State Faraday’s law of electromagnetic induction.

Faraday’s first law : When the magnetic flux linked with coil changes an e.m.f induced in the coil.
Second law : The induced e.m.f in the coil is negative rate of change of magnetic flux with coil $\mathrm{\epsilon }=-\frac{\mathrm{d\varphi }}{\mathrm{dt}}$.

Faraday’s law of electromagnetic induction

The induced electromotive force (EMF) in a circuit is directly proportional to the rate of change of the magnetic flux through the circuit. In simpler terms, when the magnetic field surrounding a conductor changes, it induces an electric current in the conductor. The magnitude of this induced EMF depends on how quickly the magnetic field changes with time.

Mathematically, Faraday's law is expressed as:

E=−dΦB/dt​​

Where:​​

• $\mathcal{E}$ is the induced EMF,
• $\Phi_B$ is the magnetic flux,
• $t$ is time.

The negative sign in the equation represents Lenz’s Law, which states that the induced EMF will always oppose the change in magnetic flux that produced it.

Key Points:

• A change in magnetic flux through a loop or coil of wire generates an EMF.
• The faster the change in magnetic flux, the greater the induced EMF.
• This principle is the foundation for many devices such as transformers, electric generators, and inductors.