What is Temperature: Definition and 1000 Discussions
Temperature is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy, present in all matter, which is the source of the occurrence of heat, a flow of energy, when a body is in contact with another that is colder or hotter.
Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have used various reference points and thermometric substances for definition. The most common scales are the Celsius scale (formerly called centigrade, denoted as °C), the Fahrenheit scale (denoted as °F), and the Kelvin scale (denoted as K), the last of which is predominantly used for scientific purposes by conventions of the International System of Units (SI).
The lowest theoretical temperature is absolute zero, at which no more thermal energy can be extracted from a body. Experimentally, it can only be approached very closely (100 pK), but not reached, which is recognized in the third law of thermodynamics.
Temperature is important in all fields of natural science, including physics, chemistry, Earth science, astronomy, medicine, biology, ecology, material science, metallurgy, mechanical engineering and geography as well as most aspects of daily life.
I got this from chatgpt:
It says "not simple and straightforward", but can we assume proportional ? So is there a visible alteration in Snell angle ? Also, for applied physics databases, what would be a pubmed equivalent, hosting all titles and synopses ? In physics the articles seem to be...
The notes my lecturer has provided state that the maximum temperature can be found taking p = 0 in the inversion curve formula, given as:
I’m not sure how to obtain this??
These are the formulas:
This is my attempt at a solution :
Not sure if this approach is right?
Quoted from the O&M manual of an electrical steam superheater:
"The Steam Superheater has eight thermocouples of the NiCr-Ni type, known as "K," attached to the heating element sheath. Four of these thermocouples are positioned near the steam outlet nozzle, where the highest temperature is...
From the graph:
$$lnR(T)=\frac{-lnR(0)T^2_○}{T^2}+lnR(0)$$
I have assumed ##R(0)## to be the value of ##R## at ##1/T^2=0## and ##T_○## to be the value of ##T## at ##lnR(T)=0##
From this I get,
$$R(T)=e^{lnR(0)×\left(1-\frac{T_○^2}{T^2}\right)}$$
$$R(T)=R(0)^{\left(1-\frac{T_○^2}{T^2}\right)}$$...
Hello !
According to what I have read on the internet, the weight of a body varies with temperature, its mass remaining unchanged according to the theory of relativity.
My question is what experiment is done to corroborate that the weight of a body increases with the increase in its...
I read that the solar wind is a stream of particles, primarily electrons and protons, flowing out from the sun at speeds as high as 900 km/s, and at a temperature of 1 million degrees. Using the equipartition theorem, I calculate that a proton moving at 900,000 meters per second exhibits a...
Is there a formula to calculate the speed of propagation of sound waves through steel (a steel bar, for example) according to the temperature of steel?
Hello guys,
I am currently running an experiment in my hobby room: I want to heat a cube in a microwave and then measure the surface temperature. Unfortunately, it takes about 20 seconds, so the cube cools down during this time which means I don't measure the actual temperature after heating...
I have been searching for the answer yet – as I'm here – didn't find it.
The current model of climate warming says the lower parts of Earth's atmosphere don't allow the IR radiation to escape freely to the outer space because the GH gas molecules keep absorbing it virtually as soon as it's been...
Say there was something that made the temperature of the universe almost absolute zero, but around you was a mini bubble where the temperature was normal, and therefore molecules could move normally around you for a small area. How would you perceive the world around you outside of the little...
How to incorporate deviation -9.2C in furnace, while its measured temperature is 909.2C and Display temperature is 900. if there is no option of offset in controller. What will be the set temperature to achieve 900C.
Hi all,
recently I started following the MIT course "Statistical Mechanics I: Statistical Mechanics Of Particles" by MIT (here).
In the second lesson Prof. Kardar introduces the concept of thermodynamic temperature analyzing the behavior of two Carnot engines that share a thermal reservour at...
(a)
(b)
Here is a plot of this function T of R
It seems that as the resistance goes up the temperature goes down. Not sure what to make of this physically speaking.
My question is about the requested log-log graph.
Above we have a function T of R, but we want a function ##\log{T}## of...
