Entropi: Forskelle mellem versioner

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== Definition ==
For en [[Reversibel proces|reversibel]] varmeudveksling <math>\delta Q_{\text{rev}}</math> er [[vejintegrale]]t af den inverse [[temperatur]] for en lukket proces generelt 0 jf. [[Clausius' sætning]]:<ref name="blundell 132">{{cite book |last1= Blundell |first1= Stephen J. |authorlink1= |last2=Blundell |first2= Katherine M. |authorlink2= |coauthors= |editor1-first= |editor1-last= |editor1-link= |others= |title= Concepts in Thermal Physics |url= https://archive.org/details/conceptsthermalp00blun_990 |edition= 1. |year= 2006 |publisher= Oxford University Press |location= |language= engelsk |isbn= 978-0-19-856770-7 |page= [https://archive.org/details/conceptsthermalp00blun_990/page/132 132] |chapter= 13.7 Clausius’ theorem}}</ref>
:<math>\oint\frac{\delta Q_{\text{rev}}}{T}=0</math>
Da det lukkede vejintegrale er 0, er <math>\frac{\delta Q_{\text{rev}}}{T}</math> vejuafhængig, hvilket vil sige, at det er differentialet af en [[tilstandsfunktion]]. Denne tilstandsfunktion defineres som entropien:
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En reversibel, [[adiabatisk]] proces - dvs. en proces uden varmeudveksling - er således også en [[isentropisk]] proces - dvs. at den har konstant entropi.<ref name="blundell 136">{{cite book |last1= Blundell |first1= Stephen J. |authorlink1= |last2=Blundell |first2= Katherine M. |authorlink2= |coauthors= |editor1-first= |editor1-last= |editor1-link= |others= |title= Concepts in Thermal Physics |url= https://archive.org/details/conceptsthermalp00blun_990 |edition= 1. |year= 2006 |publisher= Oxford University Press |location= |language= engelsk |isbn= 978-0-19-856770-7 |page= [https://archive.org/details/conceptsthermalp00blun_990/page/136 136] |chapter= 14.1 Definition of entropy}}</ref>
 
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