(27-39) A 15-loop circular coil 22cm in diameter lies in the xy plane. The current in each loop of t

(27-39) A 15-loop circular coil 22cm in diameter lies in the xy plane. The current in each loop of the coil is 7.6A clockwise, and an external magnetic field B=(0.55i+0.60j−0.65k)T passes through the coil. Determine (a) the magnetic moment of the coil, u; (b) the torque on the coil due to the external magnetic field; (c) the potential energy U of the coil in the field (take the same zero for U as we did in our discussion of Fig. 27-22).