Question

A transformer transforms.....

1) frequency

2) only voltage

3) only current

4) power


In a transformer, the resistance between its primary and secondary should be.....

1) infinity

2) zero

3) 500 ohm

4) nearly 1 K


The magnetizing current of a transformer is usually small because it has.....

1) laminated silicon steel core

2) small air gap

3) not rotating part

4) large leakage flux


Which of the following will improve the mutual coupling between primary and secondary of a transformer?

1) high reluctance magnetic core

2) Transformer hight

3) winding material of high resistivity

4) low reluctance magnetic core


The size of transformer core depends on

1) frequency

2) area of the core

3) flux density

4) both a and c


The ordinary efficiency of transformer is maximum when....

1) it runs at full load

2) it runs at half load

3) cu loss and iron losses are equal

4) runs at overload


Transformer oil must be free from.....

1) odour

2) gases

3) sulphar

4) moisture


Use of high flux density in transformer design....

1) increases the weight per kVA

2) decreases the weight per kVA

3) increases the weight per kW

4) decreases the weight per kW


In an ideal transformer, the no load primary current Io....

1) lags behind V1 by 90 degrees

2) is in phase with V1

3) leads V1 by 90 degrees

4) lags V1 by an angle lying between o to 90 degrees


Regarding the working component Iw and magnetising component Im of the no load primary current of a transformer which of the following statements is true?

1) Iw < Im

2) Iw > Im

3) Iw = Im

4) Im/Iw = constant

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Answer 1

Answer:

1 frequency

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