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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Reason for a small difference between boiling and melting temperatures of some gases

Some gases has very low difference between boiling and melting temperatures, like $\Delta T \leq 6~ \text{K}$ : $$ \text{Helium},~ \{~T_m,T_b\} =\{0.95 K , 4.222 K\} \\ \text{Neon},~ \{~T_m,T_b\...
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Why air rushes out of bottle if we pore hot water in it and close cap and squeeze when air moves out?

Suppose I fill a bottle with hot water, it inflate! Does the pressure inside bottle same as outside? I think it because as air in bottle expands due to hot water , volume of bottle also expands , ...
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Why is the macroscopic Heat capacity related to the standard deviation of microscopic energy fluctuations?

In one of the problems in my textbook (Schroeder Intro to Thermal Physics), it is shown that within the canonical ensemble, the standard deviation of the energy fluctuations for a single microscopic ...
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What Happens if One Couples two Thermal Harmonic Oscillators at Different Temperatures?

Consider two identical initially uncoupled harmonic oscillators with Hamiltonians $$\hat{H} = \frac{p_1^2}{2m}++\frac{m\omega^2x_1^2}{2},$$ $$\hat{H}_2 = \frac{p_2^2}{2m}+\frac{m\omega^2x_2^2}{2}.$$ ...
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Definition of heat when the temperature is changing in stochastic thermodynamics

I am currently studying stochastic thermodynamics, where the heat for a Brownian particle is defined by $$ dQ = -\gamma \dot{x} dx +\eta(t)dx, $$ where $\eta(t)$ is a white noise, with correlation $\...
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Second-order equation for the resistance of a filament lamp

I am trying to determine the initial resistance $ R_0 $ of a tungsten filament in a filament lamp, by quadratic approximation of the resistance $R(T) = R_0[1 + \alpha*T + \beta*T^2]$ but I can't find ...
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Is atom vibration (not speed) correlated with temperature?

As far as I know every atom vibrates / oscillates / I don't know what it's called in English with a frequency, specific for its element. I don't mean the velocity of the atom, which defines ...
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The energy rate of a hollow cavity at $T_c=1600\rm\ K$ [closed]

If I have a hollow cavity in thermal equilibrium, $T_c=1600\rm\ K$, and this cavity has a hole with $1\rm\ mm$ of diameter, where the energy quantity escapes, how can I calculate the energy rate that ...
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If you have the same amount of water filled in pails [closed]

If you get identical pails filled with the same amount of water at the same temperature, and mix the hot water from the cup with that of the water in pail #1 and the hot water from the kettle in pail #...
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Definition of temperature and modal kinetic energy

I have been told that temperature is defined as the modal kinetic energy of the particles in a substance, and it is stressed that it's the modal energy rather than the average. First up, is this ...
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How cup of water and boiling water inside a kettle dont contain the same amount of energy? [closed]

A cup of hot water with a temperature of 100 degrees Celsius has the same temperature as that of the boiling water inside a kettle but they don’t contain the same amount of heat energy. Why is this so?...
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Mollier diagram and reading the relative humidity when knowing the dry- and wet bulb temperatures

I had a thought error when reading Mollier diagrams and thankfully we have the internet to assist, but even after finding the correct sources showing the answers, I can't get out of my thought-loop to ...
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If you raise the temperature setting on a boiler, does the boiler hold hot water longer?

My family has two showers and whenever someone is using the other shower, my brother raises the temperature setting on the boiler. My brother is trying to argue with me that raising the boiler's ...
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Calculate volume of void in a thermometer

I am struggling to find a ground for this question So I have a mercury thermometer. There's a $0.2\, \mathrm{cm^3}$ void in the glass. The question asks for the new volume of void after a change in ...
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Minimum temperature of a smouldering fire? Read below

What is the lowest temperature in the hottest part of the ember of an oxygen starved low temperature smouldering fire the hypothetical fire glows a dull and faint orange at night, not red but orange, ...
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When does radiation actually happen?

