Answer to Question #210987 in Electricity and Magnetism for Nabeel khan

Question

State and explain Lenz's law the lenz's law is also a statement of law of conservation of energy. Explain, does the lenz's law violate the principle of law of conservation of energy.

Answer 1

Lenz's law upholds the general principle of the conservation of energy. If the current were induced in the opposite direction, its action would spontaneously draw the bar magnet into the coil in addition to the heating effect, which would violate conservation of energy.

The induced electromotive force with different polarities induces a current whose magnetic field opposes the change in magnetic flux through the loop in order to ensure that original flux is maintained through the loop when current flows in it.

Named after Emil Lenz, Lenz’s law depends on the principle of conservation of energy and Newton’s third law. It is the most convenient method to determine the direction of the induced current. It states that the direction of an induced current is always such as to oppose the change in the circuit or the magnetic field that produces it.

Lenz’s Law Formula

The Lenz’s Law is reflected in the formula of Faraday’s law. Here the negative sign is contributed from Lenz’s law. The expression is –

Emf=$-N\frac{∆\phi}{∆t}$

Where

Emf is the induced voltage (also known as electromotive force).

N = the number of loops.

Δϕ =Change in magnetic flux.

Δt =Change in time.