Lenz's law
Lenz's law
Lenz's law /ˈlɛnts/ is a common way of understanding how electromagnetic circuits obey Newton's third law and the conservation of energy.[1] Lenz's law is named after Heinrich Lenz, and it says:
If an induced current flows, its direction is always such that it will oppose the change which produced it.
Lenz's law is shown with the negative sign in Faraday's law of induction:
which indicates that the induced voltage (ℰ) and the change in magnetic flux (∂Φ) have opposite signs.[2] Lenz's Law is a qualitative law that refers to the direction of induced current in relation to the effect which produces it without quantitatively relating their magnitudes.
For a rigorous mathematical treatment, see electromagnetic induction and Maxwell's equations.