Electromagnetic induction due to the relative motion of a bar magnet and a coil

when a bar magnet is moved towards a coil of wire connected to a galvanometer or the coils moved towards the bar magnet, this flux through the coil change, and this chinging flux produce the induced current in the coil. when the magnet moves away from the coil, the induced current produces in the opposite direction. At the greater relative motion, the greater induced current is produced. where there is relative motion between the magnet and the coil, the galvanometer shows no current in current.

 

Electromagnetic induction is due to changing the area of the coil

when the being is distorted (unshaped) in a uniform magnetic field, the area of the coil changes which causes it to produce induced current and induced e m f. The current vanishes when the area is no longer changing (alternating).

 

For decreasing area current flows in one direction and for increasing area current flows in opposite direction. The induced current is produced only when the area keeps on changing.
An induced current is also generated when a coil of constant area is rotated in a constant magnetic field. the flux through the coil changes which causes to produce-induced e m f.

 

Mutual Induction

Two coils P and S are placed in front of each. The coil P is connected in series with a battery, a rheostat, and a switch while the other coil S is connected to a galvanometer.

 

 

The current in P grows (increases) from zero to its maximum value just after the switch is closed. this produces induces current in the coil S shown by the deflection in the galvanometer. It returns to zero when a steady current starts to flow through coil P. The deflection of current goes in the opposite direction in coil S when the switch of coil Pis suddenly opened. Due to the change (alternations) in current, the magnetic flux associated with the coil P changes momentarily. this changing flux is linked (associated) with the coil S that causes the induced current in it. Current coil P can also be changed with the help of rheostat

Electromagnetic Induction due to Electromagnet

The coil is placed in the magnetic field of the electromagnet. In this case, both the coil and the electromagnet are at rest. The magnetic field through the coil is changed by changing the current of the electromagnet which, is produced currently in the coil.