- #1
mooshasta
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Homework Statement
Consider a rubber band for which the tension, [itex]f[/itex], as a function of temperature [itex]T[/itex] and length [itex]L[/itex] is [itex]f = \kappa T (L+\gamma L^2)[/itex], where [itex]\kappa[/itex] and [itex]\gamma[/itex] are positive constants. Determine the heat flow between it and its surroundings when the rubber band is stretched reversibly and isothermically from length [itex]L_1[/itex] to length [itex]L_2[/itex].
Homework Equations
[tex]dE = TdS + fdL + \mu dN[/tex]
The Attempt at a Solution
I think the question is asking to find [itex]\left( \frac{\partial E}{\partial L} \right)_{T,N}[/itex] and integrate that. I'm not sure how to get this quantity, though, since I don't know what entropy is. Can I use the Helmholtz free energy when calculating heat transfer? I don't think so, since they are not equal...
Thank you for your help!