Answer: thin laminated sheets.
- A thin laminated sheets
- B a solid iron block
- C solid copper blocks
- D a plastic core
Correct answer: A. thin laminated sheets
Explanation: Laminating the core with insulated sheets breaks up the eddy-current paths, cutting the losses.
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.