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Lenz's Law: Definition, Formula & Application

Lenz's Law

Lenz's Law: Lenz’s law states that “The direction of the current induced in a conductor by causing the change in the magnetic field is such that the magnetic field generated by the induced current opposes the initial magnetic field which produced it”.The direction of this current flow is given by the method of Fleming’s right-hand rule. This law was named after Physicist Emil Lenz, who formulated this concept in the year 1834. This law is based on the concept of Faraday's law of Electromagnetic induction. Lenz's law is the qualitative law which states the direction of the induced current but neither takes into amount the magnitude of the current.

Lenz's Law Formula

Lenz's law states that “The direction of the current induced in a conductor is opposite to the direction of the magnetic field”. This law is analogous to the principle of conservation and Newton's third law of motion. The formula of Lenz's law is-

EMF =−N(ΔΦB/Δt)

Where, 

EMF is the Current Induced

N is the No. of Coil

ΔΦB is the Change in magnetic flux

Δt = Change in time

Lenz's Law Application

In Physics, the application of Lenz's law is-

  • Lenz’s law helps to understand the concept of Magnetic energy stored in inductors.
  • Lenz’s law also applies to Generators as well.
  • Lenz’s law is applicable to electromagnetic brakes and inductive cooktops.
  • Lenz’s law applies to AC generators and electric generators.
  • This law helps in understanding the concept relating to the metal detectors and the braking system of the train along with the microphones and card readers.
  • Lenz’s law has its application in Eddy’s current dynamometers.

Lenz's Law Experiment

To find out the direction of the induced EMF and current we generally use Lenz’s law. So the experiment related to Lenz's law is-

1st Experiment: As the current in the coil flows the magnetic field is generated. As the flow of current increases, the magnetic flux also increases. But the direction of the current is opposite to the direction of the magnetic field. 

2nd Experiment: He concluded that when the current-carrying coil is wound on an iron rod with its left end it behaves as an N-pole and is moved towards coil S, and an induced current will be produced.

3rd Experiment: He concluded that when the coil is pulled towards the magnetic flux, the coil linked with it decreases, which means that the area of the coil decreases inside of the magnetic field.

Related Links-
Newton's Law of MotionBoyles's Law
Newton's First Law of MotionCharles Law
Newton's Second Law of MotionHooke's Law
Newton's Third Law of MotionLaws of Thermodynamics
Pascal LawOhm's Law
Zeroth Law of Thermodynamics

 

Lenz's Law- FAQs

Ans. Lenz’s law states that “The direction of the current induced in a conductor by causing the change in the magnetic field is such that the magnetic field generated by the induced current opposes the initial magnetic field which produced it”.

Ans. This law was named after Physicist Emil Lenz, who formulated this concept in the year 1834.

Ans. The formula of Lenz's law is- EMF =−N(ΔΦB/Δt)

Ans. In Physics, the application of Lenz's law is- Lenz’s law helps to understand the concept of Magnetic energy stored in inductors, Lenz’s law also applies to Generators as well, Lenz’s law is applicable to electromagnetic brakes and inductive cooktops, Lenz’s law applies to AC generators and electric generators.

Ans. The negative sign in Lenz’s law indicates that the induced emf in the coil is in the opposite direction of the magnetic flux, which is linked with the coil.

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