Temperature Definition and 1000 Threads

I have known the interaction parameter of a certain liquid mixture which has the phase behaviour can be described by the lattice model. , is it possible for us to know the temperature at the critical point? Besides, if we know the temperature at the critical point, can the volume fraction of...

I have some cubic box with light bulbs controlled by a dimmer. The dimmer is calibrated in degrees (0-270). I need help in coming up with a function that would accurately predict what the temperature inside the box would be after say.. 5 or 10 minutes. Basically, I need to come up with a...

Hello, I have a general question regarding energy coupling in multi phase flow. My question comes is based on the text from this book...

Hoping someone can help me here, I'm only a student so I'm sorry if my question is badly worded. I'm doing my maths dissertation on a binary eclipsing star and I'm trying to work out the mass of one of my stars. I know the B-V value and effective temperature, and I believe the equation I need...

High school student here I am designing an experiment to test the effect of temperature on the torque required to twist a piece of metal, and need some advice on where to start researching. What I need help with is A) finding a table of the torque required to twist steel when cold, and B)...

Homework Statement A furnace is constructed with 0.5 m of fire brick, 0.15 m of insulating brick and 0.25 m of ordinary building brick. The inside surface-temperature is 1530K and the outside surface temperature is 525K. The thermal conductivities of the fire, insulating and building bricks are...

I was asked in an exam the following question: Q: How is the absolute Kelvin Thermodynamic temperature scale defined ? My answer is the following: A: The absolute zero kelvin thermodynamic temperature is defined as the temperature for which the entropy of the system is zero, i.e ##S|_{T=0} =...

Homework Statement Find the common temperature at which the inner diameter of the ring is 0.05% larger than the diameter of the sphere. Given: Lead sphere d = 5cm To = 70°C ∝ = 29x10-6/C° Steel ring d = 4.9975cm (the sphere is 0.05% larger than the inner diameter of the ring, hence this value)...

Hello Guys How are you?? Today i was studying physiology Body temperature measurement and i saw in general and in normal conditions that the oral cavity temperature is lesser than rectal temperature but why the oral temperature is lesser than rectal temperature?? And what is the reason?

Is the idea of negative absolute temperature analogous to a virtual image in geometrical optics? I was reading this article about such a negative temperature: http://www.livescience.com/25959-atoms-colder-than-absolute-zero.html It seems to me that since temperature is defined by its...

Dear Experts, I am looking for the variation of magnetic permeability of the plain carbon steel wire grade 1000 to 1095 with respect to the ambient temperature ranging from -40 deg C to 200 deg C. Any leads will be appreciated. Thank you!

Homework Statement Please consider a mixture of oxygen (1 mole), nitrogen (4 mole), and carbon dioxide (3 mole). The mixture was heated in a well - insulated vessel with 753 kJ. Determine the final temperature if the mixture is composed of real gases behaving ideally as described by Eq. 3.48...

Hi, I would like to ask you for advice with a problem, I'm working on. I have a regular shape object (glass cylinder) in which is the 100W heat source. The heat source is ind the middle of cylinder and radiates heat uniformly throughout it’s height. Heat, of course, gradually moving into...

Homework Statement Excel Table gives Temperature of Month & Avg NOAAtemp for bill Homework Equations y = mx + b (Assuming) The Attempt at a Solution 1) if we take temp of month as temp, linear model y=-0.1481*temp+124.8. 2) If we take temp for days of bill as temp, y=-0.1466*temp+124.74

Homework Statement "One way to heat a gas is to compress it. A gas at 1.00 atm at 25.0°C is compressed to one tenth of its original volume, and it reaches 40.0 atm pressure. What is its new temperature?" So, I have: P1 = 1 V1 = 1 T1 = 25 P2 = 40 V2 = 0.1 And I'm looking for T2 The question was...

Hi everyone, To begin, sorry for my english...:S I try to calcualte inner/outer surface stresses on a pipe submitted to instanatenous temperature variation on the OUTER SURFACE. I know the Roark's formua giving the stresses but with an instantaneous temperature variation on the INNER SURFACE...

