The sensitivity of a voltmeter is expressed in

 

ELECTRICAL AND ELECTRONIC MEASUREMENTS MCQs 

Q51. The sensitivity of a voltmeter is expressed in
A) Ω/V
B) V/Ω
C) A/V
D) V/A
Answer: A

Q52. The main advantage of PMMC instruments is
A) High accuracy for DC measurement
B) Can be used for AC and DC
C) Cheap and rugged
D) None
Answer: A

Q53. The power factor meter based on dynamometer type works on
A) Electromagnetic induction
B) Magnetic repulsion
C) Torque due to two alternating fluxes
D) Heating effect
Answer: C

Q54. The main source of error in moving iron instruments is due to
A) Hysteresis and stray magnetic fields
B) Spring friction
C) Gravity control
D) Eddy currents
Answer: A

Q55. The inductance is measured using
A) Anderson bridge
B) Maxwell bridge
C) Schering bridge
D) Wien bridge
Answer: B

Q56. The capacitance is measured using
A) Schering bridge
B) Maxwell bridge
C) Kelvin bridge
D) Anderson bridge
Answer: A

Q57. A Hay bridge is suitable for measuring
A) High inductance with small resistance
B) Low inductance with high resistance
C) Capacitance
D) Frequency
Answer: A

Q58. The frequency is measured by
A) Wien bridge
B) Schering bridge
C) Maxwell bridge
D) Kelvin bridge
Answer: A

Q59. The instrument used for calibration of voltmeters and ammeters is
A) Potentiometer
B) Ohmmeter
C) Energy meter
D) Frequency meter
Answer: A

Q60. In an AC bridge, the condition for balance is
A) Independent of supply frequency
B) Dependent on supply frequency
C) Depends on supply voltage
D) None
Answer: B

Q61. The deflecting torque in moving iron instruments is proportional to
A) I²
B) I
C) V
D) 1/I
Answer: A

Q62. The accuracy class of an instrument represents
A) Maximum permissible percentage error
B) Frequency range
C) Sensitivity
D) Type of damping
Answer: A

Q63. In an analog instrument, the scale is uniform if
A) Deflection ∝ Current
B) Deflection ∝ Current²
C) Deflection ∝ Voltage
D) Deflection ∝ √I
Answer: A

Q64. The torque required to overcome friction in an instrument is known as
A) Control torque
B) Frictional torque
C) Damping torque
D) Restoring torque
Answer: B

Q65. The loss of accuracy in an instrument over time is called
A) Drift
B) Lag
C) Sensitivity loss
D) Hysteresis
Answer: A

Q66. The function of a shunt in an ammeter is to
A) Divide current
B) Multiply voltage
C) Reduce resistance
D) Control torque
Answer: A

Q67. The time period of a CRO sweep circuit is
A) Reciprocal of frequency
B) Frequency
C) Voltage
D) Constant
Answer: A

Q68. The waveform of the sweep voltage in a CRO is
A) Sawtooth
B) Sine wave
C) Square wave
D) Triangular
Answer: A

Q69. The horizontal deflection in a CRO is controlled by
A) Time base generator
B) Vertical amplifier
C) Trigger circuit
D) Sweep generator
Answer: A

Q70. The peak value of AC can be measured by
A) Peak reading voltmeter
B) RMS meter
C) Average reading voltmeter
D) PMMC
Answer: A

Q71. In an electronic voltmeter, the input impedance is made high by using
A) Cathode follower circuit
B) Common emitter circuit
C) Common base circuit
D) Transformer
Answer: A

Q72. The function of a rectifier in an electronic voltmeter is
A) Convert AC to DC
B) Amplify signal
C) Regulate current
D) Produce oscillation
Answer: A

Q73. A dual-trace CRO can display
A) Two signals simultaneously
B) Only one signal
C) Only DC
D) None
Answer: A

Q74. In a digital frequency meter, the unknown frequency is determined by
A) Counting the number of cycles in a known time interval
B) Measuring peak voltage
C) Measuring RMS value
D) Measuring current
Answer: A

