Question

The plane of a flat, circular loop of wire is horizontal. An external magnetic field is directed perpendicular to the plane of the loop. The magnitude of the external magnetic field is increasing with time. Because of this increasing magnetic field, an induced current is flowing clockwise in the loop, as viewed from above. What is the direction of the magnetic field, assuming the situation is drawn on a sheet of paper?

Answer 1

According to Lenz's law, the induced current will create its own magnetic field to oppose the change of the flux of the original magnetic field.

The induced current flows clockwise, so it creates its own magnetic field into the page. This can only be in response to if the original magnetic field is pointing out of the page and increasing in strength or the original magnetic field is pointing into the page and decreasing in strength.

Since the magnetic field is said to be increasing in strength, it must be pointing out of the page.