A coil with magnetic moment 1.40 Am^2 is oriented initially with its magnetic moment antiparallel to a uniform magnetic field of magnitude 0.830 T.
What is the change in potential energy of the coil when it is rotated 180 degrees, so that its magnetic moment is parallel to the field?
u = IA = magnetic moment
U = -uBcos(phi)
The Attempt at a Solution
U1 = -uBcos(180) = -1.162J
U2 = -uBcos(360) = 1.162J
deltaU = U2-U1 = 1.162J - (-1.162J) = 2.324J
just wondering if I did the problem correctly, I'm not sure I have the correct angles; any help is greatly appreciated.