Q.
Heat treatment of muscular pain involves radiation of wavelength of about $900\, nm$. Which spectral line of H-atom is suitable for this purpose ?
$[R_H = 1 \times 10^5 \; cm^{-1}, h = 6.6 \times 10^{-34} \; Js, c = 3 \times 10^8 \; ms^{-1}]$
Solution: