Faraday's laws of electromagnetic induction
Faraday's Laws of Electromagnetic Induction:
The Faraday's experiment shows the two laws which are known as Farday's laws of electromagnetic induction
First Law (Neumann's Law): The rate of change of magnetic flux through a circuit is equal to the emf produced in the circuit. This is also known as "Neumann Law"
$e=-\frac{\Delta \phi}{ \Delta t}$
Here negative sign shows the direction of emf.
If $\Delta t \rightarrow 0$
$e=-\frac{d \phi}{ d t}$
This equation represents an independent experimental law that cannot be derived from other experimental laws.
If the circuit is a tightly wound coil of $N$ turns, then the induced emf
$e=-N\frac{d \phi}{ d t}$
$e=-\frac{d \left(N \phi\right)}{ dt}$
Here $N \phi$ is called the 'Linkage magnetic flux'.
Note: The change in flux induces emf, not the current.
Second Law (Lenz's Law): The direction of induced EMF produced in a closed circuit is such that it opposes the original cause that produces it. It is also called "Lenz's law". The direction of induced EMF is described by Fleming's right-hand rule.