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Lecture 12 — Second law of thermodynamics

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Practice questions for lecture 12
Learning objectives

Students should be able to:

  • Distinguish reversible from irreversible processes, and calculate entropy changes to decide whether a process is allowed.
  • Analyse a heat engine or a refrigerator with an energy-flow diagram, including from a pV cycle.
  • State the second law and use the Carnot cycle to find the maximum efficiency and to test a claimed device.
  • Analyse an unfamiliar engine, refrigerator or entropy problem, choosing the physics without being told.
Contact 1 — Understand

Build the physical idea. Focus: Direction.

Contact 2 — Calculate

Develop the model and method. Focus: Convert.

Contact 3 — Apply and Consolidate

Apply, integrate and transfer. Focus: Limits.