Questions tagged [adiabatic]
Thermodynamic processes that occur without exchanging heat between the system and its environment.
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Restriction on the value of adiabatic exponent
My instructor stated in his lecture that the maximum value of the adiabatic exponent, $\gamma$, can be 5/3 which is that of a monoatomic gas, but why is this so?
He also stated that this can be found ...
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How much steam and water will Earths atmosphere hold if no condensation occurs due to absent cosmic and particle impact?
Condensation and cloud formation forms due to cosmic impact of radiation and particles.
See for example Svensmark in Nature:
We show that the mass-flux of small ions can constitute an important ...
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1answer
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How much steam must Earths atmosphere hold for no condensation to occur at bottom?
If Earths atmosphere were to be expanded by adding water/steam how much would be required in order to increase the temperature enough at the bottom, due to the adiabatic temperature gradient, to ...
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Thermodynamics of a gas [closed]
If I boil a liquid and turn it into a gas and it's in a sealed container will this raise the temperature.
I may have this wrong but struggling to understand this statement:
The adiabatic compression ...
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1answer
40 views
First order wave function in adiabatic approximation
If the Hamiltonian is slowly varying in time and suppose the initial state is the n-th eigenstate of the initial Hamiltonian H(0), the adiabatic theorem says that the state will still on the n-th ...
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Adiabata for Van der Waals equation
Adiabata for ideal gas has equation
$pV^\gamma = const.$
this allows calculate $p(V) = K/V^\gamma$, where K is some constant.
Is there similar equation and preferably function $p(V)$ for gas ...
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20 views
Process both isothermal and adiabatic
Why a reversible process can't be both isothermal and adiabatic, while an irreversible one can be?
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1answer
56 views
Show that $pV^\gamma$ is a constant for an adiabatic process
Assume that gases behave according to a law given by $pV = f(T)$, where $f(T)$ is a function of temperature. I have derived the following results:
$$\displaystyle\left(\frac{\partial p}{\partial T}\...
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2answers
37 views
Why does an adiabatic process become an isothermal process when D.O.F. are high?
Say that during an adiabatic process, the pressure changes from $p_0$ to $a*p_0$, and let the heat capacities ratio be denoted by b ; using the basic adiabatic relations for an ideal gas, we can find ...
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1answer
70 views
Adiabatic Approximation, Solving the Schrödinger equation
In the adiabatic approximation one looks at the Hamiltonian
$$ H_0 = \sum_{i = 1}^{N_e} \frac{\vec{p}_i^2}{2m_e} + \sum_{i < j} \frac{e^2}{|\vec{r}_i - \vec{r}_j|} + \sum_{k < l} \frac{Z_k ...
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3answers
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Why is $dE = C_V dT$ for an ideal gas, even when the process is not constant volume? [duplicate]
I have come across the following derivation for the "equation of an adiabat for an ideal gas" in many textbooks. The following steps are referenced from a separate question:
dE=dQ+dW
dW=−pdV
dQ=0
...
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Can two quasi-static adiabates intersect? [closed]
I saw a question in my physics book that I've been trying to understand lately.
The question is simple: given two quasi-static adiabatic curves, could you find a point of their intersection? Also, ...
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51 views
Calculating final pressure in irreversible adiabatic compression
I am trying to solve the following question.
A gas is enclosed in a cylindrical can fitted with a piston. The walls of the can and the piston are adiabatic. The initial pressure, volume and ...
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1answer
33 views
Adiabatic flame temperature of ethanol in high pressure environment
I'm building a rocket engine and need to know the temperature of the gases inside the combustion chamber (ie the stagnation temperature).
The combustion chamber pressure is 5 atmospheres. The ...
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3answers
116 views
Why does the temperature have to change when there's no heat loss in an adiabatic expansion?
Adiabatic expansion is known to cool gases to a substantial temperature and it's caused by pressure drop. Now if I have a tank full of an ideal gas (nitrogen) at high pressure and temperature, and I ...
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What is the difference between arriving at the 'avoided crossing' point of a two level system adiabatically and non-adiabatically?
In the simplest case of the 'avoided crossing phenomenon' we can assume a two level system that its eigenstates $E_1(n)$ and $E_2(n)$ are functions of some continuous variable n, and there is some ...
