Current is flowing in a long, striaght conductor passing through the axis of a circular coil carrying current. What will be the mutual force acting between them ?

Explanation

In case of the striaght conductor [Fig. 1.82], if we apply Maxwell's corkscrew rule, we see that, at each point on the circular coil the direction of the magnetic field is parallel to the direction of current. We know that, no force act when the direction of current and that of magnetic field are parallel to each other. Hence. the mutual force between them will be zero.