Question

Two small identical magnets are allowed to fall freely one through a vertical solenoid of 20 m made up of copper and another in air through the same vertical distance. The time taken by the two magnets to fall will be ______.

विकल्प

• same in both the cases.

• more for the magnet falling in air.

• more for the magnet falling through the solenoid.

• infinite

Answer 1

Two small identical magnets are allowed to fall freely one through a vertical solenoid of 20 m made up of copper and another in air through the same vertical distance. The time taken by the two magnets to fall will be more for the magnet falling through the solenoid.

Explanation:

When the magnet falls through the copper solenoid, the changing magnetic flux induces an EMF in the solenoid. According to Lenz’s law, the induced current produces a magnetic field that opposes the motion of the falling magnet. This opposing force reduces its acceleration, so the magnet falls slower, taking more time compared to the magnet falling in air.