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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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Given two substances of different specific heats, how do you find the final temperature and these phase related things

Given two substances of different specific heats, how do you find the final temperature of them both, phase of either substance if there was a phase change, and how much either substance has changed ...
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How cold does Something need to be for String Theory to be relevant?

I’ve often read casually that in order for modern string theory and other competing quantum gravity theories to be tested absolutely enormous temperatures (or rather energy densities) are required. ...
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Thermal Efficiency

For a thermally efficient house, is it better for the windows to be framed with something like aluminium, or steel? I am considering the thermal conductivities, aluminium has a value of 200, while ...
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Temperature of solids and “average translational kinetic energy”

Temperature is related to the random motion of atoms and molecules in a substance. More, specifically, temperature is proportional to the average "translational" kinetic energy of molecular motion. ...
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Thermodynamics and classroom [on hold]

The temperature of a classroom with dimentions of 10*8*3 m ia to be maintained at 23 degree. there are 30 students and a teacher in the room. the metabolic rates of a student and a teacher are 320 kj/...
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Expansion of two materials between walls [closed]

Hi can you please help me with this? I have no idea how to solve it, thanks! We have 2 linked bars of circular cross section located between 2 perfectly rigid walls. One stick has a diameter d1 = 30 ...
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Could we harness the energy from room temperature? [closed]

If no atom is at absolute zero, it must have kinetic energy. Therefore, could we harness that energy, (sure for small objects, not much energy would come of it) but surely the earth itself has a ton ...
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How does the internal resistance of a cell vary with temperature?

Does anyone have a physics explanation to why the internal resistance of a battery decreases as the temperature increases?
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Finding temperature using an NTC thermistor

I am given an NTC thermistor with a resistance of 10k ohms at 25 degrees C. For the B model, B=3799K, and when in contact with the object, the thermistor has resistance 5k ohm. I am to find the ...
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What is the latent heat of whiskey?

I am a school boy and my physics abilities are very limited. I have spent hours scouring the internet and cannot find the latent heat of Whiskey. The actual question is to find the final temperature ...
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Debye Temperature for Copper

I am trying to calculate the Debye temperature, $\theta_D$, of copper using the following: $$ \theta_D = \frac{\hbar v_s}{k_B} \left( \frac{6\pi^2N}{V} \right)^{1/3} $$ I have the following values: $...
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how is temperature related to quantum vibrational states of molecules

When a molecule of greenhouse gas absorbs a photon of long wave infrared radiation it is boosted to the next allowed vibrational state. The vibrational state, as I understand it, involves deformations ...
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Derivation of Helmholtz free energy and associated relation

I am quite new in thermodynamics and I have never touched it so far. But now I have some basic questions that I hope someone can kindly explain them to me. I know the Helmholtz free energy is ...
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Time-dependent thermal expansion of air?

Every solid, gas, liquid has a coefficient of thermal expansion (measured in e.g. %/K). This assumes an equilibrium state at the new temperature My question is: what is the time rate of change ...
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Does light have any temperature?

Is there anything like cold or warm light? Everything in this world has a temperature, What about light?
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Is there any epoxy/sealant that is optically clear and can withstand temp up to 400C? [duplicate]

Any polyimides-type or any glue that can tolerate that temp AND be able to transmit visible light not uner 80% transmission?
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Does stirring a liquid add heat $Q$ to a system? [closed]

I was given a question, "A thermos bottle containing milk is shaken vigorously. Consider the milk as the system. (a) Will the temperature rise as a result of the shaking? (b) has heat ...
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Why a metallic mirror temperature cannot be read by a thermal camera?

When I look at a first surface mirror with a thermal camera I don't see the temperature of the mirror but the temperature of the reflected objects. It is like if a polished metallic surface don't lose ...
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Temperature increase of a gas in a period of time [closed]

Pardon my simple question for you physics geniuses but: I'm attempting to simulate hot air balloons for a game. I have a gas of known volume, temperature, pressure and density inside a confined space....
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Do black holes have a well-defined temperature?

According to Wikipedia, black holes emit Hawking radiation that corresponds to the spectrum a black body would emit at a temperature inversely proportional the mass of said black hole. Since the mass ...
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Measure or estimate temperature of plasma?

How would one measure or estimate the temperature of the plasma in the film below? It's a still from a YouTube film. Let's say the gas is hydrogen or deuterium, instead of Argon. How would one know ...
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Does molten solder flow towards a heat source?

When soldering both plumbing and wiring I have heard the advice that you shoulf apply solid solder opposite to your heat source, since the solder "will flow towards the heat" once it melts. Is this a ...
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why does cold water have Translucent visibility? [closed]

If ice is to formed soon, why ice Does not have Tranparent vision.
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Can a cold surface emit heat radiation?

If I place a hot body behind a cold glass, it would transmit the hot bodys radiation and thus pass heat radiation. Could the glass surface still be considered cold in terms of contact temperature, ...
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What does blackbody radiation look like for negative-temperature systems?

Using the thermodynamic definition of temperature, $$\frac{1}{T}=\frac{\partial S}{\partial U}\bigg|_{V,N}$$ negative temperatures are possible, in systems where the entropy decreases when energy is ...
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What causes a black hole to be hot?

