1. Lecture 8-- CALM
Explain as succinctly as you can, and in your own words, why, of all possible heat engines acting between two reservoirs of fixed temperature , a Carnot cycle has the greatest possible thermodynamic efficiency??
Several answers focused on aspects that the Carnot cycle shares with others e.g.
The Carnot is the most eficient because it uses a temperature cycle which brings the system back to where it started in the beginning.
A heat engine with only two reservoirs does not lose any thermal energy
The decrease in entropy of the HOT reservoir is exactly equal in magnitude to the increase in entropy of COLD reservoir. Thus the net increase in entropy of the system is zero. (i.e. it is reversible! 12 answers)

2. Chapter 3 problems (examples)

3. Lecture 8– Otto Cycle (simplified)
Isochoric (constant volume) heating and cooling, connected by adiabatic expansions and compressions.
The Internal combustion engine (ICE) is approximated by the Otto Cycle (not really closely, since in the ICE, the working fluid is not contained)

4. Definition of the Kelvin Scale
The TRIPLE POINT OF WATER (the only point in Density-Pressure,-Temperature space where solid, liquid, and gaseous H2O can coexist in equilibrium) is defined to be at K. Since 0K is defined to be absolute zero, this defines the Kelvin scale completely.
The normal melting point of water (0oC) occurs at a higher pressure (101.3 kPa rather than 612 Pa) and slightly lower temperature ( K).
We’ll talk more about this diagram in the last few weeks of the semester.
273.16K

5. P340 Lecture 10 “Practical Thermometry”
International Temperature Scale (ITS-90)
This is the accepted standard against which secondary thermometers are typically calibrated (it deviates from absolute temperature in certain regions by several mK).
0.65-5K (3He or 4He equil. vapor pressure over liquid)
3.0 to K (He gas thermometer calibrated at defined fixed points)
to K (Pt resistance thermometer calibrated at defined fixed points with set interpolation scheme).
Above K: Planck radiation law.
Fixed points are “easily” reproducible states that have a well-defined absolute temperature (such as the triple point of water (Vienna Standard Mean Ocean Water” to be even more pedantic) at K, the triple point of Argon at K, and that of Al at K, for example). We will discuss why triple points are used as fixed points toward the end of the semester.