Questions tagged [temperature]

It's the physical property that indicates the degree/intensity of heat present in a substance or an object. It can be expressed and measured according to various scales.

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Equipartition theorem for radiation in black body?

In Planck distribution of energy density for black body he solved the uv catastrophe by association of descrete energy to each mode, and by the equipartition theoreme from statistical mechanics we ...
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Does the vacuum have a temperature?

Since the vacuum polarisation leads to the appearance of particle antiparticle pairs, which have a kinetic energy, can therefore to the vacuum a temperature be attributed? If yes what is the Value of ...
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How do you know when to use specific heat for ice or water?

"A copper calorimeter can with mass 0.100 kg contains 0.160 kg of water and 0.0180 kg of ice in thermal equilibrium at atmospheric pressure. If 0.750 kg of lead at 255°C is dropped into the ...
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Effect of temperature on magnetic fields?

My class was learning the magnetic effects of current and one of the things we learnt was that the magnetic field strength produced by some conductor is going to be directly proportional to the ...
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Different Definitions for "Gibbs' Entropy"

This question suggests that for the microcanonical ensemble, additional to the "usual" definition of entropy \begin{align} \omega(E)=Tr \delta(E-H) \\ S_B=\ln \omega(E) \end{align} (Called ...
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Confusion over definition of enthalpy as $h = f(p, T)$

I've often seen in textbooks that enthalpy (h) is specified as $h = f(p, T)$. We further go ahead in differentiating $h$ to get- $$ dh = \frac{\partial h}{\partial T} dT + \frac{\partial h}{\partial ...
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Why Unruh temperature is the temperature measured by observer with $\xi = 0$?

My coordinate transformation is: \begin{align} t=\frac{1}{a} e^{a \xi} \sinh (a \eta), \quad x=\frac{1}{a} e^{a \xi} \cosh (a \eta). \end{align} The free scalar field is quantized under this ...
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Equipartition Theorem for the microcanonical ensemble - valid only in the thermodynamical limit?

I'm following the derivation of the equipartition theorem for the microcanonical ensemble, as I have seen it on wikipedia. In the end, it derives: $$ \langle x_m \frac{\partial H}{\partial x_n} \...
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An answer to an old question about a derviation of Wien's displacement law without Planck's radiation law [closed]

A derivation based on Doppler's frequency shift and a heat engine can be found in an appendix to Max Born's "Atomic Physics".
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How does the temperature term in the refractive index structure parameter for optical turbulence relate to the temperature field?

I am trying to learn about atmospheric optical turbulence and have a question about the temperature dependence of the refractive index structure parameter. This parameter is a measure of optical ...
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What is the temperature of empty space if a spaceship is travelling at half the speed of light?

Whenever someone talks about sending robots to extra-solar planets by accelerating them close to the speed of light (perhaps using lasers) - for example I believe Hawking suggested this. It always ...
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Calculate steady state temperature of an object heated by electromagnetic radiation

I would like to calculate the steady state temperature of a small cube of any material heated by electromagnetic radiation. Suppose the cube floats in air and doesn't touch anything. The air is at 20 °...
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If we double the thermal energy of a cup of boiling water100c, will the new temperature will be near 200C

If we double the thermal energy of a cup of boiling water the new temperature will be near 200 0C kindly can someone explain to me the relvent formula for thermal energy and temperature
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Shouldn't particles lose energy after collisions?

I read that particles gain energy after collisions i.e they hit a wall, but bounce back faster than before. According to my common sense, shouldn't the particle lose energy, as hitting the wall would ...
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Thought experiment on temperature dependence of black body radiation

There's a very famous thought experiment that verifies the temperature dependence of blackbody spectra The proof first assumes that two blackbodies have different spectra and then shows that this ...
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What is the upper pressure limit for solid to liquid phase border of water on 0.0 °C?

On phase diagram of water, solid to state border is a straight vertical line. Someone can argue it is only an approximation and nature cannot have vertical lines. For me however, it is clearly ...
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Can adiabatic heat exchange between different temperatures ever be reversible?

