Question

A metal ring kept (supported by a card I board) on the top of a fixed solenoid carry a current I as shown in figure. The centre of the ring coincides with the axis of the solenoid. If the current in the solenoid is switched off, then

• A. Magnetic flux linked with the mental ring increases.
• B. Current induced in the metal ring in clockwise direction.
• C. Metal ring will not remain on the cardboard.
• D. Both (1) and (2) are correct.

Answer 1

Answer: (B)

Current induced in the metal ring in clockwise direction.

Answer 2

When the current in the solenoid is switch off magnetic flux linked with the solenoid and hence with metal ring decrease current induced in the metal ring is clockwise i.e. in the same direction as the solenoid current. So they will attract each other therefore the metal ring will remain on the cardboard.