Faraday's Law: Faraday’s law also referred to as Faraday's Law of electromagnetic induction. This is the basic law of electromagnetism that anticipate how a magnetic field would interact with an electric circuit to produce an electromotive force (EMF). This phenomenon is commonly called electromagnetic induction. Faraday's Law was proposed by Michael Faraday in the year 1831. Faraday performed three main experiments for the discovery of electromagnetic induction. Faraday proposed two laws-
- First Law of Faraday of Electromagnetic Induction
- Second Law of Faraday of Electromagnetic Induction
Faraday's First Law of Electromagnetic Induction
Whenever a conductor is placed in a magnetic field which varies and an EMF gets induced across the conductor (called induced emf), and if the conductor is a closed circuit then the induced current flows through it. The magnetic field can be varied by various methods such as-
- By allowing the magnet to move.
- By allowing the coil to move.
- By rotating the coil that is relative to the magnetic field.
Faraday's Second Law of Electromagnetic Induction
According to Faraday's second law of electromagnetic induction, “the magnitude of induced EMF is equal to the rate of change of flux linkages with the coil. The flux linkages are the product of the number of turns and the flux that is associated with the coil”.
Faraday Law Formula
Suppose a magnet approaches a coil. Consider t1 and t2 as the times taken by the magnet approaching the coil.
The Flux linkage with the coil at time t1 is NΦ1.
The Flux linkage with the coil at time t2 is NΦ2
The change in the flux linkage is N(Φ2 – Φ1)
Assume the change in the flux linkage as, ΔΦ = Φ2 – Φ1
Therefore, the change in flux linkage is NΔΦ
Hence, the rate of change of flux linkage is NΔΦ/t
Taking the derivative of the above equation as, N dΦ/dt
According to Faraday’s second law of electromagnetic induction, induced emf in a coil is equal to the rate of change of flux linkage. Therefore,
EMF = N(ΔΦ/Δt)
According to Lenz’s law,
EMF = -N(ΔΦ/Δt)
Applications of Faraday’s Law
Some of the application of Faraday's Law is-
- Induction cooker
- Electromagnetic flowmeter
- Electric guitar and electric violin
- Maxwell’s equation has its basis in the converse of Faraday’s laws