Test and Measurements

11. A small swamping resistance is connected in series with operating coil of a moving coil ammeter in order to compensate for the effects of

  1. Temperature variation
  2. Hysteresis
  3. External magnetic fields
  4. Temperature inversion

Correct answer: (A)
Temperature variation

12. A Wheatstone bridge is balanced if

  1. the ratio of resistors on one side of the bridge is one while the ratio of resistors on the other side is infinity
  2. the ratio of resistors on one side of the bridge is greater than the ratio of resistors on the other side
  3. the ratio of resistors on one side of the bridge equals the ratio of resistors on the other side
  4. the bridge uses identical resistors

Correct answer: (C)
the ratio of resistors on one side of the bridge equals the ratio of resistors on the other side

13. All voltmeters except one of the following are operated by the passage of current.

  1. Moving-iron
  2. Dynamometer
  3. Electrostatic
  4. Permanent-magnet moving coil

Correct answer: (C)
Electrostatic

14. An ammeter with an internal resistance of 50 n is used to measure a current through a load resistance RL= 1 k n. Determine the percentage error of the reading due to ammeter insertion.

  1. 67.4%
  2. 6.74%
  3. 4.76%
  4. 47.6%

Correct answer: (C)
4.76%

15. An electric pyrometer is an instrument used to measure

  1. phase
  2. high temperatures
  3. frequency
  4. power

Correct answer: (B)
high temperatures

16. An element in electrons which serves as a protection against overload?

  1. Resistor
  2. Transistor
  3. Semiconductor
  4. Fuse

Correct answer: (D)
Fuse

17. An instrument in which the magnitude of the measured quantity is indicated by means of a pointer

  1. Analog instrument
  2. Digital instrument
  3. Ammeter
  4. Voltmeter

Correct answer: (A)
Analog instrument

18. An oscilloscope provides easy measurement of __________ values.

  1. instantaneous
  2. rms
  3. peak to peak
  4. average

Correct answer: (C)
peak to peak

19. As the deflection of the moving system increases, the controlling torque in an indicating instrument.

  1. Remains the same
  2. Increases
  3. Decreases
  4. Becomes zero

Correct answer: (B)
Increases

20. Attraction and repulsion instruments are considered as

  1. Moving-cell instruments
  2. Moving-iron instruments
  3. Electrodynamic instruments
  4. Dynamometer

Correct answer: (B)
Moving-iron instruments

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