Measuring Instruments MCQ Questions

1. Bolometers are used for the measurement of

(a) optical inputs
(b) thermal radiations
(c) electrical signals
(d) temperature inputs.


Answer: (b) thermal radiations
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2. A bolometer is an element which

(a) senses optical input and delivers thermal output
(b) senses thermal inputs
(c) senses electrical input and delivers thermal output
(d) senses optical input and delivers electrical output.


Answer: (a) senses optical input and delivers thermal output.
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3. Least expensive instrument for DC measurement is

(a) hot wire instrument
(b) dynamometer type moving coil instrument
(c) attraction type moving iron instrument
(d) electrostatic type instrument.


Answer: (c) attraction type moving iron instrument.
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4. To double the current range of a 50 µA 2000 Ω meter movement, the shunt resistance required is

(a) 20 Ω
(b) 200 Ω
(c) 2000 Ω
(d) 20000 Ω


Answer: (c) 2000 Ω
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5. Which voltmeter has the least power consumption?

(a) Induction type
(b) Hot wire type
(c) Electrostatic type
(d) Moving-iron attraction type


Answer: (c) Electrostatic type
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6. Which of the following instrument can be used for the measurement of temperatures above 1500 K?

(a) mercury thermometer
(b) gas thermometer
(c) thermo-electric pyrometer
(d) any of the above.


Answer: (c) thermo-electric pyrometer
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7. Meter range is normally so selected that the indications are obtained

(a) at the maximum of the scale
(b) at the middle of the scale
(c) near the initial zone of the scale.


Answer: (b) at the middle of the scale
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8. Ideally the internal resistance of an ammeter should be

(a) zero
(b) 0.1 ohm
(c) 1 ohm
(d) infinite


Answer: (a) zero
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9. In two wattmeter method, if one of the wattmeter shows negative reading, the power factor of the load should be

(a) unity
(b) lagging
(c) leading
(d) zero


Answer: (b) lagging
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10. The scale of a wattmeter gives maximum indication of 100. The current and voltage ranges are 10 A and 220 V. The multiplication factor is

(a) 2.2
(b) 22
(c) 1/22
(d) 0.5


Answer: (b) 22
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11. Which of the following instruments can be used in ac bridges for low frequencies up to 200 Hz only?

(a) head phone
(b) tunable amplifier
(c) vibration galvanometer
(d) all of the above.


Answer: (c) vibration galvanometer
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12. Maxwell bridge is used to measure

(a) Resistance
(b) Inductance
(c) Capacitance
(d) Frequency.


Answer: (b) Inductance
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13. A bridge used for measurement of capacitance is

(a) Wheatstone bridge
(b) Wein bridge
(c) Maxwell bridge
(d) Schering bridge.


Answer: (d) Schering bridge.
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14. Which of the following instruments can be used in AC bridges for the frequencies up to 100 kHz?

(a) Headphones
(b) Vibration galvanometer
(c) Tunable amplifier detector
(d) Any of the above.


Answer: (c) Tunable amplifier detector
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15. Hay’s bridge can be used for measurements on

(a) pure resistive circuits
(b) high Q inductive circuits
(c) radio frequency circuits
(d) any of the above.


Answer: (b) high Q inductive circuits
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16. Capacitor type potential divider is used to extend the range of which type voltmeter?

(a) Induction voltmeter
(b) Electrostatic voltmeter
(c) Hot wire voltmeter
(d) Electrodynamometer voltmeter.


Answer: (b) Electrostatic voltmeter
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17. Which of the following frequency meters can be used for the measurement of radio frequency?

(a) Weston frequency meter
(b) Heterodyne frequency meter
(c) Electrical resonance frequency meter
(d) Any of the above.


Answer: (b) Heterodyne frequency meter
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18. One wattmeter method is used to measure power in a three phase circuit when

(a) the power factor is unity
(b) the supply frequency is 50 Hz only
(c) the load is balanced in all three phases
(d) the supply voltage is 220 V.


Answer: (c) the load is balanced in all three phases
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19. Which method can be used to measure the power in a three phase unbalanced load system?

(a) One wattmeter method
(b) Two wattmeter method
(c) Three voltmeter method
(d) Three ammeter method.


Answer: (b) Two wattmeter method
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20. In the two wattmeter method if power factor is 0.5, then one of the wattmeters will read

(a) zero
(b) W/2
(c) W/√2
(d) W/√3


Answer: (a) zero
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21. A meggar is basically a

(a) moving iron type instrument
(b) moving coil type instrument
(c) hot wire instrument
(d) electrolytic instrument.


Answer: (b) moving coil type instrument
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22. Highest flux density exists inside which of the following instrument?

(a) moving iron type instrument
(b) moving coil type instrument
(c) hot wire instrument
(d) electro-dynamic instrument.


Answer: (b) moving coil type instrument
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23. In a moving iron instrument 12 A current causes a deflection of the needle by 60 degrees. A deflection of 15 degrees will be obtained by a current of

(a) 6 A
(b) 9 A
(c) 4 A
(d) 3 A


Answer: (a) 6 A
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24. In a moving coil instrument 12 A current causes a deflection of the needle by 60 degrees. A deflection of 15 degrees will be obtained by a current of

(a) 6 A
(b) 9 A
(c) 4 A
(d) 3 A


Answer: (d) 3 A
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25. A voltmeter has an accuracy of 5% on full scale. The percentage error while measuring 50 V will be

(a) 2.5%
(b) 5%
(c) 7.5%
(d) 10%


Answer: (d) 10%
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26. Which of the following instruments does not use the effect of current for measurement purposes?

(a) Electrostatic ammeter
(b) Hot wire meter
(c) Rectifier ammeter
(d) Moving coil ammeter.


Answer: (a) Electrostatic ammeter
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27. The number of turns in the primary of a current transformer is usually

(a) 1 to 5
(b) 10 to 50
(c) 100 to 500
(d) 1000 to 5000


Answer: (a) 1 to 5
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28. The porpoise of providing a swamping resistance in a dynamometer type moving coil instruments is

(a) to provide equal time constant for fixed coil and moving coil, when used for AC measurements
(b) to reduce the bulk of the moving coil system
(c) to reduce the current flowing through the moving coil
(d) to control the deflecting torque

Answer: (a) to provide equal time constant for fixed coil and moving coil, when used for AC measurements.

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29. Which of the following instruments will be suitable for the measurement of temperature of a furnace?

(a) Clinical thermometer
(b) Mercury thermometer
(c) Optical pyrometer
(d) Bimetallic thermometer.


Answer: (c) Optical pyrometer
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30. An electrodynamic wattmeter is not considered suitable for low power factor circuits due to

(a) inductance of voltage coil
(b) reactance of current coil
(c) power loss in voltage coil
(d) power loss in current coil


Answer: (c) power loss in voltage coil
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Measuring Instruments MCQ Questions

 

  1. Electrical Measurements MCQ Questions
  2. Measuring Instruments MCQ Questions
  3. Measuring Instruments MCQ Question Answer

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