Electromagnetic Induction

A small square loop of wire of side \(l\) is placed inside a large square loop of wire of side \(L\left(L=l^2\right)\). The loops are coplanar and their centers coincide. The value of the mutual inductance of the system is \(\sqrt{x} \times 10^{-7} \mathrm{H}\), where \(x=\) _________.