1. The primary side and secondary side of a transformer are
(a) electrically linked.
(b) magnetically linked.
(c) conductivity linked.
(d) all of the above. Answer
2. A transformer is an electric device which work on
(a) AC.
(b) DC.
(c) both AC and DC.
(d) none of the above. Answer
3. The main function of a transformer is to change
(a) power.
(b) frequency.
(c) voltage level.
(d) power factor. Answer
4. The main purpose of transformer cores lamination is to
(a) reduce copper loss.
(b) reduce eddy current loss.
(c) reduce cost.
(d) reduce hysteresis loss. Answer
5. An transformer work on principle of
(a) self-induction.
(b) mutual induction.
(c) coulomb law.
(d) ampere law. Answer
6. Transformer are rated in term of
(a) kW.
(b) kWh.
(c) kVA.
(d) kVAR. Answer
7. When the supply frequency of a transformer is increases, the iron losses will
(a) decrease.
(b) remain same.
(c) increase.
(d) none of the above. Answer
8. The transformer laminations are insulated from each other by
(a) mica strip.
(b) paper.
(c) cotton.
(d) thin coat of varnish. Answer
9. The main purpose of using Scott connection in 3 phase transformer is to transform
(a) single phase to three phase.
(b) three phase to single phase.
(c) three phase to two phase.
(d) single phase to two phase. Answer
10. Secondary winding of which transformer is kept always closed?
(a) Auto-transformer.
(b) Power transformer.
(c) Potential transformer.
(d) Current transformer. Answer
11. When the transformer are connected in parallel with incorrect polarity, it will results in
(a) poor power factor.
(b) open circuit.
(c) dead circuit.
(d) higher core loss. Answer
12. The core used in high frequency transformer is usually
(a) copper core.
(b) cost iron core.
(c) air core.
(d) mild steel core. Answer
13. Transformer will operates on its maximum efficiency when copper losses are _____ iron losses.
(a) less than
(b) equal to
(c) greater than
(d) none of these Answer
14. The full-load copper loss of a transformer is 1600 W. At half-load, the copper loss will be
(a) 6400 W.
(b) 1600 W.
(c) 800 W.
(d) 400 W. Answer
15. In the circuit diagram of a transformer, the core losses can be taken as
(a) series resistance.
(b) shunt resistance.
(c) series inductance.
(d) shunt inductance. Answer
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