# 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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### 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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### 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. ...