Eddy currents are produced when

Question

Which one out of the following is not an application of eddy currents?

Answer 1

Eddy currents are loops of electrical current induced within conductors by a changing magnetic field in the conductor. The term is named after the swirling eddies of water formed when the water flows past an obstacle under certain conditions.

Let's explore the concepts to address the given question:

Faraday's Law of Electromagnetic Induction: According to Faraday's law, a change in the magnetic field within a closed loop induces an electromotive force (EMF) in the conductor.
Eddy currents are a direct manifestation of this law, where induced currents flow in circular paths within the material.
Effect of Varying Magnetic Field: When a metal is kept in a varying magnetic field, the change in magnetic flux induces these circulating loops of current, i.e., the eddy currents. This is because the varying field causes changes in magnetic flux, and according to Faraday's law, this changing flux induces currents.

From these concepts, we can reason why the options are correct or incorrect:

A metal is kept in varying magnetic field: This is \text{Correct} since the variation in the magnetic field leads to changing magnetic flux, thus inducing eddy currents.
A metal is kept in steady magnetic field: This is \text{Incorrect} because a steady (constant) magnetic field does not change over time, so no inductive current is produced.
A circular coil is placed in a magnetic field: Simply placing a coil in a magnetic field does not guarantee inducing eddy currents unless the magnetic field is changing.
Through a circular coil, current is passed: Passing current through a coil involves active flow of current through a conductor but does not directly relate to the induction of eddy currents by itself.

Thus, the correct answer is: a metal is kept in varying magnetic field.

Answer 2

Eddy currents are loops of electrical current induced within conductors by a changing magnetic field in the conductor. The term is named after the swirling eddies of water formed when the water flows past an obstacle under certain conditions.

Let's explore the concepts to address the given question:

Faraday's Law of Electromagnetic Induction: According to Faraday's law, a change in the magnetic field within a closed loop induces an electromotive force (EMF) in the conductor.
Eddy currents are a direct manifestation of this law, where induced currents flow in circular paths within the material.
Effect of Varying Magnetic Field: When a metal is kept in a varying magnetic field, the change in magnetic flux induces these circulating loops of current, i.e., the eddy currents. This is because the varying field causes changes in magnetic flux, and according to Faraday's law, this changing flux induces currents.

From these concepts, we can reason why the options are correct or incorrect:

A metal is kept in varying magnetic field: This is \text{Correct} since the variation in the magnetic field leads to changing magnetic flux, thus inducing eddy currents.
A metal is kept in steady magnetic field: This is \text{Incorrect} because a steady (constant) magnetic field does not change over time, so no inductive current is produced.
A circular coil is placed in a magnetic field: Simply placing a coil in a magnetic field does not guarantee inducing eddy currents unless the magnetic field is changing.
Through a circular coil, current is passed: Passing current through a coil involves active flow of current through a conductor but does not directly relate to the induction of eddy currents by itself.

Thus, the correct answer is: a metal is kept in varying magnetic field.

Eddy currents are produced when

The Correct Option is A

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