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JEE Main2012PhysicsElectromagnetic InductionActual

A coil is suspended in a uniform magnetic field, with the plane of the coil parallel to the magnetic lines of force. When a current is passed through the coil it starts oscillating; it is very difficult to stop. But if an aluminium plate is placed near to the coil, it stops. This is due to :

Options

  1. Adevelopment of air current when the plate is placed.
  2. Binduction of electrical charge on the plate
  3. Cshielding of magnetic lines of force as aluminium is a paramagnetic material.
  4. Delectromagnetic induction in the aluminium plate giving rise to electromagnetic damping.

Correct answer

D. electromagnetic induction in the aluminium plate giving rise to electromagnetic damping.

Step-by-step solution

Oscillating coil produces time variable magnetic field. It cause eddy current in the aluminium plate which causes anti-torque on the coil, due to which is stops.

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