The south end of a bar magnet is pushed downward toward a wire loop in the plane of the paper. In which direction is the induced current, and which way is the induced magnetic field?

Question

Quizplus · Accepted Answer

When the south end of a bar magnet is pushed downward toward a wire loop, the magnetic flux through the loop increases. According to Lenz's law, the induced current will flow in such a way as to oppose the change that caused it. This means the induced magnetic field must oppose the incoming south pole, acting like a north pole facing it. To create a north pole on the side facing the magnet, the current must flow clockwise when viewed from above, and the induced magnetic field will point into the paper.

The South End of a Bar Magnet Is Pushed Downward