Temperature at which ground state and first excited state have equal populations

AI Thread Summary
The discussion revolves around calculating the population ratio of the ground state to the first excited state of hydrogen gas at a temperature of 10080 K, using the Boltzmann equation. The energy difference between the two states is given as 1.634e-18 joules, leading to a calculated ratio of N(2)/N(1) of approximately 0.000031665. To find the temperature at which both states have equal populations, it is clarified that one should assume N(A)/N(B) = 1, as this indicates equal populations rather than equal temperatures. The derived temperature for equal populations is -85411.7 Kelvins, although the negative value suggests a need for reevaluation of assumptions or calculations. The conversation emphasizes the importance of correctly interpreting the assumptions in the Boltzmann equation for accurate results.
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Homework Statement


Consider a pure hydrogen hydrogen gas ata tempeature of 10080 K. What is the ratio of the populations of the ground state(n=1) to the first excited state(n=2). Note that the energy difference is 1.634e-18 joules between these two states. At what temperature would both levels have equal populations?


Homework Equations



Boltzmann equation: N(B)/N(A)= g(b)/g(a) exp[(E(A)-E(B))/kT
g=2*n^2

The Attempt at a Solution


finding N(B)/N(A) was easy. N(2)/N(1)=2(2)^2/2(1)^2*exp(1.634e-18 joules)/(10080 K)(1.380 *10^-23))= .000031665

I had a difficult time finding the Temperature when both populations are equal. When both populations are equal, does that imply N(a)/N(b) = 1 because N(a)=N(B)?

Now finding the temperature is simple : 1=4 exp(1.634e-18 joules/(T(1.380e-23)) => T= -85411.7 Kelvins.

The only problem is I don't know if I should assume N(B)/N(A) = 1 , just because the temperatures are equal
 
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No, you shouldn't assume N(B)/N(A) = 1 because the temperatures are equal.
You should assume it because you assume that the populations are equal; then you fill in the formula and solve for the temperature where this occurs.

So you have obtained the right answer with the right method but with a wrong way of thought :smile:
 
CompuChip said:
No, you shouldn't assume N(B)/N(A) = 1 because the temperatures are equal.
You should assume it because you assume that the populations are equal; then you fill in the formula and solve for the temperature where this occurs.

So you have obtained the right answer with the right method but with a wrong way of thought :smile:

sorry, I meant to say that the populations are equal, so should I assume that N(a)/N(b)=1 since N(a)=N(b)
 
Then you got the right answer by the right method and a typo :)
 
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