Statistical Physics - average energy of a system.

[Jalo]

Homework Statement

Imagine a system, in contact with a heat reservoir, with three particles. Each particle may be in a state of energy 0 or ε.

What's the temperature of the reservoir such that the mean energy of the system, <E>, is 1.2ε?

Homework Equations

The Attempt at a Solution

I tried using the formula:

S = Kb ln(Ω(E))
dS/dE = Kb / Ω(E) = 1/T

However I don't think this is the right way to go. Since I only know the average value of the energy I don't think I can find the temperature of the system!

Any hints would be highly appreciated!

Thanks.

 

[kevinferreira]

The average of the energy is closely related to the temperature, through the equipartition theorem. Here, read this http://en.wikipedia.org/wiki/Equipartition_theorem
I hope it helps!