Answer to Question #126129 in Molecular Physics | Thermodynamics for Sourav Pandey

Question

Define and explain a thermodynamically reversible process

Answer 1

Reversible process:

If we take into consideration P as a thermodynamical process, it is reversible if the following conditions occur together:

• at least one corresponding inverse process P_inv (inverse transformation) exists during which heat and work are exchanged in equal amounts in absolute value but with opposite sign:

Q_n(P) = - Q_n(P_inv) and W_n(P) = - W_n(P_inv)

• The value which assumes the generic action is equal in absolute value and opposite in sign to the one of the direct process.

a(P_r) = - a(P)

In terms of brief illustration:

In the following picture:

let us assume that the system has experienced a change from state A to state B. In case the system can be restored from state B to state A, and there is no change within the universe, at that point the process is said to be a reversible process. The reversible process can be reversed completely and there is no trace left to show that the system had experienced thermodynamic change.