Question

A closed iron ring is held horizontally and a bar magnet is dropped through the ring with its length along the axis of the ring. The acceleration of the falling magnet is:

• A. equal to g
• B. less than g
• C. more than g
• D. depends on the diameter of the ring and length of magnet

Answer 1

The correct option is B less than g

Acceleration of the magnet will not be equal to g. It will be less than g. This is because, as the magnet falls, the amount of magnetic flux linked with the ring changes. An induced emf is developed in the ring which opposes the downward motion of the magnet.