Physics - Magnetism Question with Solution | TestHub

An infinitely long straight wire carries a current ${\mathrm{i}}_1$, as shown in figure. The total force on another wire CD of length $\ell$ which is placed so that c is at a distance a from the current carrying wire is $\frac{{\mu }_0{\mathrm{i}}_1{\mathrm{i}}_2}{\mathrm{N}\pi }\ln \left(\frac{{\mathrm{a}}^2+{\ell }^2}{{\mathrm{a}}^2}\right)$. Then find value of N .