Thermal Definition and 1000 Threads

Homework Statement A copper sheet of thickness 2.37mm is bonded to a Aluminum sheet of thickness 1.29mm. The outside surface of the copper sheet is held at a temperature of 100.0°C and the Aluminum sheet at 24.5°C. a) Determine the temperature of the copper-aluminum interface. b) How much...

Homework Statement An ice cube at 0.00 °C measures 14.9 cm on a side. It sits on top of a copper block with a square cross section 14.9 cm on a side and a height of 18.1 cm. The bottom of the copper block is in thermal contact with a large pool of water at 92.5 °C. How long does it take the...

Homework Statement When the temperature of liquid mercury increases by one degree Celsius (or one kelvin), its volume increases by one part in 550,000. The fractional increase in volume per unit change in temperature (when the pressure is held fixed) is called the thermal expansion coefficient...

Hi, I'm doing a group investigation on external wall insulation for my school building. The walls do not have a cavity and thus it has been proposed to put insulation over the exterior render of the wall. This is a fairly common building procedure. However, my task is to investigate the...

Homework Statement The output of a sensor which produces 10000 electrons is connected to parallel RC circuit with Resistance= 50 ohm, and the capacitance=10pF. Calculate the signal to noise ratio at temperature 300K. Homework Equations SNR= 10 log (power of signal/ power of noise) Or...

What are the problems that exists in airborne structure/ circuit ? - Electronics

Greetings all, My first post here on this forum. I'm currently revising for exams and have got stuck on a question where I'm not sure where I'm going wrong...Question: 1g of iron filings at 500 °C are inserted into a sealed 20 litre vessel containing 1 mol of an ideal monatomic gas at a...

Afternoon all. I've have the following equations: Cp - Cv = nR = Nkb Cv = nRf / 2 Cp = nR(2+f) / 2 CvlnT = -nRlnV + const where f is degrees of freedom Do the Cp and Cv just stand for pressure and volume (where both are constant), so for example can the first equation only...

Homework Statement Find an expression for thermal conductivity using kinetic theory. Given a vacuum flask of these dimensions, find the heat loss per unit time. Estimate the time taken for the water to cool down to 40 deg. Homework Equations The Attempt at a Solution...

Apologies for the break from format, but I'm not sure how to make this fit! I'm designing an experiment to compare the insulation properties of several materials. I would like to find the Thermal Conductivity (K) or the U (or R) values of these materials. However essentially all I am after...

Is there a relationship between increasing temperature in one test tube and keeping the other temperature constant and the time it takes to reach thermal equilibrium Homework Statement Is there are relationship between increasing the temperature of water and keeping the other same and the...

Can anyone explain me why the thermal boundary layer develops faster for viscous fluids? I would just say it would develop more slowly because due to high viscosities there are low reynoldsnumbers and thus less turbulence or mixing. This causes a slow homogenization of temperature (assume a...

Homework Statement In a domestic heating system, a room is warmed by a 'radiator' through which water passes at a rate of 0.12kg s-1. The steady-state difference between the inlet and outlet temperatures of the water is 6.0 K. The radiator is made of iron of thermal conductivity 80 W...

Greetings PFers, I'm working on a project where micron size metal or plastic particles are carried inside an argon or nitrogen stream at ~1 atm. The particles travel through at 1/4'' ID nylon tube before they enter a chamber where they then travel through a pyrex tube. I have four 4'', 500W...

Is Carnot efficiency the same as thermal efficiency?

What is thermal noise voltage of three resisors connected in series

1. I would like to test myself on how well I know my information about certain metals, some of them get me a bit puzzled. How would you rate the electrical conductivity of cast iron? Poor, good, excellent or best? Also the thermal conductivity of 304 stainless steel? Poor, good, excellent or...

I would like to test myself on how well I know my information about certain metals, some of them get me a bit puzzled. How would you rate the electrical conductivity of cast iron? Poor, good, excellent or best? Also the thermal conductivity of 304 stainless steel? Poor, good, excellent...

