Magnetics (Magnetic Field):

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