In order to solve this problem we must resort to Boltzmann's theory,
His theory describes how energy levels are populated within atoms. The Boltzmann equation gives ratios of level populations as a function of temperature as follow,
[tex]\frac{N_2}{N_1} =\frac{g_2}{g_1}e^{-\frac{\Delta E}{k_B T}}[/tex]
Where,
g1/g2 are the states (statistical weights)
[tex]\Delta E[/tex] Energy
T temperature
[tex]k_B[/tex] Boltzmann constant
We have all the data, thus replacing,
A) The fraction of H in 2P state at 5900K is,
[tex]\frac{N_2}{N_1} = \frac{6}{2} e^{\frac{-10.2(1.6*10^{-19})}{1.38*10^{-23}*5900}}[/tex]
[tex]\frac{N_2}{N_1} = 5.92.10^{-9}[/tex]
Note that I did the convertion in energy, remember that
[tex]1eV = 1.6*10^{-19}J[/tex]
The fraction of H in 2P state at 5900K is [tex]5.92.10^{-9}[/tex]
B) The fraction of H in 2P state at 4300K is,
[tex]\frac{N_2}{N_1} = \frac{6}{2} e^{\frac{-10.2(1.6*10^{-19})}{1.38*10^{-23}*4300}}[/tex]
[tex]\frac{N_2}{N_1} = 3.41*10^{-12}[/tex]
The fraction of H in 2P state at 4300K is [tex]3.41*10^{-12}[/tex]