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⚛️ Physics  ·  Electromagnetic Induction  ·  NEET & JEE

AC generator operates at 50 Hz. Coil has 200 turns, area 0.01 m<sup>2</sup> in field 0.5 T. Peak EMF:

Answer: 100pi V.

  • A 100pi V
  • B 200pi V
  • C pi V
  • D 50pi V

Correct answer: A. 100pi V

Explanation: E<sub>0</sub> = NBAomega = 200 x 0.5 x 0.01 x 2pi x 50 = 200 x 0.5 x 0.01 x 100pi = 100pi V.

EMF is Induced Only While Flux is ChangingΦmagnet approachingmagnet stationary inside coilEMFEMF ≠ 0 (flux changing)EMF = 0 (flux constant)t

As a magnet approaches a coil, flux rises steadily and a constant non-zero EMF is induced (Faraday's law). Once the magnet stops moving, flux stays constant and the induced EMF drops to zero - EMF only exists while flux is actively changing.

Concept context

Faraday's and Lenz's laws, motional EMF, self/mutual inductance, eddy currents, and the AC generator - how a changing magnetic flux creates an electric current.

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