Answer: Falls more slowly as it approaches the magnet, due to the retarding force from induced eddy currents opposing the change in flux.
- A Falls more slowly as it approaches the magnet, due to the retarding force from induced eddy currents opposing the change in flux
- B Falls at roughly the same rate, since gravity is the dominant force acting on either ring under usual circumstances according to most studies
- C Falls faster as it approaches the magnet, because induced currents in the ring attract it toward the magnet in the majority of documented cases
- D Slows down sharply and takes much longer to reach the magnet, well beyond the effect of the retarding force alone as widely reported
Correct answer: A. Falls more slowly as it approaches the magnet, due to the retarding force from induced eddy currents opposing the change in flux
Explanation: As the copper ring approaches the magnet, the changing flux induces a current that, by Lenz's law, opposes the motion, producing a retarding force that the non-conducting ring does not experience.
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.