Question

Which thermodynamic process must occur "infinitesimally slowly" to remain reversible?

• A. Isothermal process
• B. Adiabatic process
• C. Quasi-static process
• D. Isochoric process

Hint:

Remember: Reversible process = Quasi-static (very slow).

Answer 1

The Correct Option is C

Concept: A reversible process is an ideal thermodynamic process that occurs in such a way that the system remains in equilibrium at every stage.
Step 1: Understanding reversible process.
For a process to be reversible, it must proceed infinitely slowly so that the system remains in thermodynamic equilibrium.
Step 2: Definition of quasi-static process.
A quasi-static process is one that occurs very slowly, passing through a sequence of equilibrium states.
Step 3: Connection to reversibility.
All reversible processes are quasi-static, as they require infinitesimally slow changes.
Step 4: Evaluating the options.

• Isothermal process $\rightarrow$ Constant temperature, not necessarily slow (incorrect)
• Adiabatic process $\rightarrow$ No heat exchange (incorrect)
• Quasi-static process $\rightarrow$ Infinitesimally slow, reversible (correct)
• Isochoric process $\rightarrow$ Constant volume (incorrect)

Step 5: Conclusion.
Thus, a quasi-static process must occur infinitesimally slowly to remain reversible.