Explore topic-wise MCQs in Electrical Engineering.

This section includes 22 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.

1.

Directions: It consists of two statements, one labeled as the 'Statement (I)' and the other as 'Statement (II)'. Examine these two statements carefully and select the answer using the codes given below:Statement (I): For an energy meter, careful design and treatment of breaking magnet during its manufacture are essential in order to ensure consistency of break magnet during the use of the meter.Statement (II): Steady rotational speed of energy meter disc is directly proportional to flux of the break magnet.

A. Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)
B. Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I)
C. Statement (I) is true but Statement (II) is false
D. Statement (I) is false but Statement (II) is true
Answer» D. Statement (I) is false but Statement (II) is true
2.

Electrolytic meter is basically a/an:

A. DC ampere-hour meter
B. AC ampere-hour meter
C. AC energy meter
D. DC watt-hour meter
Answer» B. AC ampere-hour meter
3.

In an induction type energy - meter, ‘creeping’ takes place due to

A. Decrease in the strength of the banking magnet.
B. Improper lag adjustment
C. Over - compensation of the frictional torque.
D. Fluctuation of ambient temperature.
Answer» D. Fluctuation of ambient temperature.
4.

For controlling the vibration of the disc of ac energy meter, damping torque is produced by

A. Eddy current
B. Chemical effect
C. Electrostatic effect
D. Magnetic effect
Answer» B. Chemical effect
5.

An energy meter makes 100 revolutions of its disc per unit of energy. The number of revolutions made by the disc during one-hour when connected across 210 V source and drawing a current of 20 A at 0.8 pf leading is

A. 336
B. 316
C. 286
D. 256
Answer» B. 316
6.

An energy meter has constant of 300 revolutions per unit, it makes 10 revolutions in 30 seconds when it is used for energy measurement. Find the connected load in kW

A. 3
B. 2
C. 1
D. 4
Answer» E.
7.

One single phase wattmeter operating on 230 V and 5 A for 5 hours makes 1940 revolutions. Meter constant in revolution is 400. The power factor of the load will be:

A. 1
B. 0.8
C. 0.7
D. 0.6
Answer» C. 0.7
8.

Disc in an induction type energy meter rotates in the opposite direction when

A. A large capacitor is connected on the load side
B. A large inductor is connected on the load side
C. Current coil and voltage coil are wrongly connected
D. Either current coil or voltage coil is wrongly connected
Answer» E.
9.

An energy meter with a constant of 600 revolutions per unit used for energy measurement. It makes 500 revolutions in 30 seconds. Find the energy consumed by the load for an hour.

A. 1000 units
B. 100 units
C. 10 unit
D. 0.1 unit
Answer» C. 10 unit
10.

In an induction type energy meter, everything else remaining same, if the radial distance of the brake magnet poles form the spindle is decreased by 10%, the rotational speed of the disc will approximately

A. Increase by 23.5%
B. Decrease by 10.6%
C. Decrease by 19.4%
D. Increase by 11%
Answer» E.
11.

A 230 V single-phase energy meter has a constant load current of 20 A at unity power factor. If the meter disc makes 2300 revolutions for 2 hours, the meter constant will be:

A. 0.25 revolution/kWh
B. 250 revolution/kWh
C. 0.30 revolution/kWh
D. 270 revolution/kWh
Answer» C. 0.30 revolution/kWh
12.

In a single phase induction type energy meter, the deflecting torque is________the true power in the circuit.

A. Proportional to
B. Equal to
C. Greater than
D. Less than
Answer» B. Equal to
13.

In induction type watthour meters, the errors due to frictional forces at the rotor bearings and in the register mechanism is minimized by.

A. Having the product of the shunt magnet flux φ2 and series magnet flux φ1 small
B. Having the ratio of the shunt magnet flux φ2 and series magnet flux φ1 small
C. Having the product of the shunt magnet flux φ2 and series magnet flux φ1 large
D. Having the ratio of the shunt magnet flux φ2 and series magnet flux φ1large
Answer» E.
14.

In an induction type energy meter, the steady speed attained by the rotating disc is1. Proportional to the deflecting torque.2. Proportional to the resistance of the path of eddy currents.3. Inversely proportional to the effective readings of disc from its axis.4. Inversely proportional to the square of brake magnet fluxWhich of the above are correct?

A. 1, 2 and 3 only
B. 1, 2 and 4 only
C. 2, 3 and 4 only
D. 1, 2, 3 and 4
Answer» E.
15.

Holes are drilled on the disc of induction type energy meter at diametrically opposite positions to

A. Balance the disc
B. Dissipate the energy due to eddy currents
C. Increase the deflecting torque
D. Avoid creep on no load
Answer» E.
16.

‘Creeping’ is a term related to _____ instruments.

A. Dynamometer type
B. PMMC type
C. Induction type
D. Moving iron type
Answer» D. Moving iron type
17.

A 230-V, 50-A energy meter on full load test makes 61 revolutions in 37 seconds. If the meter constant is 520 rev/kwh, what is the percentage error?

A. 0.67%
B. 0.76%
C. 1%
D. 0.24%
Answer» C. 1%
18.

An ampere-hour meter is calibrated at 200 V. That meter is used on 230 v circuit for energy measurement and indicates a consumption of 700 units in certain period. What is the actual energy supplied?

A. 805 units
B. 750 units
C. 800 units
D. 780 units
Answer» B. 750 units
19.

A 230 V, single-phase domestic energy meter is connected to a constant resistive lamp load 4 A. It makes 2300 revolution in 5 hours. What is meter constant in rev/unit?

A. 500
B. 250
C. 450
D. 300
Answer» B. 250
20.

If an energy meter disc makes 10 revolutions in 10 minutes when a load of 600 W is connected to it, the meter constant in rev / kWh is:

A. 100
B. 600
C. 800
D. 200
Answer» B. 600
21.

If an induction type energy meter runs fast, it can be slowed by:

A. Lag adjustment
B. Light load adjustment
C. Adjusting the position of braking magnet and making it come closer to the centre of the disc
D. Adjusting the position of braking magnet and making it move away from the centre of the disc
Answer» E.
22.

In an energy meter, braking torque is produced to

A. Safe guard it against creep
B. Brake the instrument
C. Bring energy meter to stand still
D. Maintain steady speed and equal to driving torque
Answer» E.