# 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

(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

(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