Muddy b。in So, do we lose the capability to do work when we have an irreversible process and Why do we study cycles starting with the Carnot cycle? Is it because i is easier to work with?(MP 1C.2 1. C. 2 The Thermodynamic Temperature scale The considerations of Carnot cycles in this section have not mentioned the working medium. They are thus not limited to an ideal gas and hold for Carnot cycles with any medium Because we derived the Carnot efficiency with an ideal gas as a medium, the temperature definition used in the ideal gas equation is not essential to the thermodynamic arguments. More specifically, we can define a thermodynamic temperature scale that is independent of the working medium. To see this, consider the situation shown below in Figure C-1, which has three reversible cycles. There is a high temperature heat reservoir at T, and a low temperature heat reservoir at T For any two temperatures T, T,, the ratio of the magnitudes of the heat absorbed and rejected in a Carnot cycle has the same value for all systems JT2 Q Q Figure C-1: Arrangement of heat engines to demonstrate the thermodynamic temperature scale We choose the cycles so Q i is the same for A and C. also Q3 is the same for B and c. for a Carnot cycle QL FITL TH; n is only a fune Q2/Q2=F(7,2 AT e/03=F(T,T) But 1C-31C-3 Muddy points So, do we lose the capability to do work when we have an irreversible process and entropy increases? (MP 1C.1) Why do we study cycles starting with the Carnot cycle? Is it because I is easier to work with? (MP 1C.2) 1.C.2 The Thermodynamic Temperature Scale The considerations of Carnot cycles in this section have not mentioned the working medium. They are thus not limited to an ideal gas and hold for Carnot cycles with any medium. Because we derived the Carnot efficiency with an ideal gas as a medium, the temperature definition used in the ideal gas equation is not essential to the thermodynamic arguments. More specifically, we can define a thermodynamic temperature scale that is independent of the working medium. To see this, consider the situation shown below in Figure C-1, which has three reversible cycles. There is a high temperature heat reservoir at T3 and a low temperature heat reservoir at T1. For any two temperatures T T1 2 , , the ratio of the magnitudes of the heat absorbed and rejected in a Carnot cycle has the same value for all systems. WA WC A B C Q1 Q3 Q3 Q1 Q2 T2 T1 T3 Q2 WB Figure C-1: Arrangement of heat engines to demonstrate the thermodynamic temperature scale We choose the cycles soQ1 is the same for A and C. Also Q3 is the same for B and C. For a Carnot cycle η =+ = 1 ( ) Q Q FT T L H L H , ; η is only a function of temperature. Also Q Q FT T 1 2 12 = ( ) , Q Q FT T 2 3 23 = ( ) , Q Q FT T 1 3 13 = ( ) , . But