(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

The entropy of an ideal paramagnet is given by

[tex] S = S_0 - CU^2 [/tex]

where U is the energy, which can be positive or negative, and C is a positive constant. Determine the equation for U as a funtion of T and sketch your result.

2. Relevant equations

[tex] \frac{1}{T} = \left(\frac{\partial S}{\partial U}\right)_V [/tex]

3. The attempt at a solution

I differentiated the given equation, treating S0 as not depending on U.

[tex] \frac{1}{T} = -2CU [/tex]

[tex] U(T) = -\frac{1}{2CT} [/tex]

so far so good i hope. But in the question it says U can be positive or negative.. But in my last equation the only way of getting U positive is by having a negative temperature??

Or should I just answer that the energy is strict negative in this case?

Any help will do!

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# Entropy of an ideal paramagnet

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