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Concepts Of Physics MCQ Edition [Volume 2]PhysicsElectromagnetic Induction

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

Options

  1. Awill undergo oscillations
  2. Bwill travel with a nearly constant speed
  3. Cwill come to rest inside the tube
  4. Dwill move with an acceleration equal to g

Correct answer

B. will travel with a nearly constant speed

Step-by-step solution

When a bar magnet falls through a vertical copper tube, the magnetic flux linked with the tube changes continuously. This changing magnetic flux induces eddy currents in the walls of the copper tube. According to Lenz's law, the direction of these induced eddy currents is such that they oppose the downward motion of the magnet. The upward opposing magnetic force is proportional to the velocity of the falling magnet. As the speed of the magnet increases, the opposing force also increases. Eventually, the upward magn

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