Homework Statement 1 mole of ideal gas with internal energy U= 3/2 RT , expands from initial volume Vi = 1/10 Vo following the equation p=(− po / Vo ) V +po . Find (a) the highest temperature reached by the gas during the expansion and (b) the maximum amount of heat taken in by the gas...

I am trying to explain the following statement in my own words... Would it be correct to say that.. I am unsure if a vibrational state is simply a different energy state or something more specific? Do the electron temperature, vibrational temperature and rotational temperature all...

Somehow I am worried it is a can of worms, but I will still try. This started with a student confused with statements describing critical temperature for the gas/liquid equilibrium. Some books and sources state it is the highest temperature AT which it is possible to liquefy the gas just by...

Hi all, I'm trying to find a special refrigeration device that can goes from -40 Degrees to 70 degrees. I need this machine for a laboratory to test sensors in differente temperatures. Does anyone knows where can I find something like that? Kind Regards Vicente

I have a question for my Astro homework and I am a little unsure as to whether I am going in the right direction Question Using an expression that relates luminosity, size and temperature of a star, and assuming all Main Sequence stars have the same mean density, determine the relationship...

Which one is cheaper to do if I have a reactor at 45 bar, 80C and wish to distill a substance before it enters another reactor at 15 bar, 150C?

I thought this would be the most logical way to post this, but give me some grace if it is not because this is my first time posting on this site (then relinquish the grace and tell me how to do it properly haha). First: When a physics problem says "sliding past point P" does that mean it stops...

Homework Statement You come across a dead body at 3 PM. Its temperature is 83.6 F. 30 minutes later its temperature is 78.6 F. How long was the guy dead before you found him? Homework Equations ##\frac{dT}{dt}=-k(T-Tair)## T(0) = 83.6 F T(0.5) = 78.6 F The Attempt at a Solution This is a...

Homework Statement A 3-m3 rigid vessel contains steam at 10 MPa and 500 degC. The mass of the steam is? I know this question involves using a thermo-table, I'm just very confused on how to find mass from the given information. Homework Equations Maybe PV=nRT The Attempt at a Solution I...

Hi, I'm working on my thesis and I need to calibrate some gas sensors that I'm building. I need controlled conditions(temp, RH and a known gas concentration) in order to calibrate the sensors. I'd love to know some idea to make a sealed box in which I trace and vary those parameter. I've...

water is flowing in the closed looped pipe equipped with preheater. there are pressure and temperature gauges before the preheater and after the preheater. which pressure gauge should i use to know whether the outlet preheater temperature has reached the saturation temperature?

Hi everyone, I'm trying to understand why laser diodes need a stronger input current to start lasing when their temperature increases. If I tried to add thermal transitions to the rate equations governing the evolutions of an atom quantum level populations (let's say ##n_{up}## and...

Homework Statement [/B] After doing a lab on air compressors, we were asked to calculate Error in Pressure, Temperature and time measurements taken (all at 30 second intervals). We took pressure and temperature values at time = 0,30,60,90,120,150 and 180 seconds. We repeated the experiment 5...

What's up guys. Is there anyone who can challenge to solve this theoretical problem that can help to solve my house problem? There's an empty outdoor swimming pool that has width a, length b, and depth c, such as its volume = abc. The temperature of outside is -3 C° and we are trying to fill...

In "The Art of Electronics" the following is said: "A comparator in a circuit is a handy device that switches its output according to the relative voltages at its two input terminals. There is a temperature sensing device, a thermistor, which decreases in resistance by about 4%/°C. So we’ve made...

Hello, I am trying to figure out how much the human skin temperature would increase when the skin is illuminated by radiation of a certain intensity (W/m^2). We can assume that the skin has an emissivity and absorptivity both equal to 1. For instance, imagine the skin illuminated by the sun (I=...

Homework Statement As you know it's finals time and I desperatly need help with one physics task (it's not my main subject, but I still have to pass it -.-). Here it is: According to data below count temperature-depended entropy and entropy itself for reaction: CH4 + 2 O2 = CO2 + 2 H2O CH4...

Hi folks, I have a question, I will first write down some old truths and then ask what is unclear to me. Now we know that Boltzmann's constant is the average kinetic energy of one molecule of ideal gas, related to its temperature T. The German scientist Clausius defined entropy change of some...

