unit is Am . From Eq. ( . ), we see that the torque ττ vanishes when m is either parallel or antiparallel to the magnetic field B .
This indicates a state of equilibrium as there is no torque on the coil (this also applies to any object with a magnetic moment m ). When m and B are parallel the FIGURE . (a) The area vector of the loop ABCD makes an arbitrary angle θ with the magnetic field. (b) Top view of the loop.
The forces F and F acting on the arms AB and CD are indicated.