Question

Figure below shows two infinitely long and thin current carrying conductors $X$ and $Y$ kept in vacuum, parallel to each other, at a distance ${}^{\prime }a$
How much force per unit length acts on the conductor $Y$ due to the current flowing through $X$? Write your answer in terms of $\left(\frac{{\mu }_0}{4\pi }\right),I_1,I_2$ and $a$.
(Derivation of formula is not required)

Answer 1

The force per unit length is given by:

$\frac{F}{l}=\frac{{\mu }_{0}2I_1{I}_2}{4\pi a}$