# Electrical Transformer MCQ [Questions with Answers]

A transformer is an electrical device that steps the ac voltage from one level to another.

## A transformer works on

A transformer works on:

1. AC only
2. DC only
3. Both of these

## A transformer performs conversion

A transformer performs conversion:

1. AC to DC
2. DC to AC
3. AC from one level to other
4. DC from one level to other

Correct answer: 3. AC from one level to other

## The windings of the power transformer are

The windings of the power transformer are:

## A transformer requires

A transformer requires:

1. Damped magnetic flux
2. Constant magnetic flux
3. Decreases magnetic flux
4. Alternating magnetic flux

Correct answer: 4. Alternating magnetic flux

## Keeping constant voltage, by increasing the supply frequency of the transformer the magnetising component

Keeping constant voltage, by increasing the supply frequency of the transformer the magnetising component:

1. Increases
2. Decreases
3. Will remain the same
4. Any of these

## With an increase in load, the flux in the transformer core

With an increase in load, the flux in the transformer core:

1. Increases
2. Decreases
3. Remains same
4. Any of these

## Short circuit test is used to measure

Short circuit test is used to measure:

1. Copper losses only
2. Core losses only
3. Both of these
4. None of these

Correct answer: 1. Copper losses only

## Open circuit test is used to measure

Open circuit test is used to measure:

1. Copper losses only
2. Core losses only
3. Both of these
4. None of these

Correct answer: 2. Core losses only

## A transformer with 10 number of primary turns and 20 number of secondary turns, having vp = 10 V will provide Vs

A transformer with 10 number of primary turns and 20 number of secondary turns, having vp = 10 V will provide Vs:

1. 5
2. 10
3. 15
4. 20

## If we want to operate a 60 Hz transformer on 50 Hz, the applied voltage

If we want to operate a 60 Hz transformer on 50 Hz, the applied voltage:

1. Should be reduced by one fifth
2. Should be increased by one fifth
3. Should be reduced by one-sixth
4. Should be increased by one-sixth

Correct answer: 3. Should be reduced by one sixth

## Generally a transformer having rating 5 kVA is

Generally a transformer having rating 5 kVA is:

1. Natural air-cooled
2. Oil cooled
3. Water-cooled
4. Pressurized water-cooled

## The transformer winding having a greater number of turns is

The transformer winding having a greater number of turns is:

1. High voltage winding
2. Low voltage winding
3. Any of these

Correct answer: 1. High voltage winding

Explanation: From formula:

Vp/Vs = Np/Ns

## A transformer core having air gap has expected to have

A transformer core having air gap has expected to have:

1. Decreased hysteresis losses
2. Increased magnetizing current
3. Increased eddy currents
4. None of these

Correct answer: 2. Increased magnetizing current

## A transformer is efficient device for the reason being

A transformer is efficient device for the reason being:

1. It uses capacitive coupling
2. It uses inductive coupling
3. It has two coils
4. It is static device

Correct answer: 4. It is static device

Unlike other rotating machines (like synchronous motors, induction motors) a transformer is a static device meaning it does not have any rotating parts. Thus a transformer has no mechanical losses which increase the efficiency of the transformer.

## More Transformers MCQ

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