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All Electrical Engineering MCQs

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

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2431Electrical EngineeringMedium

The arcing contacts in a circuit breaker are made of________?

Aelectrolytic copper

Bcopper tungsten alloy

Cporcelain

Daluminium alloy

Correct answer

B. copper tungsten alloy

Explanation

The correct answer is copper tungsten alloy.

2432Electrical EngineeringMedium

The frequency of domestic power supply in Pakistan is________?

A100 Hz

B60 Hz

C200 Hz

D50 Hz

Correct answer

D. 50 Hz

Explanation

The correct answer is 50 Hz.

2433Electrical EngineeringMedium

The total resistance of a parallel circuit is 50 Ω. If the total current is 120 mA, the current through the 270 Ω that makes up part of the parallel circuit is approximately________?

A120 mA

B22 mA

C220 mA

D50 mA

Correct answer

B. 22 mA

Explanation

The correct answer is 22 mA.

2434Electrical EngineeringMedium

As the temperature of a transistor goes up, the base-emitter resistance________?

Anone of the above

Bincreases

Cdecreases

Dremains the same

Correct answer

C. decreases

Explanation

The correct answer is decreases.

2435Electrical EngineeringMedium

For which of the following ratings of the transformer differential protection is recommended?

Aequal to and above 25 MVA

Bnone of the above

Cabove 30 kVA.

Dequal to and above 5 MVA

Correct answer

D. equal to and above 5 MVA

Explanation

The correct answer is equal to and above 5 MVA.

2436Electrical EngineeringMedium

In which of the following appUcations, direct current is absolutely essential?

AElectrolysis

BVariable speed operation

CTraction

DIllumination

Correct answer

A. Electrolysis

Explanation

The correct answer is Electrolysis.

2437Electrical EngineeringMedium

A certain inverting amplifier has a closed-loop voltage gain of 25. The Op-amp has an open-loop voltage gain of 100,000. If an Op-amp with an open-loop voltage gain of 200,000 is substituted in the arrangement, the closed-loop gain________?

Aincreases slightly

Bremains at 25

Cdoubles

Ddrops to 12.5

Correct answer

B. remains at 25

Explanation

The correct answer is remains at 25.

2438Electrical EngineeringMedium

The total deficiency or excess of electrons in a body is known as________?

Acharge

Bvoltage

Cpotential gradient

Dcurrent

Correct answer

A. charge

Explanation

The correct answer is charge.

2439Electrical EngineeringMedium

Time constant of a circuit is the time in seconds taken after the application of voltage to each________?

A90% of the maximum value

B25% of maximum value

C50% of maximum value

D63% of maximum value

Correct answer

D. 63% of maximum value

Explanation

The correct answer is 63% of maximum value.

2440Electrical EngineeringMedium

A n-channel D-MOSFET with a positive VGS is operating in ________?

Athe enhancement-mode

Bsaturation

Ccut off

Dthe depletion-mode

Correct answer

A. the enhancement-mode

Explanation

The correct answer is the enhancement-mode.

2431Electrical EngineeringMedium

The arcing contacts in a circuit breaker are made of________?

Aelectrolytic copper

Bcopper tungsten alloy

Cporcelain

Daluminium alloy

Correct answer

B. copper tungsten alloy

Explanation

The correct answer is copper tungsten alloy.

2432Electrical EngineeringMedium

The frequency of domestic power supply in Pakistan is________?

A100 Hz

B60 Hz

C200 Hz

D50 Hz

Correct answer

D. 50 Hz

Explanation

The correct answer is 50 Hz.

2433Electrical EngineeringMedium

The total resistance of a parallel circuit is 50 Ω. If the total current is 120 mA, the current through the 270 Ω that makes up part of the parallel circuit is approximately________?

A120 mA

B22 mA

C220 mA

D50 mA

Correct answer

B. 22 mA

Explanation

The correct answer is 22 mA.

2434Electrical EngineeringMedium

As the temperature of a transistor goes up, the base-emitter resistance________?

Anone of the above

Bincreases

Cdecreases

Dremains the same

Correct answer

C. decreases

Explanation

The correct answer is decreases.

2435Electrical EngineeringMedium

For which of the following ratings of the transformer differential protection is recommended?

Aequal to and above 25 MVA

Bnone of the above

Cabove 30 kVA.

Dequal to and above 5 MVA

Correct answer

D. equal to and above 5 MVA

Explanation

The correct answer is equal to and above 5 MVA.

2436Electrical EngineeringMedium

In which of the following appUcations, direct current is absolutely essential?

AElectrolysis

BVariable speed operation

CTraction

DIllumination

Correct answer

A. Electrolysis

Explanation

The correct answer is Electrolysis.

2437Electrical EngineeringMedium

A certain inverting amplifier has a closed-loop voltage gain of 25. The Op-amp has an open-loop voltage gain of 100,000. If an Op-amp with an open-loop voltage gain of 200,000 is substituted in the arrangement, the closed-loop gain________?

Aincreases slightly

Bremains at 25

Cdoubles

Ddrops to 12.5

Correct answer

B. remains at 25

Explanation

The correct answer is remains at 25.

2438Electrical EngineeringMedium

The total deficiency or excess of electrons in a body is known as________?

Acharge

Bvoltage

Cpotential gradient

Dcurrent

Correct answer

A. charge

Explanation

The correct answer is charge.

2439Electrical EngineeringMedium

Time constant of a circuit is the time in seconds taken after the application of voltage to each________?

A90% of the maximum value

B25% of maximum value

C50% of maximum value

D63% of maximum value

Correct answer

D. 63% of maximum value

Explanation

The correct answer is 63% of maximum value.

2440Electrical EngineeringMedium

A n-channel D-MOSFET with a positive VGS is operating in ________?

Athe enhancement-mode

Bsaturation

Ccut off

Dthe depletion-mode

Correct answer

A. the enhancement-mode

Explanation

The correct answer is the enhancement-mode.