A current loop of magnetic moment m is placed in a uniform magnetic field B. The net force on the loop is:

1. In a uniform field, the forces on opposite arms of the loop are equal and opposite. 2. These forces cancel pairwise, so the net force is zero. 3. They do, however, form a couple, producing a torque. 4. Hence force = 0 while torque $= mB\sin\theta$ may be non-zero. _Source: syllabus Physics Ch 4 "Moving Charges and Magnetism", p.155_