# Energy Meter Theory - MCQs with answers

## Energy Meter Theory - MCQs with answers

Q1. The instrument which works only with dc is

A. Electrolytic motor
B. Mercury motor
C. Induction motor
D. Both (a) and (b)

ANSWER: D. Both (a) and (b)

Q2. The electrolytic energy meters are essentially

A. A true watt-hour meter
B. An ampere hour meter
C. Either watt-hour or ampere hour meter
D. Neither watt-hour nor ampere hour meter

ANSWER: B. An ampere hour meter

Q3. An electrolytic ampere hour meter can be converted into watt-hour meter by

A. Multiplying them by the voltage of the circuits in which it is used

B. Multiplying them by the current of the circuits in which it is used

C. Multiplying them by the power of the circuits in which it is used

D. Cannot be converted

ANSWER: A. Multiplying them by the voltage of the circuits in which it is used

Q4. Commutator type meters can be used for

A. Ac supply
B. Dc supply
C. Both ac and dc supply
D. None of these

ANSWER: C. Both ac and dc supply

Q5. In case of motor meters, the speed of rotation is

A. Directly proportional to the current in case of ampere hour meter and to power in case of watt-hour meter

B. Directly proportional to the current in case of ampere hour meter and inversely proportional to the power in case of watt-hour meter

C. Inversely proportional to the current in case of ampere hour meter and directly proportional to the power in case of watt-hour meter

D. Inversely proportional to the current in case of ampere hour meter and to power in case of watt-hour meter

ANSWER: A. Directly proportional to the current in case of ampere hour meter and to power in case of watt-hour meter

Q6. In motor meters, the speed control of the rotating system is done by using

A. Permanent magnet
B. Train of gear wheels and dials
C. Pinion
D. All of these

Q7. Commutator motor meters are

A. Ampere hour meter
B. True watt-hour meter
C. Either ampere hour meter or true watt-hour meter
D. None of these

ANSWER: C. Either ampere hour meter or true watt-hour meter

Q8. The induction type single-phase watt-hour meters uses

A. Control spring
B. Pointer
C. Brake magnet and spindle
D. All of these

ANSWER: C. Brake magnet and spindle

Q9. In induction watt-hour meter, due to shunt magnet the torque is not zero power factor. It can be compensated by using

B. Power factor compensator
C. Drilling holes in the disc on a diameter
D. Both (a) and (b)

ANSWER: D. Both (a) and (b)

Q10. For friction compensation in an induction watt-hour meter is done by making

A. The ratio of the shunt magnet flux and series magnet flux large with the help of two shading bands

B. The ratio of the series magnet flux and shunt magnet flux large with the help of two shading bands

C. The ratio of the shunt magnet flux and series magnet flux large with the help of three shading bands

D. The ratio of the series magnet flux and shunt magnet flux large with the help of three shading bands