Question

Two circular coils $A$ and $B$ are placed close to each other. If the current in coil $A$ is changed, some current will be induced in the coil $B$. Give reason.

Answer 1

The given problem is an exceptional phenomenon that we can easily observe with an experiment or in our daily life sometimes. We must think clearly about how the change in current in coil $A$ can make a difference in coil $B$- the cause may be an electric field or something other than an electric field.

Complete solution:
We have the two circular coils $A$ and $B$ placed very close to each other. It is undeniable that this electric current in coil $A$ will produce an electric field, and this electric field will also produce a magnetic field in its surroundings. This magnetic field will have some specific direction and magnitude depending on the direction and magnitude of the current through the circular coil $A$. When the current through the circular coil $A$ changes, it will also change the magnetic field in its surroundings. Since the two coils are near each other, some electromotive force will be induced in the circular coil $B$, and the associated magnetic field will also change. This change in the associated magnetic field is the reason behind the induction of current in coil $B$. This process is known as electromagnetic induction.

Note: Electromagnetic induction has made our life a lot easier. Due to this phenomenon, we can now quickly produce electric current or electromotive force if specific by just changing the magnetic field. The electromotive force is only induced when there is a change in the magnetic field; otherwise, it vanishes. Devices such as motors, transformers, and generators work on this basic principle.