Lenz's Law, Eddy Currents & Induced Electric Field
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:
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Answer: (d)
- The oscillating coil changes the magnetic flux through the nearby aluminium plate.
- Eddy currents are induced in the plate; by Lenz's law they oppose the coil's motion.
- This electromagnetic damping stops the coil. Answer (d).