Question

When a piece of iron is placed in a time-varying magnetic field, it gets heated.Identify the possible reason for this heating.
A. Eddy current
B. faraday’s current
C. Fleming’s current
D. None of the above

Answer 1

The phenomenon of the heating of a piece of iron when placed in a time-varying magnetic field can be understood once we have a fresh idea of the different types of current.

Complete answer:
When we talk about faraday’s current, we are generally talking about faraday’s law of induction which emphasises how a magnetic field is produced by an electric current and vice-versa, how in a conductor an electric current is generated in a changing magnetic field.

But it does not explain the phenomenon of the heating of the iron piece in the question
Fleming’s left-hand rule, on the other hand, illustrates when a current-carrying conductor is placed in a magnetic field, a force is experienced by the conductor which is perpendicular to both the field and to the direction of the current flow.

And this also has no explanation of the heating of the iron piece. However, the correct answer is Eddy currents as it explains how a continuous change in the magnetic flux through the rod induces a current in the rod which in return heats up the core.

Hence, the correct answer is option A.

Note: Eddy current is named specifically that way because these currents are exactly similar to those of eddies. Apart from the eddy current, such currents are also named Foucault’s current.