State Ampere's circuital law and explain its mathematical expression.

(N/A) Ampere's circuital law states that the line integral of the magnetic field $\vec{B}$ around any closed loop is equal to $\mu_0$ times the total current $I$ passing through the surface enclosed by the loop.
Mathematically,it is expressed as: $\oint \vec{B} \cdot d\vec{l} = \mu_0 I_{enclosed}$.
Here,$\oint$ represents the line integral over a closed path,$\vec{B}$ is the magnetic field,$d\vec{l}$ is the infinitesimal element of the path,$\mu_0$ is the permeability of free space,and $I_{enclosed}$ is the net current threading the loop.