We know that,
Conduction Heat Transfer Q = KA(t2-t1)/thickness
K is the coefficient of thermal conductivity. If T2 = 1020°C and T1= 22°C also consider we know A and thickness value.
K depends on temperature. K varies with temperature. For all the materials we have a tabular data of K for...
I have two bodies, one at a higher temperature say 1000°C (Body A) and the other is at 22°C (Body B).
Body A emits Radiation (Surface to Surface interaction). The temperature of Body A is maintained by a constant supply of Energy.
The Body B will absorb the Radiation Energy from Body A, and its...
First, I calculated the heat required for the ice to melt:
Q=mLf
Q=0.150×330
Q=49.5 J
Then, I calculated the final temperature of the water by forming the following equation:
Q=mcΔT
−49.5=(0.15+0.35)×4200×(Tf −80)
Tf=80.0 degrees Celcius
But the answer says 32 degrees Celsius.
Assume there is a boundary seperates two medium with different heat conductivity [κ][/1] and [κ][/2]. In one medium, the temperature distribution is [T][/1](r,θ,φ) and on the other medium is [T][/2](r,θ,φ). What is the relationship between [T][/1] and [T][/2] ?
Is it - [κ][/1]grad [T][/1]=-...
## \Omega(E_1)## is the number of microstates accessible to a system when it has an energy ##E_1## and ##\Omega(E_2)## is the number of microstates accessible to the system when it has an energy ##E_2##. I understand that each microstate has equal probability of being occupied, but could...
Hi guys, I am currently exploring dissertation ideas and have been looking into the heat recovery potential from domestic gas boilers and ovens. More specifically, I am seeing if it is viable to collect heat from these appliances during or after their use, and then pump this heat into the attic...
Hi everyone, I am currently a third year University Student in the UK and I'm in the midst of doing my dissertation.
My dissertation topic (Effective methods of decreasing the thermal Conductivity of Housing Materials) requires that I produce several experiments to test and analyse a certain...
Hi all, I have been having some issues trying to show that a reversible expansion of gas does not create new entropy. Assistance is greatly appreciated!
So suppose that a gas expands reversibly as shown below at fixed temperature
At fixed temperature, internal energy doesn't change so...
Homework Statement
Hi all, I am having issues with the following problem. Assistance is greatly appreciated!
Homework Equations
The Attempt at a Solution
a) The "law of mass action" I know of is just the equilibrium constant, which I wrote in terms of partial pressures at equiilbrium
$$K...
For a reaction defined as such,
$$A\rightleftharpoons B$$
the equilibrium constant ##K## is defined by ##K = p_B / p_A##, with ##p## denoting the partial pressure (edit: at equilibrium). However, if ##K<<1##, which implies ##p_A >> p_B##, it is said that the backwards reaction dominates and that...
Hi all, I have an issue with understanding the following passage in the aforementioned book. I have uploaded the relevant passage as an image below. Any assistance is greatly appreciated!
The paragraph under equation (22.57) says that the total Helmholtz function ##F## is a sum of Helmholtz...
Hi all, I have encountered the idea of a heat bath but am slightly perplexed as to what it is.
There was a textbook example that looked to find the number density expression for gas molecules as a function of position (image below). It then said that the probability ##P(z)## of finding the...
Homework Statement
Instead of pumping heat into the cabaret air from the outside air, you could simply put an electric space heater inside the cabaret. A space heater turns electrical energy directly into thermal energy. Why would operating a space heater consume more electric power than...
Homework Statement
During the winter, your climate control system must begin warming the cabaret air so that the cabaret air is hotter than outdoor air. Amazingly enough, it can do this relatively efficiently by transferring heat from the outside air into the cabaret. However, your system must...
Homework Statement
You arrange your climate control system so that as it pumps heat out of the cabaret air and thereby chills and dries that air. Part of the heat your system removes from the cabaret air goes to the outdoor air and part goes back to the cabaret air. It turns out that delivering...
Homework Statement
Having chilled the air until it contains only the perfect amount of moisture, you want to reheat it to the ideal cabaret temperature. You could use an electric space heater or wood fire, but you already have another source of heat: the same system that chilled the air in the...
Homework Statement
You're in Paris, working on your first novel and short on cash. The owner of the cabaret downstairs has offered to take care of your rent if you'll help her design a climate control system for the place. It gets too hot and damp in the summer, and too cold and dry in the...
Hello, I am writing a blog article about storing solar energy as heat. Can someone credible check this?
I calculated I need 185.4 liters of vegetable oil to substitute a 6.4kWh battery if I had the same energy conversion (Tesla says 90%) and energy loss over time (no idea about this value) as...
Homework Statement
Find the admissible current density Jadm for a wire that has no insulation and also for a wire that has two layers of insulation and compare it to Jadm for the case when the wire has only one layer of insulation.
2. The attempt at a solution and equations
In the image...
Hi all,
I'm performing a thermal analysis of a satellite subsystem (antenna). However, I'm having some issues relating to the model that I'm implementing on ANSYS.
I've already computed the values for the solar flux, albedo and IR that the satellite is subject and I've applied it to different...
We did an activity today in class where we placed an empty 2L bottle in the Freezer, let it contract, then calculated the coeffcient of volumetric expansion using ΔV = VoβΔT. We got pretty close to the accepted value. The question is.....
Does the coefficient of thermal expansion only work for...
Homework Statement
Two systems in diffusive equilibrium have equal chemical potentials. We can use this fact to solve the following problem. We begin with a closed system consisting of a liquid such as water in diffusive equilibrium with its vapour. At the start, only the liquid and its vapour...
Homework Statement
I'm having some trouble with this problem as it seems my concept of the problem is completely wrong. Could someone look through my solutions and point out what I understood wrongly?
Thanks in advance.
Homework Equations
The Attempt at a Solution
a) 21 macrostates -...
Homework Statement
Calculate the volume of 1.00 mol of liquid water at 20°C (at which its density is 998 kg>m3),and compare that with the volume occupied by 1.00 mol of water at the critical point, which
is 56 * 10-6 m3. Water has a molar mass of 18.0 g>mol.
Full answer please!
Thanks...
Homework Statement
The question below is asking how long it would take for the cooler side of the handle to heat up till its unbearably hot.
I'm having a bit of trouble trying to understand the solution and would like some guidance.
I can't seem to get how the ##\Delta T ## that represents...
Homework Statement
Homework Equations
Thermodynamic Identity
The Attempt at a Solution
While I was able to work out the problem with the help of the hint, I couldn't completely understand the implication of said hint. The hint suggests that the equations for Chemical Potential in a process...
Homework Statement
Homework Equations
##dS = \frac{1}{T} (dU - PdV)## assuming dN = 0
The Attempt at a Solution
I have actually managed to solve all 4 parts correctly, except for the fact that I solved Part d) with the Sackur-Tetrode equation rather than the thermodynamic identity.
I...
HI,
I have application where i need to lift metal plate, 3kg weight, ( 3mmX 15mm), 250degree.C hot, for the period of 1min and put it back. For lifting purpose i am using actuators. As i have no opportunity to make hole in plate i have to use magnet for lifting purpose. I got Electromagnet...
Homework Statement
Homework Equations
dQ/dt = -kA(dT/dx)
The Attempt at a Solution
I tried to use Fourier's law of Conduction on this one. I subbed dT for (Θ0 - Θ1), and l(t) (function for thickness of ice against time) for dx, reason being that the sheet of ice should get thicker.
I then...