Practice question · Multiple choice
Work is path-dependent, yet Joule used mechanical work to establish a unique internal energy function. How does restricting measurements to adiabatic boundaries resolve this contradiction?
Hints
- What varied between Joule's trials even though the measured work remained identical?
- Why cannot non-adiabatic paths uniquely determine the change in internal energy?
Show the answer
C. Adiabatic work depends solely on endpoints, defining a state function
Why
Adiabatic work uniquely fixes energy changes because isolating the system prevents boundary leakage, whereas non-adiabatic routes allow variable heat exchanges. Equating adiabaticity with irreversibility confuses boundary constraints with process dynamics.
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