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. Calculate the magnetic force acting on the loop.

Answer 1

Solution.

Radius of circular loop = r

Flowing constant current =I

Placed at uniform magnetic field = B

The magnetic field is perpendicular to the plane of the paper. 

Force acting on loop is given by

$F=i(l×B) =ilBsin\theta$

Since the direction of current is opposite, forces will cancel each other.

Therefore,

all forces acting on the diametrically opposite elements will cancel out in pair. So we say that the net force on the loop will be zero.