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Rectifiers and Converters

Study 58 Electrical Engineering MCQs with correct answers and explanations.

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41Electrical EngineeringMedium

Glass rectifiers are usually made into units capable of D.C. output (maximum continuous rating) of ________?

A400 A at 400 V

B500 A at 500 V

C100 A at 100 V

D300 A at 300 V

E200 A at 200 V

Correct answer

B. 500 A at 500 V

Explanation

The correct answer is 500 A at 500 V.

42Electrical EngineeringMedium

In a mercury arc rectifier characteristic blue luminosity is due to________?

Ahigh temperature

Belectron streams

Ccolour of mercury

Dionization

Correct answer

D. ionization

Explanation

The correct answer is ionization.

43Electrical EngineeringMedium

The voltage drop between the anode and cathode, of a mercury arc rectifier comprises of the following________?

Acathode drop and arc drop

Banode drop and cathode drop

Canode drop and arc drop

Danode drop, cathode drop and arc drop

Correct answer

D. anode drop, cathode drop and arc drop

Explanation

The correct answer is anode drop, cathode drop and arc drop.

44Electrical EngineeringMedium

The internal efficiency of a mercury arc rectifier depends on________?

Ar.m.s. value of current

Bvoltage and current

Ccurrent only

Dvoltage only

Enone of the above

Correct answer

D. voltage only

Explanation

The correct answer is voltage only.

45Electrical EngineeringMedium

The ignited or auxiliary anode in mercury arc rectifier is made of________?

Acopper

Baluminium

Cgraphite

Dboron carbide

Correct answer

D. boron carbide

Explanation

The correct answer is boron carbide.

46Electrical EngineeringMedium

Which of the following statement is incorrect?

ACopper oxide rectifier is not a perfect rectifier

BCopper oxide rectifier finds use in control circuits

CCopper oxide rectifier is not stable during early life

DCopper oxide rectifier has a low efficiency

ECopper oxide rectifier is a linear device

Correct answer

E. Copper oxide rectifier is a linear device

Explanation

The correct answer is Copper oxide rectifier is a linear device.

47Electrical EngineeringMedium

Normally, which of the following is used, when a large-scale conversion from AC. to D.C. power is required?

AMercury arc rectifier

BMotor converter

CMotor-generator set

DRotary converter

Correct answer

A. Mercury arc rectifier

Explanation

The correct answer is Mercury arc rectifier.

48Electrical EngineeringMedium

Which of the following is reversible in action?

ARotary converter

BNone of the above

CAny of the above

DMotor generator set

EMotor converter

Correct answer

A. Rotary converter

Explanation

The correct answer is Rotary converter.

49Electrical EngineeringMedium

Ageing of a selenium rectifier may change the output voltage by________?

Anone of the above

B5 to 10 per cent

C15 to 20 per cent

D25 to 30 per cent

Correct answer

B. 5 to 10 per cent

Explanation

The correct answer is 5 to 10 per cent.

50Electrical EngineeringMedium

A rotary converter operates at a________?

Azero power factor

Blow power factor

Cnone of the above

Dhigh power factor

Correct answer

D. high power factor

Explanation

The correct answer is high power factor.

Which of the following statement is incorrect?

ACopper oxide rectifier is not a perfect rectifier

BCopper oxide rectifier finds use in control circuits

CCopper oxide rectifier is not stable during early life

DCopper oxide rectifier has a low efficiency

ECopper oxide rectifier is a linear device

Correct answer

E. Copper oxide rectifier is a linear device

Explanation

The correct answer is Copper oxide rectifier is a linear device.