1. Absolute Temperature We showed:Energy efficiency of the Carnot cycle is independent of the working substance. Definition of temperature independent of any material property A temperature scale is an absolute temperature scale if and only if where, andare the heats exchanged by a Carnot cycle operating between reservoirs at temperatures T 1 and T 2. Measurement of Temperature ratio T1T1 T2T2

2. As discussed earlier, unique temperature scale requires fixed point or Kelvin-scale: T fix =T tripel =273.16K It turns out: proportional to thermodynamic Temperature T empirical gas temperature Why Because: Calculation of efficiency of Carnot cycle based on yields With a=1

3. From definition of thermodynamic temperature If any absolute temperature is positive all other absolute temperatures are positive there is an absolute zero of thermodynamic temperature when the rejected heat 0 T=0 can never be reached, because this would violate the Kelvin statement however