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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Is it cold inside a black hole? [duplicate]

What is the temperature inside a black hole? It may be very cold, or very hot. Or just the surrounding temperature. Or maybe neither, because the concept of temperature makes no sense inside somehow?...
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Can temperature difference in a conductor induce charge in it?

Assume a metallic rod which is heated on its right end to maintain a constant temperature gradient in the rod. Now if we take any crossection in the rod,the right side part of the cross section has ...
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Temperature dependency on $D_2O$ stratification

The original problem is the research of low energy consuming process to take away D2O from drinking water. Reading the Q&As on this post, particularly the answer provided by @DjohnM, I would like ...
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Are you warmer or colder when there's too much dead air insulation?

These 2 statements are both true, but I'm having trouble reconciling them, please help: When you're sleeping in a sleeping bag, you want the sleeping bag to be form fit (hence the mummy shape). If it'...
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How to do integration in the form below? [on hold]

The original equation of Newton's law of cooling is $$\mathrm dT/\mathrm dt = -k(T-M),$$ but now I'm going to enhance the model, so I decide to add a variable which is $$\mathrm dT/\mathrm dt = -k(T-M)...
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Would a micro black hole have enough energy to heat and liquefy the Earth from within without consuming it first?

Let's say an alien race drops a microscopic 72135 metric ton black hole into the center of the earth. It's Schwarzchild radius is too small (only 0.0001071103 femtometers) so it won't actually be able ...
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Why do balloons get cold when they deflate? [duplicate]

When I deflate balloons by cutting one end and letting the air out, why does the surface of the balloon feel cooler?
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Is internal energy frame-dependent? [duplicate]

In the realm of kinetic theory of gases, the internal energy of gas is solely due to the sum of kinetic energies of all particles, since kinetic energy is frame dependent I was thinking whether a ...
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What is the overall rate of heat conduction through two pipes of different dimensions if the thermal conductivity is not constant?

I am trying to work out how I would find the rate of heat transfer through two pipes made of the same material that are joined at their ends but which have different cross-sectional areas and lengths. ...
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If our solar system was filled with air instead of the vacuum, would earth be colder or hotter?

Would the heat from the sun be transferred better to earth, since air is an isolator inferior to vacuum thus producing a hotter environment? Or would the energy be absorbed and dissipated in the air,...
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How do I determine the shape of steam?

When you dip a fork into a plate of hot food right off the stove and pull it out again with a forkful of food, it generates water vapour steam from the temperature difference. I am wondering how the ...
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Why is it hot before raining?

What causes the temperature hike before a rain? I have heard explanations like one that says as the moisture rises, you sweat more. Can somebody provide a more scientific explanation for this.
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Extreme temperatures, relativity and kinetic theory

According to kinetic theory, average kinetic energy is proportional to temperature. Supposing $k_BT/2$ per particle, can we use relativity and kinetic theory to calculate, e.g., the temperature and ...
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Solid in Liquid Heat Transfer (Temperatures/Entropy Changes)

Suppose we have a solid of temperature $T_s$ and heat capacity $C_p$ submerged into a pool of water that has temperature $T_w$. If $T_s \gt T_w$ and the pressure of the isolated pool-solid system is ...
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Temperature of a sphere heating up in the sun (average emissivity of the sphere unknown)

I'm stuck at the following exercise: Imagine an aluminum sphere that is painted matte white with an emissivity of $\epsilon=0.10$ at visible wavelengths and $\epsilon=0.95$ at wavelengths ...
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Perpetual motion of zeroth kind?

Perpetual motions are classified by which law it breaks: Perpetual motion of first kind breaks the first law of TD. It generates energy from nowhere. Perpetual motion of second kind breaks the ...
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How much heat do colors absorb?

A common grade school experiment is to compare how hot different materials get in direct sunlight. See examples here, here and here for example. The premise is generally two identical objects of ...
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How to convert cc to bar?

In astronomy/astrophysics, medium density is often given in cc, particles per cubic centimeter. Also, the temperature of the medium is usually given, in Kelvins. For some materials the melting point ...
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Where can I find a table for NIST standards on temperature and pressure?

The Wikipedia article Standard conditions for temperature and pressure notes that IUPAC and NIST are two of the most common standards for temperature and pressure in use. Even if I could have gotten ...
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Will a tall narrow cup keep a cup coffee warmer than a more evenly dimensioned cup?

I noticed a colleague had a tall narrow cup for his coffee, and it got me thinking about whether it would retain heat for longer or not. Assume two cups, both are cylindrical, and both hold the same ...
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What is the difference between degree celsius and celsius degree? [duplicate]

It seems similar but can you guys please answer it that what is a specific difference between degree celsius and celsius degree?
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Open circuit voltage of solar panel in relation to temperature

How do we calculate the effect of temperature on the open circuit voltage of a solar panel? The source: https://www.pveducation.org/pvcdrom/solar-cell-operation/effect-of-temperature offers an answer,...
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Multiple heat sources on the same object, conduction only

If we have a bar of steel "AB" (or any type of material) exposure to a heating source (100 celsius for example) from the "A" end, assume conduction heat only. Now, I added a second heating source on ...
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Which one is better to boil water, using high heat or less heat?

Consider that I have a water boiling kettle as below. Assume that it is made of metal, not plastic (but plastic probably also will do). Assuming I can adjust the power it uses to boil the water with ...
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Does measuring the air temperature near a 21 lane asphalt highway impact measurements?

The official temperature in Sydney is measured at the Sydney Observatory. This is located near the city side of the Sydney Harbour Bridge - which is a major highway. My question is Does measuring ...
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Blackbody curves at low temperature

There is already a post here concerning a blackbody curve in visible light. The answer was helpful in that it stated that an object emitting visible light would emit some higher energy photons in x-...
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How does a photon raise the temperature of a gas?

