Question

State ampere's law?

Answer 1

Ampere's Law:

1. According to Ampere's law, the magnetic field line integral around a closed path is equal to the product of the magnetic permeability of that space and the total current through the area bounded by that path.
2. The equation of Ampere's Law can be written as$\oint \stackrel{\rightharpoonup }{B.}\stackrel{\rightharpoonup }{dl}={\mu }_{0}I$.
3. Ampere's law provides an additional method for calculating the magnetic field caused by a given current distribution.

Explanation of ampere's law:

We'll find the magnetic field at a point due to a long straight current carrying conductor.

For this, we imagine an Ampereian loop which is circular with the center at the wire and passing through the point P.

$\int B.dl={\mu }_{0}I$
Since the path is a circle, the magnetic field intensity B is uniform throughout because every point is equidistant.

$$\begin{gathered} {\mu }_{0}I=B.\int dl \\ {\mu }_{0}I=B.2\mathrm{\pi r} \\ \mathrm{B}=\frac{{\mathrm{\mu }}_0\mathrm{I}}{2\mathrm{\pi r}} \end{gathered}$$