# Electrical Measurement and Instrumentation MCQ (Multiple Choice Questions)

1. Which of the following method of measurement does a bridge circuit uses?
a) relative
b) comparison
c) absolute
d) differential
View Answer

Answer: b
Explanation: A bridge circuit makes use of a comparison measurement method. In this method the bridge compares the value of an unknown component with a standard value of a given component.

2. Which of the following is the most popular method for measuring low resistance?
a) ducter ohmmeter method
b) kelvin double bridge method
c) ammeter-voltmeter method
d) potentiometer method
View Answer

Answer: b
Explanation: Kelvin’s double bridge is used for the measurement of low resistances of the order of 1ῼ or less. Ammeter voltmeter method is used for the measurement of current flowing through and the voltage across the circuit.

3. Which of the following method is used for the measurement of Medium Resistance?
a) Direct-Deflection method
b) Anderson Bridge
c) Kelvin’s double bridge method
d) Carey-Foster bridge method
View Answer

Answer: d
Explanation: Kelvin’s double bridge method is used for measurement of Low Resistance, Anderson Bridge is not used for measurement of Resistance, and Direct-Deflection method is used for Measurement of High Resistance.

4. Which of the following is the most sensitive detector for single frequency value?
a) oscillator
b) headphone
c) tuned detector
d) vibration galvanometer
View Answer

Answer: c
Explanation: A vibration galvanometer is used for detecting the balance condition. The oscillator is used as a source of the supply voltage. The tuned detector is the most sensitive detector for a single frequency value.

5. Under which of the following conditions a bridge is balanced?
a) When no current flows
b) When the temperature of the circuit is high
c) When power dissipation is high
d) When no voltage drop across the circuit
View Answer

Answer: a
Explanation: At balance condition, no current flows through the headphones present in the AC bridge circuit. As a result the detector indicates null deflection at balance condition.
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6. Unknown capacitance value is obtained by _________
a) using a vibration galvanometer
b) using capacitance of other ratio arms
c) comparison with standard
d) using a tuned detector
View Answer

Answer: c
Explanation: Tuned circuit is used for detecting balance condition. Vibration galvanometer is used for the same purpose. Unknown value of capacitance is obtained by comparing it with a standard value.

7. Which of the following is a balance equation for computing the resistance?
a) R1 = R2R4
b) R1 = R3R4
c) R1 = R2 R3
d) R1 = R2 R3R4
View Answer

Answer: d
Explanation: The balance equation for computing the resistance in an Anderson’s bridge is given by the equation R1 = R2 R3R4.
where, R2, R3 and R4 are the known non-inductive resistances.

8. Inductance control is obtained by _________
a) using R5
b) using R4
c) using R2
d) using Lx
View Answer

Answer: c
Explanation: In an inductance comparison bridge, the resistance R2 and R3 are variable. The value of resistance R2 is varied so as to control the inductance of the bridge.

9. A Schering bridge can be used for the ______________
a) protecting the circuit from temperature rises
b) testing capacitors
c) measuring voltages
d) measuring currents
View Answer

Answer: b
Explanation: A Schering bridge can be used with both low voltage as well as high voltages. A Schering bridge is basically used for the measurement of small capacitances at low voltages with high precision.

10. What is the dependence of frequency on the balance equation?
a) varies by a factor of 2
b) depends on the detector used
c) independent
d) depends on the supply magnitude
View Answer

Answer: c
Explanation: In a high voltage Schering bridge, the balance equation does not depend on the frequency of operation of the circuit. A detector is only used for detecting the balance condition in a bridge circuit.

11. Which of the following is the guarding arm?
a) capacitance C
b) resistance R
c) parallel RC combination
d) series RC combination
View Answer

Answer: c
Explanation: The series combination of R and C in a Wagner earth device forms a potential divider across the ratio arms. It is also known as the guard arm.

12. Which of the following can be measured using Maxwell’s Inductance Capacitance Bridge?
a) Capacitance
b) Frequency
c) Mutual Inductance
d) Inductance
View Answer

Answer: d
Explanation: For measuring Capacitance De-Sauty’s Bridge and Schering Bridge should be used. For measuring Frequency Wien’s Bridge is used. For measuring Mutual Inductance Heaviside and Campbell’s Bridge are used.

13. A multiplier is __________
a) non-capacitive
b) capacitive
c) non-inductive
d) resistive
View Answer

Answer: c
Explanation: A multiplier is basically a non-inductive, high resistance that is used to extend the range of a D.C. voltmeter. Multiplier consists of a low range D.C. voltmeter connected in series with it.

