Measuring Instruments Objective Type Questions

1. An ammeter is …………… instrument.

(i) an indicating
(ii) an integrating
(iii) a recording
(iv) none of the above

2. The controlling torque of an indicating instrument ………. as the deflection of the moving system increases.

(i) remains unchanged
(ii) decreases
(iii) increases
(iv) none of the above

3. When the pointer of an indicating instrument comes to rest in the final deflected position,

(i) only controlling torque acts
(ii) only deflecting torque acts
(iii) both deflecting and controlling torques act
(iv) none of the above

4. When the pointer of an indicating instrument is in motion, then deflecting torque is opposed by 

(i) controlling torque only
(ii) damping torque only
(iii) both damping & controlling torques
(iv) none of the above

5. The pointer of an indicating instrument is generally made of 

(i) copper
(ii) aluminium
(iii) silver
(iv) soft steel

6. When the pointer of an indicating instrument is in the final deflected position 

(i) deflecting torque is zero
(ii) controlling torque is zero
(iii) damping torque is zero
(iv) both deflecting & controlling torques are zero

7. In eddy current damping, disc or former is made of a material that is a  

(i) conductor but non-magnetic
(ii) conductor but magnetic
(iii) non-conductor and non-magnetic
(iv) non-conductor but magnetic

8. In general, fluid friction damping is not employed in indicating instruments although one can find its use in ………

(i) dynamometer wattmeter
(ii) hot-wire ammeter
(iii) induction type energy meter
(iv) Kelvin electrostatic voltmeter

9. Permanent-magnet moving coil instrument can be used for 

(i) a.c. work only
(ii) d.c. work only
(iii) both d.c. and a.c. work
(iv) none of the above

10. The scale of a permanent-magnet moving coil instrument is uniform because 

(i) of effective eddy current damping
(ii) external magnetic fields have no effect
(iii) it is spring controlled
(iv) it has no hysteresis loss

11. Shunts are generally made of ……..

(i) copper
(ii) aluminium
(iii) silver
(iv) manganin

12. The range of a permanent-magnet moving coil instrument is 0 – 10 A. If the full- scale deflection current of the meter is 2 mA, then multiplying power of the shunt is 

(i) 2500
(ii) 10000
(iii) 5000
(iv) none of the above

13. A moving coil instrument having meter resistance of 5Ω is to be used as a voltmeter of range 0 – 100 V. If the full-scale deflection current is 10 mA, then required series resistance is 

(i) 20 Ω
(ii) 1000 Ω
(iii) 9995 Ω
(iv) none of the above

14. The multiplying power of the shunt of a milliammeter is 8. If the circuit current is 200 mA, then current through the meter is

(i) 200 mA
(ii) 25 mA
(iii) 1600 mA
(iv) none of the above

15. The material of the shunt should have  …….. temperature co-efficient of resistance.

(i) negligible
(ii) positive
(iii) negative
(iv) none of the above

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

(i) temperature variation
(ii) external magnetic fields
(iii) hysteresis loss
(iv) none of the above

17. A moving coil voltmeter gives full-scale deflection of 100 V for a meter current of 1 mA. For 45 V reading, the meter current will be 

(i) 0.45 mA
(ii) 1.45 mA
(iii) 2.22 mA
(iv) none of the above

18. Dynamometer type instruments can be used for ……….

(i) a.c. work only
(ii) d.c. work only
(iii) both d.c. and a.c. work
(iv) none of the above

19. A dynamometer instrument is chiefly used as a ……. …..

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

20. In a dynamometer type instrument, damping is provided by 

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