i am just wondering, is it possible to find the velocity of a single electron that is accelerated by a certain potential difference? Also im having trouble with this homework problem: A coil with a magnetic moment of 1.40 A*m^2 is oriented initially with its magnetic moment antiparallel to a uniform magnetic field of magnitude 0.845T. 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? I remember that antiparallel means when two vectors just have the same direction cept that they are opposite signs so wouldnt the change in PE just be 0? I'm not too sure about that one.