The temperature of a fixed volume of a gas is increased when it interacts with radiation. Why does the temperature increase (i.e. why does the velocity of a gas molecule increase) when a photon is ...
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Obtaining $\beta = \frac{1}{k_B T}$ from first principles derivation

I'm nearly at the end of this derivation but totally stuck so I'd appreciate a nudge in the right direction Consider a set of N identical but distinguishable particles in a system of energy E. These ...
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Why a superconductor expel magnetic lines of force from inside completely when cooled below critical temperature?

Suppose a superconductor which is in a normal state (i.e. $T>Tc$) is subjected to a magnetic field. As soon as magnetic field switched from 0 to some value, eddy currents will develop on the ...
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Ohms law hold till what temp?

Is the Ohm's law verified to hold true at all temperatures? If not, then till what temperature does the Ohm's law hold? I think it is valid only till $0$ K and above. Am I right in my thinking?
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Is water the only substance freezing at 0°C?

When reviewing with my son his science homework (12 years old = ~7th grade, 5ème in France), he told me that "when the phase transition graph shows a plateau between phases then the substance is pure. ...
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At what rate does a wet clothing decrease the temperature of a human body?

The question is required for my project, but it is frankly too hard for me... The variables that I consider are: Human Body: 36.5(C) Air: 20(C) Sunlight Intensity: 1,368(W/m^2) Wind Speed: 20(km/hr) (...
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Mathematical formulation of the concept of temperature

We were taught the following. Consider three systems $A$, $B$ and $C$, which have exactly two independent variables each, $(X,Y)$, $(X’,Y’)$ and $(X’’,Y’’)$. Thermal equilibrium for $A$ and $B$ is ...
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Why are temperature and specific volume independent properties?

The state postulate says that the state of a simple compressible system is completely specified by two independent, intensive properties. Two properties are independent if one property can be varied ...
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How to include temperature effect in optical bloch equations (optical pumping)?

My problem is about the optical pumping of Alkali atoms by circularly polarized pump light. Consider a circular polarized light ($\Delta m=+1$) $$\vec{E}(z,t)= \vec{E}^{(+)}_0 e^{-i\nu t}+c.c. $$ ...
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Why do cool things warm up slower than hot things cool down?

EDITED After reading the answers and many of the comments, I realised I did not put nearly enough restrictions on this question. The scenario I am assuming is as follows: There are two cups of ...
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Does warmer air of the same humidity condense faster?

Warmer air can hold more moisture but can it also release it's moisture faster when touching a cold surface? If air is warmed (for example by the hot side of a thermoelectric cooler ) before it moves ...
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Higgs critical temperature?

Higgs mechanism is defined to operate (give spontaneous symmetry breaking) below some critical temperature. As mentioned, for ex. in Wikipedia: Below some extremely high temperature, the field ...
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What are the practical reasons for have a high or low finesse value for a laser?

I was just wondering if someone could expand on what finesse of a laser cavity is, from my lecture notes I know how one would calculate it via the equation: $$F=\frac{4R}{(1-R)^2}$$ where $R$ is the ...
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How heated metal colors relate to black body color at the same temperature?

I have been looking for a comparison of black body color temperature, like this one from wikipedia (scale in Kelvin): with the heated metal color, like the one below (for alloy steel, source): So it ...
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How to calculate Temperature Humidity Wind Index?

I would like to know how to calculate Temperature Humidity Wind Index (THW Index)? I know how to calculate Heat Index and Wind Chill. I am asking this because my weather station Davis Vantage Pro2 ...
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How is temperature related to color?

I spent some time studying about temperatures and color of objects. It turns out that as we heat something it turns to red, then yellowish white and if we heat it more it turns to bluish-white. Like ...
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Finding the temperature of a gas using the $P$-$V$ diagram [closed]

I need to know a way to relate the P-V curve of an ideal gas to its temperature.I found a similar question on stackexchange but couldn't understand how the relationship between a point and the ...
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Distance $E_F-E_i$ in a compensated semiconductor

Given two energy level diagrams for a compensated conductor: At $0~\text{K}$ At $500~\text{K}$ I want to determine for which diagram is the Fermi level closest/farthest from $E_i$. It's a ...
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Why doesn't water in water barometer boil?

I have read that the pressure in a water barometer at the top of the water column is around 0.5 psi and at such low pressures water should boil at around ~26°C (Room temperature). [1] [2] (source:...
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Using AC with the windows open - will the house cool off quicker?

The other night, a few of my friends and I got into a cool (although some would argue it was heated) argument about the efficiency of cooling a house with air conditioning. I wanted to leave the ...
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Why is my solar panel more efficient as the temperature increases, rather than less efficient?

I have recently performed an experiment in which I placed a solar panel inside a closed box, together with a heater and a lamp (60W). I increased the temperature using a heater from 20ºC to 50ºC. The ...
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If I stood next to a piece of metal heated to a million degrees, but in a perfect vacuum, would I feel hot?

A friend of mine told me that if you were to stand beside plate of metal that is millions of degrees hot, inside a 100% vacuum, you would not feel its heat. Is this true? I understand the reasoning ...
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Do radioactive materials have a property for their natural heat output?

Consider room temperature, would a fissile/fissionable element be naturally warmer to the touch (or a sensitive thermometer) compared to say a glass of water (because the atoms have more ongoing ...
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The quickest way to reduce an isolated system's temperature

If you are in an isolated room, having an air conditioner and a ceiling fan. What is the quickest way to cool the room. Using only the air conditioner or both of them?