Answer: 133.3 V.
- A 94.2 V
- B 133.3 V
- C 188.5 V
- D 66.7 V
Correct answer: B. 133.3 V
Explanation: Peak emf = 2πfNBA = 188.5 V. Therefore E<sub>rms</sub> = E<sub>0</sub>/√2 = 133.3 V.
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.