Michael Faraday discovered electromagnetic induction in 1831 and published his results for the experiments.
For the experiment, he wrapped two wires around the opposite sides of an iron ring. He plugged one of the wires into a galvanometer and observed as he connected the other side of the wire to a battery. As expected (due to the discovered properties of electromagnets), he observed the wave of electricity (a transient current) to flow when he connected the wire to the battery and another one when he disconnected the wire to the battery. He explained the electromagnetic induction by using the concept of lines of force.
Any change that occurs in the magnetic environment of the coil of wire causes voltage (emf) to get induced in the coil. Voltage is generated irrespective of how the change is produced. The change can be brought out by change in the magnetic field strength, by moving the magnet away or towards the coil, by moving the coil out on inside the magnetic field, by rotating the coil with relation to the magnet or etc.
The Faraday’s law states that- “The induced electromotive force in any closed circuit is equal to the negative of the time rate of change of the magnetic flux enclosed by the circuit.”
Faraday gave out two laws for induction-
- The change in magnetic field in the coil of a wire would cause voltage to be induced in the coil. With a closed conductor circuit, an induced current also starts to circulate through the circuit.
- The magnitude of the induced voltage in the coil is equal to the rate of change of the flux that is linked with the coil. The flux linkage of the coil is number of turns in the coil times the flux that is associated with the coil.
Faraday’s law serves as a summary of the ways a voltage can get generated by change in magnetic environment. It also involves the interaction of the charge with the magnetic field. The induced voltage in a coil is said to be equal to the negative of the number of turns in a coil times the rate of change of magnetic flux.
LIMITATIONS OF THE FARADAY’S LAW
- It holds only when the closed circuit is made of a loop of infinitely thin wire.
ACCOMPLISHMENTS OF THE FARADAY’S LAW
- It explains the working behind generators, electrical motors, inductors, and electrical transformers.
- It also establishes the relationship between the magnetic field and electric circuit.