A hydrogen atom changes its state from $n=3$ to $\mathrm{n}=2$. Due to recoil, the percentage change in the wave length of emitted light is approximately $1 \times 10^{-n}$. The value of $n$ is $\_\_\_\_$ . [Given $\mathrm{Rhc}=13.6 \mathrm{eV}, \mathrm{hc}=1242 \mathrm{eVnm}, \mathrm{h}=6.6 \times 10^{-34} \mathrm{Js}$, mass of the hydrogen atom $\left.=1.6 \times 10^{-27} \mathrm{~kg}\right]$