TRANSFORMER-MCQ

1.Which of the following does not change in transformer ?

A. current
B. voltage
C. frequency
D. all the above

Ans: C

2. The efficiency of transformer is maximum when

A. copper loss=hysteresis loss
B. copper loss=eddy current loss
C. hysteresis loss=eddy current loss
D. core loss=copper loss 

Ans: D

3.The transformer ratings are usually expressed in

A. ampere
B. KVA
C. KW
D. voltage

Ans: B

4. The transformer ratings are usually expressed in

A. ampere
B. KVA
C. KW
D. voltage
Ans: B

5. Which of the following does not change in a transformer ?

a.current
b. voltage
c. frequency
d. all the above

Ans: C

6. For parallel operation of single phase transformers it is necessary that they should have

A. same efficiency
B. same polarity
C. same KVA rating
D. same no.of turns on secondary side

Ans: B

7. A certain transformer has 400 turns in the primary winding and 2,000 turns in the secondary winding. The turns ratio is

A. 0.2 
B. 0.4
C. 5 
D. 25

Ans: A

8. The main purpose of performing open-circuit on a transformer is to measure its

a) copper loss
b) core loss
c) total loss
d) insulation resistance

Ans: B

9. Secondary current of a step down transformer is

A. Lower than primary current

B. Higher than primary current

C. Equal to primary current

D. Double than primary current

Ans: B

10. Principle of statically induced emf is used in 

A. transformer
B. motor
C. generator
D. battery

Ans: A

11. A buchholz relay can be installed on

A. auto-transformers
B. welding transformers
C. air-cooled transformers
D. oil-cooled transformers

Ans: D