Two circular coils $P$ and $Q$ of 100 turns each have same radius of $\pi \mathrm{~cm}$. The currents in $P$ and $R$ are $1 A$ and $2 A$ respectively. $P$ and $Q$ are placed with their planes mutually perpendicular with their centers coincide. The resultant magnetic field induction at the center of the coils is $\sqrt{x} ~m T$, where $x=$$\underline{\hspace{2cm}}$. [Use $\mu_0=4 \pi \times 10^{-7} \mathrm{~TmA}^{-1}$]