Carnot Cycle Simulator
Classroom worksheet · Interactive simulation: https://lkforge.com/tools/physics/carnot-cycle/
Name: Date:
Learning objectives
- Describe the four steps of the Carnot cycle.
- Compute Carnot efficiency from reservoir temperatures.
- Explain the second-law limit on heat engines.
Variables to change
- Hot reservoir temperature
- Cold reservoir temperature
Procedure
- Run the cycle and identify the two isothermal and two adiabatic steps.
- Raise the hot-reservoir temperature and observe the efficiency.
- Lower the cold-reservoir temperature and observe the efficiency.
Observations
Record the efficiency for several combinations of hot and cold temperatures.
Questions
- Write the Carnot efficiency.
- How do you raise a Carnot engine’s efficiency?
- Can any real engine beat the Carnot efficiency between the same reservoirs?
- Why can’t efficiency reach 100%?
- Name the four processes of the Carnot cycle.
Answer key (instructors)
- 1. η = 1 − Tc/Th, with temperatures in kelvin.
- 2. Increase the hot-reservoir temperature or decrease the cold-reservoir temperature.
- 3. No — Carnot sets the maximum possible efficiency; real engines fall short due to irreversibility.
- 4. That would need Tc = 0 K (unreachable) or Th → ∞; the second law forbids converting all heat to work.
- 5. Isothermal expansion, adiabatic expansion, isothermal compression, adiabatic compression.
The Carnot cycle — two isothermal and two adiabatic steps — is the most efficient possible engine between two reservoirs, with η = 1 − Tc/Th. Real engines fall short, and the second law forbids 100% efficiency.