# 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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### 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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### In summer when air temperature higher than 37 degree celsius, is it better to wear more clothes to keep cool？ [duplicate]

Usually wearing more clothes will keep us warm, as we did in winter. In summer, we wear less to allow better heat dissipation to keep us cool. However, according to the Second Law of Thermodynamics, ...
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### Calculating temperature change out of a room [closed]

Currently I'm trying to find how the outside temperature affects the internal temperature of a room through its walls. I'm trying to use the convection heat transfer equation to find the exterior wall ...
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### Definition of heat from stat phys [duplicate]

I don't really understand how to couple the idea of entropy as info with heat. Let's say that you have an isolated system. A cube with a a series of movable partitions parallel to a face of the curve. ...
1 vote
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### Energy output calculations for the very big heat exchanger [closed]

It recently emerged the concept of using deep wells as heat exchangers. It can be visualized as a long (2000 m) vertical tube with an inner diameter of 162 mm (the outer pipe diameter is 177.8 mm, ...
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### Trouble understanding the classic approximation of a black body as a hole on a cavity

While studying the Rayleigh-Jeans attempt to explain the spectral energy distribution of black bodies I have trouble understanding the concept of a black body as a small hole on a cavity. We define a ...
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### Why does capillary in gas thermometer have a temperature and pressure gradient?

I have been learning thermodynamics using Heat and Thermodynamics by Zemansky, in which he mentions The gas in the capillary connecting the bulb with the manometer has a temperature gradient, that is,...
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1 vote
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### Why there is a delay before canned fruits float to the top?

This question may appear silly compared to others asked on this site, yet, I can't get my head around it. After pouring boiling water into a canning jar with berries, berries stay at the bottom of the ...
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### Monopoles and matter conservation [closed]

It seems i may have figured out the totality of the quantum physics challenge based on the form of magnetic and not electromagnetic dynamics. Magnetic monopoles going basically 1 0 1 0 with its spin, ...
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### Can particles feel hot to the touch? [closed]

The other day, I got a tiny splash of hot cooking oil on my hand. But I could barely feel it because it was so small. That made me wonder: how hot would a small collection of atoms need to be for me ...
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### Pressure dependence on temperature [closed]

I was doing a problem on airflow around a wing, and how water will condensate on a point on the back of the wing. After reading the solution, it said that "The relative change of the pressure of ...
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### Will a Modified Maxwellian Demon Experiment Using Charged Particles Be Able to Recycle Heat?

(If necessary this experiment can be conducted in an environment where gravity is negligible to avoid gravitational effects.) Two adjacent containers are filled with a homogenous gas composed of ...
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### How does Superconductiviy change in 3D to 2D or vice versa? [closed]

I can't really understand how these transition works, maybe someone could recommend me reading something about these tranisiontions in superconductors. How does a 3d supercon transition to 2d or vice ...
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### Best Cooling method for apartment [closed]

Let's say there are two rooms in a apartment represented by this photo Room 2 has a ac unit attached to the window Room 1 does not but there is an opening between room 1 and room 2 In that opening a ...
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### Why does the temperature-volume diagram look the way it does?

Suppose we have a piston-cylinder system containing compressed water (water that is not about to vaporize). The pressure of water is equal to the sum of atmospheric pressure and the pressure exerted ...
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### How is the change in internal energy zero for the following scenario:

in the problem, they are removing partitions one by one. when they remove the first partition they've mentioned in the solution that internal energy will remain constant in the process (and after ...
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### Could you make a fire torch with electricity? [closed]

Similar to a blowtorch, is there a way to generate a flame without using gas or liquid fuel(like butane, propane, etc)? (source) For example I'm thinking about those portable air heaters, could one ...
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### Why Does Every Member of the Ensemble Perform Work Equal to the Change in Free Energy During a Quasiequilibrium Process?

I'm studying Jarzynski's 1997 paper on the Jarzynski Equality. In the second part of the proof (from equation (9) to equation (10) in the paper), Jarzynski considers the following process: considering ...
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### How to turn a sum into an integral?

In, An Introduction to Thermal Physics, page 235, Schroder wants to evaluate the partition function $$Z_{tot}=\sum_0^\infty (2j+1)e^{-j(j+1)\epsilon/kT}$$ in the limit that $kT\gg\epsilon$, thus he ...
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### Regarding the absorption property of a blackbody

Consider a blackbody of surface area $S_b$ and at temperature $T_b$. It is placed inside an evacuated chamber (to neglect all the effects of convection), with walls of chamber at temperature $T_c$ and ...
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### Energy range when deriving heat capacity in Sommerfeld model

In my textbook, they assume a scenario in which the thermal energy of electrons is $k_BT << E_F$ , then only electrons which are near the Fermi level could be excited due to external thermal ...
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### What would the temperature of the tropics be if the atmosphere did not try to balance out heat the latitudinal surplus and deficit

The atmosphere acts to even out the heat imbalnce between the surplus at the tropics and the deficit at the poles. Assuming that the composition and density of the atmosphere stay the same, what ...
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### Argument for relationship between density of states and degrees of freedom and energy

From Reif's Fundamentals of Statistical and Thermal Physics chapter 2.5 Behaviour of the density of states: Can anyone give a clear explanation for why the density of varies rapidly as Energy ($E$) ...
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