A circular coil lies flat on a horizontal surface. A bar magnet is held above the center of the coil with its north pole pointing down. If the magnet is dropped from this position what is the direction
Of the induced current in the coil, as viewed from above?
A) counterclockwise
B) clockwise
C) An emf but no current is induced in the coil.
D) There is no current in the coil.

Question

Quizplus · Accepted Answer

When the north pole of the magnet approaches the coil, the magnetic flux through the coil increases. According to Lenz's law, the induced current will flow in such a direction as to oppose the change causing it. This means it will create a magnetic field opposing the magnet's approach. Viewed from above, this requires a counterclockwise current, which would create a north pole on the upper face of the coil to repel the approaching north pole of the magnet.

A Circular Coil Lies Flat on a Horizontal Surface