Re: [問題] 一題物化

[nanokevin (明日幸福今日修)]

※ 引述《spysea ( )》之銘言：
: Show that two phases are in thermal equilibrium only if their
: temperatures are the same.
: 請問一下這一題要從哪裡證明起?
: 謝謝回答
equilibrium in an isolated system =>dS = 0
let two phases A and B

dS=dSa+dSb=0

by S=S(U,V)
Assume the system is mechanically rigid=> dV=0
then

dS=(dSa/dUa)v *dUa + (dSb/dUb)v *dUb = (1/Ta)dUa+(1/Tb)dUb=0

Since dUa=-dUb =>Ta=Tb

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