Q75. The working of LVDT is based on
A) Mutual induction
B) Self-induction
C) Hall effect
D) Seebeck effect
Answer: A

Q76. The output of an LVDT is
A) AC voltage proportional to displacement
B) DC voltage
C) Current
D) Resistance
Answer: A

Q77. The strain gauge works on
A) Change in resistance due to mechanical deformation
B) Induction principle
C) Capacitance principle
D) Piezoelectric effect
Answer: A

Q78. The bridge used for measurement of strain is
A) Wheatstone bridge
B) Kelvin bridge
C) Maxwell bridge
D) Schering bridge
Answer: A

Q79. The Hall effect sensor is used to measure
A) Magnetic field
B) Pressure
C) Temperature
D) Speed
Answer: A

Q80. A thermistor is used for
A) Temperature measurement
B) Pressure measurement
C) Voltage measurement
D) Frequency measurement
Answer: A

Q81. The thermistor has
A) Negative temperature coefficient of resistance
B) Positive temperature coefficient
C) Zero coefficient
D) Constant resistance
Answer: A

Q82. The piezoelectric transducer converts
A) Pressure into voltage
B) Voltage into pressure
C) Temperature into current
D) Displacement into resistance
Answer: A

Q83. In strain measurement, the gauge factor is
A) Ratio of fractional change in resistance to strain
B) Ratio of resistance to strain
C) Ratio of voltage to strain
D) None
Answer: A

Q84. The working principle of an electrostatic voltmeter is
A) Attraction between charged plates
B) Magnetic field
C) Heating effect
D) Eddy current
Answer: A

Q85. The frequency response of a CRO is limited by
A) Bandwidth of vertical amplifier
B) Sweep circuit
C) Time base
D) Beam intensity
Answer: A

Q86. The most common error in digital instruments is
A) Quantization error
B) Parallax error
C) Human error
D) Loading error
Answer: A

Q87. The digital multimeter has an advantage of
A) No parallax error
B) Low accuracy
C) Large loading effect
D) Low input impedance
Answer: A

Q88. A null-type instrument gives
A) No deflection at balance
B) Maximum deflection at balance
C) Constant deflection
D) None
Answer: A

Q89. The working principle of a potentiometer is
A) Comparison of unknown emf with known voltage
B) Deflection method
C) Magnetic coupling
D) Heating effect
Answer: A

Q90. A dynamometer wattmeter can measure
A) Both AC and DC power
B) Only DC power
C) Only AC power
D) None
Answer: A

Q91. The main advantage of a moving iron instrument over PMMC is
A) It can measure both AC and DC
B) More sensitive
C) Linear scale
D) Low hysteresis
Answer: A

Q92. The term “precision” means
A) Repeatability of measurement
B) Closeness to true value
C) Error-free measurement
D) None
Answer: A

Q93. The damping in moving coil instruments is
A) Eddy current damping
B) Air friction damping
C) Fluid damping
D) None
Answer: A

Q94. The function of the control spring in a PMMC instrument is
A) Provides controlling torque
B) Provides damping
C) Increases sensitivity
D) Reduces error
Answer: A

Q95. The dielectric loss of a capacitor can be measured using
A) Schering bridge
B) Maxwell bridge
C) Anderson bridge
D) Wien bridge
Answer: A

Q96. The form factor for a sine wave is
A) 1.11
B) 1.414
C) 0.707
D) 1
Answer: A

Q97. The peak factor of a sine wave is
A) 1.414
B) 1.11
C) 0.707
D) 2
Answer: A

Q98. The instrument used to measure power factor in 3-phase system is
A) Dynamometer type power factor meter
B) Moving coil meter
C) PMMC voltmeter
D) Electrostatic voltmeter
Answer: A

Q99. The main function of a filter circuit in measurement systems is
A) Remove unwanted noise and harmonics
B) Amplify signal
C) Convert AC to DC
D) None
Answer: A

Q100. The most accurate instrument for DC measurement is
A) PMMC
B) Moving iron
C) Hot-wire instrument
D) Electrodynamometer
Answer: A