Heat treatment of muscular pain involves radiation of wavelength of about 900 nm. Which spectral line of H-atom is suitable for this purpose? [ R_H…

Heat treatment of muscular pain involves radiation of wavelength of about $\displaystyle 900$ nm. Which spectral line of H-atom is suitable for this purpose? $$\begin{aligned} & {\left[\mathrm{R}_{\mathrm{H}}=1 \times 10^5 \mathrm{~cm}^{-1}, \mathrm{~h}=6.6 \times 10^{-34} \mathrm{Js},\right.} \\ & \left.\mathrm{c}=3 \times 10^8 \mathrm{~ms}^{-1}\right] \end{aligned} $$