14. The windings of a C.T. are ________
a) tied together
b) shorted
c) wound over one another
d) grounded
View Answer

Answer: c
Explanation: Using cylinders made of Bakelite, the windings of a C.T. are wound over one another. This setup is mounted on a steel tank sheet filled with transformer oil.
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15. How is the voltage ratio dependent on the frequency?
a) they aid each other
b) depends on the setup of the circuit
c) they are independent of each other
d) they oppose each other
View Answer

Answer: d
Explanation: As the voltage ratio changes, the frequency also changes. It depends on the relative value of the core loss component Io as well as the leakage reactance. The effects due to the voltage ratio and the change in frequency oppose each other.

16. Increasing secondary burden _____________
a) decreases Is
b) keeps Is constant
c) decreases Ip
d) increases Is
View Answer

Answer: d
Explanation: When the secondary burden of a potential transformer increases, it leads to an increase in the secondary current. As a result the primary current also increases.

17. Which of the following device is used to measure power in A.C. circuits?
a) ammeter
b) wattmeter
c) voltmeter
d) ohmmeter
View Answer

Answer: c
Explanation: A.C. circuits make use of power factor of the circuit in addition to the current flowing through the circuit and the voltage across the circuit. As a result, a wattmeter is used to measure A.C. power.

18. When the moving coil in a Dynamometer type wattmeter deflects ________
a) pointer doesn’t move
b) current flows
c) voltage is generated
d) pointer moves
View Answer

Answer: d
Explanation: In a Dynamometer type wattmeter, when the moving coil deflects the pointer moves over the scale. The pointer then comes back to rest at a point where the deflecting torque equals the controlling torque.

19. What is the effect of capacitance on wattmeter reading?
a) opposite to that of resistance
b) aiding the capacitance
c) aiding the inductance
d) opposite to that of inductance
View Answer

Answer: d
Explanation: For lagging power factor of the load, the wattmeter reading is more. As a result, the wattmeter shows a reading opposite to that of the inductance.
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20. Which of the following compares the output in a successive approximation type DVM?
a) comparator
b) diode
c) op amp
d) rectifier
View Answer

Answer: a
Explanation: A comparator is used to compare the output of the digital to analog converter in a successive approximation type DVM. As a result the comparator provides high or low signals.

21. Which of the following is the main device used in the linear ramp technique?
a) non-linear ramp
b) linear ramp
c) asymptotic ramp
d) exponential ramp
View Answer

Answer: b
Explanation: The linear ramp technique essentially consists of a linear ramp. It is either positive or negative going. Range of the linear ramp varies from –12 V to +12 V. Base range varies from –10 V to +10 V.

22. Which of the following determines the rate of measurement cycles?
a) multivibrator
b) oscillator
c) oscilloscope
d) amplifier
View Answer

Answer: c
Explanation: Initiation of the measurement cycles is taken care of by the sample rate multivibrator. This vibrator oscillates at the rate of 1000 cycles per second. It is adjusted by a front panel control.

23. Which of the following determines light intensity in a CRT?
a) current
b) fluorescent screen
c) voltage
d) momentum of electrons
View Answer

Answer: d
Explanation: Momentum of the electrons gives the intensity or brightness of the light emitted from the fluorescent screen due to electron bombardment. It is given as the product of the no of electrons and their speed.

24. Which of the following technique of a Dual Trace Oscilloscope maintains the phase between the signals?
a) Mixed mode
b) Alternate mode
c) Analog mode
d) Chop mode
View Answer

Answer: b
Explanation: In a Dual Trace Oscilloscope, the alternate mode of operation enables to maintain the correct phase relationship between the signals from the channels A and B.

25. Which of the following oscilloscope is used in a digital storage oscilloscope?
a) dual trace
b) conventional
c) multi trace
d) modern
View Answer

Answer: b
Explanation: A digital storage oscilloscope makes use of a conventional cathode ray tube. As a result, the cost is reduced.

26. In which of the following method of acquisition, pretrigger event is lost?
a) Sequential repetitive sampling
b) Real time sampling
c) Analog Sampling
d) Random repetitive sampling
View Answer

Answer: a
Explanation: In Sequential repetitive sampling, pretrigger information cannot be captured. And the pretrigger view is lost. It can be used only in microwave digital oscilloscope as a result.

27. Which of the following is the main function of auxiliary equipment?
a) non-linear response
b) linear response
c) ramp response
d) unit step response
View Answer

Answer: b
Explanation: The typical functions of auxiliary equipments include linearization and limit compression for the input signals. Individual instruments or a digital computer is used to perform these functions.

