PV Graph Rev vs Irrev: Adiabatic Differences

[cns]

What's the difference in the PV graph for a reversible process vs. an irreversible process?

I know for adiabtic you would get a smooth (log like) downwards cruve if it's reversible but what about ireeversible?

Thanks

 

[dacruick]

I'm pretty sure a reversible process travels along the same curve while the irreversible process will have 2 separate paths.

check out wikipediea http://en.wikipedia.org/wiki/Reversible_process_(thermodynamics ) it could be useful.

 

[DrDu]

Which p do you want to use in your pV diagram in case of an irreversible process?

 

[cns]

thanks I think I got it. Its just I straight vertical line down then across to where the final pt is suppose to be

cheers :D

 

[PJC01]

for your question! The main difference between the PV graph for a reversible process and an irreversible process is the shape of the curve. In a reversible process, the curve will be smooth and continuous, while in an irreversible process, the curve will be jagged and discontinuous.

This is because in a reversible process, the system is able to reach equilibrium at each step, meaning that the pressure and volume are constantly changing in small increments. This results in a smooth, logarithmic curve on the PV graph.

On the other hand, in an irreversible process, the system is not able to reach equilibrium at each step. This can be due to factors such as friction, heat transfer, or other external factors. As a result, the pressure and volume change in larger, discontinuous increments, leading to a jagged curve on the PV graph.

Additionally, the area under the curve on a PV graph represents the work done by the system. In a reversible process, the area under the curve is equal to the work done, as all the energy is used to do work. However, in an irreversible process, some energy is lost as heat, so the area under the curve will be smaller than the actual work done.

In summary, the main difference in the PV graph for a reversible and irreversible process is the shape of the curve, with a smooth curve for reversible and a jagged curve for irreversible. This difference is due to the ability of the system to reach equilibrium at each step and the loss of energy as heat in an irreversible process.