All Questions
Tagged with thermodynamicscarnot-cycle
236 questions
0votes
0answers
56views
In the $T$-$S$ diagram, area between $S$ axis and curve is heat added or rejected, then what is significance of area between curve and $T$ axis?
I was studying second law, where it said that for a reversible process, $dQ=TdS$, the parameter Tds is energy, then what does the sdT signify (as sdT is also energy). Can we say that sdT is work, as ...
2votes
2answers
96views
From Carnot Cycle to Clausius Inequality to Entropy Derivation
In our syllabus we have discussed around the Carnot Cycle and his heat machine idea. From what I have understood until now, is that Carnot wanted to imagine the ideal heat machine, the one that ...
user379700
4votes
2answers
861views
Confusion about reversibility of a carnot engine
I recently posted a question about entropy and the conversation changed topic to bring up an interesting question. @Chemomechanics explained that for a transformation to be reversible it is needed ...
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1vote
2answers
73views
In an Otto cycle engine, why not have the crankcase in a vaccuum?
In a 4-stroke engine, it is extremely difficult to have high efficiency because the hot gases are not allowed to expand until they are atmospheric pressure. But what if they weren't expanding against ...
user431618
2votes
3answers
138views
Is Carnot theorem applicable to black holes?
As I know, there is a simple method to take almost all $mc^2$ from mass by dropping it to the black hole. Doesn't this violate Carnot theorem? Or does it define the temperature of black hole as very ...
1vote
1answer
153views
"Universality" of Carnot cycles
In his answer to the discussion "Historical view of the second law of thermodynamics as a complete differential" (https://physics.stackexchange.com/q/823281) @hyportnex wrote that: Contrary ...
0votes
1answer
168views
At what stage in the Carnot cycle, does a Carnot engine produce work?
I am currently confused as to how exactly a Carnot engine (ideal engine) produces work. I will explain my current understanding of how a Carnot engine works: A piston containing gas is placed into ...
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2answers
95views
Contradiction in the Carnot Cycle?
The carnot cycle is reversible, because the temperature difference between heat reservoir and fluid is extremely low, so that heat can flow in both directions. Also, the carnot cycle is described as ...
1vote
2answers
59views
What happens if you factor in the energy required to switch between the reservoirs and insulating stand of the Carnot engine?
I'm reading about the Carnot cycle (as a non-physicist!) and much of the focus is on the idealisation around the infinite time needed due to the requirement of only infinitesimal differences in ...
0votes
1answer
44views
Efficiency of thermal (rankine) power plants based on ambient temperature?
so I'm preparing for an interview and this is a common question that they always ask, Say there are two power plants working on ideal rankine cycle One in Alaska (low ambient temperature) and one in ...
0votes
1answer
57views
Relation between heat quotient and temperature quotient
Is $$\frac{Q_c}{Q_h} = \frac{T_c}{T_h}$$ valid for any reversible ideal cycle Or just for the Carnot cycle?
2votes
1answer
138views
Application of Stokes theorem in closed thermodynamic cycles
I was reading a book on thermodynamics when I came across the following: "Any closed thermodynamic cycle can be approximated by infinitely many Carnot cycles". I realize that because the ...
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1answer
55views
Why do we need an adiabatic expansion in the Carnot cycle? [duplicate]
As we know that 1st process is an reversible isothermal expansion during this the system is in quasi static equilibrium which helps in increasing the volume of the system but why does the second step ...
1vote
0answers
92views
Is there a specific commercial or experimental implementation of the Carnot cycle? [closed]
I have been unable to find an example of a Carnot engine implemented practically, beyond the drinking bird (which has not revolutionized technology as far as I know). I understand the Stirling and ...
0votes
1answer
139views
How does Heat flows in Carnot engine? [duplicate]
According to fundamental concept of thermal conduction, heat flows from higher temperature to lower temperature. As in Carnot cycle, there is isothermal expansion and compression as a process i.e. ...
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