Two very long, straight , parallel wires carry steady currents ` I &-I` respectively . The distance between the wires is `d`. At a certain instant of time, a point charge `q` is at a point equidistant from the wires , in the plane of the wires. Its instantaneous vel,ocity ` v` is perpendicular to this plane. The magnitude of the force due to the magnetic field acting on the charge at this instant is

Options

A. `(mu_(0)Iqv)/(2pid)`
B. `(mu_(0)Iqv)/(pid)`
C. `(2mu_(0)Iqv)/(pid)`
D. Zero

Answer

D

Explanation

Net magnetic field due to both the wires will be downward as shown in the figure.

Since, anglebetwene v and b is `180^(@)` , therefore magnetic force `F_(m)=q(vxxb)=0`