When does a body actually starts radiating: either above absolute zero temperature, all bodies start radiating? or when it absorbs heat from surrounding and then increases its temperature, then it ...
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Why temperature of an object doesn't change when that object is in motion? [duplicate]

Temperature: Measure of random kinetic energy of molecules Here's what I'm trying to say we have two book, and we place on book on moving truck and other on ground, so according to definition our ...
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It seems a stove top coil / burner element defies black body radiation

Most glow charts say that incipient red Heat is 1000 Fahrenheit or 540 Celsius , and bright orange is just shy of 2,000 Fahrenheit or 1093 celsius . But my fluke thermocouple rated at over 2,000 ...
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Why does color confinement fail at high temperatures?

The explanation for color confinement that I see everywhere is that as the distance between quarks increases, the strong force between them approaches a constant value. Once the quarks get far enough ...
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Is it possible to attain absolute 0 temperature? [duplicate]

I think it is impossible to attain this temperature in normal circumstances. As energy would be applied from surrounding areas and energy flow from higher to lower potential and hence all the heat ...
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What class of spacetimes has an associated temperature?

It is very well known that the Schwarzschild metric carries a temperature inversely proportional to the mass. Is there a much wider class of spacetimes that has temperatures associated with it? What ...
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Physical temperature and antenna temperature

I have read some documents on the subject, but until now, unfortunately, I still do not have a good understanding of them, most likely due to personal shortcomings that start from physics. In this ...
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Heating a rod of any material at one end without losing heat to the surrounding

I am interested in learning about heat flow but I am a noob. Suppose there is a rod of finite length that can conduct heat. Suppose we always keep one end of the rod at a temperature say $u$. Will the ...
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About ions cooling and its thermal energy

I'm trying to understand how entropy and ions correlate. let's say we have a isolated ion in a chamber, this ion is supposed having a thermal entropy defined by some formula i don't know, how would ...
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Why is $c_p/c_v$ term introduced in adiabatic process?

In an adiabatic process we know there is no change in enthalpy or basically enthalpy change is zero. which means any external work done the internal energy does equal opposite work so as to keep $dH=0$...
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Tell me, please, in laymen terms, about how water expands/shrinks with temperature changes

When you freeze water in a glass jar, it explodes (which kinda suggests that water, unlike other substances, expands under lower temperatures). And yet, the latest IPCC report says [p. 15] that half ...
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Failure of Drude like model and temperature dependence of ionic conductivity

Purcel models ionic conductivity[1] $\sigma$ in what seems to be a Drude like model, and gets for an electrolite like NaCl $$\sigma \approx Ne^2\left(\frac{N_+ \tau_+ }{M_+}+\frac{N_- \tau_- }{M_-}\...
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The effect of temperature on Coulomb's law

I have read a sentence in an electrical engineering article but I couldn't understand it. It said: on Earth Temperatures around 150 million degrees Celsius are required to overcome Coulomb's law. the ...
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Making sense of Entropy being energy over temperature

Over the internet, I found many resources that explain very well what entropy represents. However, the dimensions still appear hard for me to make sense of: energy, simply put, is the ability to do ...
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If temperature is proportional to average kinetic energy, then is the air around me actually at a higher temperature than, say, my table?

I know that thermometers work by conduction, meaning that the particles in the alcohol inside the thermometer will always get to the same average speed of the particles of the surrounding substance ...
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Finding final equilibrium temperature?

"A 100g mass is heated with a strong flame for 10 seconds then placed into a crucible on a heat proof mat. After cooling for 5 minutes the 100g mass is at 67.6C while the table it's resting on is ...
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Why bother having a heat source when all the heat 'escapes' to the outside of a room?

