An aluminium ring B faces an electromagnet A. The current `I` through A can be altered.

Options

A. If I decreases A will repel B
B. Whether I increases or decreases, B will not experience any force
C. If I increases, A will repel B
D. If I increases, A will attract B.

Answer

C

Explanation

As I increases, the strength of the electromagnet A increases and the flux linked with the aluminium ring B will increase, so an e.m.f. will be induced in the ring B. according to Lenz.s law of electromagnetic induction, the direction of induced e.m.f. should be such that it will oppose the very cause (here increase flux linked with the ring) due to which it is created. to achieve that the ring will repel the electromagnet and as a reaction, the electromagnet A will repel the ring B.