Measurement and Instrumentation MCQs Quiz Multiple Choice Questions & Answers

1. Basically a potentiometer is a device for

1. comparing two voltages
2. measuring a current
3. comparing two currents
4. measuring a voltage

2. Commonly used instruments in power system measurement are

1. induction
2. moving coil or iron
3. rectifier
4. electrostatic

3. Commonly used standard capacitor is

1. spherical type
2. concentric cylindrical type
3. electrostatic type
4. multilayer parallel plate type

4. Damping of the Ballistic galvanometer is made small to

1. get first deflection large
2. make the system oscillatory
3. make the system critically damped
4. get minimum overshoot

5. E.m.f. of a Weston cell is accurately measured by

1. electrostatic voltmeter
2. hot wire voltmeter
3. isothermal voltmeter
4. electrodynamic voltmeter

6. For handling greater currents induction wattmeters are used in conjunction with

1. potential transformers
2. current transformers
3. power transformers
4. either of the above

7. For measurement of inductance having high value, we should use

1. Maxwells bridge
2. Maxwell Wein bridge
3. Hays bridge
4. Any of the above

8. For measurement of mutual inductance we can use

1. Anderson bridge
2. Maxwells bridge
3. Heaviside bridge
4. Any of the above

9. For measurements on high voltage capacitors, the suitable bridge is

1. Wein bridge
2. Modified De Santys bridge
3. Schering bridge
4. Any of the above

10. For measuring a very high resistance we should use

1. Kelvins double bridge
2. Wheat stone bridge
3. Meggar
4. None of the above

11. For measuring current at high frequency we should use

1. moving iron instrument
2. electrostatic instrument
3. thermocouple instrument
4. none of the above

12. If an inductance is connected in one arm of bridge and resistances in the remaining three arms

1. the bridge can always be balanced
2. the bridge cannot be balanced
3. the bridge can be balanced if the resistances have some specific values

13. If an instrument has cramped scale for larger values, then it follows

1. square law
2. logarithmic law
3. uniform law
4. none of the above

14. If the current in a capacitor leads the voltage by 80°, the loss angle of the capacitor is

1. 10°
2. 80°
3. 120°
4. 170°

15. In a 3-phase power measurement by two wattmeter method the reading of one of the wattmeter was zero. The power factor of the load must be

1. unity
2. 0.5
3. 0.3
4. zero

16. In a 3-phase power measurement by two wattmeter method, both the watt meters had identical readings. The power factor of the load was

1. unity
2. 0.8 lagging
3. 0.8 leading
4. zero

17. In a dynamometer 3-phase power factor meter, the planes of the two moving coils are at

1. 0°
2. 60°
3. 90°
4. 120°

18. In a low power factor wattmeter the compensating coil is connected

1. in series with current coil
2. in parallel with current coil
3. in series with pressure coil
4. in parallel with pressure coil

19. In a low power factor wattmeter the pressure coil is connected

1. to the supply side of the current coil
2. to the load side of the current coil
3. in any of the two meters at connection
4. none of the above

20. In a meggar controlling torque is provided by

1. spring
2. gravity
3. coil
4. eddy current

21. In a portable instrument, the controlling torque is provided by

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

22. In a Schering bridge the potential of the detector above earth potential is

1. a few volts only
2. 1 kV
3. 5 kV
4. 10 kV

23. In a single phase power factor meter the phase difference between the currents in the two pressure coils is

1. exactly 0°
2. approximately 0°
3. exactly 90°
4. approximately 90°

24. In a vibrating reed frequency meter the natural frequencies of two adjacent reeds have a difference of

1. 0.1 Hz
2. 0.25 Hz
3. 0.5 Hz
4. 1.5 Hz

25. In a Weston frequency meter, the magnetic axes of the two fixed coils are

1. parallel
2. perpendicular
3. inclined at 60°
4. inclined at 120°

26. In a Weston synchronoscope, the fixed coils are connected across

1. bus-bars
2. incoming alternator
3. a lamp
4. none of the above

27. In an AC. co-ordinate potentiometer, the currents in the phase and quadrature potentiometer are adjusted to be

1. out of phase by 90°
2. out of phase by 60°
3. out of phase by 30°
4. out of phase by 0°

28. In an Anderson bridge, the unknown inductance is measured in terms of

1. known inductance and resistance
2. known capacitance and resistance
3. known resistance
4. known inductance

29. 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

30. In majority of instruments damping is provided by

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

31. 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

32. In Weston synchronoscope the moving coil is connected across

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

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

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

34. Instrument transformers are

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

35. 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

36. 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

37. 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

38. Most sensitive galvanometer is

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

39. Murray loop test can be used for location of

1. ground fault on a cable
2. short circuit fault on a cable
3. both the ground fault and the short-circuit fault
4. none of the above

40. Operating torques in analogue instruments are

1. deflecting and control
2. deflecting and damping
3. deflecting, control and damping
4. vibration and balancing

41. Resistances can be measured with the help of

1. wattmeters
2. voltmeters
3. ammeters
4. ohmmeters and resistance bridges

42. Standard resistor is made from

1. platinum
2. maganin
3. silver
4. nichrome

43. Systematic errors are

1. instrumental errors
2. environmental errors
3. observational errors
4. all of the above

44. The adjustment of position of shading bands, in an energy meter is done to provide

1. friction compensation
2. creep compensation
3. braking torque
4. none of the above

45. The chemical effect of current is used in

1. D.C. ammeter hour meter
2. D.C. ammeter
3. D.C. energy meter
4. none of the above

46. The desirable static characteristics of a measuring system are

1. accuracy and reproducibility
2. accuracy, sensitivity and reproducibility
3. drift and dead zone
4. static error

47. The disc of an instrument using eddy current damping should be of

1. conducting and magnetic material
2. non-conducting and magnetic material
3. conducting and non-magnetic material
4. none of the above

48. The electrical power to a meggar is provided by

1. battery
2. permanent magnet D.C. generator
3. AC.generator
4. any of the above

49. The function of shunt in an ammeter is to

1. by pass the current
2. increase the sensitivity of the ammeter
3. increase the resistance of ammeter
4. none of the above

50. The gravity controlled instrument has crowded scale because current is proportional to

1. balancing weight
2. deflection angle
3. sine of deflection angle