Measuring Instruments MCQ

21. The moving system of an indicating type of electrical instrument is subjected to

1. A defecting torque
2. A controlling torque
3. A damping torque
4. All of the above

22. Determine the absolute error of measurement if the measured value of resistance of 20.65 Ω and true value = 20.55 Ω

1. 0.1 Ω
2. 0.2 Ω
3. 0.3 Ω
4. 0.4 Ω

23. Energy savings potential of variable torque applications compared to constant torque application is-

1. Higher
2. Minor
3. Equivalent
4. None of the above

24. The controlling torque in the power factor meter is given by

1. Spring control
2. Sensor control
3. Gravity control
4. None of the above

25. The effect of stray magnetic fields on the actuating torque of a portable instrument is the maximum when the operating field of the instrument and the stray fields are

1. Perpendicular
2. Parallel
3. Inclined at 60°
4. Inclined at 30°

26. Indicating instruments should be

1. Undamped
2. Critically damped
3. Over damped
4. Under damped

27. What is a Weston frequency meter?

1. Moving coil instrument
2. Moving iron instrument
3. Dynamometer type instrument
4. Induction instrument

28. To maximize the driving torque in an induction type instrument, the flux produced by shunt coil and series coil should be

1. In phase with each other
2. In quadrature with each other
3. Displaced by 45° with respect to each other
4. Out of phase with respect to each other

29. In indicating instruments the springs are mainly used to

1. Conduct the current to the coils
2. Hold the pivot in position
3. Control the pointer movement
4. Reduce the vibration of the pointer

30. _________ instrument is free from hysteresis and eddy current errors.

1. Electrostatics
2. Moving iron
3. Moving coil-permanent magnet type
4. Moving coil dynamometer type