A closed, circular loop has a counter-clockwise current flowing through it as viewed by a person on the right, as shown in the figure. If a second closed circular loop with the same radius approaches this loop with constant velocity along a common axis as shown, in what direction will a current flow in the approaching loop as viewed by the person on the right?
A) clockwise
B) counter-clockwise
C) No current will be induced because the velocity of approach is constant.

Question

A closed, circular loop has a counter-clockwise current flowing through it as viewed by a person on the right, as shown in the figure. If a second closed circular loop with the same radius approaches this loop with constant velocity along a common axis as shown, in what direction will a current flow in the approaching loop as viewed by the person on the right? 
A) clockwise 
B) counter-clockwise 
C) No current will be induced because the velocity of approach is constant.

Quizplus · Accepted Answer

According to Faraday's law, when a closed loop moves through a magnetic field, an electromotive force (EMF) is induced in the loop. The direction of the induced current is determined by Lenz's law, which states that the current flows in a direction that opposes the change that produced it. In this case, the approaching loop moves towards the stationary loop with a constant velocity, which means that there is a changing magnetic flux through the approaching loop. The changing magnetic flux induces an EMF in the approaching loop, and the induced current flows in a direction that creates a magnetic field that opposes the motion of the stationary loop. The magnetic field of the approaching loop needs to be in the opposite direction of the stationary loop to oppose its motion. Therefore, the induced current flows in a clockwise direction as viewed by the person on the right.

A Closed, Circular Loop Has a Counter-Clockwise Current Flowing Through