# Tagged Questions

Covers the study of (mostly homogeneous) macroscopic systems from a heat/energy/entropy point of view. Maybe combine with [tag:statistical-mechanics].

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### How does the fundamental assumption of statistical physics make sense?

Consider two systems A and B in thermal contact. System A has $N_A=3$ simple harmonic oscillators and the system B has $N_B=3$ simple harmonic oscillators as well. Each system has a number of energy ...
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### Heat diffusion in a house

I was wondering about this problem (which is NOT homework, it's one of my mental problems due to what surrounds me): supposing I'm in a room, and it's winter. Heating is on, the boiler works and the ...
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### How to determine the amount of light energy (photons) being released from an incandescent light bulb?

I have got this all down pat: 1.Collision with a moving particle excites an atom. 2.This causes an electron to jump to a higher energy level. 3.The electron falls back to its original energy level, ...
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### Adiabatic filling of a container

Suppose a thermally insulated container is filled with atmospheric air until the pressure reaches 5000 psi. This could represent the filling of a diving cylinder, before thermal dissipation becomes ...
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### What is the net radiative balance between two blackbodies with different temperature?

Context In trying to understand a crop productivity model, I want to figure out how to derive the equation for the net exchange of longwave radiation between two adjacent blackbodies (soil and ...
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### Extreme heating by Sun on Earth- Can eggs be fried?

Will it be possible to fry eggs in Sahara desert by just keeping them under the sun? If so, then will the radiated eggs be any different? Or will we have to use the solar cooking concept to some ...
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### Office Air Conditioning and Open Windows

Today is nice and sunny and the air con is on in the office. It's a fairly large office seating 20 people, 30x30x15ft with 20 small windows and a single large AC unit on the back wall where there are ...
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### Can we make a Maxwell's Demon using Quantum Computers?

Although I'm reasonably sure that quantum computing advances will not lead to the ability to construct a machine that globally violates the 2nd law of thermodynamics, it feels like a difficult ...
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### design of the heat exchanger…in chimney

I want to design a heat exchanger in a chimney in order to utilize heat from chimney. I have done several experiments, but I could not determine the exact length of tube (carrying water), such that ...
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### If humans were able to catch all sun energy reaching the earth for their use, will the climate change?

I guess that energy will be used up and, at the end, will contribute to heat the earth, so I see no big differences... please explain your point of view.
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### If I put 3 bottles of water next to each other in the fridge, which one is cold first?

I was wondering: If I put three bottles of water next to each other in the fridge, which one is cold first? Does it matter? Is it the one in the middle because it gets refrigerated by the other two? ...
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### Compressibility factor and deviation from ideal gas behaviour

I have recently started to study the deviation of ideal gas behavior. The source from which I am reading doesn't give me an intuitive understanding of the compressibility factor. I dont understand how ...
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### By how much does the temperature of a cool Cola can increase by condensation of the ambient moisture on its surface?

Assuming standard ambient temperature and pressure, how can we estimate the increase in the temperature of a typical, cool beverage can produced by the condensation of ambient moisture on its surface? ...
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### Can an adiabatic, isentropic transformation be irreversible?

My question is very similar to this, but I decided to ask another question because I felt that the problem deserved to be addressed in a more specific and formal way and I also wanted to discuss a ...
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### Why is water not considered a proper liquid in terms of thermometers?

We were just discussing about why liquids in general are used in glass thermometers. I was wondering why water isn't considered a proper liquid. Is it because of the way is expands differently to ...
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### Why does the sign of Delta H indicate whether the reaction is exothermic or endothermic?

If $\Delta H = Q + W$ (assuming constant conditions), then there are two terms involved in calculating $\Delta H$, only one of which measures heat gained/released. It is possible then for $\Delta H$ ...
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### When does the Boltzmann distribution apply?

What are the requirements for a system to be described by the Boltzmann distribution in equilibrium? For example, should all the particles be identical? No attractors in the phase space? ...
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### Intuitive explanation of the shape of the Maxwell-Boltzmann distribution

At higher temperatures (for an ideal gas), the Maxwell-Boltzmann distribution is spread more widely and has a lower maximum. At lower temperatures, the spread is much more narrow and the peak is much ...
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### What is the word describing the pairs: temperature and energy, chemical potential and particle number?

I keep forgetting the word describing the pairs of coupled quantities in stat. mech. e.g. inverse temperature $\beta$ and internal energy $E$ or chemical potential $\mu$ and particle number $N$. I ...
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### Is it possible to produce higher temperature than the light source with passive device only?

Suppose the light source is a black body with average temperature 2000K, and I want to use it to heat another black body to 2500K, via passive devices only. Here passive device means lens, mirror, ...
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Wich one of the two cases will be more suitable A hotter body for instance candle with its flame with the pic in infrared region of emissivity will emit more microwave radiation or a colder one with ...
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### How to see intuitively that $\kappa_T$ is constant for solids?

In thermodynamics we define $$\kappa_T = -\dfrac{1}{V}\left(\dfrac{\partial V}{\partial p}\right)_T.$$ By this definition, if we are treating $V$ as a function of $p$ and $T$, then $\kappa_T$ is ...
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### Heat and Thermodynamics [duplicate]

What is the temperature of air in the upper part of our atmosphere? I read somewhere that it is of the order of 1000 K, but then, why is it cold there? My question is different from the ...
My problem: A thin-walled tube (length $L$, diameter $D$ and wall thickness $t \ll D$) is in a vacuum. It is held on one end (at $x=0$) by a heat source at constant temperature $T(0)=T_0$. The only ...
From Statistical Physics, 2nd Edition by F. Mandl: Two vessels contain the same number $N$ molecules of the same perfect gas. Initially the two vessels are isolated from each other, the gases ...