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A transformer is used to reduce the main...

A transformer is used to reduce the mains supplyof 220V to 22V.If the currents in the primary and secondary are 2A and 15A respectively, then the efficiency of the transformer is

A

0.65

B

0.75

C

0.8

D

0.9

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CHETANA PUBLICATION-Electromagnetic Induction-EXERCISE
  1. In relation to a transformer, the relation np/ns= 20, indicate that

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  2. In an ideal transformer, the number of turns in the primary is 120 and...

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  3. A transformer is used to reduce the mains supplyof 220V to 22V.If the ...

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  4. The core of a transformer is laminated

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  5. A step down transformer of efficiency 80% is used on a 1000V line to d...

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  6. Henry is equivalent to

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  7. The primary winding of transformer has 200 turns and its secondary win...

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  8. A transformer is used to reduce the main supply of 220 V to11 V. If th...

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  9. The ratio of the turns in the primary and secondary coils of transform...

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  10. A current in one coil changes from 5 A to 3 A in 0.2 sec and the co-ef...

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  11. The current in the coil changes from 3A to 6 A in 3sec. If the induced...

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  12. If south pole of the magnet is moved towards the coil then the nearer ...

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  13. The current in the choke coil decreasing at the rate of 3 A//s and cho...

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  14. The phenomenon of producing an induced e.m.f. in a conductor due to th...

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  15. Faraday's laws of electromagnetic induction is related to

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  16. To induce an e.m.f. in a coil, the magnetic flux

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  17. The co-efficient of self induction of a coil is the ratio of

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  18. The S.I. unit of inductance Henry can be written as

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  19. The number of turns in primary and secondary coil of transformer are 1...

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  20. Lenz's law is in accordance with law of conservation of

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