Magnetic Force: The magnetic force ( on a charge q moving with velocity ina magnetic field is given both in magnetude and direction, by
= q( x )
The Biot and Savart Law: Consider an infinitesinal element of length 'dl' of a wire carrying current I. The magnetre field d at P because of is given by the law: Magnetic field due to current in a straight line: (Secondary Information)
at P due is = l = R cot, dl = - R cosec2d, r = R cosec
on a charge q moving with velocity
ina magnetic field 
is given both in magnetude and direction, by 
is given by the law: 
at P due 
, dl = - R cosec2d
