilizes its gain

Answer: (c)

29. Using mechanical chopper we cannot achieve high chopping rates due to their
a) Input impedance
b) Output impedance
c) Response time
d) Inertia

Answer: (d)

30. The CMRR of a typical IC OPAMP is
a) 70 dB
b) 80 dB
c) 85 dB
d) 75 dB

Answer: (b)

31. A ————– is usually a display device used to produce a paper record of analog wave form.
a) Graphic pen recorder
b) Electron microscope
c) X-Y recorder
d) Oscilloscope

Answer: (a)

32. The _________ of a recording system is the magnitude of input voltage required to produce a standard deflection in a recorded trace.
a) Accuracy
b) Linearity
c) Sensitivity
d) Resolution

Answer: (c)

33. A recorder is said to have good frequency response when the sensitivity of the system is _________ for all frequencies present in the signal.
a) Unity
b) Zero
c) Infinity
d) Constant

Answer: (d)

34. In phase response of a recorder noise level ___________ with the band width of a system
a) Increases
b) Decreases
c) Reaches unity
d) Reaches infinity

Answer: (a)

35. Function of microscope is
S1: To magnify object, under observation
S2: To resolve the object
a) S1 is true & S2 is false
b) S2 is true & S1 is false
c) Both S1 & S2 are true
d) Both S1 & S2 are false

Answer: (c)

36. In electron microscope the projection of the motion on a plane normal to magnetic
induction (B) will be a circle of radius (r) =
a) mVsin?+eB
b) mVsin?/eB
c) mVsin?-eB
d) mVsin?*eB

Answer: (b)

37. Match the following
1. Electron microscope – (A) Electron gun
2. Oscilloscope – (B) Condensing magnetic lens
3. Galvanometric recorder – (C) Recording head
4. Magnetic recorder – (D) Drive motor
a) 1-A, 2-B, 3-C, 4-D
b) 1-D, 2-C, 3-B, 4-A
c) 1-B, 2-A, 3-D, 4-C
d) 1-C, 2-D, 3-A, 4-B

Answer: (c)

38. In PMMC writing system, the magnitude of pen deflection is proportional to
S1: Current flowing through the coil
S2: Voltage in the coil
a) S1 is true & S2 is false
b) S2 is true & S1 is false
c) Both S1 & S2 are true
d) Both S1 & S2 are false

Answer: (a)

39. Duration of rotation of pen in the PMMC system depends upon ___________
a) Phase angle
b) Frequency
c) Magnitude
d) Direction

Answer: (d)

40. The shorter wave length of the electron permits the detailed examination of tiny objects due to reduction of ___________ effects
a) Reflection
b) Diffraction
c) Refraction
d) Polarization

Answer: (b)

41. Which of the following recorder gives slow response
a) X-Y recorder
b) Oscillographic
c) Galvanometric
d) Magnetic
Answer: (c)

42. The use of storage oscilloscope
S1: Viewing rapidly changing non repetitive wave forms
S2: Recording average values
a) S1 is true & S2 is false
b) S2 is true & S1 is false
c) Both S1 & S2 are true
d) Both S1 & S2 are false

Answer: (b)

43. In X-Y recorders, the self balancing potentiometers plot emf as a function of
a) Another emf
b) Frequency
c) Time
d) Pressure
Answer: (a)

44. In strip chart recorders, the self balancing potentiometers plot emf as a function of
a) Another emf
b) Frequency
c) Time
d) Pressure

Answer: (c)

45. The slewing speed of X-Y recorder is
a) 1.6 m/s
b) 1.3 m/s
c) 1.4 m/s
d) 1.5 m/s

Answer: (d)

46. The resolution limit of electron microscope is
a) 2 A.V
b) 1 A.V
c) 1.5 A.V
d) 1.2 A.V

Answer: (b)

47. _____________ is also known as halftone storage or mersh storage.
a) Variable persistence storage
b) Bistable storage
c) Flat storage
d) CRT

Answer: (a)

48. Storage oscilloscope operates on the principle of
a) Primary emission
b) Deflection
c) Secondary emission
d) Diffusion

Answer: (c)

49. The writing speed of fast storage oscilloscope is
a) 2000 cm/?s
b) 1000 cm/?s
c) 1500 cm/?s
d) 2500 cm/?s

Answer: (a)

50. Stress and strain curves are plotted using
a) Magnetic tape recording
b) X-Y recording
c) Galvanometric
d) PMMC writing systems

Answer: (b)