the coil

The coil in Fig. 28-55 carries current i = 2.00 A in the direction indicated, is parallel to an xz plane, has 3.00 turns and a an area of 4.00 x 10^-3 m², and lies in a uniform magnetic field  mT. what are (a) the magnetic potential energy of the coil-magnetic field system and (b) the magnetic torque (in unit-vector notation) on the coil?