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All Electrical Engineering MCQs

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671Electrical EngineeringMedium

The maximum power developed in a synchronous motor will depend on________?

Anone of the above

Bthe rotor excitation, supply voltage and maximum value of coupling angle (90°)

Cthe rotor excitation and supply volt-age both

Dthe supply voltage only

Ethe rotor excitation only

Correct answer

B. the rotor excitation, supply voltage and maximum value of coupling angle (90°)

Explanation

The correct answer is the rotor excitation, supply voltage and maximum value of coupling angle (90°).

672Electrical EngineeringMedium

The minimum armature current of the synchronous motor corresponds to operation at________?

Aunity power factor

B0.707 power factor lagging

C0.707 power factor leading

Dzero power factor leading

Correct answer

A. unity power factor

Explanation

The correct answer is unity power factor.

673Electrical EngineeringMedium

The effective resistance of an iron-cored choke working on ordinary supply frequency is more than its true resistance because of________?

Airon loss in core

Bincrease in temperature

Ccapacitive effect between adjacent coil turns

Dskin effect

Correct answer

A. iron loss in core

Explanation

The correct answer is iron loss in core.

674Electrical EngineeringMedium

In deriving ac equivalent circuit for an amplifier circuit, we short circuit________?

Aall resistors

Ball inductors

Call transistors

Dall capacitors

Correct answer

D. all capacitors

Explanation

The correct answer is all capacitors.

675Electrical EngineeringMedium

Which of the following quantities remain the same in all parts of a series circuit ________?

AResistance

BCurrent

CVoltage

DPower

Correct answer

B. Current

Explanation

The correct answer is Current.

676Electrical EngineeringMedium

Which of the following statements is correct ________?

AElectrolytic capacitor must be connected in the correct polarity

BCeramic capacitors must be connected in the correct polarity

CMica capacitors are available in capacitance value of 1 to 10 pF

DAir capacitors have a black band to indicate the outside foil

Correct answer

A. Electrolytic capacitor must be connected in the correct polarity

Explanation

The correct answer is Electrolytic capacitor must be connected in the correct polarity.

677Electrical EngineeringMedium

A current of 16 amperes divides between two branches in parallel of resistances 8 ohms and 12 ohms respectively. The current in each branch is________?

A6.4 A, 6.9 A

B4.6 A, 6.9 A

C4.6 A, 9.6 A

D6.4 A, 9.6 A

Correct answer

D. 6.4 A, 9.6 A

Explanation

The correct answer is 6.4 A, 9.6 A.

678Electrical EngineeringMedium

In a synchronous motor, the magnitude of stator back e.m.f. & depends on________?

Aspeed of the motor

Bboth the speed and rotor flux

Cd.c. excitation only

Dload on the motor

Correct answer

C. d.c. excitation only

Explanation

The correct answer is d.c. excitation only.

679Electrical EngineeringMedium

If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be________?

Ahigh

Bsmall

Cthe same as rated voltage

Dzero

Correct answer

D. zero

Explanation

The correct answer is zero.

680Electrical EngineeringMedium

Platinum is used in________?

Aheating element in high temperature furnace

Belectrical contacts

Cthermocouple

Dall of the above

Egrids of special purpose vacuum tubes

Correct answer

D. all of the above

Explanation

The correct answer is all of the above.

The maximum power developed in a synchronous motor will depend on________?

Anone of the above

Bthe rotor excitation, supply voltage and maximum value of coupling angle (90°)

Cthe rotor excitation and supply volt-age both

Dthe supply voltage only

Ethe rotor excitation only

Correct answer

B. the rotor excitation, supply voltage and maximum value of coupling angle (90°)

Explanation

The correct answer is the rotor excitation, supply voltage and maximum value of coupling angle (90°).

Which of the following statements is correct ________?

AElectrolytic capacitor must be connected in the correct polarity

BCeramic capacitors must be connected in the correct polarity

CMica capacitors are available in capacitance value of 1 to 10 pF

DAir capacitors have a black band to indicate the outside foil

Correct answer

A. Electrolytic capacitor must be connected in the correct polarity

Explanation

The correct answer is Electrolytic capacitor must be connected in the correct polarity.