The
magnetic moment of a flat
current-carrying loop (current =
I), area =
A) is
IA The magnetic moment is a
vector quantity that points along the field line
perpendicular to the plane of the loop. In terms of the magnetic moment, the
torque on a flat coil with N loops in a
magnetic field B is
τ = N · (IA) · B sin θ,
where θ is the angle between the field and the magnetic moment vector.