Question

Two parallel wires in free space are $10$ cm apart and each carries a current of $10$ A in the same direction the force exerted by one wire on the other per meter length is:

Answer 1

Distance between two parallel wires (x) = 10 cm =0.1 m;

current in each wire $i_1=i_2=10A$

and length of wire l is 1 cm

force of wire is f $\frac{{\mu }_0{i}_1{i}_2\times l}{2\pi x}=\frac{(4\pi \times {10}^7)\times 10\times 10\times 1}{2\pi \times 0.1}=2\times {10}^{-4}N$