Explanation:
Given that,
Energies of a quantum system
E₁ = 0.0 eV
E₂ = 5.0 eV
E₃ = 8.5 eV
We need to calculate the wavelength
Using formula of energy
![E=\dfrac{hc}{\lambda}](https://tex.z-dn.net/?f=E%3D%5Cdfrac%7Bhc%7D%7B%5Clambda%7D)
An electron transits from 5.0 eV to 0.0 eV
Thereby emitting a photon
For E₁ = 5.0 eV,
Using formula of energy
![E_{1}=\dfrac{hc}{\lambda_{1}}](https://tex.z-dn.net/?f=E_%7B1%7D%3D%5Cdfrac%7Bhc%7D%7B%5Clambda_%7B1%7D%7D)
Where, E = energy
h = Planck constant
= wavelength
Put the value into the formula
![5.0\times1.6\times10^{-19}=\dfrac{6.63\times10^{-34}\times3\times10^{8}}{\lambda_{1}}](https://tex.z-dn.net/?f=5.0%5Ctimes1.6%5Ctimes10%5E%7B-19%7D%3D%5Cdfrac%7B6.63%5Ctimes10%5E%7B-34%7D%5Ctimes3%5Ctimes10%5E%7B8%7D%7D%7B%5Clambda_%7B1%7D%7D)
![\lambda_{1}=\dfrac{6.63\times10^{-34}\times3\times10^{8}}{5.0\times1.6\times10^{-19}}](https://tex.z-dn.net/?f=%5Clambda_%7B1%7D%3D%5Cdfrac%7B6.63%5Ctimes10%5E%7B-34%7D%5Ctimes3%5Ctimes10%5E%7B8%7D%7D%7B5.0%5Ctimes1.6%5Ctimes10%5E%7B-19%7D%7D)
![\lambda_{1}=2.486\times10^{-7}\ m](https://tex.z-dn.net/?f=%5Clambda_%7B1%7D%3D2.486%5Ctimes10%5E%7B-7%7D%5C%20m)
![\lambda_{1}=248.6\ nm](https://tex.z-dn.net/?f=%5Clambda_%7B1%7D%3D248.6%5C%20nm)
An electron transits from 8.5 eV to 0.0 eV
Thereby emitting a photon
For E₂ = 8.5 eV,
The wavelength of photon
![\lambda_{2}=\dfrac{6.63\times10^{-34}\times3\times10^{8}}{8.5\times1.6\times10^{-19}}](https://tex.z-dn.net/?f=%5Clambda_%7B2%7D%3D%5Cdfrac%7B6.63%5Ctimes10%5E%7B-34%7D%5Ctimes3%5Ctimes10%5E%7B8%7D%7D%7B8.5%5Ctimes1.6%5Ctimes10%5E%7B-19%7D%7D)
![\lambda_{2}=1.463\times10^{-7}\ m](https://tex.z-dn.net/?f=%5Clambda_%7B2%7D%3D1.463%5Ctimes10%5E%7B-7%7D%5C%20m)
![\lambda_{2}=146.3\ nm](https://tex.z-dn.net/?f=%5Clambda_%7B2%7D%3D146.3%5C%20nm)
An electron transits from 8.5 eV to 5.0 eV
Thereby emitting a photon
For E₃ = 8.5-5.0 =3.5 eV,
The wavelength of photon
![\lambda_{3}=\dfrac{6.63\times10^{-34}\times3\times10^{8}}{3.5\times1.6\times10^{-19}}](https://tex.z-dn.net/?f=%5Clambda_%7B3%7D%3D%5Cdfrac%7B6.63%5Ctimes10%5E%7B-34%7D%5Ctimes3%5Ctimes10%5E%7B8%7D%7D%7B3.5%5Ctimes1.6%5Ctimes10%5E%7B-19%7D%7D)
![\lambda_{3}=3.5517\times10^{-7}](https://tex.z-dn.net/?f=%5Clambda_%7B3%7D%3D3.5517%5Ctimes10%5E%7B-7%7D)
![\lambda_{3}=355.2\ nm](https://tex.z-dn.net/?f=%5Clambda_%7B3%7D%3D355.2%5C%20nm)
Hence, This is the required solution.