Two long parallel straight wires X and Y separated by a distance of 5 cm in air carry currents of 10A and 5A respectively in opposite directions. Calculate the magnitude and direction of the force on a 20 cm length of the wire Y.

Explanation

`F= (mu_0 I_1 I_2l)/(2 pi r) = (4 pi xx 10^(-7) xx 10xx5 xx .020)/(2 pi xx 0.05) = 4 xx 10^(-5)N`
The direction of the force is perpendicular to the length of wire Y and acts away from X (repulsion).