Posted by Circuits Arena on Friday, 4 May 2018
Lenz's Law of Electromagnetic Induction is the artlcle explaining Lenz's Law Lenz's law is based on Faraday's law of induction, so before understanding Lenz's law; one should know what ...
Lenz's Law
Lenz's law is based on Faraday's law of induction, so before understanding Lenz's law; one should know what is Faraday’s law of induction? When a changing magnetic field is linked with a coil, an emf is induced in it.
This change in the magnetic field may be caused by changing the magnetic field strength by moving a magnet towards or away from the coil, or moving the coil into or out of the magnetic field as desired. Or in simple words, we can say that the magnitude of the emf induced in the circuit is proportional to the rate of change of flux.
Lenz's Law
Lenz's law states that when an emf is generated by a change in magnetic flux according to Faraday's Law, the polarity of the induced emf is such, that it produces a current that's magnetic field opposes the change which produces it.
The negative sign used in Faraday's law of electromagnetic induction indicates that the induced emf ( ε ) and the change in magnetic flux (δΦB) have opposite signs.
Where,
ε = Induced emf
δΦB = change in magnetic flux
N = No of turns in the coil
Reason for Opposing, Cause of Induced Current in Lenz's Law?
As stated above, Lenz's law obeys the law of conservation of energy and if the direction of the magnetic field that creates the current and the magnetic field of the current in a conductor is in the same direction, then these two magnetic fields would add up and produce the current of twice the magnitude and this would, in turn, create more magnetic field, which will cause more current and this process continuing on and on leads to violation of the law of conservation of energy.
If the induced current creates a magnetic field which is equal and opposite to the direction of the magnetic field that creates it, then only it can resist the change in the magnetic field in the area, which is in accordance to Newton's third law of motion.
