Lenz’s Law and Induced Current in Magnetic Fields

FARADAY’S SECOND LAW :

Second law is about the quantity of emf produced in the coil.

Faraday’s second law of electromagnetic induction states that the magnitude of induced emf is equal to the rate of change of magnetic flux  linked with the coil.

LENZ’S LAW :

The current induced in a  loop flows  in such a way, so as to create a magnetic field opposite to the direction of the field that causes it.

SIGNIFICANCE OF THE NEGATIVE SIGN :

When a magnet is moved towards the coil or down the tube,work is to be done against the force.Thus, there is a transformation of mechanical energy into electrical energy.We say that Lenz’s follows the law of conservation of energy.

LENZ’S LAW- ACCORDING TO LAW OF CONSERVATION OF ENERGY:

A bar magnet as it falls throught  the hollow region of a tube made up of copper experiences a retarding  force.As the magnet goes down,the flux through the section of the tube changes.Because of this, the tube now has a small current flowing through it.According to Faraday, a moving magnetic field would generate a current.It has two options,it either accelerates the falling magnet or it slows it down.

LAW OF CONSERVATION OF ENERGY:

When a magnet is moved towards the coil or down the tube,work is to be done against the force.Thus, there is a transformation of mechanical energy into electrical energy.We say that Lenz’s follows the law of conservation of energy.

FIRST OPTION :

If the magnet gets accelerated ,the rate of change of flux would increase, further accelerating the magnet,it would be a source of infinite energy.It is against the law of conservation of energy.

SECOND OPTION:

As the magnet falls, the changing magnetic field sets up  induced current in the tube which opposes the motion of the magnet.Lenz deduced that, the magnetif field must slow the magnet down, otherwise law of conservation of energy would be  bypassed.