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. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] B [/accordion-item][/accordion]
2. A transformer is an electric device which work on
(a) AC.
(b) DC.
(c) both AC and DC.
(d) none of the above. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] A [/accordion-item][/accordion]
3. The main function of a transformer is to change
(a) power.
(b) frequency.
(c) voltage level.
(d) power factor. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] C [/accordion-item][/accordion]
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. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] B [/accordion-item][/accordion]
5. An transformer work on principle of
(a) self-induction.
(b) mutual induction.
(c) coulomb law.
(d) ampere law. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] B [/accordion-item][/accordion]
6. Transformer are rated in term of
(a) kW.
(b) kWh.
(c) kVA.
(d) kVAR. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] C [/accordion-item][/accordion]
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. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] C [/accordion-item][/accordion]
8. The transformer laminations are insulated from each other by
(a) mica strip.
(b) paper.
(c) cotton.
(d) thin coat of varnish. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] C [/accordion-item][/accordion]
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. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] C [/accordion-item][/accordion]
10. Secondary winding of which transformer is kept always closed?
(a) Auto-transformer.
(b) Power transformer.
(c) Potential transformer.
(d) Current transformer. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] D [/accordion-item][/accordion]
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. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] C [/accordion-item][/accordion]
12. The core used in high frequency transformer is usually
(a) copper core.
(b) cost iron core.
(c) air core.
(d) mild steel core. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] C [/accordion-item][/accordion]
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 [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] B [/accordion-item][/accordion]
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. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] D [/accordion-item][/accordion]
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. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] B [/accordion-item][/accordion]
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