An electron is in an orbit of hydrogen atom with angular momentum  $\frac{3h}{2\pi }$. The minimum wavelength of the emitted radiations is (h-Planck’s constant, R-Rydberg constant)  

$\mathrm{If} \mathrm{angular} \mathrm{momentum} \mathrm{of} \mathrm{the} \mathrm{electron} \mathrm{is} \frac{3\mathrm{h}}{2\mathrm{\pi }} \mathrm{it} \mathrm{is} \mathrm{in} \mathrm{the} \mathrm{third} \mathrm{orbit}$

$$\begin{gathered} \mathrm{Minimum} \mathrm{wavelength} \mathrm{or} \mathrm{maximum} \mathrm{frequency} \mathrm{of} \mathrm{transition} \\ \mathrm{a} \mathrm{transition} \mathrm{from} 3\mathrm{rd} \mathrm{to} \mathrm{ground} \mathrm{level} \end{gathered}$$

$$\begin{gathered} \frac{1}{\lambda }=R\left(\frac{1}{1}-\frac{1}{9}\right)=\frac{8R}{9} \\ \lambda =\frac{9}{8R} \end{gathered}$$