Two long parallel wires carrying currents `2.5 A` and `I` (ampere) in the same directon (directed into the plane of the paper) are held at `P` and `Q`, respectively such that they are perpendicular to the plane of paper. The points `P` and `Q` are located at distance of `5 m` and `2m` respectively from a collinear point `R` (see figure).

a. An electron moving with a velocity of `4xx10^5` m/s along the positive x-directionn experieces a force of magnitude `3.2xx10^-20` `N` at the point `R`. Find the volume of `I`.
b. Find all the positions at which a third long parallel wire carrying a current of magnitude `2.5 A` may be placed, so that the magnetic induction at `R ` is zero.

Answer

(a) 4A (b) `x = +- 1 m` w.r.t R