A bar magnet is released from rest along the axis of a very long vertical copper tube. After some time the magnet will (a) move down with almost constant speed (b) move down with an acceleration equal to g (c) move down with an acceleration greater than g (d) oscillate inside the tube

Answer: (a). Eddy currents in the tube give a retarding force that grows with the magnet's speed. Speed increases until this force equals mg; then net force is zero. The magnet then moves down with almost constant (terminal) speed. Answer (a).

A bar magnet is released from rest along the axis of a very long… | JEE Main 2023 (10 Apr, Shift 2)

Q15JEE Main 2023 · 10 APR · SHIFT 2Easy

Lenz's Law, Eddy Currents & Induced Electric Field

A bar magnet is released from rest along the axis of a very long vertical copper tube. After some time the magnet will

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Answer: (a)

Eddy currents in the tube give a retarding force that grows with the magnet's speed.
Speed increases until this force equals $mg$ ; then net force is zero.
The magnet then moves down with almost constant (terminal) speed. Answer (a).

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Lenz's Law, Eddy Currents & Induced Electric Field question from JEE Main 2023 (10 Apr, Shift 2)

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