Find the mean number density of particles in the stellar atmosphere.

[Jon.G]

Homework Statement

The atmosphere of a star has a mean radiation pressure of 0.33 N m^-2and a mean gas pressure of 8300 N m^-2. Calculate:
a) the mean number density of particles in the stellar atmosphere, and
b) the radiation pressure in a stellar atmosphere with twice the effective temperature.

Homework Equations

$Radiation pressure = \frac{4 \sigma T^{4}}{3c}$ where σ = 5.67*10^-8

The Attempt at a Solution

a) From the radiation pressure equation, I get T=6016K
and I'm not sure where to go from here. I would have thought to have used pV=nRT, but then that bring volume into the equation. I know it's probably really simple and is just something I am forgetting, but I just can't figure it out :/


b) Multiply the given value (0.33) by 16, as it is T⁴
5.28Pa


Thanks

 

[haruspex]

I would have thought to have used pV=nRT, but then that bring volume into the equation.

You wish to find n/V, right?

 

[Jon.G]

:S
Yes I do.
... I don't even know what to say, how could I not see that?

Thanks