Question

State and explain Lenz’s law for induced e.m.f.

Answer 1

Hint : Lenz’s law states the direction of the current flow. Lenz’s law states that the current induced in the circuit which is due to the change in the magnetic field is directed which opposes the change in the flux and it exerts the mechanical force which opposes the motion.

Complete Step By Step Answer:
In simple words, Lenz’s law states that when an emf is generated by the change in the magnetic flux according to Faraday's law, the polarity of the induced emf is in such a way that it produces an electric current that is magnetic field opposed to the change which produces it.
The negative sign applied to the Faraday’s law of the electromagnetic induction which indicates the induced (emf) and the change in the magnetic flux have the opposite signs.
$\varepsilon = - N\dfrac{{d\phi }}{{dt}}$
Here B is the magnetic field and N is the number of the turns in the coil.
Lenz’s law obeys the law of the conservation of energy. When the direction of the magnetic field which creates the current and the magnetic field of the current in the conductor are in the same then it results two magnetic fields which would add up and produces the current of double the magnitude which creates more magnetic field and causes more current and leads to the violation of the law of the conservation of the energy.

Note :
Remember the difference between Lenz's and Faraday's law. The most important concepts of electricity are Faraday's law of magnetic induction. Faraday’s law relates to the rate of change of the magnetic flux through the magnitude of the electromagnetic force induced in the loop. It describes the induction of emf in a conductor and calculates the emf produced in the conductor which comes across at the way of changing magnetic fields and causes the flow of current in the wires.