State and explain Lenz.s law for induced emf.

Explanation

Statement : The polarity of induced emf is such that it tends to produce a current which opposes the change in magnetic flux that produced it.
Diagram:

Explanation : When North pole of a bar-magnet is moved towards the coil (fig.1). emf is induced in the coil. This induces current in the anti-clock wise direction through the coil so as to generate North-pole. This opposes the movement of the magnet.
When North-pole is moved away from the coil(Fig.2) emf induces again. This current in the clockwise direction through the coil so as to generate South-pole. It opposes the movement of the magnet.