18 questions linked to/from What is entropy really?
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### Understanding entropy [duplicate]

I am currently doing some research on entropy and I am trying to get my head around the concept. One thing that I am getting right now is that entropy is just an application of probability and ...
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### What is the real definition of entropy? [duplicate]

In our bio class our teacher told us that entropy was the amount of heat lost by a system. But I had learned before that entropy was like chaos / disorder in a closed system. Which definition Is right,...
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### What is entropy? [duplicate]

Can somebody please explain in detail what is entropy not a definition like its measure of disorderness. A complete introduction from basics to what parameters it depends on as a thermodynamics point ...
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### Why are the laws of thermodynamics “supreme among the laws of Nature”?

Eddington wrote The law that entropy always increases holds, I think, the supreme position among the laws of Nature. If someone points out to you that your pet theory of the universe is in ...
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### Is information entropy the same as thermodynamic entropy?

Context In one of his most popular books Guards! Guards!, Terry Pratchett makes an entropy joke: Knowledge equals Power, which equals Energy, which equals Mass Pratchett is a fantasy comedian and ...
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### Intuitive understanding of the entropy equation

In thermodynamics, entropy is defined as $d S = \dfrac{\delta q_{\rm }}{T}$. This definition guarantees that heat will transfer from hot to cold, which is the second law of thermodynamics. But, why ...
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### Why is black hole entropy not an extensive quantity?

The Bekenstein entropy for a black hole is proportional to the surface area $A$ of the black hole $$S_{BH} = \frac{k_B}{4 l_P^2} A$$ with the Planck length $l_P = \sqrt{\frac{\hbar G}{c^3}}$. The ...
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### Is there any intuitive explanation as to why is entropy is a state function?

In my textbook there is a proof that entropy is a state function but there is no intuition given there. What is the intuition behind entropy(∫dQ/T) being a state function. Why would we have ...
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### When can entropy be negative?

I don't really understand the basic principles behind this and so I am looking for a good explanation on it. My lecture notes use inequalities like $dS \geq 0$, yet in a question involving ...
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### Proving that the Boltzmann entropy is equal to the thermodynamic entropy

I've been trying to understand how we can equate the Boltzmann entropy $k_B \ln \Omega$ and the entropy from thermodynamics. I'm following the approach found in the first chapter in Pathria's ...
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### Can entropy be regarded as energy dispersal?

In several answers here the claim has been made that thermodynamic entropy can be regarded as energy dispersion. See, in particular here, and here and here. This is apparently the pet theory of a ...
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### Why is entropy k times log of multiplicity?

We define entropy to be log of multiplicity. Is it just to reduce a large number like multiplicity or does it have any physical significance? Further, only if entropy is defined so, we get the correct ...
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### Why is this a good definition of temperature?

I have started studying thermodynamics and they defined temperature in a statistical way: $$\frac{1}{k_BT}=\frac{d \ln(\Omega)}{dE}$$ where $k_B$ is the Boltzmann constant, $T$ is the temperature, \$...