I've been told, A volume 2X of Temperature 0.5*(T1+T2) is always at higher entropy than thermally insulated volumes, 'X' at T1, 'X' at T2 put together. Let's take Sys1 (A volume 2X of Temperature 0.5*(...
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Temperature and friction relationship

I was actually conducting an experiment investigating the influence of temperature on the coefficient of friction. I am having trouble understanding the scientific reasoning behind the way it can ...
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Does anything in an incandescent bulb actually reach its color temperature (say 2700 K)?

This question is inspired by a question about oven lightbulbs over on the DIY stack. It spawned a lengthy comment discussion about whether an incandescent lightbulb with a color temperature of 2500 K ...
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Why does a good thermos keep a cold drink to temp twice as long as a hot drink?

I've owned a number of insulating vessels. It seems the best they can do for keeping a hot drink hot is about 5 hours. The same vessels will keep cold drinks with ice intact overnight, sometimes ...
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Is superconductance restricted to an extremely low temperature? Or can it be effectively replicated using some other technique?

A type of electrical amplifier is proposed in which only magnetism and it’s analogous current exists for the most part. There is no voltage and no wattage (to speak of) in which electricity has to ...
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Area under $T$-$s$ diagram for an internally reversible process? [closed]

In Cengel and Boles, it is said that the area under a $T$-$s$ diagram for an internally reversible process is equal to the total heat transfer during the process. The example given of an internally ...
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Velocity distribution function and Boltzmann factor

In Blundell and Blundell's Thermal physics book there is a chapter on the explanation of the Boltzmann distribution. It is explained that for canonical ensemble with a reservoir at temperature $T$ in ...
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Can you superheat coffee?

As far as I know, heating clean water can lead to superheating to over 100 degrees but how clean does it have to be? Coffee is almost all water but is it clean enough to lead to superheating? What ...
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Temperature vs electric conductivity in a solid

Generally with increase in temperature the chemical potential is reduced which would mean at lower temperatures the electric conductivity should become higher. But for semiconductors if we lower ...
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Surface Energy Dependence on Temperature

Surface energy is an energy needed to increase surface area of the interphase by unit or excess energy molecules have on the surface compared to the bulk. This means that surface energy will depend on ...
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Do we always have a choice of state variables, and how is temperature in general a state function?

I am reading Steane's fantastic Thermodynamics: A Complete Undergraduate Course and am a bit stumped as to the assertion being made that, for example, temperature is a state function. Suppose I model ...
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River freezing conditions

Quite uncommon -8°C here in Hamburg at the moment I write, and I thought: Surely our local rivulet is frozen over. In retrospect this was silly, the "rivulet" is 3rd order and has a very ...
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Is it better to line dry inside or outside a house? [closed]

On a winter night (so no radiation from the sun), my house is 10°C warmer than outside. Both temperatures are above freezing. I measured the humidity and found out it to be the same both outside and ...
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Entropy change of a falling object [closed]

I have question which essentially asks the entropy change of a sword of initial temperature $593\,\mathrm{K}$, mass $1.2\,\mathrm{kg}$ and S.H.C of $0.13\,\mathrm{J}\cdot\mathrm{K}^{-1}\cdot\mathrm{g}^...
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Difference in temperature due to height

I observed a strange phenomenon today. I brought my milk and it was steaming hot so i left it for a while so that it could cool down a bit. It was cooled enough and there was cream on the surface and ...
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Does smaller bulb increase the sensitivity of a liquid-in-glass thermometer? does a smaller flask increase the sensitivity?

as for a thermometer, what's the difference between a bulb and a flask? I have seen contradictory answers about how the size of a bulb affects the sensitivity. One says a a small size will be better ...
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Why doesn't the eigenfrequency of a bottle change with different temperatures? [closed]

So I thought I had a smart idea to measure the temperature by blowing on a bottle. I had the idea that inside (20 degrees celsius) it would have a certain eigenfrequency e.g. 240 Hz and outside it ...
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Does temperature affect a substances mass?

So I'm currently learning thermodynamics from the Openstax AP Physics book but a statement has arisen that I'm confused about. As you can see in the picture, I've highlighted the text that, to me, ...
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How parker solar probe survives death rays?

