Two concentric circular coils with radii $1 \mathrm{~cm}$ and $1000 \mathrm{~cm}$, and number of turns 10 and 200 respectively are placed coaxially with centers coinciding. The mutual inductance of this arrangement will be ___________ $\times 10^{-8} \mathrm{H}$. (Take, $\pi^{2}=10$ )