Homework Statement If a block of 250 grams of lead (specific heat (c) =130) at 315 degrees celsius is placed in a 200 gram aluminum (c=900) calorimeter cup containing 900 grams of water (c=4.1), and the calorimeter and the water are both initially at 15 degrees celsius, what is the equilibrium...

I'm about to do an experiment on second sound in superfluid helium. Reading the lab manual it says we will generate it by putting a heater into the fluid and then passed an AC current through it. What we are going to measure is apparently the 'normal fluid fraction', which I guess under the two...

Homework Statement You would like to put a solar hot water system on your roof, but you're not sure it's feasible. A reference book on solar energy shows that the ground-level solar intensity in your city is 750 W/m^2 for at least 5 hours a day throughout most of the year. Assuming that a...

Homework Statement "A well-insulated bucket of negligible heat capacity contains 120 g of ice at 0°C. If 20 g of steam at 100°C is injected into the bucket, what is the final equilibrium temperature of the system?" Homework Equations $$Q_{fus} = m_{water}L_{fus}$$ $$Q_{vap} =...

Hi, I've been asked to heat a sample that contains Fe2O3, amongst some other things, to a temperature where Fe2O3 will decompose. I am unable to find the temperature at which I would need to heat the sample and I'm not entirely convinced this is actually possible with the equipment I have...

This is probably a very basic engineering question, but I'm from an energy policy background and the resources I've found (such as this) are quite detailed. Internal combustion engines such as automobile engines and aircraft (jet and piston powered) produce more power in colder environments and...

Can someone explain why when you increase the temperature on an endothermic reaction, it yields more products? Is it because the activation energy is higher in an endothermic reaction, so there is more time for the products to form? also why does decreasing the temperature yield more products in...

I am working on a project to stockpile and freeze photographic film and paper for later use. This is not for academic or commercial purposes, but just for personal use. I've been experimenting and am stumped as t the following: I place a package of film in a ziplock bag in an environment of...

Homework Statement I'm asked to find the specific heat of Metal X in this simulation: http://group.chem.iastate.edu/Greenbowe/sections/projectfolder/flashfiles/thermochem/heat_metal.html Mass of Metal X = 120 g Temp of Metal X = 220 degrees Mass of Water = 30 g Initial Temp of Water = 20...

I was just wondering: why does lower kinetic temperature imply population inversion? I've read this is true in a few (astrophysics) texts regarding molecular clouds, although this seems to be a more general result that I haven't really read an entire explanation for. Nevertheless, do you have...

1.If temperature is just a measurement of KE, can a system with higher temperature contains lower internal energy than a system with lower temperature? 2.Can energy flow from an object with higher temperature to an object with lower temperature even if the internal energy of the object with a...

Hi, how to predict indoor temperature with or without HVAC? I have the internal temperature's value, the external temperature's value and the temperature of HVAC's air output. I want two function, one with HVAC on and other with mode off. Hp: start time 0, end time Tend. Tend has values from 0...

Homework Statement I have ##C= NK_B (\frac{\epsilon}{K_B T})^{2}e^{\frac{\epsilon}{K_B T}}\frac{1}{(e^{\frac{\epsilon}{K_BT}}+1)^2} ## and need to sketch ##C## vs. ##T## Homework Equations See above The Attempt at a Solution I have ##C= NK_B (\frac{\epsilon}{K_B...

We know that for a closed system, isobaric heating decreases the humidity and isothermal compression increases the humidity. But assuming that we start with the volume completely filled with humid air, is it not true that any increase in temperature must also increase the pressure? If so...

The heat source for this experiment is a compost pile (1 cubic meter), I know that the inside of the pile will reach approximately 50C for 2 weeks or so. Right now it's winter so the temperature will stay around 0C (average). The thermal conductivity of compost can vary greatly but in this case...

Homework Statement what happens to wavelength if temperature increases? Homework Equations V= lambda * frequency The Attempt at a Solution I'm guessing since no change to frequency is stated?.. and I know that the speed of sound increases as temperature increase. The wavelength would have to...