In a Carnot cycle, heat flows only on the two isotherms.

Starting with hot isothermal expansion, which sequence completes a Carnot engine cycle?

• Adiabatic expansion, cold isothermal compression, adiabatic compression
• Cold isothermal compression, adiabatic expansion, adiabatic compression
• Adiabatic compression, cold isothermal compression, adiabatic expansion

Th is the hot reservoir temperature and Tc is the cold one. Which expression gives the Carnot efficiency?

• 1 - Th/Tc, with both temperatures in kelvin
• Tc/Th, with both temperatures in kelvin
• 1 - Tc/Th, with both temperatures in kelvin

A student uses 27 °C and 127 °C directly in Tc/Th. What change is needed?

• Use Celsius temperatures because the gap is fixed.
• Use kelvin temperatures before taking their ratio.
• Use the Celsius temperature gap instead of a ratio.

A Carnot engine runs between 600 K and 300 K. Give its efficiency as a decimal.

Why can no engine exchanging heat only with the same two fixed-temperature reservoirs beat Carnot?

• Its choice of fuel releases more energy than fuels used in every other engine.
• Its reversibility sets the second-law limit between those reservoirs.
• Its cycle returns all rejected heat as work without using a cold reservoir.

A Carnot engine between 400 K and 300 K absorbs 800 J of heat per cycle. Give the maximum work in J.

The area enclosed by a clockwise Carnot loop on a pV diagram equals the net work done by the gas per cycle.