A short bar magnet of moment `0*32JT^-1` is placed in a uniform external magnetic field of `0*15T`, if the bar is free to rotate in the plane of the field, which orientations would correspond to its, (i) stable and (ii) unstable equilibrium? What is the potential energy of the magnet in each case?
A. when m is anti-parallel to B, U `=4.8 xx 10^(-2)J`
B. when m is perpendicular to B, U = 0
C. when m is perpendicular to B, U = `4.8 xx 10^(-2)J`
D. None of the above