Page 870 - Basic Electrical Engineering

5. The extension of range of an ammeter and a voltmeter can be made respectively by

a. using multiplier and shunt
b. using shunt and multiplier
c. using series capacitor and a series inductor
d. reducing the spring tension of the deflecting system.

6. To increase the sensitivity of a deflecting-type instrument

a. torque–weight ratio of the moving system should be high
b. torque–weight ratio of the moving system should be low
c. it should be lightly damped
d. the control torque must be reduced.

7. A permanent-magnet moving-coil instrument cannot be used for ac measurement because on
ac the deflecting system will

a. not respond to the quick alternating torques and will stay in its initial position
b. respond to ac signal but will not move because of inertia
c. get burnt out
d. give incorrect reading.

8. In a moving-iron-type instrument the current flowing throgh the coil, I and the torque
developed T are related as
d

a. T α I
d

b.

2
c. T α I
d

d. .

9. Wattmeters are of

a. permanent-magnet moving-coil type
b. dynamometer type
c. moving-iron type
d. hot-wire type.

10. Basic difference between an ammeter and a voltmeter is that

a. an ammeter is a low-resistance instrument while a voltmeter is a high-resistance
instrument