Question 316: Electromagnetic Induction

Question

Eddy currents are produced when

Accepted Answer

Eddy currents are induced currents that are generated within conductors when they are exposed to a changing magnetic field. According to Faraday's Law of Electromagnetic Induction, a change in magnetic flux through a conductor induces an electromotive force (emf) in the conductor. If the conductor is a solid piece, like a thick metal plate, circulating currents (eddy currents) are produced within it.
Given the options, let us analyze each to determine when eddy currents are produced:
Option A:
A thick metal plate is kept in a steady magnetic field.
A steady magnetic field means that there is no change in magnetic flux. Without a change in magnetic flux, no emf is induced, and hence no eddy currents are produced.
Option B:
A circular coil is placed in a steady magnetic field.
Similar to Option A, a steady magnetic field will not cause changes in magnetic flux linkage through the circular coil, so no eddy currents are produced.
Option C:
A steady current is passed through a coil.
A steady current in a coil generates a steady magnetic field, but since the field is not changing, it does not induce emf in nearby conductors. Therefore, no eddy currents are produced.
Option D:
A thick metal plate is kept in a varying magnetic field.
A varying magnetic field causes changes in magnetic flux through the metal plate, inducing emf within it. This induced current forms closed loops within the conductor, known as eddy currents.
Therefore, the correct answer is:
Option D: a thick metal plate is kept in a varying magnetic field

Answer

a thick metal plate is kept in a steady magnetic field

Answer

a circular coil is placed in a steady magnetic field

Answer

a steady current is passed through a coil

Answer

a thick metal plate is kept in a varying magnetic field

Electromagnetic Induction

Eddy currents are produced when

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