It is perpendicular to the arm AB of the loop
and exerts a force F1 on it which is directed into the
plane of the loop Its magnitude is,
F1 = I b B
Similarly, it exerts a force F2 on the arm CD and F2
is directed out of the plane of the paper F2 = I b B = F1
Thus, the net force on the loop is zero There is a
torque on the loop due to the pair of forces F1 and F2