What is lentz law in magnatism?

Answer 1

IF by Lentz law, you mean Lenz's law it is the law that for current to be induced through a wire with a magnetic field work must be done to push the magnet into the field and to pull it out of the field.

"An induced current is always in such a direction as to oppose the motion or change causing it"

(http://en.wikipedia.org/wiki/Lenz%27s_law)

Answer 2

Lentz's law, also known as Lenz's law, states that the direction of an induced current in a conductor will be such that it opposes the change in magnetic flux that produced it. This law is a consequence of the conservation of energy and helps to determine the direction of induced currents in electromagnetic systems.