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Physics

Faraday’s Law & Lenz’s Law

This point is part of the HSC Physics syllabus Module 6: Electromagnetism under Electromagnetic Induction.

Faraday’s law and Lenz’s law are the basis for how motors work. This stems from Newton’s third law, that every action has an equal and opposite reaction. So when there is a change in flux through a coil, we’re going to see the opposite reaction through the voltage and current readings of the coil.

 

Faraday’s Law

Any change in a magnetic field will induce a potential difference across a conductive surface proportional to the change in flux.

  • V = voltage
  • B = magnetic field
  • A = area
  • t = the time
V= N \frac{\delta BA }{\delta t}

 

Faraday & Lenz’s Law

Lenz’s law states that the current produced from Faraday’s law creates a magnetic field which opposes that of the initial change in flux.

V= -N \frac{\delta BA }{\delta t}
  • V = voltage
  • B = magnetic field
  • A = area
  • t = the time

Note: this has a minus before the N.