Describe a quasistatic process and its role in reversibility

A quasistatic (quasi-equilibrium) process proceeds via infinitely small steps, with the system relaxing to equilibrium after each step. Properties remain uniform throughout the system.

Role in Reversibility

1. Necessary condition: Reversible → must be quasistatic so the path can be retraced exactly.
2. Not sufficient: Quasistatic alone is not enough; any dissipation (friction, viscosity, resistance) makes the process irreversible.

Therefore, a truly reversible process is both quasistatic and free of dissipation.