Question

A copper ring is held horizontally and a bar magnet is dropped through the ring with its length along the axis of the ring. Then, the acceleration of the falling magnet (neglect air resistance) will be

• A. equal to g
• B. less than g
• C. greater than g
• D. zero

Answer 1

The correct option is B less than g

As the magnet falls the flux through the ring changes. Regardless whether the flux increases or decreases, by Lenz's law a current is induced in the ring that opposes the change in flux. This induced current induced a magnetic field that interacts with the falling magnet and decreases the acceleration of fall below $g$.