Figure $28-45$ shows a rectangular 20 -turn coil of wire, of dimensions 10 $\mathrm{cm}$ by 5.0 $\mathrm{cm} .$ It carries a current of 0.10 $\mathrm{A}$ and is hinged along one long side. It is mounted in the $x y$ plane, at angle $\theta=30^{\circ}$ to the direction of a uniform magnetic field
of magnitude 0.50 $\mathrm{T}$ . In unit-vector notation, what is the torque acting
on the coil about the hinge line?