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All Electrical Engineering MCQs

Study 3,658 Electrical Engineering MCQs with correct answers and explanations.

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1601Electrical EngineeringMedium

A 500 kW, 3-phase, 440 volts, 50 Hz, A.C. induction motor has a speed of 960 r.p.m. on full load. The machine has 6 poles. The slip of the machine will be________?

A0.01

B0.04

C0.02

D0.03

Correct answer

B. 0.04

Explanation

The correct answer is 0.04.

1602Electrical EngineeringMedium

In a series–parallel circuit, individual component power dissipation are calculated using________?

Aa percent of the voltage division ratio squared

Btotal current squared multiplied by the resistor values

Ca percent of the total power depending on resistor ratios

Dindividual component parameters

Correct answer

D. individual component parameters

Explanation

The correct answer is individual component parameters.

1603Electrical EngineeringMedium

A sine wave has a frequency of 50 Hz. Its angular frequency is ________ radian/second.

A50 jt

B25 JT

C5 n

D100 n

Correct answer

D. 100 n

Explanation

The correct answer is 100 n.

1604Electrical EngineeringMedium

The r.m.s. value of pure cosine function is________?

A0.707 of peak value

B0.5 of peak value

Csame as peak value

Dzero

Correct answer

A. 0.707 of peak value

Explanation

The correct answer is 0.707 of peak value.

1605Electrical EngineeringMedium

Which of the following materials is used in the manufacture of resistance grids to be used in the starters of large motors?

ASteel

BCast-iron

CCopper

DAluminium

Correct answer

B. Cast-iron

Explanation

The correct answer is Cast-iron.

1606Electrical EngineeringMedium

In variable speed motor________?

Aa weaker commutating field is needed at low speed than at high speed

Bsame commutating field is needed at low speed than at high speed

Cnone of the above is correct

Da stronger commutating field is needed at low speed than at high speed

Correct answer

A. a weaker commutating field is needed at low speed than at high speed

Explanation

The correct answer is a weaker commutating field is needed at low speed than at high speed.

1607Electrical EngineeringMedium

Efficiency of a power transformer is of the order of________?

A25 per cent

B98 per cen t

C100 per cent

D50 per cent

Correct answer

B. 98 per cen t

Explanation

The correct answer is 98 per cen t.

1608Electrical EngineeringMedium

A zener diode utilizes ________ characteristics for its operation?

Areverse

Bnone of the above

Cboth forward and reverse

Dforward

Correct answer

A. reverse

Explanation

The correct answer is reverse.

1609Electrical EngineeringMedium

If the supply frequency to the transformer is increased,”the iron loss will________?

Adecrease

Bincrease

Cany of the above

Dnot change

Correct answer

B. increase

Explanation

The correct answer is increase.

1610Electrical EngineeringMedium

For VGS = 0 V, the drain current becomes constant when VDS exceeds ________?

AVDD

Bcut off

DVP

Correct answer

D. VP

Explanation

The correct answer is VP.

In a series–parallel circuit, individual component power dissipation are calculated using________?

Aa percent of the voltage division ratio squared

Btotal current squared multiplied by the resistor values

Ca percent of the total power depending on resistor ratios

Dindividual component parameters

Correct answer

D. individual component parameters

Explanation

The correct answer is individual component parameters.

In variable speed motor________?

Aa weaker commutating field is needed at low speed than at high speed

Bsame commutating field is needed at low speed than at high speed

Cnone of the above is correct

Da stronger commutating field is needed at low speed than at high speed

Correct answer

A. a weaker commutating field is needed at low speed than at high speed

Explanation

The correct answer is a weaker commutating field is needed at low speed than at high speed.