I was hoping someone could lend a hand with a question about thermodynamics. It's been years since I've done work on thermodynamics. Let's say I have a plastic 275 gallon liquid container, filled with a mixture of Propylene Glycol and Water (50/50 by volume). The container is placed inside of...

Homework Statement You build a heat engine that takes 1.00 mol of an ideal diatomic gas through the cycle abc, where segment bc is isobaric and segment ca is isochoric. calculate the thermal efficiency of the engine. this is a 5 part problem and I already solved for Wo and Wo=Qo I solved...

Homework Statement A deuteron is the nucleus of a hydrogen isotope and consists of one proton and one neutron. The plasma of deuterons in a nuclear fusion reactor must be heated to about 300 million K. (a) What is the RMS speed of the deuterons? Is this a significant fraction of the speed of...

Hi, I have to plan and carry out an experiment on thermal radiation as part of my physics lab module. The description of the experiment is as follows: Investigate the radiation from a bulb filament as a function of input power, using a pyrometer to measure the temperature of the filament...

Homework Statement Helium in an ideal Diesel cycle is compressed from 4 L to 0.25 L, and then it expands during the constant pressure heat addition process to 0.50 L. Under air standard conditions, the thermal efficiency of this cycle is: a) 79.5% b) 20.5% c) 61.4% d) 67.4% e) 84.3%...

1. Units of the Thermal de Broglie wavelength? 2. λ = h / (2*pi*mkT)^(.5) 3. through dimensional analysis i get S (J / kg)^.5 can you even have .5 of a unit?

Ok so I found something online but I need to understand this problem Prove that the ratio of the adiabatic compressibilty ks to the isothermal compressibility kr is equal to the ratio of the specific heat at constant colume, Cv, to that at constant pressure, Cp Definitions of the...

Homework Statement How much work is done on the gas in the process shown in figure P12.24. This is from College Physics: A strategic approach, 2nd addition, by Knight, et al. Ch.12, #24 The graph shown is kPa vs V(cm^3). It's a constant temperature process (isobaric) at 200 kpa. I was able to...

[b]1. Find an expression that relates T and V in a process in which the entropy S is constant, by doing the following: a) From thermodynamic identity dS=(1/t)dU + (p/v)dV find the expression for dS as a function of T and V (and dT and dV). b) Integrate the expression found in (a)...

Homework Statement A scuba diver is 17.4m below the surface of the lake, where the water temperature is 8.25∘C. The density of fresh water is 1000 kg/m3. The diver exhales a 23.6cm3 bubble.What's the bubble's volume as it reaches the surface, where the water temperature is 15.1∘C? Homework...

Homework Statement A 61.00m long steel measuring tape is calibrated for use at 20.0∘C. How long is this tape under the following conditions: a hot day with 38∘C? Express your answer using four decimal places and include the appropriate units. i've been losing my mind over this, i swear...

This is not a homework question, but a conceptual question that I am trying to understand. We all have experienced/heard that if you put a completely full water bottle with the cap on in the freezer, the bottle cracks as the water freezers. The explanation is that the water expand as it...

Hello, the task is the following: Consider a two-level system with thermal population. a) Show that the rate equation for the state N_2 is the following: \frac{dN_2}{dt}=w(N_1-N_2)-\frac{N_2-N_2^e}{\tau} w=B_{12}\rho({\nu}) \,\,\, N_2=N_2^p+N_2^e\,\,\, N_1=N-N_2 N_2^p is the portion of...

For a nonmetal what determines thermal conductivity is the propagation of lattice vibrations. As T increases these lattice vibrations collide with each other more often. Does this mean that the thermal conductivity will de- or increase?

I am planing to study thermal physics on my own as I got an incompetent faculty who doesn't know anything about this subject. I want to have a detailed understanding about the topic. So can somebody suggest me which book I should follow from the following list. 1. Schroeder, Thermal...

In the harmonic approximation, why is the volume of a crystal not temperature dependent? Does it have something to do with the fact that the amplitude of a harmonic oscillator is independent of the frequency?