From my limited understanding of physics, it seems that the heat of a black hole is caused by vibrations in quanta of space, where quanta of space can be viewed as the elementary building blocks of a ...
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What underlying physical quantity do we measure when measuring the temperature of gases?

When we measure the temperature of, say air, or any other gas, what physical quantity do we measure? Is it the kinetic energy of molecules? Is this affected by pressure and density? And if so, how?
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Variation of speed of sound with humidity and temperature?

I am building a sonar using Arduino and I needed to accurately use the speed of sound. I also have a humidity and temperature sensor, and I wanted to know what is the formula for the speed of sound ...
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Intuition about the congruence of readings of Celsius and Fahrenheit scales at -40°C [closed]

At -40°C temperature, the Fahrenheit scale also shows -40°F. But how is this ever possible? They are two different scales! What's the intuition behind this?
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How are the Planck numbers of energy, temperature, measurement, etc. formulated?

Why is Planck everywhere? So, the Planck temperature (1.41679 x 10^32 Kelvin), the measurement, (1.6 x 10-35 m), and whatever else has a boundary named after Max Planck seems to be a very specific ...
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Effect of volume changes on temperature in gases

If I decrease the volume of a certain container containing a gas; the KE of the particles will increase and therefore the temperature should increase. But according to Charles's law both of these are ...
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Entropy generated for a warm bath heating a cold rock

Put a cold rock of heat capacity $C_r$ and temperature $T_{r1}$ into an insulated fluid bath of finite heat capacity $C_b$ (the bath is not a reservoir) and temperature $T_{b1}$. Now let the entire ...
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Is it possible to generate conditions such that the temperature difference created by current is high enough to sustain it?

We know that current can generate temperature difference and vice-versa. But is it possible to generate such conditions that the temperature difference created by current is high enough to sustain it?...
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Is temperature a Lagrange multiplier of energy?

Someone told me that temperature is a Lagrange multiplier of energy... Is this true? Why?
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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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Difference between pressure and temperature

If I am given the average kinetic energy of the molecules of a gas or a liquid, how can I tell if the fluid will burn me/crush me/both if I immerse my hand in it? Equivalently, what is the difference ...
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Why is the cosmological “Axis of evil” surprising?

I know this is probably a silly question but i'm not sure I understand why it is special that radiation is cooler on one side of our solar system than the other. It seems like it would indicate that ...
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Is absolute zero relative? [duplicate]

Can the absolute zero value depend on the relative velocity of the observer? Can the absolute zero value depend on the intensity of the local gravity?
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Room temperature related question

If two objects are +10C and -10C from room temperature, would they converge to the same temperature at the same time? Say, room temperature is 20C and object a) is at 30C and object b) is at 10C would ...
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Spring constant low dependence from temperature

I am working on a low cost interferometer in order to detect tides effects. I intend to observe fringes changes while changes in gravitacional force causes displacement on a spring wich has a mass ...
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Why can't we plot irreversible processes on a $T$-$S$ diagram?

In the book "Heat and Thermodynamics" by Zemanky, It is stated that "only reversible processes can be plotted on a $T$-$S$ diagram. Since the definition of entropy involves a reversible change in ...
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Hagedorn transitions in 10 D and 11 D string/M-theories?

Are there Hagedorn transitions in 10D superstrings and 11D M-theory?
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What is the value of absolute zero: $-273.15\ \rm °C$ or $-273.16\ \rm °C$?

What is the value of absolute zero? 0K= -273.15 °C Or -273.16 °C It has been confused in different scientific scriptures. The first definition on Dictionary.com, for example.
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Finite Temperature Quantum Field Theory

In a QFT at finite temperature we consider the Euclidean time to be periodic, i.e. we consider a theory on the manifold $\mathbb{R}^{d - 1} \times S^1$, where the spatial coordinates are in $\mathbb{R}...
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Black Body radiation curve - Does it depend only on temperature.? [duplicate]

Couple of questions on Black body radiations 1. Blackbody emits a continuous spectrum. But blackbody is an idealized body. Do normal objects like a bulb or a table emit a continuous spectrum too.? 2. ...
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Formula for calculation when object temperature will be equal as outside

I'm searching for formula to calculate the time for an object temperature will be equal to outside of it. For example: we put metal with temperature 50 degrees on a table where the air temperature is ...
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Langevin equation. What is the meaning of temperature?

Consider a system of $N$ particles, subject to some interaction potential $U$ (e.g. Lennard-Jones) and to thermal noise. The equation of motion is given using the Langevin equation: $$m_i \ddot{\bf r}...
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If I move an object with my hand, will the object's temperature increase? [duplicate]

From my understanding, temperature is proportional to the average kinetic energy of particles. If I move an object with my hand, then it will gain kinetic energy. Therefore, its' particles average ...
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In a vacuum can a cooler body radiate Infrared radiation to a warmer body?

I mentioned vacuum, because I want to discount the effects of conduction or convection. I simply want to know if some of the infrared radiation(IR) goes from the cooler body to the hotter body? How ...
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Why does pitch of string instruments drop in an air conditioned room?

Frequency is directly proportional to square root of tensile force and inversely proportional to square root of length of vibrating column(string length). How can a metallic string contract more than ...