question_answer

An aluminium ring B faces an electromagnet A. The current I through A can be altered                   [Kerala PET 2002]

A)            Whether I increases or decreases, B will not experience any force

B)            If I decrease, A will repel B

C)            If I increases, A will attract B

D)            If I increases, A will repel B

Correct Answer: D

Solution :

                   If current through A increases, crosses (X) linked with coil B increases, hence anticlockwise current induces in coil B. As shown in figure both the current produces repulsive effect.