Question

When a permanent magnet is moved towards a coil, current is induced in the coil by Faraday’s law. What is the source of energy associated with the current produced?

Answer 1

Hint: Concept of magnetic flux and electromotive force will be used to get the correct answer. Electromagnetic induction is the cause of induced current in the case given above. Induction of electric current in a coil due to changing magnetic flux is called electromagnetic induction.

Complete step by step answer:
When a magnet is moved towards the coil then a current is induced in the coil due to the phenomenon of electromagnetic induction. Due to the relative movement between the magnet and the coil an electromotive force (EMF) is induced which in turn causes the current in the coil. Current is induced only during the relative motion and as the movement stops the current flow will also stop. Changing magnetic flux is the main cause of the induction of current in the coil. In fact the mechanical energy due to the relative motion is the source of energy for the current induced.
Hence, we conclude that mechanical energy is converted into electrical energy and it is mechanical energy which acts as a source for electric current.

Additional Information:
We should also know the basics of Faraday’s laws of electromagnetic induction. Faraday’s laws of electromagnetic induction is a combination of two basic laws, which are as follows:-
$(i)$ Faraday’s first law of electromagnetic induction states that when a conductor is placed in a changing magnetic field then an electromotive force (EMF) is induced which in turn produces current if the circuit is closed.
$(ii)$ Faraday’s second law of electromagnetic induction states that the induced EMF in the coil is equal to the rate of change of flux linkage.

Note:
We should remember that the current is induced in the coil as long as there is relative motion between the coil and the magnet and as the relative motion stops the current will also vanish. Faster the relative motion, more is the magnitude of induced current. We should also keep in mind that EMF is a measurement of the energy which causes the current.