New answers tagged temperature
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Why is the $ΔT$ for the heat transfer of the copper segment, like in the picture, $(100 - T)$ instead of $(T - 100)$?
The equation being applied is Fourier's law.
$\Delta T$ doesn't represent a temporal change (where we might apply a convention of $T_\mathrm{final}-T_\mathrm{initial}$) but a spatial change. ...
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A bit funny practical task: frozen dumplings in boiled water, how temperature changes and when will boil again?
Assuming you have boiling water and standard conditions (T = 20°C, P = 101.3 kPa) and do not add any energy to it, it will stop boiling due to heat loss to the environment. There is no need to add the ...
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Resistivity: related to $V/I$ or $dV/dI$?
In principle, we distinguish static and differential resistivity. The differential resistivity depends from the point on the current-voltage characteristics where we calculate the derivative, so we ...
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Why Curie temperature is bigger for smaller lattice in 2D Ising model
Why numerical simulation gives seemingly wrong result?
The exact expression for $T_c$ is given by
$$T_c=\frac{2J}{\ln\left(\sqrt{2}+1\right)}\approx 2.269\,J,$$
where we assume that $k_B=1$. This ...
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Calculating temperature when it is lower than your thermometers can read?
Take some liquid, put 10% of it in the freezer, wait a few hours. Measure the temperature of the liquid you left out, then pour in the liquid from the freezer, and measure again. The temperature of ...
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Calculating temperature when it is lower than your thermometers can read?
Adding a known amount of energy via a microwave oven
Pour a known volume/mass of water into a lightweight plastic cup. Let's assume you pour 100 ml = 100 g.
Place the cup into the freezer and allow it ...
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Thermodynamics and Special Relativity
What happens to the temperature of a body (not in the body frame) as it approaches the speed of light?
As discussed in this article, no one can tell you the answer, at least unless you choose a ...
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Frost on my windshield at 40° f on a clear cold still morning?
Yes, different kinds of heating/cooling (heat transfer) have different "strengths".
Contact heating/cooling is when you touch a warm/cold object and heat flows from the warm to the cold side....
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Calculating temperature when it is lower than your thermometers can read?
The freezing point of water ethylene glycol mixtures depends in the concentration of ethylene glycol. You can find data for this on the Engineering Toolbox web site (a valuable source of all sorts of ...
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Calculating temperature when it is lower than your thermometers can read?
Mass of polystyrene cup + lid (with hole for thermometer) = $m_{\rm c}\,\rm g$ (assume thermal capacity is negligible)
Mass of polystyrene cup + lid + water = $m_{\rm c+w}\,\rm g$
Mass of water = $m_{\...
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Second Law of Thermodynamics and heat flow
The cold water "gain" heat and the air in the dining room "loose"
heat. But, why the temperature in the dining room remain the same?
Should it be colder?
It is cooler. But the ...
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Second Law of Thermodynamics and heat flow
The answer is yes to both, if heat is transferred from a large object to the small one, it changes the temperature of both large and small objects.
In the case of the room we consider that the room is ...
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Critical Temperature of a Bose-Einstein Condensate
Usually the exponent depends on the geometry of the trap.
3/2 corresponds to a purely harmonic trap.
The experiment of Ketterle uses a "Doughnut shape trap".
For uniform potentials, the ...
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Zeroth Law of Thermodynamics on Thermometer
You place a thermometer in thermal contact with system $A$ and get a "reading" $R$ on the thermometer.
As an example $R$ could be a mark at the position of the top of the mercury column in a ...
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Do black holes recapture the CMB?
An isolated black hole has capture cross-section $A=\pi (27/4) R_S^2=\pi 27 G^2M^2/c^4$ and hence absorbs $P_{in}=\sigma A T_{CMB}^4$ Watt from the CMB. Meanwhile it emits Hawking radiation with power ...
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Do black holes recapture the CMB?
No, because black holes themselves eventually evaporate into heat. It's known as Hawking radiation.
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Does electron have a temperature in the atom?
I have little to say about QCD, but I will try to analyse this question from thermodynamics perspective. And I think I have a decent answer.
