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:
- Adevelopment of air current when the plate is placed.
- Binduction of electrical charge on the plate
- Cshielding of magnetic lines of force as aluminium is a paramagnetic material.
- Delectromagnetic induction in the aluminium plate giving rise to electromagnetic damping.
Solution & Step-by-step Explanation
When the coil oscillates, it creates a changing magnetic flux in the nearby aluminium plate. This induces eddy currents in the plate. According to Lenz's law, these eddy currents produce a magnetic field that opposes the motion of the coil. this phenomenon is known as electromagnetic damping, which quickly brings the coil to rest.