Question

In which of the following process the system and surrounding comes back to its original state after the process is complete?

• A. Quasi-static Process
• B. Reversible process
• C. Both a and b
• D. Isobaric process

Answer 1

Answer: (C)

Both a and b

Quasi-static Process and Reversible are process the system and surrounding comes back to its original state after the process is complete?

In thermodynamics, a quasi-static process is a thermodynamic process that happens slowly enough for the system to remain in internal equilibrium. An example of this is quasi-static compression, where the volume of a system changes at a rate slow enough to allow the pressure to remain uniform and constant throughout the system.

Any reversible process is necessarily a quasi-static one. However, quasi-static processes involving entropy production are irreversible. An example of a quasi-static process that is not reversible is a compression against a system with a piston subject to friction—although the system is always in thermal equilibrium, the friction ensures the generation of dissipative entropy, which directly goes against the definition of reversible. A notable example of a process that is not even quasi-static is the slow heat exchange between two bodies at two finitely different temperatures, where the heat exchange rate is controlled by an approximately adiabatic partition between the two bodies—in this case, no matter how slowly the process takes place, the states of the two bodies are never infinitesimally close to equilibrium[clarification needed], since thermal equilibrium requires that the two bodies be at the same temperature.