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## Homework Statement

We are investigating hydrogen in a plasma with the temperature 4500 ºC. Calculate the probability per atom and second for stimulated emission from 2p to 1s if the lifetime of 2p is 1.6 ns

## Homework Equations

##A=\frac{1}{\Sigma \tau}##

$$A_{2,1} = \frac{8*\pi *h * f^3*B_{2,1}}{c^3}$$

## The Attempt at a Solution

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hmmm, I'm not sure how to approach this problem. I took the inverse of the life time and got that A= ##6.25*10^8 S^{-1}.##

But I'm not sure where to start or what formulas to use.

The only formula I know of which takes temperature into account is

Doppler line width: ##\Delta F = constant * f_0 * \sqrt(T/M) ## which I can't see how to apply in this case at all.

Any input on where to start?