Measurement MCQ Part-4

Measurement MCQs

1. Which one of the following types of instruments can be used to determine the rms values of high magnitude (10 kV) and of any wave shape?

a. Electrostatic instruments

b. Induction instruments

c. Dynamometer type instruments

d. Moving iron instruments

2. Which one of the following instruments will have poorest overloading capacity?

a. Hot wire instrument

b. Permanent magnet instrument

c. Induction type instruments

d. Moving coil instruments

3. Which voltmeter would you select for measuring 50,000 V direct current?

a. Electrodynamometer 

b. Electrostatic voltmeter

c. Hot wire voltmeter

d. Moving coil voltmeter

4. To increase the current measurement range of an ammeter, it is_______.

a. Shunted by a low resistance 

b. Put in series with a low resistance 

c. Put in series with a high resistance

d. Shunted by a high resistance

5. How can a milliammeter be used as a voltmeter?

a. By connecting a high resistance in series with the instrument

b. By connecting a low resistance in series with the instrument

c. By connecting a high resistance in parallel with the instrument

d. By connecting a low resistance in parallel with the instrument

6. The primary current in CT is dictated by__________.

a. The load current

b. The core of the transformer

c. The secondary burden

d. None of the above

7. The secondary of a CT is never left open-circuited because otherwise ______.

a. Heat dissipation in the core will be very large

b. The core will be saturated and permanently magnetised rendering it useless

c. Dangerously high emfs will be induced in the secondary

d. All of the above

8. Instrument transformers are known to introduce magnitude and phase errors in measurements. These are primarily due to_______.

a. Open and short circuit parameters of the instrument transformers

b. Measurement errors inherent in the meter connected to the transformer secondary

c. Improper connections on the primary side

d. None of the above

9. The clamp-on ammeter used for______.

a. High dc current

b. Low dc current

c. High ac current

d. Low ac current

10. In case of a PT with the increase in load on secondary side_______.

a. Both of the ratio error and phase angle error decrease

b. The ratio error decreases but phase angle error increases

c. The ratio error increases but the phase angle error decreases

d. Both of the ratio error and phase angle increase

11. The moving coil dynamometer wattmeter is connected_______.

a. Across the load

b. In series with load

c. Across the supply

d. In series with the fixed coil

12. Dynamometer type wattmeters are suitable for_______.

a. Only high voltage ac circuits

b. Only dc circuits

c. Only ac circuits

d. Both ac and dc circuits

13. The pressure coil of a dynamometer type wattmeter is________.

a. Purely inductive 

b. Purely resistive

c. Highly resistive

d. Highly inductive

14. A dynamometer type wattmeter responds to the _______.

a. Peak value of active power

b. Peak value of reactive power

c. Average value of reactive power

d. Average value of active power

15. Due to the effect of inductance in the pressure coil, a dynamometer type wattmeter_____.

a. Always reads lower than the actual value

b. Reading is independent of the power factor

c. Reads high on lagging power factor and low on leading power factor

d. Reads low on lagging power factor and high on leading power factor

16. In a low power factor wattmeter, why is a compensating coil employed?

a. To neutralize the capacitive effect of pressure coil

b. To compensate for inductance of pressure coil

c. To compensate for error caused by power loss in the pressure coil

d. To compensate for the error caused by eddy currents

17. Electrodynamic type wattmeter have large errors while measuring power in ac circuits at low power factor conditions, since the voltage across and the current through the_______.

a. Pressure coil are not in quadrature

b. Pressure coil are not in phase

c. Current coil are not in quadrature

d. Current coil are not in phase

18. How can the power supplied to a frequency  heating system be measured?

a. By moving iron ammeter and voltmeter

b. By thermocouple type wattmeter

c. By induction type wattmeter

d. By dynamometer wattmeter

19. In the power measurement by ammeter-voltmeter method, if the voltmeter is connected across the load, then the value of the power will be_________.

a. The sum of power consumed by the load, ammeter and voltmeter

b. The sum of power consumed by the load and voltmeter

c. The sum of the power consumed by the load and ammeter

d. The power consumed by the load

20. Holes are drilled on the opposite sides of the disc of an induction type energy meter to_____.

a. Increase the deflecting torque

b. Dissipate the energy due to eddy currents

c. Balance the disc

d. Avoid creep on no load

21. A Merz price demand indicator indicates_______.

a. Average maximum demand over a specified period of time 

b. Maximum demand 

c. Maximum energy consumption

22. In a vibrating reed type frequency meter, all the reeds________.

a. Are of identical dimension and weight

b. Have different natural frequencies

c. Have the same natural frequencies

d. Are not placed closed to an electromagnet

23. Which one of the following frequency meter is suitable for measuring radio frequency?

a. Heterodyne frequency meter

b. Electrical resonance frequency meter

c. Weston frequency meter

d. Vibrating reed frequency meter

24. Which one of the following is used for the measurement of 3-phase power factor?

a. Polarised-vane power factor meter

b. Phase-angle watt hour meter

c. Crossed-coil power factor meter

d. Power factor meter

25. For low resistance (from few micro ohms to one ohm) measurement, which bridge is used?

a. Wheatstone bridge

b. Kelvin bridge

c. Guarded Wheatstone bridge

d. Maxwell bridge