a. Which law is demonstrated in the above figures?
b. State the law.
c. Explain the action that takes place in the above figures.

Explanation

a. Lenz.s law.
b. The direction of the induced e.m.f. is given by Lenz.s law. The law state that the direction of the induced e.m.f. or current is such as to oppose the cause that produced it. i.e., `varepsilonprop(-dphi_(B))/(dt),varepsilon=(-dphi_(B))/(dt)`, the constant of proportionality is unity.
c. If fig E.4a, when the N-pole is introduced in the coil, induced current flows so that the current in the coil is anticlockwise as seen from left. In fig E.4b, as the magnet is taken away, the induced current flowing clockwise at the left end produces a south pole apposing the motion of North pole away.