Describe Lenz's law.

Lenz law is used to find the direction of induced emf in the coil.

It state taht the direction of induced emf in the coil is such that it always opposes the change due to which it is produced.

Suppose there is a coil and a north pole of the magnet comes nearer to the coil. Due to changing magnetic flux an induced emf is developed in the coil whose direction is such that the north pole moves away. That means this face of the coil behaves like a north pole and the current flows at this face is in anticlockwise wise direction.