Electromagnetic Induction - Result Question 7

7. A coil of resistance 400Ω is placed in a magnetic field. If the magnetic flux ϕ (wb) linked with the coil varies with time t (sec) as ϕ=50t2+4. The current in the coil at t=2sec is :

[2012]

(a) 0.5A

(b) 0.1A

(c) 2A

(d) 1A

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Answer:

Correct Answer: 7. (a)

Solution:

  1. (a) According, to Faraday’s law of induction

Induced e.m.f. ε=dϕdt=(100t)

Induced current i at t=2sec.

=|εR|=+100×2400=+0.5A

The magnetic flux linked with a loop does not change when magnet and loop are moving with the same velocity.



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