Question:
Heat treatment of muscular pain involves radiation of wavelength of about $900 \mathrm{~nm}$. Which spectral line of H-atom is suitable for this purpose ?
${\left[\mathrm{R}_{\mathrm{H}}=1 \times 10^{5} \mathrm{~cm}^{-1}, \mathrm{~h}=6.6 \times 10^{-34} \mathrm{Js}\right.}$
$\left.\mathrm{c}=3 \times 10^{8} \mathrm{~ms}^{-1}\right]$
Correct Option: 2,
Solution:
Paschen, $\infty \rightarrow 3$