What is the temperature due to death rays alone excluding plasma. Clearly it's now possible for any material to survive that. It's 20x closer than earth so radiation is 400x. 150million km / 7 million ...
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Does heat balances out or Temperature balances out?

Let's say we have $2$ elements Tin: Thermal Capacity $226\ \text {J/kg°C}$ Magnesium: Thermal Capacity $1024\ \text {J/kg°C}$ Let's say I have a $1\ \text{kg}$ block of each element at $40°C$, and I ...
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Why is kelvin used for Energy Separation in atoms?

I have been reading a 1974 paper on the anisotropy of Sm$^{3+}$ ions, in which the authors say the following: IN THE series of trivalent rare-earth ions, Sm$^{3+}$ is unique in the sense that the ...
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Difference between extremes thermodynamic temperatures [duplicate]

Why is it that the minimum temperature in the universe is -273.15 C (absolute zero) while the maximum reaches up to trillions of trillions of trillions of degrees, why no keep it at +273.15 C. Why ...
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In which cases temperature rise is possible? And why (microscopically) what's happening? [duplicate]

Consider these five situations: Gas container is placed in a fast moving train (assuming (train) its speed is constant). Liquid was instead put in the container and placed on moving train Gas ...
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Why pressure of gas even after given some non zero constant speed remains same?

Consider a situation where a cubic vessel (with horizontal and vertical faces) contains an ideal gas at normal temperature and pressure. The vessel is being carried by a rocket at speed of $v$ in the ...
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Is it possible to compress gas without making it hotter?

First of all, this is just a purely theoretical thought experiment: Let us consider another situation. Suppose that the piston moves inward, so that the atoms are slowly compressed into a smaller ...
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Temperature-Humidity-Wind (THW) index for hot and cold weather [duplicate]

Does anyone know the formula (or the algorithm, even a fortran code) to calculate the Temperature-Humidity-Wind (THW) index not from the heat index but in general? (someone published a (too simple?) ...
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Why is the burning temperature of different species of wood so different? [closed]

If you have read Farenheit 451, you may have the idea that paper (or perhaps wood in general) burns at 451F. However, in fact, different species of wood burn at widely different temperatures. Here is ...
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In 2d CFT, if the partition function is $Z=\text{Tr}q^{L_0-c/24}$, where is the analogue of temperature?

In 2d CFT, restricting to the holomorphic part of the theory, the torus partition function is given by $$Z(q)=\text{Tr}q^{L_0-c/24}$$ where $L_0$ is the element of the Virasoro algebra, i.e. mode of ...
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Why is my $p$-$T$ graph gradient increasing for decreasing radius when it should be decreasing in hard sphere collisions?

Why is my $p$-$T$ gradient decreasing for increasing radius of spheres when it should be increasing? I'm simulating some hard sphere collisions with $Radius_{container}=10,$ and varying pressure and ...
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If I maintain air temperature in a room, but allow humidity to vary, will room objects remain at the same temperature?

Let's say I have a room with a HVAC system and I'm trying to keep objects in the room at a constant body temperature. My HVAC system maintains a constant air temperature, but the relative humidity in ...
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Enthalpy of vaporization temperature dependence equation?

Does an equation for the enthalpy of vaporization, $\Delta H_{vap}$ as a function of temperature, $T$, over a large temperature range exist? I have seen some sources mention Watson's Law as a possible ...
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How hot is a primordial black hole and does it has angular momentum?

I am fascinated by these elusive phenomenon, they are formed in the early stage of the universe where it is not homogeneous and some regions are very dense enough to undergoes gravitational collapse. ...
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Why doesn't the thermometer go back to ambient temperature after I take my temperature?

These past days I had a fever and I have taken my temperature many times with the thermometer in the photo. I think this is just like a mercury thermometer, even if it's a newer one that does not ...
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If you were invisible, would you also be cold? [closed]

If you were invisible, would you also be cold? (Since light passes through you, so should thermal radiation.) Additionally, I'd like to know if you were wearing invisible clothes, would they keep you ...

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