Question

what is lenz law???? how is it useful.

Answer 1

lenz law states that when we move magnet near a electric coil ,then the pole near the coil generates the same pole in the conductor ,and when we move away the magnet from coil ,it generates opposite pole.

Answer 2

Lenz law is a common way to understand how electromagnetic circuits obey Newton's third law and the conservation of energy. Lenz law obeys Newton's third law of motion(I.e to every reaction there is always an equal and opposite reaction).
Lenz law states that the current induced in a circuit due to a change or a motion in magnetic
field is so directed as to oppose the change in flux and to exert a mechanical force opposing the motion.
hope it helps*_*