1. The value of flux involved m the e.m.f. equation of a transformer is
(a) average value.
(b) r.m.s. value.
(c) maximum value.
(d) instantaneous value. Answer
2. The all day efficiency of a transformer is also known as
(a) load efficiency.
(b) power efficiency.
(c) current efficiency.
(d) energy Efficiency. Answer
3. Power transformers are generally designed to have maximum efficiency at
(a) no load.
(b) half load.
(c) near full load.
(d) any load. Answer
4. Distribution transformers are generally designed to have maximum efficiency at
(a) no load.
(b) half load.
(c) near full load.
(d) any load. Answer
5. In a tap changing transformer, the tapping are provided on
(a) primary side.
(b) secondary side.
(c) high voltage side.
(d) low voltage side. Answer
6. The noise produced by a transformer is termed as
(a) zoom.
(b) hum.
(c) ringing.
(d) buzz. Answer
7. The most common method of cooling in a power transformer is
(a) natural air cooling.
(b) air blast cooling.
(c) oil cooling.
(d) any of the above. Answer
8. At what load the efficiency of a transformer will be zero?
(a) full load.
(b) half load.
(c) no load.
(d) none of the above. Answer
9. Efficiency of a power transformer is nearly
(a) 50 %.
(b) 80 %.
(c) 98 %.
(d) 100 %. Answer
10. When the load on a transformer is increases, the eddy current is
(a) increases.
(b) decreases.
(c) remain same.
(d) none of the above. Answer
11. When the load on a transformer is increases, the copper losses are
(a) increases.
(b) decreases.
(c) remain same.
(d) none of the above. Answer
12. When the load on a transformer is decreases, the hysteresis losses are
(a) decreases.
(b) increases.
(c) remain same.
(d) none of the above. Answer
13. Current transformers are also known as
(a) series transformers.
(b) parallel transformers.
(c) auto transformers.
(d) isolation transformers. Answer
14. Potential transformers are also known as
(a) series transformers.
(b) parallel transformers.
(c) auto transformers.
(d) isolation transformers. Answer
15. Secondary winding of which transformer should never be open circuits when primary is energized?
(a) Auto transformer.
(b) Potential transformer.
(c) Current transformer.
(d) Isolation transformer. Answer