- #1
Crush1986
- 207
- 10
Homework Statement
The problem is to calculate the temperature of a one solar mass black hole
Homework Equations
[tex] S = \frac{8\pi^2GM^2k}{hc} [/tex]
[tex] E = Mc^2 [/tex]
[tex] \frac{1}{T} = \frac{\partial S}{\partial U} [/tex]
The Attempt at a Solution
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My first solution I pulled out an [tex] Mc^2 [/tex] Which left my equation looking like [tex] S = \frac{k8\pi^2GM} {hc}*U [/tex] and did the partial derivative with respect to U of the entropy equation. I found that I was off by a factor of two (I think, I don't for sure know the right answer but some friends got answers 1/2 as much as my answer).
I think I know why and I just want to check out my reasoning. By only factoring out one U instead of U^2 I left an M in the equation. But M and U are intricately related right? So I must take out a U^2 in order to take out all of the M's in the original equation. It is only then that I get the correct result (That being 6.14 *10^-8 K, which I believe to be right but I'm also not entirely sure.)
Does this sound like a reasonable conclusion as to why I'm probably wrong?
Thank you for any help you can offer!