# Faradays Law of Induction

## Faradays law of electromagnetic induction

- From experiments on EM induction, faraday came to conclude then an emf was being induced in the coil when the magnetic flux linked to it was being changed either by

**(i)** Moving magnet close or away from the coil(experiment 1)

**(ii)** Chnaging amouny of current in the primary coil or motion of either of the coils relative to each other (experiment 2)
- From these observations faraday enunciated an important law.
The magitude of the induced emf produced in the coil is given by

where Φ is the magnetic flux as given by equation (1) .ξ is expressed in volts
- If the circuit is a tightly wound coil of N turns then total flux linked by N turns coil is NΦ.So induced EMF is whole coil is

Above equation only give the magnitude of the induced EMF and it does not give its direction.
- we know that unit of magnetic flux is
1 weber=1 T.m
^{2}
- If magnetic flux linking a single turn changes at a rate of 1weber per second then
Induced emf=Magnetic flux/time=1 weber/sec
Now since weber=Nm/Amp

Hence 1 weber/sec= 1 N.m/A.s =1 Joule/coulumb

- Hence the unit of emf is volt.