AIPMT 2010 Physics and Chemistry Paper

When loop is placed in the magnetic field then magnetic moment of coil
τ=NiBA‌sin‌θ
τmax=NiBA
Force

→

F

1 and

→

F

2, which are acting on coil, are equal in magnitude but opposite in direction
Force

→

F

3 and

→

F

4 are equal in magnitude but opposite in direction, create magnetic moment. In this way force F acting on one side of loop and force −F acting on remaining side of loop.