Electromagnetic Induction

Many scientists tried to invent electric current from the magnetic field when Oerested invented electromagnetic effect. Among the scientists who worked on this subject, Michael Faraday of England, Joseph Henry of America and H.F.E. Lenz of Russia achieved success individually. But at first Michael Faraday published the result of his experiments in 1831. He shows that a variable magnetic field can produce electromotive force which creates electric current through a closed circuit. The phenomena to produce electric current in a closed circuit by variable magnetic field is called electromagnetic induction. Faraday made two experiments to invent electromagnetic induction. You can also do the experiments.


Experiment-: An insulated wire is wound over a card board cylinder in the form of a coil. Connect a galvanometer with two sides of this coil to understand the presence of electric current. You have to open the non conducting cover during the time of connection. Now insert the south pole of a magnet bar inside the coil. What’s happening?

Deflection of the galvanometer is taking place. It means the current is flowing through the coil. Now remove the magnet. What’s happening? The deflection of galvanometer will be the opposite of that time when magnet was entered to the coil. If the magnet is kept stationary now, the galvanometer will show the deflections when the coil is moved towards or away from the magnet. If the coil is moved away from the magnet, we can see the deflection at the opposite side.