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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Water mixture at different temperatures

Let's say that we mix homegeneously and instantly cold water at $t^\circ $ C and hot water at $T^\circ$ C (like in a water tap) in ratio $p:1$. My question is the following: What is the instant ...
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Does the cold affect electrical conduction?

Disclaimer: I'm not experienced in many phyiscal nor electrical terms and I have no idea where to ask this question elsewhere. I'd be open for a move request if needed. Today when using public ...
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Is the *measured* temperature inside a hollow black body the same if we place a thermometer inside it or let it make contact with the body itself?

Imagine the inside of a black body shell with non-zero thickness. Inside the shell, there is photon gas produced by the shell [at a temperature much higher than zero, say $1000(K)$]. Is there is a ...
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Time for black body to cool to a given temperature

I'm trying to figure out the time required for a blackbody to cool assuming it only looses heat via radiation. I can estimate the mass, specific heat, surface area, emissivity, initial temperature, ...
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Maximum achievable mechanical work when heating water

I am doing a question about finding maximum achievable mechanical work when 1L of liquid water is heated from T₁ to T₂ at atmospheric pressure. The solution is $$W = \int_{T_1}^{T_2} \frac{T - T_1}{T} ...
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How is quantum mechanics consistent with statistical mechanics?

Let's say we have an harmonic oscillator (at Temperature $T$) in a superposition of state 1 and 2: $$\Psi = \frac{\phi_1+\phi_2}{\sqrt{2}}$$ where each $\phi_i$ has energy $E_i \, .$ The probability ...
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Calculate temperature decrease of an evaporating droplet

I have a small droplet of Cyclohexane which evaporates at room temperature and ambient pressure. I measured the volume at two different times ($\Delta V=1.5\times10^{-10}$ m$^3$). I would like to ...
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Conceptual meaning of Thermal States

Thermal states are generally defined as $$\tau(\beta)= \frac{e^{-\beta H}}{\mathrm{Tr}(e^{-\beta H})}$$ What are some physical statements one can make about them? A system in thermal equilibrium is ...
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What are the differences between specific latent heat and latent heat?

What are the differences between specific latent heat and latent heat? As far as I know, latent heat is the heat required or released during the change of state, without change of temperature. So ...
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The microcanonical ensemble approach to calculating the entropy of an ideal gas [duplicate]

I would like to set up the following problem. Assume I have a box of volume $V$ with $N$ noninteracting particles in it. The energy of each particle can be $\mathcal{E}_i$ such that $\sum_i \mathcal{E}...
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What formulas do I need to calculate the time it takes for a room with opened window to become the same temperature as outside?

I want to calculate how long I have to open my window to become the same temperature as outside. To make things more easy let’s assume there’s almost no wind helping the exchange of temperature.
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Does heat transfer actually from high temperature to low temperature?

Consider Object A which has a temperature of 70°C and Object B which has a temperature of 20°C. The objects are placed right next to each other. Now, as far as i know, the temperature is defined as ...
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Why do hot objects tend to emit shorter wavelength? [closed]

So how do the temperature and wavelength related and why do hot objects tend to emit shorter wavelength?
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Difference between color and effective temperature

What is the difference between color temperature and effective temperature of a star? I have gone through the pages at wikipedia, but I still do not understand that. Can anyone please help?
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Unmagnetized plasmas in space

Please, I need some information about high temperature plasmas in astrophysical environments. To my knowledge, plasmas in astrophysical environments are magnetized (is it true?). Are there ...
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water pipes break when temperature goes down, how to estimate the energy involved?

Normally low temperature is associated with lower energy state and high temperature with higher energy state. There is an apparent paradox when a water pipe breaks due to low temperature: when ...
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How to formulate surface temperature of a material exposed to sunlight and wind?

I am currently searching for a model or an approach (reference, course, demonstration) to formulate and estimate surface temperature of a known material (for example, concrete, metal), exposed to ...
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Kinetic Theory of Solids

Is there a clean way to examine temperature for solids and liquids in classical mechanics like the kinetic theory for gases? I'd like to get a good explanation that doesn't involve much in the way of ...
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Question about China's Artificial Sun

I have read recently in many websites dedicated to science that China has made an artificial sun hotter than the 'sun'. My question is how did they make a thing that can withstand such a high ...
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Will a room heat quicker with a fan blowing on a hot surface? Why?

I got into an argument with someone who thinks that blowing air across a fireplace will make the room heat more slowly, but based upon the principles computer heat sinks use to get heat away the room ...
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Effect of temperature on specific weight

How much of an impact has a temperature difference when the specific weight of an object in water is measured, e.g. the weight of a mussel in seawater. Would the two scenarios yield the same specific ...
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Missing link re: how does kelvin relate to temperature when talking about color temperature?

I am an electrician at a commercial electrical company. There is an in-house training program that posits the datum that when talking about the designations of color temperature for lights (for ...
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How to combine RTD sensor tolerance with system resolution

I have a Pt1000 resistance temperature detector (RTD) with stated tolerance --for some positive temperature t-- of 0.15+0.002*t[degC]. At the same time, the resolution of my readout system is 0.01 ...
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Why do macro black holes take ridiculous amounts of time to evaporate—unlike micro black holes which dissolve in even less than a second?

Why do macro black holes take ridiculous amounts of time to evaporate, considering that micro black holes dissolve in even less than a second? Does this mass-based behavior imply that the matter ...
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entropy in isolated system

Ok, so the question is about the concept of increasing entropy. We obtain the result (by utilizing the Clausius inequality theorem) $dS = \frac{dQ_{rev}}{T} \geq \frac{dQ_{irr}}{T}$. Then it's stated ...
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What was wrong with the old definition of temperature scale in kelvin?

