Clausius' deduction (1865) FIGURE 20-5 The Carnot cycle Heat In a cyo the cycle for the Carnot engine Isothermal begins at point a on this Pl ue20-1 schemata sus曰e expansion diagram (1)The gas is first panded isothermally, with addition of heat @), along path ab at temperature TH. (2)Next d→ he gas expands adia Adiabatic Adiabatic from b to c-no heat is exchanged compression lexpansion but the temperature drops to TL (3)The gas is then compressed at int temperature Ti, path c to d d 0=0 and heat e. flows out. (4)Finally he gas is compressed adiabatically path da, back to its original state. No Carnot engine actually exists, but as a theoretical engine it played e= W/QH c→d Isothermal important role in the development of thermodynamics 1-Q/QH compression = H Q /T HLL 0 1-TL/TH dorer ∑(Q/T)=0 0e= W/ QH = 1-QL /QH =1-TL /TH Clausius’ deduction (1865) QL / TL=QH /TH, QH/ TH-QL /TL =0 (Q/T)=0  = 0 T dQrev