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Consider a metal ring kept on top of a f...

Consider a metal ring kept on top of a fixed solenoid (say on a carboard) The centre of the ring coincides with the axis of the solenoid. If the current is suddenly switched on then

A

The metal ring is attracted

B

The metal ring is jumped up

C

No change in magnetic flux through the ring when switch is suddenly closed

D

Can not be decided.

Text Solution

Verified by Experts

The correct Answer is:
B
This happen because the flux increase will casue a counter clockwise current (as seen from the top in the ring in figure) i.e opposite direction to that in the solenoid
This making the samesense of flow of current in the ring (when viewed from the bottom of the ring) and solenoid forming same magnetic pole infront of each other. Hence they will repel each other and the ring will move upward.
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