Carnot Cycle

Concept:

Step 1: Observation.
Efficiency depends only on temperatures.

Step 2: Conclusion.
Independent of working substance.

Step 1: Understanding the Concept:
First law of thermodynamics: . If all heat is used for work, .

Step 2: Detailed Explanation:
implies temperature constant (isothermal process).
Work done by gas = heat supplied, so gas expands.
Thus, isothermal expansion.

Step 3: Final Answer:
The process is isothermal expansion.