Answer: 12.3 W.
- A 6.17 W
- B 24.7 W
- C 12.3 W
- D 49.4 W
Correct answer: C. 12.3 W
Explanation: E0 = 2πfNBA = 2π × 50 × 200 × 0.5 × 0.001 = 31.4 V, so Erms = 22.2 V. Total resistance is 20 Ω, giving I = 1.11 A. Load power = I2R = 12.3 W.
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.