Two concentric circular loops of radii $r_1=30 \mathrm{~cm}$ and $r_2=50 \mathrm{~cm}$ are placed in $X-Y$ plane as shown in the figure. A current $\mathrm{I}=7 \mathrm{~A}$ is flowing through them in the direction as shown in figure. The net magnetic moment of this system of two circular loops is approximately