In the figure, the inner loop carries a clockwise current I that is increasing. The resistor R is in the outer loop and both loops are in the same plane. The induced current through the resistor R is
A) from a to b.
B) from b to a.
C) There is no induced current through the resistor.

Question

In the figure, the inner loop carries a clockwise current I that is increasing. The resistor R is in the outer loop and both loops are in the same plane. The induced current through the resistor R is 
A) from a to b. 
B) from b to a. 
C) There is no induced current through the resistor.

Quizplus · Accepted Answer

According to Lenz's law, the induced current will oppose the change that produces it. Since the current I in the inner loop is increasing in a clockwise direction, the induced current in the outer loop will flow in the opposite direction, which is counterclockwise. Using the right-hand rule, we can see that this counterclockwise current will result in a magnetic field pointing out of the page, which will generate a clockwise current in the resistor R. Therefore, the induced current through the resistor will flow from a to b.

In the Figure, the Inner Loop Carries a Clockwise Current