Two coils,1 and 2,with iron cores are positioned as shown in the figure.Coil 1 is part of a circuit with a battery and a switch.

-Assume S has been closed for a long time.Which one of the following statements is true when coil 1 and its core are moved toward point B?
A)There is no induced current in r.
B)There is a magnetic field in coil 1 that points toward B.
C)There is an induced current in R that flows from left to right.
D)There is an induced current in R that flows from right to left.
E)There is an induced magnetic field in coil 2 that points toward B.

Question

Two coils,1 and 2,with iron cores are positioned as shown in the figure.Coil 1 is part of a circuit with a battery and a switch.
 
-Assume S has been closed for a long time.Which one of the following statements is true when coil 1 and its core are moved toward point B?
A)There is no induced current in r. 
B)There is a magnetic field in coil 1 that points toward B. 
C)There is an induced current in R that flows from left to right. 
D)There is an induced current in R that flows from right to left. 
E)There is an induced magnetic field in coil 2 that points toward B.

Quizplus · Accepted Answer

When coil 1 and its core are moved towards point B, the magnetic flux passing through coil 2 changes. According to Faraday's law of electromagnetic induction, this change in magnetic flux induces an EMF in coil 2 which leads to an induced current. This induced current generates a magnetic field that opposes the change in magnetic flux i.e. towards coil 1. 
By Lenz's law, the direction of the induced current in coil 2 is such that it opposes the change in magnetic flux that caused it. Therefore, the induced current in R should flow from right to left. Hence, option D is the correct choice.

Two Coils,1 and 2,with Iron Cores Are Positioned as Shown