Question

What experiment do you suggest to understand Faraday’s law? What items are required? What suggestions do you give to get good results for the experiment? Give precautions also.

Answer 1

Hint : Faraday’s first law states that varying magnetic flux induces emf into the coil. This emf, in turn, induces a current into the coil. This method of inducing emf into a coil as a result of changing magnetic flux is called electromagnetic induction.

Complete step by step answer
Materials required: A bar magnet, copper wire, galvanometer.
Procedure:
Make a circular coil out of the copper wire and connect the ends of the coil to the positive and negative terminals of the galvanometer.
Take the bar magnet and keep it at a distance stationary with respect to the coil. Mark the readings on the galvanometer.
Now move the bar magnet in and out of the copper coil and note the galvanometer reading.
Observations:
When the bar magnet is kept stationary near the coil, the galvanometer shows no deflection. When the bar magnet is moved into the coil, the galvanometer shows deflection from the mean position, and when the bar magnet is moved outside the coil, the galvanometer deflects to the opposite side.
Result and explanation:
The magnetic flux associated with the magnet remains constant when the bar magnet is kept stationary. But when the bar magnet is moved in and out of the coil, the magnetic flux associated with it changes as it crosses the coil and induces an emf which in turn induces a current in the coil which is why the galvanometer shows deflection.
Precautions:
-The bar magnet should have enough strength to show deflection in the galvanometer.
-The galvanometer reading should point to zero reading when at rest.
-The copper coil should be kept on an insulating surface.

Note
The coil should not be touched while experimenting. Faraday's second law gives the magnitude of the induced emf and says that it is directly proportional to the rate of change of magnetic flux. It is given by
$emf\propto -\dfrac{d\phi }{dt}$
Here, $\phi $ is the magnetic flux and its SI unit is Weber(Wb).