A circular coil with 200 turns has a radius of 2.0 cm. (a) What current through the coil results in a magnetic dipole moment of $3.0 \mathrm{Am}^{2}$ ? (b) What is the maximum torque that the coil will experience in a uniform field of strength $5.0 \times 10^{-2} \mathrm{T} ?$ (c) If the angle between $\mu$ and $B$ is $45^{\circ},$ what is the magnitude of the torque on the coil?
(d) What is the magnetic potential energy of coil for this orientation?