Question

Two thin long parallel wires separated by a distance b are carrying a current i amp each. The magnitude of the force per unit length exerted by one wire on the other is

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

Force per unit length $=\frac{{\mu }_0}{4\pi }.\frac{2i_1{i}_2}{r}=\frac{{\mu }_0}{2\pi }.\frac{i^2}{b}$