The Biot–Savart law

Ø   The Biot–Savart law is used for computing the megneic field generated by an elecric current.It relates the magnetic field to the magnitude, direction, length, and proximity of the electric current.The law is valid in the magnetostatic approximation.

                           Electric currents (along closed curve)

Ø   The Biot–Savart law is used for computing the resultant magnetic field B at position r generated by a steady current I, a continual flow of charges which is constant in time and the charge neither accumulates nor depletes at any point.

                                           
Ø   Where

dl is a vector whose magnitude is the length of the differential element of the wire,

μ0 is the magnetic constant,

 is the unit vector of r