Lenz's law, definition, explanation

Definition:-

"The electric current induced in a circuit or somewhere, always tries to decrease the source which produces it or flow in opposite direction to decrease its effect."  

Lenz's law expand the law of electromagnetism which only tell about induced electric current.

Explanation:-

As we came to know through Lenz's law that the current induced, always tries to do opposite, for the source which is producing it, 

Example:-

lets take an example of a permanent magnet and a coil. 

When we bring the magnet north pole near to the coil there will be change in magnetic field across coil as we move magnet, thus because of changing magnetic field there will induce electric current in it. As we bought the north pole of magnet to the coil, so current induced in coil will start to flow in such a direction that it will make north pole of it towards the permanent magnet north pole, as everybody knows that, like poles of magnet repel each other, hence there, these two north pole will also follow the same rule. And When we will try to bring back the magnet then the current induced in the coil will flow in such a direction, that it will make south pole towards the permanent magnet north pole, where unlike poles attract each other, hence they will attract each other. 

So by doing this current induced in the coil is trying to oppose the source(permanent magnet). By pushing it back when we bring near it(creating north pole towards north pole of magnet) and by pushing it closer when we bring back the magnet(by creating south pole towards the magnet.)

Faraday'laws of electromagnetic induction

Faraday's have proposed 2 main Laws,
Faraday's law of electromagnetic induction is also known as law of electromagnetism.

Faraday's first law:-

This law is the base of electric generators and motors.

Faraday's law stated that,
"When ever we place a conductor in a magnetic field which is varying with time then there will induced current in the conductor."
And if conductor is connected to a closed circuit then this current will flow through it.

Explanation:-

If a conductor is placed in a field of magnet, if both conductor and magnet are stationary then there will no induced emf in it. But when we will move magnet away from the conductor then magnetic field will change through conductor and then EMF(electromotive force) will induced in conductor. Even if we keep magnet stationary and move conductor then also emf will induced.

Faraday's Second law:-

We use this law often,

"The EMF induced in a coil is equal to the change of flux(by a magnet or something other) with the time. "

Where E is the induced EMF, and N is the number of turns of coil phi is the flux and t is the time.

Explanation:-

When a current is flowing through the coil then there is flux around the coil, when current will change then flux will also changes. And then EMF will induce in a coil.

The induced EMF could increase by:

1.By increasing the number of turns of coil.

2. By increasing rate of changing flux. by changing current rapidly.

3. By using good core on which coil is wound.