Ampere's Circuital Law:

Ampere's circuital law states that the line integral of the magnetic field (circulation of H ) around a closed path is the net current enclosed by this path. Mathematically,

                                           ......................................(4.8)

The total current I _enc can be written as,  
               
                                           ......................................(4.9)                            
By applying Stoke's theorem, we can write

                                          
                                          ......................................(4.10)
which is the Ampere's law in the point form.