A squat refrigerator magnet sits on a table with its north pole facing up and its south pole down. We push a ring of wire lying on the table directly toward the magnet. What direction does current flow in the ring when viewed from above? (A wooden table will not affect the magnet's field.)

Question

Quizplus · Accepted Answer

When the ring is pushed toward the magnet, the magnetic field through the ring increases. According to Lenz's law, the induced current will flow in such a direction as to oppose the change causing it. Since the north pole of the magnet is facing up, to oppose the increase in magnetic flux, the current must flow in a direction that creates a north pole on the approaching face of the ring, which, when viewed from above, is counterclockwise.

A Squat Refrigerator Magnet Sits on a Table with Its