Measuring Instruments Objective Type Questions

21. Dynamometer type  ……. has uniform scale.

(i) ammeter
(ii) wattmeter
(iii) voltmeter
(iv) none of the above

22. The instrument in which springs provide the controlling torque as well as serve to lead current into and out of the operating coil is  ……… instrument.

(i) moving-iron
(ii) hot-wire
(iii) permanent-magnet moving coil
(iv) none of the above

23. If current through the operating coil of a moving-iron instrument is doubled, the operating force becomes 

(i) two times
(ii) four times
(iii) one-half time
(iv) three times

24. The full-scale deflection current of a moving coil instrument is about 

(i) 50 mA
(ii) 1 A
(iii) 3 A
(iv) 2 A

25. For measuring high values of alternating current with a dynamometer ammeter, we use a ………

(i) shunt
(ii) multiplier
(iii) potential transformer
(iv) current transformer

26. Hot-wire instruments have ………. scale.

(i) uniform
(ii) log
(iii) squared
(iv) none of the above

27. The full-scale voltage across a moving coil voltmeter is about …….. 

(i) 10 V
(ii) 5 V
(iii) 100 V
(iv) 50 mV

28. Moving-iron instruments have  ………. scale.

(i) uniform
(ii) squared
(iii) log
(iv) none of the above

29. The range of a moving-iron a.c. ammeter is extended by 

(i) a shunt
(ii) a multiplier
(iii) changing number of turns of operating coil
(iv) none of the above

30. To measure high-frequency currents, we mostly use …….. ammeter.

(i) hot-wire
(ii) dynamometer
(iii) moving-iron
(iv) thermocouple

31. For the measurement of high direct voltage (say 10 kV), one would use   …… voltmeter.

(i) permanent-magnet moving coil
(ii) electrostatic
(iii) hot-wire
(iv) moving iron

32.  ……… is most expensive.

(i) D’Arsonval movement
(ii) Moving-iron
(iii) Dynamometer
(iv) none of the above

33. Electrostatic instruments are used as 

(i) voltmeters only
(ii) ammeters only
(iii) both ammeters and voltmeters
(iv) wattmeters only

34. An electric pyrometer is an instrument used to measure ……. .

(i) phase
(ii) frequency
(iii) high temperatures
(iv) none of the above

35. The best type of meter movement is ……… movement.

(i) iron-vane
(ii) D’Arsonval
(iii) dynamometer
(iv) none of the above

36.  ……… instruments are most sensitive.

(i) moving-iron
(ii) hot-wire
(iii) dynamometer
(iv) permanent-magnet moving coil

37. In induction type ammeter, damping is provided.

(i) air friction
(ii) eddy current
(iii) fluid friction
(iv) none of the above

38. The most commonly used induction type instrument is  

(i) induction voltmeter
(ii) induction wattmeter
(iii) induction watt-hour meter
(iv) induction ammeter

39. All voltmeters except ……..voltmeters are operated by the passage of current. (i) moving-iron

(ii) electrostatic
(iii) dynamometer
(iv) permanent-magnet moving coil