## What is Electromagnetic Induction?

Electromagnetic Induction was **discovered by Michael Faraday** in 1831 and James Clerk Maxwell mathematically described it as Faraday’s law of induction.

Electromagnetic Induction is a current produced because of voltage production (electromotive force) due to a changing magnetic field.

This either happens when a conductor is placed in a moving magnetic field (when using AC power source) or when a conductor is constantly moving in a stationary magnetic field.

Michael Faraday arranged a conducting wire as per the setup given below, attached to a device to measure the voltage across the circuit. When a bar magnet was moved through the coiling, the voltage detector measures voltage in the circuit.

*Through his experiment, he discovered that there are certain factors that influence this voltage production. They are:*

: The induced voltage is directly proportional to the number of turns/coils of the wire. Greater the number of turns, greater is voltage produced*Number of Coils*: Changing magnetic field affects the induced voltage. This can be done by either moving the magnetic field around the conductor or moving the conductor in the magnetic field.*Changing Magnetic Field*

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## Applications of Electromagnetic Induction

Based on his experiments we now have *Faradayâ€™s law* according to which *the amount of voltage induced in a coil is proportional to the number of turns of the coil and the rate of changing magnetic field.*

### Electromagnetic Induction Formula

*Mathematically, the induced voltage can be given by the following relation:*

e = N Ã— dÎ¦ / dt |

*Where,*

**e**is the induced voltage (in volts)**N**is the number of turns in the coil**Î¦**is the magnetic flux â€“ the amount of magnetic field at a surface (in Webbers)**t**is the time (in seconds)

The significance of this discovery is a way of producing electrical energy in a circuit by using magnetic fields and not just batteries. Everyday machines like motors, generators and transformers work on the principle of electromagnetic induction.

**Did you know that the principle of electromagnetic induction is also involved in the working of a credit card strip when you swipe it across the card machine? How do you think this works?Â ***[Hint: The strip is magnetic]*

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