Question

Two long parallel copper wires carry currents of $5A$ each in the opposite direction . If the wires are separated by a distance of $0.5m$, then the force between the two wires is

• A. ${10}^{-5}N$ attractive
• B. ${10}^{-5}N$ repulsive
• C. $2\times {10}^{-6}N$ attractive
• D. $2\times {10}^{-5}N$ repulsive.

Answer 1

The correct option is B ${10}^{-5}N$ repulsive

$F=\frac{\mu i_1{i}_2}{2\pi d}=\frac{2\times {10}^{-7}\times 5\times 5}{0.5}={10}^{-5}N$
Since currents are opposite so the force is repulsive.