# Transformer MCQs Part 27

## In an autotransformer, the primary and secondary are coupled

In an autotransformer, the primary and secondary are coupled:

1. Electrically
2. Magnetically
3. Both of these
4. None of these

Correct answer: 3. Both of these

1. Greater
2. Lesser
3. Nearly the same
4. None of these

## The voltage regulation of a transformer is negative when its load power factor is

The voltage regulation of a transformer is negative when load power factor is

1. Unity
2. Lagging
4. Zero

See Explanation below:

## The current transformer is type of

The current transformer is type of

1. Transformer that is used with an AC Voltmeter
2. Transformer that is used with an AC Ammeter
3. Transformer that is used with an DC Voltmeter
4. Transformer that is used with an DC Ammeter

Correct answer: 2. Transformer that is used with an AC Ammeter

A transformer having 400 primary turns and 100 secondary turns 100 has 20 A current through its primary has

A transformer having 400 primary turns and 100 secondary turns 100 has 20 A current through its primary has:

1. 4 A at secondary
2. 40 A at secondary
3. 5 A at secondary
4. 80 A at secondary

Correct answer: 4. 80 A at secondary

Explanation:

Is/Ip = Np/Ns

Is  = (400/100) * 20 = 4 * 20 = 80 A