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All Electrical Engineering MCQs

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

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2131Electrical EngineeringMedium

What will happen to an insulating medium if voltage more than the breakdown voltage is applied on it________?

AIt will get punctured or cracked

BIt will become magnetic

CIts molecular structure will get changed

DIt will melt

Correct answer

A. It will get punctured or cracked

Explanation

The correct answer is It will get punctured or cracked.

2132Electrical EngineeringMedium

The Biot-savart’s law is a general modification of________?

AFaraday’s laws

BLenz’s law

CAmpere’s law

DKirchhoffs law

Correct answer

C. Ampere’s law

Explanation

The correct answer is Ampere’s law.

2133Electrical EngineeringMedium

Average resistance of human body is________?

A1500 ohms

B1000 ohms

C500 ohms

D2000 ohms

Correct answer

B. 1000 ohms

Explanation

The correct answer is 1000 ohms.

2134Electrical EngineeringMedium

The maximum output voltage of a certain low-pass filter is 15 V. The output voltage at the critical frequency is________?

A15 V

B21.21 V

C10.60 V

D0 V

Correct answer

C. 10.60 V

Explanation

The correct answer is 10.60 V.

2135Electrical EngineeringMedium

To reverse the direction of rotation of acapacitor start motor while it is running we should________?

Adisconnect motor from the supply till it stops then reconnect it to supply with reversed connection of main or auxiliary winding

Breverse the direction of connections of the auxiliary winding and immediately connect it to supply

Creverse the direction of connection of the auxiliary winding and after motor comes to rest then connect auxiliary winding to the supply

Ddisconnect motor from supply and immediately reconnect it to supply with reversed connections of the main winding

Correct answer

A. disconnect motor from the supply till it stops then reconnect it to supply with reversed connection of main or auxiliary winding

Explanation

The correct answer is disconnect motor from the supply till it stops then reconnect it to supply with reversed connection of main or auxiliary winding.

2136Electrical EngineeringMedium

In practice, voltage gain is expressed________?

AAs a number

BIn volts

CNone of the above

DIn dB

Correct answer

D. In dB

Explanation

The correct answer is In dB.

2137Electrical EngineeringMedium

In forward blocking mode of a thyristor________?

Ajunction J3 is in forward bias and J1, J2 is in reverse bias.

BJunction J1 and J2 is in forward bias and J3 is in reverse bias.

CJunction J1, J3 is in reverse bias and J2 is in forward bias.

Djunction J2 is in reverse bias and J1, J3 is in forward bias.

Correct answer

D. junction J2 is in reverse bias and J1, J3 is in forward bias.

Explanation

The correct answer is junction J2 is in reverse bias and J1, J3 is in forward bias..

2138Electrical EngineeringMedium

An open-circuit test on a transformer is conducted primarily to measure________?

Acopper loss

Btotal loss

Cnone of the above

Defficiency

Einsulation resistance

Fcore loss

Correct answer

F. core loss

Explanation

The correct answer is core loss.

2139Electrical EngineeringMedium

The efficiency of a transformer, under heavy loads, is comparatively low because________?

Avoltage drop both in primary and secondary becomes large

Bsecondary output is much less as compared to primary input

Ccopper loss becomes high in proportion to the output

Diron loss is increased considerably

Correct answer

C. copper loss becomes high in proportion to the output

Explanation

The correct answer is copper loss becomes high in proportion to the output.

2140Electrical EngineeringMedium

When 4 volts e.m.f. is applied across a 1 farad capacitor, it will store energy of________?

A8 joules

B2 joules

C4 joules

D6 joules

Correct answer

A. 8 joules

Explanation

The correct answer is 8 joules.

To reverse the direction of rotation of acapacitor start motor while it is running we should________?

Adisconnect motor from the supply till it stops then reconnect it to supply with reversed connection of main or auxiliary winding

Breverse the direction of connections of the auxiliary winding and immediately connect it to supply

Creverse the direction of connection of the auxiliary winding and after motor comes to rest then connect auxiliary winding to the supply

Ddisconnect motor from supply and immediately reconnect it to supply with reversed connections of the main winding

Correct answer

A. disconnect motor from the supply till it stops then reconnect it to supply with reversed connection of main or auxiliary winding

Explanation

The correct answer is disconnect motor from the supply till it stops then reconnect it to supply with reversed connection of main or auxiliary winding.

In forward blocking mode of a thyristor________?

Ajunction J3 is in forward bias and J1, J2 is in reverse bias.

BJunction J1 and J2 is in forward bias and J3 is in reverse bias.

CJunction J1, J3 is in reverse bias and J2 is in forward bias.

Djunction J2 is in reverse bias and J1, J3 is in forward bias.

Correct answer

D. junction J2 is in reverse bias and J1, J3 is in forward bias.

Explanation

The correct answer is junction J2 is in reverse bias and J1, J3 is in forward bias..

The efficiency of a transformer, under heavy loads, is comparatively low because________?

Avoltage drop both in primary and secondary becomes large

Bsecondary output is much less as compared to primary input

Ccopper loss becomes high in proportion to the output

Diron loss is increased considerably

Correct answer

C. copper loss becomes high in proportion to the output

Explanation

The correct answer is copper loss becomes high in proportion to the output.