Question:
A bar magnet is released from rest along the axis of a very long, vertical copper tube.After some time the magnet
A bar magnet is released from rest along the axis of a very long, vertical copper tube.After some time the magnet
Updated On: Jul 5, 2022
- will stop in the tube
- will move with almost contant speed
- will move with an acceleration g
- will oscillate
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The Correct Option is B
Solution and Explanation
By Lenz's Law , as long as the magnet has a non zero acceleration, the flux linking with the aluminium tube will keep changing, and hence to opposes it a current and accompanying magnetic field will be induced that opposes that change in flux.
This induced field will repel the the magnet in the direction opposite to its motion. Eventually the magnetic repulsion due to induced field by Lenz's Law will be equal to the gravitational pull on the magnet and it will reach a constant velocity.
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Concepts Used:
Electromagnetic Induction
Electromagnetic Induction is a current produced by the voltage production due to a changing magnetic field. This happens in one of the two conditions:-
- When we place the conductor in a changing magnetic field.
- When the conductor constantly moves in a stationary field.
Formula:
The electromagnetic induction is mathematically represented as:-
e=N × d∅.dt
Where
- e = induced voltage
- N = number of turns in the coil
- Φ = Magnetic flux (This is the amount of magnetic field present on the surface)
- t = time
Applications of Electromagnetic Induction
- Electromagnetic induction in AC generator
- Electrical Transformers
- Magnetic Flow Meter