- #1
sadhu
- 155
- 0
can anyone proove "kelvin plank" statement of second law of thermodynamics or atleast show that it is always followed in any cyclic process...
Testing Kelvin Planck's Second Law of Thermodynamics
- Context: Undergrad
- Thread starter sadhu
- Start date
Click For Summary
Discussion Overview
The discussion centers around the Kelvin Planck statement of the second law of thermodynamics, specifically seeking proof or demonstration that it is consistently followed in cyclic processes. Participants explore the relationship between the Kelvin Planck and Clausius statements of the second law, while emphasizing the desire for independent proof without reliance on established principles or concepts like entropy.
Discussion Character
- Exploratory, Technical explanation, Debate/contested
Main Points Raised
- One participant requests proof that the Kelvin Planck statement is always followed in cyclic processes.
- Another participant suggests that proving the Kelvin Planck statement is equivalent to proving the Clausius statement, proposing a method to show that if Clausius is false, then Kelvin Planck must also be false.
- A different participant clarifies their intent to prove the statement independently, without referencing other forms of the second law or the Carnot cycle, expressing uncertainty about their own progress and seeking more rigorous methods.
- One participant expresses frustration over a lack of responses to their previous inquiries about proving the second law, indicating they have attempted their own analysis but are unsure of its validity.
Areas of Agreement / Disagreement
Participants do not appear to reach a consensus on the proof of the Kelvin Planck statement, and multiple competing views and methods are presented without resolution.
Contextual Notes
Participants express limitations in their approaches, including the desire to avoid using established laws or concepts like entropy, which they believe cannot be proven independently.
Who May Find This Useful
This discussion may be of interest to those studying thermodynamics, particularly in the context of the second law and its implications for cyclic processes.
- #2
sadhu
- 155
- 0
am i gone mad ,no one knows it...come on
- #3
Andrew Mason
Science Advisor
Homework Helper
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I think this question is asking you to prove that the Kelvin Planck statement of the second law follows or is equivalent to the Clausius statement of the second law.sadhu said:
First of all, you should state the Kelvin Planck statement of the second law and also state the second law (Clausius statement).
Then assume that the Clausius statement is not true (heat flows from cold to hot without adding work) and show that it follows that Kelvin Planck is not true. So not-Clausius is false (and not-KP is false): ie.Clausius must be true (and so Kelvin Planck must be true).
Hint: assume that heat Q can flow from cold to hot without doing work, then put a heat engine in there which takes the same amount of heat (Q) from the hot reservoir as flows from the cold and produces W work delivering Q' heat flow to the cold reservoir. You can see that the hot reservoir is not really doing anything (Q flows in and Q flows out) so you can ignore it and just consider Q flowing from the cold reservoir to the heat engine. AM
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- #4
sadhu
- 155
- 0
sorry
but what i mean is to show that the statement
"kelvin plank"
"heat cannot be converted into work with 100% efficiency(without giving some to cold body)"
is followed in every cyclic process ,without using other forms of the 2 law or carnot
cycle or any such statement which is a part of second law or uses it .
i.e to prove it independently
because it will automatically prove every other part of it except the one including the concept of entropy which i think can,t be prooved..
well i have made some progress in it but i am not sure that my proove is genuine one or not hence i wanted someone to come up with some other more rigourous methods to do it.
but thanks for your reply...
but what i mean is to show that the statement
"kelvin plank"
"heat cannot be converted into work with 100% efficiency(without giving some to cold body)"
is followed in every cyclic process ,without using other forms of the 2 law or carnot
cycle or any such statement which is a part of second law or uses it .
i.e to prove it independently
because it will automatically prove every other part of it except the one including the concept of entropy which i think can,t be prooved..
well i have made some progress in it but i am not sure that my proove is genuine one or not hence i wanted someone to come up with some other more rigourous methods to do it.
but thanks for your reply...
Last edited:
- #5
sadhu
- 155
- 0
search for proof
well if you all remembered i recently asked the question about prooving(not deriving) 2 law
but no one gave me the answer i wanted. so i was left to do on my own ,well i came up with an
analysis but don't know whehter it is right or wrong
so here i put to everyone to analyse it and check
well if you all remembered i recently asked the question about prooving(not deriving) 2 law
but no one gave me the answer i wanted. so i was left to do on my own ,well i came up with an
analysis but don't know whehter it is right or wrong
so here i put to everyone to analyse it and check
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