Faraday’s Laws of Electromagnetic Induction
Based on his studies on the phenomenon of electromagnetic induction, Faraday proposed the following two laws.
First law
Whenever the amount of magnetic flux linked with a closed circuit changes, an emf is induced in the circuit. The induced emf lasts so long as the change in magnetic flux continues.
Second law
The magnitude of emf induced in a closed circuit is directly proportional to the rate of change of magnetic flux linked with the circuit.
Let φ1 be the magnetic flux linked with the coil initially and φ2 be the magnetic flux linked with the coil after a time t. Then
Rate of change of magnetic flux = (φ2 – φ1)/t
According to Faraday’s second law, the magnitude of induced emf is, e α = (φ2 – φ1)/t. If dφ is the change in magnetic flux in a time dt, then the above equation can be written as; e α dφ/dt