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3answers
206 views
Reversible vs. Irreversible Expansion
Suppose I have a gas in a piston expanding adiabatically against atmospheric pressure. If I do this reversibly, the final state is uniquely specified by the final volume $V_F$ of the gas.
What ...
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3answers
356 views
Why the entropy change is not zero in the irreversible adiabatic process?
Why the entropy change is not zero in the irreversible adiabatic process?
while it is defined as the integral of the heat added to the system over its temperature
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Hannay's angle for a spin half interacting with a magnetic field that varies adiabatically over time
Does it make sense to talk about the Hannay's angle for a magnetic moment with spin 1/2?
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1answer
27 views
Does adiabatic quantum computation require the initial and final ground states to be non-orthogonal?
Background
At a recent talk, I was told by the speaker that it is not possible to adiabatically transfer from one ground state $|\psi_0 \rangle$ to another $|\psi_1 \rangle$ if these states are ...
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1answer
187 views
Understanding Adiabatic Processes in a practical sense
We all know the basic understanding of the adiabatic phenomenon: ideal gas expands and cools, compresses and heats up. Now by expand, let take a quick look at a scenario: let assume there is a tank ...
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Calculate the work for moist air adiabatic expansion and compression?
( During expansion some water vapor condenses and is removed from the system. )
More details:
Initial conditions: t 25C, p 1013 mB, humidity 100%,
then expansion to ~ 450 540 mB
through the double ...
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Adiabatic Expansion of Air blown from mouth [duplicate]
Why is the air blown from our mouth of different temperature as the size of the opening of mouth changes?
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3answers
1k views
What is quasi-static process?
What is the formal definition of quasi static process?
I am accustomed with it a bit intuitively, i want to know the formal definition of this. At some source I found the definition of somewhat ...
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2answers
84 views
Can $PV^\gamma$ be treated as an entropy function?
In a reversible adiabatic process, $PV^\gamma=\text{const.}$ but reversible adiabat $\iff$ isentrope so does that mean $PV^\gamma$ can be treated as a function for entropy?
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Deduce if path is adiabatic from the state space
Can we deduce, for quasistatic processes, if a process is adiabatic by purely looking at its path in state space?
Take, for example, the process of stirring a liquid to heat it up (adiabatic) and ...
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96 views
How to calculate work for irreversible adiabatic processes?
By the first law, we know $\text{d}U=\delta Q+\delta W$ and, on adiabats, we know $\text{d} U=\delta W$. But what is $\delta W$ for irreversible adiabatic processes? Take a thermally isolated ...
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1answer
48 views
First law needs adiabat definition but adiabat definition needs heat definition in first law
It is usually said that the best formulation of the first law of thermodynamics is that work is path independent on adiabatic paths. From there, you can define the state function of internal energy ...
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1answer
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Defining internal energy for adiabatically inaccessible states
As is well known, a good way to define the internal energy in classical thermodynamics is to define the difference in internal energy of two points as the amount of adiabatic work from one point to ...
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4answers
72 views
Thermodynamic process
"During this process, the system is always in thermal equilibrium with the surroundings."
Does this statement means the process is adiabatic? Since the temperature of both systems is the same, there ...
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2answers
114 views
Why is $C_V$ used in this derivation? [duplicate]
In his lecture (26:30-38:40), Shankar derives the adiabatic pressure-volume relationship $P_1V_1^\gamma = P_2V_2^\gamma$, where $\gamma = C_P / C_V$, from the First Law of Thermodynamics $\Delta U =Q -...
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3answers
243 views
In an adiabatic process, why is it that if work is done very quickly then there is no time for energy transfer to the surrounding?
I don't seem to understand the logic in adiabatic process of how 'if work is done on the system very quickly e.g. compress a piston containing n number of gas particles, there is no time for energy to ...
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731 views
What is the meaning of $PV^\gamma=$ constant in an adiabatic process?
In an adiabatic process, heat transfer doesn't occur and hence $\Delta U=-W$ (an increase in internal energy due to work done on the system or a decrease in internal energy due to work done on the ...
