Question

What is the basic cause of induced EMF.

Answer 1

Hint: Induced EMF, also known as induced electromotive force, electromagnetic induction, and electromotive force induction is defined as the generation of a potential difference in a coil due to the changes in the magnetic flux through it. In more basic words, electromotive Force or EMF is said to be induced when the flux linking with a conductor or coil changes.

Formulae used:
\[\mathcal{E} = - \dfrac{{\partial \phi }}{{\partial t}} = - \dfrac{{\partial B.A}}{{\partial t}}\]
Where \[\mathcal{E}\] is the EMF generated, $B$ is the magnetic field, $A$ is the area vector perpendicular to the surface of the coil and $t$ is time.

Complete step by step solution:
The most basic cause of an induced EMF is change in magnetic flux.
This can happen due to two reasons;
1. Placing the electric conductor in the presence of a changing magnetic field. As the EMF generated depends on either a small change in area vector or magnetic field, therefore this will cause an induction of EMF
2. Placing a current carrying coil that is moving constantly in a stable and static magnetic field. This will cause a change in the area vector and hence, EMF will be generated.

Additional Information:
Induced EMF has several applications such as;
a) Its use in galvanometers
b) Its use in generators
c) Its use in transformers.
All three of these devices work on the principle of induction of electromotive force.

Note: Note that a constant magnetic field along with no movement in the current carrying coil cannot generate EMF. Either of those two quantities has to change continuously for EMF to be induced. Even if both the quantities change, EMF will be induced.