Electromagnetic induction

Discovered by Michael Faraday


Whenever a conductor is placed in the varying magnetic field, electromagnetic fields are induced known as induced emf. 

Electromagnetic induction:-

Electromagnetic induction can be generated in two ways, namely when the electric conductor is kept in a moving magnetic field and when the electric conductor is constantly moving within a static magnetic field. The phenomenon of electromagnetic induction was first discovered by Michael Faraday when he moved a bar magnet through an electric coil. He noticed a change in voltage of the circuit. He later deduced the factors that could influence the electromagnetic induction as the number of coils, the strength of the magnet, the changing magnetic fields and the speed of relative motion between coil & magnet.


The number of turns in the coils/wire is directly proportional to the induced voltage. In other words, greater voltage is generated when the number of turns is higher. The changing magnetic field also influences the voltage which is induced. The speed of the relative motion between the coil and magnet was also found to affect the induced voltage or electromagnetic induction as rising in velocity cuts the lines of flux at a faster rate. This results in more induced electromagnetic force or voltage.


The induced voltage in an electromagnetic induction is described by the following equation as:

e = N × dΦdt



e = voltage induced (measured in volts)

t = time (measured in seconds)

N = number of turns found in the coil

Φ = magnetic flux (measured in Webers)


Many types of electrical equipment such as motors, generators and transformers function based on the principle of the electromagnetic induction.

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