Could someone provide an ainformation what is the temperature inside the Large Hadron Collider (or similar systems) where the colision of particles happens? THANK YOU!!!!
Here is the table
As far as I can tell what we have here are four constant-volume thermometers (each column represents a thermometer). These thermometers work by having a certain constant volume of some specific gas in a bulb. We immerse the bulb in whatever temperature we would like to measure...
Considering the approximation of perfect gas, I don't understand why at higher altitude the temperature is lower.
Intuitively it is clear to me, but I do not understand the kind of transformation that takes place; the gas is free to expand and the pressure too is not constant, since it decreases...
I posted another question about a thermodynamic system with three coordinates, namely, that of a metallic wire. We can describe that system with temperature, wire tension, and wire length.
The result derived in that question was that the partial derivative of wire tension relative to absolute...
It took me a while to understand (I think) the concepts below. I have two questions.
1) What does "absolute" mean in the term "absolute temperature scale"?
2) What is the difference between the two constant-volume hydrogen gas thermometers (one at high pressure the other at low pressure)...
In case of adiabatic process, we all know that the relation between temperature and pressure and that's given below:
P. T(γ/(1-γ)) = Const.
therefore, P = Const. T(γ/(γ - 1))
or, ΔP = Const. (γ/(γ - 1)).ΔT(1/(γ - 1))
It's just an attempt to find out the relation. Don't know how much correct I...
I can visualize gas molecules, contained in a vessel, randomly bouncing into each other. As temperature increases, the collisions occur more rapidly. I suppose this also applies to liquids. I'll guess that a liquid's boiling point is where the molecular collisions become so violent that...
Well... that: Please, could you please assist me in obtaining a rough estimate of the distance from the Sun at which a planet resembling Venus or a hypothetical Venus-like planet (for the sake of simplicity) would have a habitable-zone surface temperature? A "back-of-the-envelope" educated...
My main question here is about how we actually justify, hopefully fairly rigorously, the steps leading towards converting the sum to an integral.
My work is below:
If we consider the canonical ensemble then, after tracing over the corresponding exponential we get:
$$Z = \sum_{n=0}^\infty...
For this problem,
The solution is,
However, why must we use absolute temperature for the ideal gas law (i.e why can we not use Celsius for T)
Many thanks!
My first assumption is that the temperature dependence on the mobilities can be neglected, and so we would have:
$$R_H(T)= \frac{1}{e} \frac{p_v(T)\mu_h^2-n_c(T)\mu_e^2}{(p_v(T)\mu_h+n_c(T)\mu_e)^2}$$
The expression for the electron and hole densities could be derived from...
Hello everyone,
I deposit a thin film of HTM based carbazole and I measure the PL at lower tempertaure . by fiiting the experimental results with 5 peaks . I notice the dissapering of peak 1 at 300K and peak 3 at 200K. What is the nature of the interaction that can occur at lower temperature of...
FIGURE 5 shows an electrically heated oven and its associated control
circuitry. The current, I, to the oven's heating element is fed from a
voltage-controlled power amplifier such that I = EK1. A voltage, VD, derived
from a potentiometer, sets the desired oven temperature, TD. The oven...
(a)
I know some of the apparatus needed for the experiment, such as DC power supply, ammeter, voltmeter, maybe rheostat. But I don't know how to change the temperature of diode. What is the correct and safe way to change the temperature of diode?
Thanks
How to correctly determine the temperature of electrons in an ion source based on ECR?
Is it possible to use the Saha equation?
##\frac{n_en_i}{n_a}=\frac{g_eg_i}{g_a}*3*10^{21} T^{3/2} e^{-J/T}##
Using the search, I found the McWhirter criterion for the applicability of the formula above:
##n_e...
As part of our UG curricula in Physics major, we have a practical in which we have to draw the calibration curve of an NTC ##10~\mathrm{\Omega}## thermistor, and then construct a circuit to maintain the temperature of a water bath.
The calibration curve of our thermistor. The Prof. said that...
Usually, the mental image of temperature is: an internal property of a bulk of matter, which typically describes the average kinetic plus rotation/vibration energy of molecules, so we imagine a gas in which temperature is a measure of how quick molecules are, and how frequently they collide one...
