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A bar magnet is released from rest along the axis of a very long vertical copper tube. After some time the magnet will -
- move down with an acceleration equal to g
- oscillate inside the tube
- move down with almost constant speed
- move down with an acceleration greater than g
Correct answer: move down with almost constant speed
Solution
As the bar magnet falls through the copper tube, it induces an electric current in the tube due to electromagnetic induction. This current creates a magnetic field that opposes the motion of the magnet, resulting in a drag force that eventually balances the gravitational force, causing the magnet to fall at a nearly constant speed.
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