A circular 10-turn coil with a radius of 5.0 cm carries a current of 5 A. It lies in the xy plane in a uniform magnetic field = 0.05 T iˆ+ 0.3 T kˆ . The coil rotates so that its magnetic moment, μ, is aligned with the magnetic field. The potential energy of the system when the coil's magnetic moment is aligned with the field is___________.