28. Which of the following is the best example of a single-channel data acquisition system?
a) APM
b) DPM
c) CPM
d) BPM
View Answer

Answer: b
Explanation: A digital panel meter usually abbreviated as DPM is the best example of a single channel data acquisition system.

29. Which of the following technique is most widely used in the single channel data acquisition system?
a) Successive approximation
b) Delta Sigma approximation
c) Flash approximation
d) Counter type approximation
View Answer

Answer: a
Explanation: The successive approximation technique is most widely used in a single channel data acquisition system. This is due to the fact that it has a high value of resolution and high speed.

30. Which of the following is the main objective of process control?
a) to control electrical parameters
b) to control optical parameters
c) to control physical parameters
d) to control mechanical parameters
View Answer

Answer: c
Explanation: Process control is mainly used in order to control the physical parameters including temperature, pressure, flow rate, force, etc.

## Chapterwise Multiple Choice Questions on Electrical Measurement and Instrumentation

Our 1000+ MCQs focus on all topics of the Electrical Measurement and Instrumentation subject, covering 100+ topics. This will help you to prepare for exams, contests, online tests, quizzes, viva-voce, interviews, and certifications. You can practice these MCQs chapter by chapter starting from the 1st chapter or you can jump to any chapter of your choice.

## 1. Electrical Measurement MCQs on Measurement of Resistance

The section contains Electrical Measurement multiple choice questions and answers on bridges basics, bridge circuits advantages, wheatstone bridge balance condition and sensitivity, wheatstone bridge applications, limitations and measurement errors, kelvin bridge, earth resistance measurement, merger and its applications, advanced problems on medium and high measurement, resistance measurement and electrical instruments problems.

## 2. Electrical Measurement Multiple Choice Questions on Measurement of Inductance and Capacitance

The section contains Electrical Measurement and Instrumentation questions and answers on ac bridges basics, sources and detectors, bridge balance equation, capacitance and inductance comparison bridge, anderson and schering bridge, high voltage schering bridge, maxwell’s inductance capacitance bridge, maxwell bridge limitations, advanced problems on inductance measurement using ac bridges, bridges grounding and shielding.

## 3. Electrical Instrumentation MCQs on Extension of Instrument Ranges

The section contains Electrical Measurement and Instrumentation MCQs on shunts and multipliers, instrument transformers and its advantages, current transformers errors and design features, c.t. and p.t. differences, potential transformers error reduction and characteristics, advanced problems on indicating instruments, c.t and p.t.

## 4. Electrical Measurement MCQs on Measurement of Power and Related Parameters

The section contains Electrical Measurement and Instrumentation multiple choice questions and answers on dynamometer type wattmeter, dynamometer wattmeter errors, induction type single phase energy meter, lag adjustment devices, friction and overload compensation, phase sequence indicator, single phase energy meters errors and adjustments, advanced problems on power measurement.

## 5. Electronic Instruments Multiple Choice Questions

The section contains Electrical Instrumentation questions and answers on electronic instruments advantages, electronic voltmeter and multimeter, digital voltmeter and its performance, successive approximation and ramp type dvm, potentiometric and dual slope integrating type dvm, autoranging, digital multimeter and advanced problems on qmeter.

## 6. Electrical Instrumentation MCQs Oscilloscopes

The section contains Electrical Instrumentation MCQs on oscilloscope, cathode ray tube, signal display principles, delay line, cro front panel controls, time base, time base generator principle, ttl triggering, dual trace and beam oscilloscope, acquisition methods, digital storage oscilloscope, cro measurements and applications, advanced problems on crt and cro.

## 7. Electrical Measurement and Instrumentation MCQs on Data Acquisition System

The section contains Electrical Measurement and Instrumentation multiple choice questions and answers on data acquisition system objectives, analog and digital data acquisition system, pc based, single and multiple channel data acquisition system.

## 8. Electrical Instrumentation Multiple Choice Questions on Transducers

The section contains Electrical Instrumentation questions and answers on process control system, transducers, transducers classification and characteristics, potentiometric resistance transducers, strain gauges operation, and types, strain gauge measurement technique, resistance temperature detector, thermistor, pressure sensor, inductive and capacitive transducers, thermoelectric, piezoelectric and photoelectric transducers.

## 9. Electrical Measurement and Instrumentation MCQs on Display Devices

The section contains Electrical Measurement and Instrumentation MCQs on recording data objectives and requirements.

If you would like to learn "Electrical Measurements" thoroughly, you should attempt to work on the complete set of 1000+ MCQs - multiple choice questions and answers mentioned above. It will immensely help anyone trying to crack an exam or an interview.

Wish you the best in your endeavor to learn and master Electrical Measurements!

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