Two concentric, circular wire loops, of radii $r_{1}=20.0 \mathrm{cm}$ and $r_{2}=30.0 \mathrm{cm},$ are located in an $x y$ plane; each carries a clockwise current of 7.00 $\mathrm{A}$ (Fig. $28-48 )$ . (a) Find the magnitude of the net magnetic dipole moment of the system.
(b) Repeat for reversed current in the inner loop.