Looking at the given values, I thought the specific heat formula could be used to calculate the final temperature of the air: c = Q/mΔT. Since the final temperature is the sum of the initial temperature and the change in temperature, the formula can be rearranged to ΔT = Q/m*c.
Q = 30 W * 10 s...
An insulated container (constant volume, adiabatic) contains an Ideal gas with pressure P1 and temperature T1.
We open the container's hatch for a few seconds and let some particles escape from the container, then we close the hatch again. We know container's pressure has reduced by exiting...
For this problem,
The solution is,
I understand their logic for their equation, but when I was trying to solve this problem, I came up with a different expression:
##\Delta A = \Delta L_x\Delta L_y##
##\Delta L_x =\Delta L_y = \Delta L## since this is a square.
##\Delta A = \Delta L^2##...
I have the following task and I am not getting anywhere:
A steel tank with 15 m³ volume, well insulated from the outside, contains air at a temperature of 288 K and a pressure of 1 bar. It is connected to a compressed air line via a valve that is initially blocked. which constantly supplies...
Hello everyone, since several weeks, no response from the other forums, I tried to compute a simple model for a greenhouse in a garden. First idea was to compute mass transfer, Navier-Stokes and heat equation all together but in my knowledge no analytical solution exists.I need to build a simple...
I have a cube with a volume of 1000m3 at an initial temp of 290K. The bottom side (10m by 10m) is open to the ambient air. I put this cube into a huge fridge and cool the whole volume by 5K. I close the open side by placing a cover on it. This cube has now got a volume of air at a temperature of...
I am a high school student and recently I have been working on a project about how temperature affects the frequency of a string emits. I have read blogs like https://www.physicsforums.com/threads/tension-and-frequency-with-change-in-temperature.833185/ and completed the part of thermal...
When I try P_rel_e = P_ideal I couldn't get a single number that is close to the given T_Max. It might be that I used the wrong equations but I am not sure. Can anyone give me some guidence on this question?
The commonly called value of the temperature at recombination is 3000 K.
According to this reference the process of recombination can be described by the Saha equation:
3.1. Recombination and the formation of the CMB
Recombination happens quickly (i.e., in much less than a Hubble time t ~...
(1) Incorrect, since the root mean square speed(c^2)is directly proportional to the temperature, but it will just affect the average kinetic energy, doubling the k.e., but not related to the potential energy.
(2) Correct, since the volume of gas is directly proportional to the temperature
(3)...
The answer given for part (c) in the back is that temperature doesn't change as the gas in cylinder A expands to fill cylinder B.
The thermodynamic system here is composed of the two cylinders A and B joined by some pipe.
But, I cannot find a satisfactory explanation for temperature...
The other day I read on a website that a lower evaporator airflow causes lower low pressure side saturation temperatures and higher delta T on an air-conditioner. Now I think I know why a lower evaporator airflow would cause a high delta T. If there is less air moving over the evaporator, the...
Hello,
My house has some heat loss. As an example I know the outside door temperature. How can I calculate the heat loss delta if I reduce the door temperature by 1 degree?
I know that there is a formula to calculate a heat loss based on the U-value of a fabric. But I can't get those values...
TL;DR Summary: Help needed with plotting heat maps, using data we gathered in an experiment.
Hello,
so I'm having problems with analysing data, which we gathered from an experiment we did in class. This is meant as a type of non-guided experiments class, where we are just given an initial...
I have a question about the temperature of HII gas. According to Table 1.3 in Draine's book (physics of the interstellar and intergalactic medium) this temperature is T~10^4 K.
I get a similar value by using the Saha equation for a hydrogen gas.
However, a naive estimate of the same temperature...
Hello,
I am stuck how to proceed with the equations below.
The problem:
A tank containing ##m_0## mass, with a temperature of ##T_0##, is to be filled with a total mass of ##m_1##, with the constant mass flow rate ##G## and temperature ##T_1## during ##t_p## seconds. ##T_0>T_1##. Other than the...