lawyer

Lenz's law gives the direction of induced current set up due to electromagnetic induction.

It states that an induced current will flow in such a direction so as to oppose the cause that produces it. The cause that produces the current is change of flux linkage of the coil

for Lenz's law Experiment:

Explanation of Lenz's law:

The following is an explanation as to why Lenz's law is true: If the magnetic field associated with this current were in the same direction as the change in magnetic field that created it, these two magnetic fields would combine to give a net magnetic field which would in turn induce a current with twice the magnitude. This process would continue creating infinite current from just moving a magnet; a violation of the law of conservation of energy.

Take a permanent magnet and a coil in front of it, with the north pole nearest the coil, and place a small camera on the north end of the magnet. As you bring the magnet closer to the coil, you are increasing the flux through the coil. Then by Lenz's law, the current will be in counterclockwise direction as viewed by the camera.

If you bring the magnet away from the coil, you are decreasing the flux through the coil. Therefore, the current should be induced in the clockwise direction as viewed from the camera.

What if you keep the magnet at rest but increase the field strength of the magnet? In this case you are increasing the flux through the coil. Now one must read Lenz's law carefully:

The current associated to this emf will be such that the flux it creates opposes the change in flux that created it.

Similarly, if we keep the magnet at rest but decrease the field strength of the magnet, the current will be induced in the clockwise direction as viewed by the camera.

Another possible situation is increasing the area of the coil. In this case, we are increasing the flux through the coil so that a current is induced by Faraday s law. Note that increasing the area of the coil is equivalent to bringing the magnet closer to the coil; both cases effectively increase the magnetic flux through the coil. Therefore, the current will be induced in the counterclockwise direction as viewed by the camera.

Decreasing the area of the coil is equivalent to bringing the magnet away from the coil since both cases effectively decrease the flux through the coil. Therefore, decreasing the area of the coil will induce a current in the clockwise direction.

Note how we always specified the direction of the induced current with reference to the camera. In general, physics pays a lot of importance to reference frames.