The north 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?
A) clockwise, into the paper
B) clockwise, out of the paper
C) counter-clockwise, into the paper
D) counter-clockwise, out of the paper
E) There is no induced current.

Question

Quizplus · Accepted Answer

According to Lenz's Law, the induced current will flow in a direction that opposes the change in magnetic flux. As the north end of the magnet approaches the loop, the magnetic flux through the loop increases into the paper. To oppose this increase, the induced current will create a magnetic field out of the paper, which requires a counter-clockwise current.

The North End of a Bar Magnet Is Pushed Downward