# Quasi equilibrium and non flow reversible in a simpler way?

1. Sep 15, 2010

### mikhailpavel

Can anyone explain me quasi equilibrium and non flow reversible in a simpler way? It is from thermodynamics and i am getting difficulty to understand it

2. Sep 16, 2010

### Andrew Mason

Re: Thermodynamics

Quasi equilibrium is a state in which the system is arbitrarily close to equilibrium that can be reversed with an arbitrarily small change in conditions. For example, an interface between a heat reservoir with infinite heat capacity at temperature T and a gas at temperature T - dT where dT is an infinitessimal: Heat flows from the slightly hotter reservoir to the gas and the gas expands just enough to keep its temperature at T-dT. The process can be reversed by heating the gas an infinitessimally small amount to T + dT so that the heat flows from the gas to the reservoir. The gas can be compressed isothermally using arbitrarily close to the same amount of work that the gas did when it expanded.

AM