Save Time: In essence, protons and neutrons exhibit ...
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Steam from a cup of coffee
I think it's rather simple question.
For a steam you may use PV= RT as equation of state.
atmosphere is constant pressure system.
for constant P , V is directly proportional to T. And density (d) is ...
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Steam from a cup of coffee
The amount of water that air can take up before the water creates fog or visible steam depends on temperature. The colder the air, the less water it needs to create fog/steam. It is the same principle ...
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Does electron have a temperature in the atom?
From the way the question was formulated, I deduce that some clarification on some basic concepts is needed.
If we speak of electrons in an atom, we can safely ignore physics at much larger energy ...
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Does electron have a temperature in the atom?
There is technically a way to incorporate the concept you are trying to talk about; I gave you an upvote to undo the downvotes you are getting on this question.
There is a reason why there is a ...
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Does electron have a temperature in the atom?
You cannot speak of a temperature of a single particle, Temperature is an ensemble property. The electron is - as far as we can tell - a fundamental particle unlike the proton (which is a composite ...
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Do there exist materials whose Opacity varies with temperature?
a Material that becomes more Opaque as it gets hotter?
Many meats and other proteins exhibit this property
Salmon:
Other fish:
Chicken:
But perhaps the best example is egg whites:
Now, I think I ...
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Do there exist materials whose Opacity varies with temperature?
There are certainly materials which change colour with temperature. This behaviour is called thermochromism.
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How does a blackbody heat up if it emits all radiation that it absorbs?
it emits all the radiation that it absorbs by definition?
This is not the correct definition of a black body. The Wikipedia definition of a black body says:
A black body or blackbody is an idealized ...
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How does a blackbody heat up if it emits all radiation that it absorbs?
A blackbody is in thermodynamic equilibrium. It is not getting hotter or colder.
Having realised this, then it is more straightforward to understand why a true blackbody emits as much radiation as it ...
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How does a blackbody heat up if it emits all radiation that it absorbs?
To begin with, in real life the absorptivity and emissivity are not exactly the same as both of these things are functions of wavelength. This means it is possible for an object sitting in sunlight to ...
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Can sublimation explain why flavored water can suddenly freeze when being taken out of a freezer?
No it isn't. it is possible for a sample of water to be cooled below the freezing point and yet remain liquid, if there are no suitable nucleation sites to trigger the phase change. then if the ...
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Is the intensity of light ONLY dependent on the number of photons, and nothing else?
Your answer is right but in particular range of frequency which give hotness or degree of hotness, but for frequencies which do not raise temperature it won't work as scale of measurement.
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PROOF of Only Hot to Cold Heat Transfer
The laws of thermodynamics possess a probabilistic nature: they are expected to hold on average, but there is nothing to preclude their temporary violation when we go beyond the thermodynamic limit. ...
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Temperature and correlation with evaporation
As mentioned in the comments, there is no reason that the temperature should remain constant as water evaporates unless it is supplied with some source of heat. In fact, since the enthalpy of the ...
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Convert radiation density into temp in degrees kelvin
By using the integrated energy density of a blackbody radiation field, which is
$$u = \frac{\pi^2}{15}\frac{(k_BT)^4}{(\hbar c)^3}\ .$$
Divide this by $c^2$ to get the equivalent mass density.
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Water Vapour and Liquid Water Interactions
There is absolutely nothing stopping them, and in fact water molecules are constantly hopping between the phases to a degree dictated by the temperature of the system. The proper term used to describe ...
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Temperature of gas particle travelling in space doesn't make sense
Thermal radiation is kinetic energy becoming orbital energy that gets radiated away when electrons revert to their ground state, right? The electron in a hydrogen atom can't lose energy if it's in the ...
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Temperature of gas particle travelling in space doesn't make sense
It appears you have two main misconceptions about temperature.
Temperature is a macroscopic property of a collection of molecules. A single molecule doesn’t have a temperature.
Temperature is a ...
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Temperature of gas particle travelling in space doesn't make sense
A single molecule does not have a temperature. This has been explored before in several questions. See this search for some examples.
For a system to have a temperature it needs to be in thermal ...
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