Measurements and Instrumentation

16

Assertion (A): For best results the system of a D'Arsonval galvanometer should be slightly under damped.

Reason (R): Degree of damping affects the time taken by the instrument to come to final position.

A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true R is false
D. A is false R is true

17

Crompton potentiometer has

A. 14 coils and a slide wire all having the same resistance
B. 14 coils and a slide wire but the resistance of slide wire is half that of each coil
C. 14 coils each of different resistance
D. 14 coils out of which 7 coils have resistance which is twice that of remaining 7 coils

18

Measurement of non-electrical quantity involves the following subsystems

  1. Amplifier block
  2. Display block
  3. Instrumentation block
  4. Transducer block
The correct sequence of these blocks is

A. 4, 1, 3, 2
B. 4, 3, 1, 2
C. 1, 3, 2, 4
D. 1, 2, 3, 4

19

If two time varying signals of equal magnitudes and 90° phase displacement are applied to X and Y plates of CRO, the display will be

A. a straight line
B. a circle
C. an ellipse
D. a rectangle

20

It is required to measure the true open circuit emf of a battery. The best device is

A. dc voltmeter
B. ammeter and known resistance
C. dc potentiometer
D. either (a) or (c)