As shown in the figure,two solenoids are side by side.The switch S is initially open.When S is suddenly closed,the direction of the induced current through the resistor R is
A)from a to b.
B)from b to a.
C)No current is induced.

Question

As shown in the figure,two solenoids are side by side.The switch S is initially open.When S is suddenly closed,the direction of the induced current through the resistor R is 
A)from a to b. 
B)from b to a. 
C)No current is induced.

Quizplus · Accepted Answer

When S is closed, current flows through both solenoids. Due to the magnetic field produced by the current, the magnetic flux changes in the solenoid on the right. This changing magnetic flux induces an electromotive force (EMF) that causes a current to flow in the opposite direction to the original current in the solenoid on the right. This induced current will flow from b to a, creating a clockwise current loop that includes the resistor R. Therefore, the direction of the induced current through the resistor R is from b to a.

As Shown in the Figure,two Solenoids Are Side by Side