Testing Kelvin Planck's Second Law of Thermodynamics

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SUMMARY

The discussion centers on proving the Kelvin-Planck statement of the second law of thermodynamics, which asserts that heat cannot be completely converted into work without some heat being transferred to a cold body. Participants suggest that demonstrating the equivalence of the Kelvin-Planck statement and the Clausius statement is essential. By assuming the Clausius statement is false, one can derive that the Kelvin-Planck statement must also be false, thereby reinforcing its validity. The discussion emphasizes the need for rigorous proof independent of other thermodynamic principles.

PREREQUISITES
  • Understanding of the Kelvin-Planck statement of the second law of thermodynamics
  • Familiarity with the Clausius statement of the second law of thermodynamics
  • Basic knowledge of heat engines and thermodynamic cycles
  • Concept of work and energy transfer in thermodynamic processes
NEXT STEPS
  • Research the mathematical formulation of the Kelvin-Planck statement
  • Study the Clausius statement and its implications in thermodynamics
  • Explore independent proofs of the second law of thermodynamics
  • Examine the role of entropy in thermodynamic processes
USEFUL FOR

Students of physics, thermodynamics researchers, and engineers interested in the foundational principles of energy conversion and efficiency in cyclic processes.

sadhu
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can anyone proove "kelvin plank" statement of second law of thermodynamics or atleast show that it is always followed in any cyclic process...
 
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am i gone mad ,no one knows it...come on
 
sadhu said:
can anyone proove "kelvin plank" statement of second law of thermodynamics or atleast show that it is always followed in any cyclic process...
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.

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
 
Last edited:
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...:approve:
 
Last edited:
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
 

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