Determining the Temperature of a Hydrogen Gas

[captainjack2000]

Homework Statement

A gas of hydrogen atoms has a fraction of atoms found in the n=2 quantum state of 0.05. What is the temperature of the gas?

The Attempt at a Solution

I think the gas molecules have an energy E=5/2kT (rather than E=kT ?? because diatomic gases have 5 degrees of freedom?)

E=Ry(1/n^2)?

not sure how to continue

 

[Redbelly98]

Since the question indicates these are hydrogen atoms, it is not considered a diatomic gas in this case.

Try looking up Boltzmann Factors in your textbook.

 

[captainjack2000]

So the Boltzmann factor is
exp(-E/kT)=0.05

I still don't understand what you would take as the energy of the gas. It can't have a factor of kT because then the T would cancel...