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 ?
$\left[\mathrm{R}_{\mathrm{H}}=1 \times 10^{5} \mathrm{~cm}^{-1} \cdot \mathrm{h}=6.6 \times 10^{-34} \mathrm{Js}, \mathrm{c}=3 \times 10^{8} \mathrm{~ms}^{-1}\right]$
Correct Option: 1
$\frac{1}{\lambda}=\mathrm{R}_{\mathrm{H}}\left(\frac{1}{\mathrm{n}_{1}^{2}}-\frac{1}{\mathrm{n}_{2}^{2}}\right)$
$\mathrm{n}_{1}=3, \mathrm{n}_{2}=\infty$
$\frac{1}{\lambda}=\mathrm{R}\left(\frac{1}{9}\right) \Rightarrow \lambda=\frac{9}{\mathrm{R}}=\frac{9}{10^{5}}=9 \times 10^{-5} \mathrm{~cm}=900 \mathrm{~nm}$
Click here to get exam-ready with eSaral
For making your preparation journey smoother of JEE, NEET and Class 8 to 10, grab our app now.