In Li^++, electron in first Bohr orbit is excited to a level by a radiation of wavelength λ. When the ion gets deexcited to the ground state in all…

In $\displaystyle \mathrm{Li}^{++}$, electron in first Bohr orbit is excited to a level by a radiation of wavelength $\displaystyle \lambda$. When the ion gets deexcited to the ground state in all possible ways (including intermediate emissions), a total of six spectral lines are observed. What is the value of $\displaystyle \lambda$ ? (Given : $\displaystyle \mathrm{h}=6.63 \times 10^{-34} \mathrm{Js}$; $$\left.\mathrm{c}=3 \times 10^8 \mathrm{~ms}^{-1}\right) $$