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All Electrical Engineering MCQs

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

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1571Electrical EngineeringMedium

D.C. generators are normally designed for maximum efficiency around________?

Arated voltage

Ball of the above

Cfull-load

Drated r.p.m.

Correct answer

C. full-load

Explanation

The correct answer is full-load.

1572Electrical EngineeringMedium

The charge required to liberate one gram equivalent of any substance is known as ________ constant

AFaraday’s

BBoltzman

Ctime

Correct answer

A. Faraday’s

Explanation

The correct answer is Faraday’s.

1573Electrical EngineeringMedium

Addition of 0.3 to 4.5% silicon to iron ________ the electrical resistivity of iron?

Adecreases

Bincreases

Cdoes not change

Correct answer

B. increases

Explanation

The correct answer is increases.

1574Electrical EngineeringMedium

Due to which of the following reasons copper and aluminium are not used for heating elements?

AVery large length of wires will be required

BAll of the above

CBoth have great tendency for oxidation

DBoth have low melting point

Correct answer

B. All of the above

Explanation

The correct answer is All of the above.

1575Electrical EngineeringMedium

A crystal diode utilises …………….. characteristic for rectification

Aforward

Bforward or reverse

Creverse

Dnone of the above

Correct answer

A. forward

Explanation

The correct answer is forward.

1576Electrical EngineeringMedium

The plugging gives the________?

Ahighest torque braking

Bsmallest torque braking

Czero torque braking

Dnone of the above

Correct answer

A. highest torque braking

Explanation

The correct answer is highest torque braking.

1577Electrical EngineeringMedium

Dielectric strength of a material depends on________?

Atemperature

Bmoisture content

Cthickness

Dnone of the above

Eall of the above

Correct answer

E. all of the above

Explanation

The correct answer is all of the above.

1578Electrical EngineeringMedium

Which of the following is not an operating cost?

AFuel cost

BSalaries of high officials

CSalaries of operating staff

DMaintenance cost

Correct answer

B. Salaries of high officials

Explanation

The correct answer is Salaries of high officials.

1579Electrical EngineeringMedium

The speed of a D.C. series motor is________?

Ainversely proportional to the armature current

Bproportional to field current

Cproportional to the armature current

Dproportional to the square of the armature current

Correct answer

A. inversely proportional to the armature current

Explanation

The correct answer is inversely proportional to the armature current.

1580Electrical EngineeringMedium

A synchronous motor is running with normal excitation. When the load is increased, the armature current drawn by it increases because

Apower factor is decreased

Bspeed of the motor is reduced

Cnone of the above

DEr (net resultant voltage) in armature is increased

EEb (back e.m.f.) becomes less than V (applied voltage)

Correct answer

D. Er (net resultant voltage) in armature is increased

Explanation

The correct answer is Er (net resultant voltage) in armature is increased.

The speed of a D.C. series motor is________?

Ainversely proportional to the armature current

Bproportional to field current

Cproportional to the armature current

Dproportional to the square of the armature current

Correct answer

A. inversely proportional to the armature current

Explanation

The correct answer is inversely proportional to the armature current.

A synchronous motor is running with normal excitation. When the load is increased, the armature current drawn by it increases because

Apower factor is decreased

Bspeed of the motor is reduced

Cnone of the above

DEr (net resultant voltage) in armature is increased

EEb (back e.m.f.) becomes less than V (applied voltage)

Correct answer

D. Er (net resultant voltage) in armature is increased

Explanation

The correct answer is Er (net resultant voltage) in armature is increased.