Question

State Lenz’s Law and give an example of how it is used

Answer 1

According to Lenz's law

It can be written mathematically as

`e=-N(d\Phi)/(dt)`

Here, e is the emf.

N is the number of loops.

The derivative is the change in magnetic flux with respect to time.

The negative sign indicates the opposing nature.

Lenz's law is used in Ac generators, eddy current, microphones, and so on.

In an AC generator, the direction of current in the coil changes due to a change in the magnetic field.

Suppose we have to calculate emf in the coil,

if the number of turns in the coil is 1 i.e. N = 1.

The change in magnetic flux be - 3 x 10^(-3) Wb

The change in time will be dt = 0.04 s

The emf can be calculated as

`\begin{gathered} e=-N(d\Phi)/(dt) \\ =-1((-3*10^(-3)))/(0.04) \\ =0.075\text{ V} \end{gathered}`