Questions tagged [thermodynamics]
Covers the study of (primarily homogeneous) macroscopic systems from a heat/energy/entropy point of view. Consider also using the tag: [statistical-mechanics].
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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 ...
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Enthalpy at constant pressure/volume
Enthalpy is defined as the heat the goes into (leaves) a system at constant pressure.
$dH =TdS+ d(PV) = TdS + PdV + VdP$
For some reason, most texts simply write $dH = TdS + VdP$ but haven't they ...
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Calculating a space and time dependant temeprature profile of a very cylindrical heat source in an infinite medium [closed]
I am trying to calculate the time and space depenadant temperature profile of an infinite medium after inserting a very long cylindrical heat source into it using Green's function. The heat source ...
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Why is Sun's energy entropy low on Earth?
Warning i dont have physics background, having said that i was recently looking into sun's radiation energy entropy and i had couple of questions.
So it is said that we can utilize the energy from the ...
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Thermal flunctuations of density in thermal equlibrium? [closed]
According to physics a fluid or gas in thermal equilibrium is not exactly homogeneous. Locally its density undergoes random fluctuations which are small compared to the corresponding equilibrium value....
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Is the energy spectrum of molecules of an ideal gas at equilibrium in an isolated system the Maxwell-Boltzmann distribution? [closed]
The energy spectrum of an ideal gas at equilibrium in a closed system at thermal equilibrium with its surroundings is described by the Maxwell-Boltzmann distribution. If the system is then isolated ...
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How quickly can you reduce temperature of content in a jar by running cold water over it? [closed]
If I have a glass jar with a metal lid that contains 24floz of water @ 70F and I continuously run 45F water over the top of the closed jar, how long will it take for the 24fl oz to reach 45F?
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The usage of temperature in quantum mechanics
This is a follow up question for my previous question, because now I am more confused than I was before.
In a regular quantum mechanics course, temperature plays no role as it does not appear in the ...
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Isentropic or isenthalpic expansion for the remaining fluid in a previously pressurised tank? [closed]
Imagine a container filled with ammonia at 25 bar and 100 degC. Assume that an orifice is opened, so that fluid can flow through ...
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Heating an object with black body radiation to above the temperature of the source
A recent question and its answers say that you could not use sunlight to heat something to above the temperature of the Sun. There was some discussion of the need for the bodies to be in ...
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When is the temperature relevant for a quantum many body system?
Let me illustrate my question with an example. Suppose I want to consider a system of $N$ identical bosons. The Hamiltonian of the system is typically of the form:
$$H_{N} = \sum_{j=1}^{N}(-\Delta_{x_{...
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Does color temperature limit how much a laser of a given wavelength can heat a target?
The Sun has a peak wavelength of around 500 nm and an effective surface temperature of 5770 K, and sunlight cannot be focused to make something hotter than the Sun, because this would be heat flowing ...
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Why won't there be any transfer of heat energy when ice at 0°C is in contact with water at 0°C in a closed container?
In my book, Concise Physics of Selina Publications for Class IX, it's written there that "If there is no transfer of heat between the two bodies placed in contact, they are said to be at the same ...
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Where can I find the derivation of the law of mass action for liquids?
I already asked this in chemistry and all they gave me was a link to the historical derivation. https://chemistry.stackexchange.com/q/68195/
But this derivation relies on the Maxwell-Botlzmann ...
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When does equilibrium mean accessible microstates are represented with equal probability in an ensemble of systems?
I'm confused to when a system in equilibrium is to be found in any one of its acessible states with equal probability (accoriding to the postulate of equal a priori probabilities). Reif in his book ...
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