Graph of several thermodynamic processes

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Discussion Overview

The discussion revolves around the interpretation of a graph depicting several thermodynamic processes, specifically focusing on the implications of various processes on pressure and volume states in a thermodynamic cycle. Participants explore the relationships between different states and the conditions under which they occur, including isochoric and isothermic processes.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether state D would have the same pressure as state A if the process from A to D was not included, considering the implications of the isochoric process from B to C.
  • Several participants express confusion regarding the graphical representation, noting potential misinterpretations of isochoric and isobaric processes.
  • A participant suggests that the graph in post #1 is mostly correct but indicates that segment BC should be vertical.
  • Another participant clarifies that the process CD is an isothermic volume reduction to a specific pressure, which can be chosen by the executor of the cycle.
  • There is a reiteration of the initial doubt regarding whether pressure would remain the same without the last isochoric condition, indicating ongoing uncertainty.

Areas of Agreement / Disagreement

Participants express differing views on the accuracy of the graphical representation and the implications of the thermodynamic processes. There is no consensus on the interpretation of the graph or the specific outcomes related to pressure and volume states.

Contextual Notes

Participants have noted potential errors in the graphical representation, including the direction of arrows and the interpretation of process types. The discussion reflects a need for clarification on these points, which may affect the understanding of the thermodynamic cycle.

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Homework Statement
Graph these processes on a PV graph : Isothermal expansion from state A to B, isochoric pressure increment from B to C,
isothermal contraction from C to D, isobaric contraction from D to A.
Relevant Equations
!!!
I graphed it similar to this

IMG_20240314_204917.jpg


My query is say if the last process wasn't mentioned, I.e the process from A TO D, would the state D have the same pressure as state A then? In thermodynamics for a reversible system we say that if it undergoes a change in pressure volume the exact pressure and volume can he achieved when we reverse it, considering the temperature is constant. But here since we underwent an isochoric process from B to C and then reversed it, would it have ended at the same pressure of A if not for the last condition?
 
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Did you post the picture you intended to post?
I see the arrows going in the wrong direction, isochoric (at the same volume) and isobaric (at the same pressure) misinterpreted, etc...
 
BvU said:
Did you post the picture you intended to post?
I see the arrows going in the wrong direction, isochoric (at the same volume) and isobaric (at the same pressure) misinterpreted, etc...
Oh, sorry my question is typed wrong

[Post edited by a Mentor]
 
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BvU said:
Did you post the picture you intended to post?
I see the arrows going in the wrong direction, isochoric (at the same volume) and isobaric (at the same pressure) misinterpreted, etc...
All fixed! Please give it another read i interchanged D & B by mistake
 
BvU said:
Did you post the picture you intended to post?
I see the arrows going in the wrong direction, isochoric (at the same volume) and isobaric (at the same pressure) misinterpreted, etc...
Hi, if you have some free time, please consider clearing my doubt. Thankyou.
 
Back from a short vacation, but I think we need more expertise. @Chestermiller ?
 
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Fwiw: CD is an isothermic volume reduction down to a particular pressure. Whoever executes the cycle can choose that pressure; since DA is supposed to be isochoric, the choice of P at A makes sense.
 
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BvU said:
Back from a short vacation, but I think we need more expertise. @Chestermiller ?
It seems to me the graph in post #1 is correct, except BC should be vertical.
 
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BvU said:
Fwiw: CD is an isothermic volume reduction down to a particular pressure. Whoever executes the cycle can choose that pressure; since DA is supposed to be isochoric, the choice of P at A makes sense.
That was the doubt if pressure would have remained the same if the last isochoric condition wasnt there. Got it. thanks
 
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