What are eddy currents? Explain its applications

In Physics, eddy currents are electrical currents induced a conductor by a changing magnetic field. It is the principle used to heat cooking vessels in induction cooktops and slow down rollercoasters. Unpleasantly, they also cause heating in the cores of transformers (alleviated by laminating the core).
Basically, you have a spinning disc made of conducting material (usually copper). When you place a magnetic field through the copper disc, eddy currents are generated which oppose the spinning of the disc, slowing it down. This effect would decrease if you were to cut slits in the disc, as the eddy currents would be interrupted.
Otherwise, "eddy current" can refer to smoke or water eddies for which physical eddy currents are named. Basically, move your hand through water. See how the water moves in circles around the edges of your hand? Those are water eddies.

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Apoorva Arora

IIT Roorkee

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