[Physics] Quasistatic vs Reversible processes

reversibilitystatistical mechanicsthermodynamics

Would it be fair to state the difference between quasistatic and reversible processes as follows?:

  1. A process is quasistatic if at every point in the process the system is in equilibrium with itself.

  2. A process is reversible if it is quasistatic and at every point in the process the system is in equilibrium with its environment.

Best Answer

Quasistatic precess: quasistatic process is the process that evolves so slow that every point can be viewed as equilibrium during the process.

As for the reversibility of the process, literally reversible process is quasistatic process in which the increasing in entropy is extremely small,i.e.,the entropy is constant throughout the process. To summary, quasistatic process is the process in which every instantaneous states is equilibrium;reversible process is the quasistatic process in which the entropy does not increase,but the quasistatic is not necessarily a reversible, that depents on the entropy—increasing or not.

In addition, I think that whether a process is quasistaic has nothing to do with if the system is isolated or not.If the system is isolated it is in equilibrium itself.If the "system" is in contact with something else, they can composite a big system whose entropy determines the reversibility of the process.

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