Magnetic Current

Question

A conducting circular loop of radius r carries a constant current i. It is placed in a uniform magnetic field B such that B is perpendicular to the plane of the loop. The magnetic force acting on the loop is

Answer 1

The correct answer is: zero

Net magnetic force on any current carrying loop in uniform magnetic field is zero.

Explanation:

Let's consider a small arc of the circular loop, the force is proportional to IdLxB. Using the right hand rule we see that the force is acting towards the centre. But a similarly elemental arc is exactly opposite to the considered arc. But the current flows in opposite direction. Hence the forces cancel each other.