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1answer
73 views
Adiabatic Availability?
In the textbook
"Thermodynamics: Foundations and Applications" by Elias P. Gyftopoulas and Gian Paolo Beretta (Dover).
In chapter 5, on page 73 (section 5.3) the book says:
Adiabatic availability ...
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1answer
629 views
Intersection of Adiabatic curves
Can two adiabatic process paths intersect on a plot? This question is for both reversible and irreversible processes. There are some answers for this question on Quora, but they mostly address only ...
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4answers
125 views
Adiabatic expansion Vs pulling a syringe after closing its mouth
I've read that adibatic expansion always results in a decrease in temperature.
Since temperature is average kinetic energy, I don't get how kinetic energy can decrease when we increase the volume. ...
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1answer
397 views
Adiabatic closed system work
The closed system work PdV is path dependent but it is path independent for an adiabatic process as can be shown by applying conservation of energy on a closed system (dQ = dE + PdV),here dE is change ...
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3answers
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Adiabatic Process: Fast or Slow? [duplicate]
I have always used adiabatic process to be fast, so that the system doesn't get enough time to exchange energy in the form of heat. But as I was reviewing adiabatic process from the Resnick, Halliday, ...
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Name of this type of cooling system?
If you pump around air in a cyclic tube at a high speed, and one part of the tube is narrower than the rest of the tube, the air flow will have to increase in speed when it enters the narrow part in ...
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3answers
350 views
Thermal expansion of solid body and calculation of work produced
From the information about thermal expansion on Wikipedia, I found that if I heat a steel rod that's 1-meter in length and 1-cm in diameter steel rod to 100 degrees Celsius, then it will expand by ...
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2answers
960 views
Internal energy of a reversible adiabatic process
what happens to the heat transfer and the internal energy in a system that undergoes reversible adiabatic process back to its original state. Bearing in mind that heat $Q$ was transferred at the ...
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2answers
352 views
Internal Energy Change for a free adiabatic expansion
I was watching a video from mitocw in which the professor wrote that:
dU = dw(reversible)
If we consider a free expansion, then the work done must be 0.
The process is also adiabatic implying that ...
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1answer
196 views
Thermodynamics adiabatic transformation
I have the following question as howework, I think I don't have enough information to solve it.
Given are $p_1=311$ kN/m$^2$, $T_1=333$ K, $T_2=853$ K.
Asked are $p_2$, ratio $V_1/V_2$, and $R$ if ...
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1answer
172 views
Rigorous Laughlin pumping argument
Is there a way to justify formally the Laughlin pumping argument? It is often argued that the spectral flow of Landau levels while varying the flux inserted through the Corbino ring should account for ...
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1answer
79 views
Maximum velocity of piston pushed by a gas on adiabatic irreversible expansion [closed]
I am currently studying for my country's IPhO selection process and thermodynamics has to be one of my favorites right now. However I came across a very odd problem that is making me revise a lot of ...
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2answers
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Can the ideal gas expand adiabatically and irreversely?
Suppose that the ideal gas is expanding adiabatically from the state $(P_1, V_1, T_1)$ to the state $(P_2, V_2, T_2)$
I think this process can be allowed to happen reversibly or irreversibly, but ...
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1answer
405 views
Entropy change in a reversible adiabatic expansion of ideal gas
Below is P-V curves of 1 mole of ideal gase for temperature 700K, 500K and 300K each.
Now I would like to calculate entropy change of the system along the path from (1) to (3), which is adiabatic ...
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1answer
74 views
Adiabatic processes
Adiabatic process is a process that involves no interactions other than work.
What I interpret from this is that change in energy = change in work done.
however it is not the case but it’s the ...
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1answer
46 views
magnetic refrigeration and adiabatic processes
Suppose we have a magnetic material that is well insulated from its environment, and we then ramp up the current in a helmholtz coil that encloses the magnet. We then observe an increase in the magnet'...
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2answers
868 views
Adiabatic reversible and irreversible process
If I have 2 gases $A$ and $B$ which are at an initial state ($P_1$,$V_1$,$T_1$) and one gas say $A$ is taken through a reversible adiabatic process and the other gas $B$ through an irreversible ...
