Faraday’s laws explain the relationship between electric circuit and magnetic field. This law is the basic working principle of the most of the electric motors, generators, transformers, inductors, etc.
Faraday’s First Law
It states that whenever a conductor is placed in a varying magnetic field, an emf gets induced across the conductors (called an induced emf) and if the conductor is a closed circuit then induced current flows through it.
Faraday’s Second Law
According to this law, the magnitude of induced electromagnetic field (emf) is equal to the rate of change of flux linked with the coil. The flux linkage is the product of number of turns and the flux associated with the coil. The emf induced in a closed circuit is proportional to the time rate of change of magnetic flux linking the circuit.
where e is the induced emf, f is the magnetic flux. The negative sign indicates that the direction of the induced emf is opposite to the cause that produces it.
Lenz’s Law
It states that when an emf is induced according to Faraday’s law, the polarity (direction) of that induced
emf is such that it opposes the cause of its production.
Thus, by considering Lenz’s law,
The negative sign shows that the direction of the induced emf and the direction of change in magnetic field have opposite sign.
