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A transformer is used to reduce the main...

A transformer is used to reduce the main supply of 220 V to11 V. If the current in the primary and secondary coils are 5A and 90 A respectively, the efficiency of transformer is

A

0.6

B

0.75

C

0.4

D

0.9

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CHETANA PUBLICATION-Electromagnetic Induction-EXERCISE
  1. Henry is equivalent to

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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  16. Magnetic flux associated with area element ds kept in magnetic inducti...

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  17. Induced e.m.f. produced in the coil is 4mV. What is the change in flux...

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  18. Foucault's current is also

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  19. What is SI unit of magnetic flux density?

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  20. Why induced emf is called back emf?

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