Wikipedia's article on the recent change to the definition of the SI base units states, as the reason for changing the definition of the kelvin: A report published in 2007 by the Consultative ...
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Calculating rate of change of thermal energy and applying that to usage in calculating the time it takes to reach equilibrium

So if I have an experiment with two gases that are identical and have a specific heat of 100 j/(KM) and there is a divider in between the gases with a surface area of 1 square meter, and a thickness ...
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Finding temperature at junction of rods

Let's say I have three tubs, from left to right Tub 1, Tub 2, Tub 3. Tubs 1 and 3 are at 50 degrees Celsius and Tub 2 is at 10 degrees Celsius. Tubs 1 and 2 are connected by a copper rod, and tubs 2 ...
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At what temperature is the band gap value when obtained from Arrhenius plot?

Using the equation $$\ln{R}=\ln{R_0} + \frac{E_G}{2k_B T}$$ we can obtain the band gap value $E_G$ by measuring a sample's resistance $R$ with changing temperature $T$ and using the parameters of the ...
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Why do physicists think that the dark matter is cold?

Most of the dark matter in the Universe is cold or nonrelativistic which rules out neutrinos as dark matter candidate as they are hot or relativistic. But why do physicists think that the dark matter ...
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Temperature-pressure plot for superconducting records?

Eremets et al. (arXiv:1812.01561, Nature 569, 528–531 (2019)) and Hemley et al. (arXiv1808.07695, PRL 122, 027001 (2019)) have reported new high-temperature record for superconductivity, as covered by ...
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In thermal spas the temperature of steam is about $50^{\circ}C$, but feels way hotter. Why?

So when you're in hot water and start to move or something the steam feels really hot even though I read its temperature is about 50 degrees Celsius in thermal spas. So why does it feel that warm?
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Proving that $c_V$ is positive

On my professor's lecture notes he claims that $c_V>0$. Intuitively, this would have been my guess as well but he mentions how you can prove this by constructing a setup: "Construct an isolated ...
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What is temperature as a function of time in Fourier's Law?

Can we find temperature as a function of time using Fourier's Law of thermal conduction? For example: If we have two square parallel plates of a given length, width, and distance apart with one ...
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Does the inertia of an object changes with its temperature? [closed]

$F=ma$ is not accurate enough at relativistic speeds. Does the inertia of a rigid body related to its temperature?
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Can body of one temperature ever cause higher temperature in another body?

If you have one body that radiates heat at a constant rate and, forgive my simple assumption, thus constant temperature, and a body that may absorb this heat, may the temperature of second body ever ...
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Thermodynamics: Units in calculations of heat (Q)

When calculating an unknown variable in the quantity of heat equation for a system, let's say mixing water of 80 degrees C and ice of -20 degrees C that achieves thermal equilibrium at 10 degrees C (...
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Greatest volumetric heat capacity at very low temperatures

There is a theoretical device that I want to keep at a temperature of 3 K using a liquid helium coolant loop, and a block of material as heat sink, initially at 0.1 K. The main limitation is the ...
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Shouldn't a cold object feel less gravity? [closed]

The premises for my question are, Gravity isn't a force but curved spacetime "If gravity isn't a force, how does it accelerate objects?" (complicated answer) If the answer below, to the question ...
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Probability at temperature in system has energy

Salutations, I'm starting in statistical mechanics and reviewing some related studying cases I would like to understand what occurs in small systems with normal modes of vibration, for example, a ...
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Naive question about thermodynamics for use in a riddle

I am a mathematician with very little awareness of the physical world, begging for wisdom. I would like to have verification that my idealized physical model makes sense, for use in a riddle. I ...
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Why is -273.15 °C the low temperature limit for the universe? [closed]

According to Ideal Gas Law the lowest temperature of an ideal gas can be $-273.15 °C$. This temperature is also considered the lowest temperature in the universe. But it is the lowest possible ...
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Calculating temperature of objects after colliding

So, I'm making a physics engine, and I need to know what is the temperature object A has after colliding with object B. Object A is 10 earths in diameter, and is 10 earths in mass. Object B is 5 ...
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How to calculate the ground state of Ising model at non-zero temperature

I'm studying the quantum Ising model, i.e. with Hamiltonian $H= -h\sum_{i}X_i-\sum_{\langle i,j\rangle}Z_iZ_j$. I know conceptually how to compute the ground state of the Ising model at zero ...
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How should I find an average for data that randomly fluctuates?

I have data for the temperature of a flame at a given height above the burner. The temperature fluctuates quite a bit (see figure), but there is definitely an "average" value that it tends to ...
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Temperature at different points in a metal rod during heat conduction

$$ k = \frac{\frac{Q}{t}}{A(\frac{T_1 - T_2}{L})} $$ where k is thermal conductivity of the solid, Q is total amount of heat transferred, t is time taken for the heat transfer, A is area of the cross ...
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Why does the warm air rises up?

Warm air has more energy than cold air. This means that according to the Einstein equation $E = mc^2$ the warmer air has a greater mass than the cold one. Why is the warm air rising, if it has a ...
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Is absolute zero still 0 Kelvin?

Following the recent decision to change the definition of SI units, I understand that Kelvin is no longer defined in terms of the number 1/273.16. Does that mean that absolute zero is no longer ...
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How to arrive at the thermodynamic definition of entropy?

My question is, how do we say that, $$dS=\dfrac{dQ}{{T}} ~?$$ How do we relate heat and temperature to entropy? Why is the temperature in the denominator? Can we replace heat by work? How does ...
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Kelvin and kinetic theory of gases

I know that the degree of freedom increase by 2 when the temperature is high and decrease by 2 when the temperature is low. A dumb question here, what temperature is considered as 'high temperature' ...