Question

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

Answer 1

Here r = 5 cm = 0.05 m, I₁ = 10 A, I₂ = 5A, l = 20 cm = 0.2 m, F = ?

Since F = \(\frac{\mu_0}{4\pi} \frac{2I_1I_2}{r}l\)

∴ F = \(\frac{10^{-7}\times 2\times 10 \times 5 \times 0.2}{0.05}\)

or F = 4 x 10^-5 N

The direction of F acting on conductor Y is in the plane of the paper, perpendicular to Y and is directed away from conductor X.