Measurement and Instrumentation Multiple Choice Questions and Answers

51. In an energymeter braking torque is produced to

1. safe guard it against creep
2. brake the instrument
3. bring energy meter to stand still
4. maintain steady speed and equal to driving torque

52. In majority of instruments damping is provided by

1. fluid friction
2. spring
3. eddy currents
4. all of the above

53. In order to achieve high accuracy, the slide wire of a potentiometer should be

1. as long as possible
2. as short as possible
3. neither too small not too large
4. very thick

54. In Weston synchronoscope the moving coil is connected across

1. bus-bars
2. incoming alternator
3. fixed coils
4. any of the above

55. Induction type single phase energy meters measure electric energy in

1. kW
2. Wh
3. kWh
4. VAR

56. Instrument transformers are

1. potential transformers
2. current transformers
3. both a and b
4. power transformers

57. is an instrument which measures the insulation resistance of an electric circuit relative to earth and one another

1. Tangent galvanometer
2. Meggar
3. Current transformer
4. None of the above

58. It is required to measure the true open circuit e.m.f. of a battery. The best device is

1. D.C. voltmeter
2. Ammeter and a known resistance
3. D.C. potentiometer
4. None of the above

59. Most common form of A.C. meters met with in every day domestic and industrial installations are

1. mercury motor meters
2. commutator motor meters
3. induction type single phase energy meters
4. all of the above

60. Most sensitive galvanometer is

1. elastic galvanometer
2. vibration galvanometer
3. Duddlb galvanometer
4. spot ballistic galvanometer