question_answer

Two long thin parallel wires are placed at a distance (r) from each other carrying equal current \[I\] in opposite direction. The magnitude of force per unit length which is exerted by each wire on the other is :

A) \[\frac{{{\mu }_{0}}{{I}^{2}}}{r}\]                             

B)        \[\frac{{{\mu }_{0}}{{I}^{2}}}{2\pi r}\]                    

C) \[\frac{{{\mu }_{0}}I}{2\pi r}\]                   

D)        \[\frac{{{\mu }_{0}}^{2}I}{2\pi {{r}^{2}}}\]