plz answer.

An electric field is present at a distance r from a charged particle and this is inversely proportional to the square of the distance and directly proportional to the charge.

Experiments show that the magnetic field is also proportional to q and to 1/r^2. This field is given by B=μ 0 /4pi(qv sinΦ)/r^2. This field is perpendicular to the plane containing the line from the source point to the field point and the particle's velocity vector.