If thermal resistance is additive, then how can the thermal conductivity of two (or more) materials be combined? Can it? Eg. a wall filled with straw and air, a hollow brick, a mixture of polystyrene and fibreglass wool (just some random ideas off the top of my head).

The question: A perfect gas undergoes the following cyclic processes: State 1 to 2 cooling at constant pressure. State 2 to 3 heating at constant volume. State 3 to 1 adiabatic expansion. Deduce an expression for the thermal efficiency of the cycle in terms of r the...

Good day, I was recently asked to look into the process of thermal annealing of thin metal films in order to induce nanoparticle formation. However, I have been terribly unsuccessful in finding any sources that describe exactly how this works. I understand the basic idea of thermal annealing...

Hi all, could somebody have a look over my answers for this question please? The value I got for the second part seems quite feeble. Homework Statement The Attempt at a Solution [SIZE="4"]Part a) Key m = mass cs = specific heat bronze cm = specific heat molten bronze Tfus...

Homework Statement 160 grams of boiling water (temperature 100° C, heat capacity 4.2 J/gram/K) are poured into an aluminum pan whose mass is 950 grams and initial temperature 26° C (the heat capacity of aluminum is 0.9 J/gram/K). (a) After a short time, what is the temperature of the water...

Hello, i'm doing my prep for my lab experiment tomorrow and have a few questions about the experiment. The schematic is attached. My lab script says the following; 2 questions. It says the precise rate of flow of water through the heat exchanger is unnecessary to know. Is this...

The question is: Consider a thermal battery - a device for storing mechanical energy. Use two large containers as heat reservoirs where one contains ice and water in equilibrium and the other contains steam and water in equilibrium. Both are held at pressure=1atm. Energy is stored by using a...

Hello everybody, Here is a problem I have. QUESTION: The main span of a bridge has a length of 473 m. On each end there are the expansion joints like the one on the photo below. One day the city changed from -4 to +15 degrees between 6 in the morning and 2 in the afternoon. At 6 in...

Homework Statement I performed an experiment recently, which required me to heat a flask and an unknown compound to constant weight. The unknown was supposed to be a mixture of calcium sulfate dihydrate and NaCl. My goal for this lab was to determine the % NaCl in the mixture. My percent error...

Homework Statement A brass bar and an aluminium bar are each attached opposite each other to immovable walls. (There is a diagram, but I think the idea is clear enough). There is a gap between the two bars of 1.3x10-3m at 28°C. At what temperature will the gap be closed? coefficient of...

Assumptions 1) a=absorption 2) f=fission 3) ∅=neutron flux 4) time independent 5) group 1, fast neutrons 6) group 2, thermal neutrons 7) All fission neutron are boring in fast group 8) All neutrons created by thermal group, thus vƩf2 exists vƩf2 does not 9) Down scattering occurs but up...

I have a system with two gasses separated by a wall as in a heat exchanger. One of the gasses changes temperature by the action of an outside agent and I'm trying to estimate the heat flow between the two gasses over time. I know that thermal diffusivity is a factor in this, but I don't know...

If a fast moving thermal neutron can be slowed down to increase absorption chances, is there a way it can be brought a halt? If yes, what will be the behavior of such neutron?(Apart from a simple fact that reaction comes to a halt)

Here is the experiment in brief for those uninitiated : http://media.uws.ac.uk/~davison/labpage/leedisk/leedisk.html My question is, when the steady state has been obtained (heat flowing into Brass Disc = heat flowing out of it), why do we remove the upper Brass Base and then heat the disc...

Though this topic mentions climate change, I don't think it really is about it that, strongly anyway. I've just joined and noticed a ban on climate change discussions before posing this one, I don't think this is one, but if it is, I suppose the beast must have one of it's many heads chopped...

Hey guys, I was reading about thermal states and now I have a doubt: is a thermal state always a mixed state with density matrix ρ=exp(-βH)/Tr(exp(-βH)), or is there also a pure thermal state? Thank you