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 that S has been closed for a long time.Which one of the following changes will result in an induced magnetic field in coil 2 that points toward C?
A)The switch S is opened.
B)The iron core is removed from coil 1.
C)Coil 1 and its core are moved toward A.
D)Coil 1 and its core are moved toward B.
E)Coil 2 and its core are moved toward C.

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 that S has been closed for a long time.Which one of the following changes will result in an induced magnetic field in coil 2 that points toward C?
A)The switch S is opened. 
B)The iron core is removed from coil 1. 
C)Coil 1 and its core are moved toward A. 
D)Coil 1 and its core are moved toward B. 
E)Coil 2 and its core are moved toward C.

Quizplus · Accepted Answer

Moving coil 1 and its core toward B will decrease the magnetic flux through coil 2 from left to right, according to Lenz's law, the induced magnetic field in coil 2 will oppose this change by increasing the magnetic flux from left to right, which means it points toward C.

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