Answer: sinusoidal (alternating).
- A sinusoidal (alternating)
- B a constant direct value
- C always zero
- D triangular in shape
Correct answer: A. sinusoidal (alternating)
Explanation: A uniformly rotating coil produces a sinusoidally varying EMF - the basis of an AC generator.
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.