In the figure, two solenoids are approaching each other with speed v as shown. 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, two solenoids are approaching each other with speed v as shown. 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 Faraday's Law of Electromagnetic Induction, a changing magnetic field will induce an electromotive force (EMF) in a nearby conductor. In this case, as the solenoids approach each other, the magnetic field between them is changing. This change in magnetic flux will induce an EMF in the resistor, causing an induced current to flow. Using Lenz's Law, the direction of the induced current will oppose the change in magnetic flux that caused it. Therefore, the induced current will flow from point a to point b, opposite to the direction of the approaching solenoids. Thus, the correct answer is A.

In the Figure, Two Solenoids Are Approaching Each Other with Speed