Halliday-Resnick makes the following argument: Suppose that a room of volume $V$ with diatomic ideal gas (air) at temperature $T_1$ and pressure $p_0$ is heated by a furnace to $T_2$ with constant ...
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Understanding Daniel Schroeder's comic of interpreting enthalpy and Gibb's free energy

In this answer by Steeven on the meaning of Enthalpy, the following image is used to explain it: In this comic, I don't understand two things: Why is the energy required to make space for the rabbit ...
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Why does the change in length depend on the initial length of a rod?

When a rod of some length is heated then it undergoes linear expansion (also areal and volumetric) but I don't understand Why does the amount of expansion depend on the initial length of the rod ? If ...
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Why is the $\frac {1} {\beta T}$ a constant (Boltzmann Constant)?

I have been studying Statistical Mechanics from the Book "Statistical Mechanics by R.K. Pathria & Paul D. Beale". So, in chapter 1, it discusses about Statistical basis of Thermodynamics,...
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Best way to calculate $T_0$ of a laser diode material

In the following website it is described that to calculate the T0 of a laser diode, I have to take a laser of specified geometry, find the threshold currents at different temperatures and plot their ...
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Working of phase changes on a molecular level [duplicate]

I am frustrated by thinking about it Whenever i ask someone why temperature does not change, the person says it is because heat goes into changing the intermolecular forces, and not KE. I WANT TO KNOW ...
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Why and how exactly does the quantity of energy radiated per second increase with the temperature of the radiating object?

I read in my textbook that the quantity of energy (in the form of electromagnetic waves) radiated per second increases with the temperature of the radiating object. However, I can see two ways of ...
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How much Curie temperature is obtained according to the Stoner model?

In Stoner model for itinarant ferromagnetism, the spin ordering of electrons is caused by the Coulomb interaction $U$ for onsite repulsion leading to the reduction of total energy against to the ...
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Plasma diagnostics - Langmuir probe

I was wondering how the position (changing the radial distance) of the single cylindrical Langmuir probe in the chamber tube affects the measured results. I was measuring the electron temperature etc. ...
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Can we feel heat in outer space? [duplicate]

Is there air outside of earth atmosphere? If not, could we feel heat coming from sun?
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What does this assumption mean in heat exchanger analysis?

I'm studying heat transfer at graduate level, and in the process of deriving LMTD of a heat exchanger, the book took the following assumption : Any axial heat conduction will be neglected. What that ...
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How is the freezing of water analyzed with the first law of thermodynamics?

For the first law of thermodynamics ($\Delta E_{int} = Q + W$), it would seem that since $\Delta T = 0$, then the equation simplifies into $0=0+W$. However, since ice is less dense than water, volume ...
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How can metal workers dip their hands into molten lava without injury?

According to Halliday-Resnick, metal workers have observed that they can dip a hand very briefly into hot molten metal without ill effects. A quick Google query pulls up responses based on the ...
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What happens when ice and water are placed together at the same temperature in an isolated system?

Suppose ice and water (not necessarily of the same mass) are both at $0^{\circ}$C and placed into a perfectly insulated, sealed container so that it is filled completely. If we leave this system alone ...
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How fast does methane rise in atmosphere?

Archimedes' principle states that the upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially, is equal to the weight of the fluid that the body displaces. If ...
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Why can't both beakers have same temperature after some "finite time"?

There is this question in H.C Verma's book I have solved the question and got the right answer but analysing the answer indicates something weird. Here's the answer of that question The answer ...
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Does farting make the room cooler, or warmer?

It's a hot summer day and you've just had some refreshing salad. Unfortunately all the veggies seem to have caused some... gas. Is this good news, or bad news, as far as the physical temperature of ...
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How to calculate gas equation (not necessarily ideal) when the internal energy depends solely on the temperature?

I know that for an ideal gas it can be shown through the equation of state and the Maxwell relationships, that the energy of the gas depends only on temperature. But my question is how can I calculate ...
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Comparison of change in entropy

If in both an isobaric and isothermal process, the volume of one gram hydrogen gas (which is evidently by the formula $n=\frac{m}{M}$ is $0.5$ mole) is expanded $4$ times the original volume then ...

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