Zaymiey

⚛️ Physics  ·  Electromagnetic Induction  ·  NEET & JEE

The magnetic flux through a 50-turn coil varies as Φ = 0.02 sin(100t) Wb. The peak induced emf is:

Answer: 100 V.

  • A 100 V
  • B 50 V
  • C 20 V
  • D 200 V

Correct answer: A. 100 V

Explanation: Peak emf = N&omega;&Phi;<sub>0</sub> = 50 &times; 100 &times; 0.02 = 100 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.

Read the full Electromagnetic Induction notes →