Podcast #128: We chat with Kent C Dodds about why he loves React and discuss what life was like in the dark days before Git. Listen now.

Thermodynamic processes that occur without exchanging heat between the system and its environment.

246 questions
Filter by
Sorted by
Tagged with
413 views

first time poster in this site. I am trying to create a small program to make a graph of the Carnot cycle. For isothermals I am simply trying to look for points where P*V would give the same ...
406 views

### Calculating heat absorbed from expanding gas [closed]

I'm trying to calculate the amount of heat absorbed per kg of different types of gas, namely compressed air and carbon dioxide. Starting with carbon dioxide, I found that the Joule-Thompson ...
1k views

### reversible vs irreversible work for adiabatic process

I have a gas transitioning adiabatically between A ($P_1$, $V_1$) and B ($P_2$, $V_2$) where $P_1>P_2$ and $V_2>V_1$. The question is to determine the net work done on the gas if the gas is ...
493 views

Adiabatic lapse rate is defined as $$\Gamma_a \equiv -\left(\frac{dT}{dz}\right)_{\rm parcel}=-\frac{R_{\rm a} T}{c_p \,p}\left(\frac{dp}{dz}\right)_{\rm parcel} = \frac{g}{c_p}$$ $R_a$ is gas ...
1k views

### Calculating mass flow rate, force of thrust produced compressed air discharge

This one's a bit of a doozy, so please feel free to comment on any one single part or parts to this physics problem. The setup is simple--I have a container (an empty bottle) which I fill with a ...
814 views

### Filling of a gas in a cylinder

The problem statement is as follows: An insulated rigid vessel of volume $V$ initially contains $N_i$ moles of an ideal gas at temperature $T_i$. A pipe is now connected to the vessel and the same ...
2k views

### Adiabatic expansion of ideal gas and dependence of temperature on volume

We know that for an ideal gas $$PV=nRT,$$ where $P$ is pressure, $V$ volume, $n$ amount of substance in moles, and $T$ the temperature of the gas. We can easily derive that, for a (non-free) ...
329 views

### How to calculate the entropy change in an adiabatic process? [closed]

A 2 cm long, 10 mm diameter and 1.5 kW electric heater is used to heat 30 kg water in an insulated container.The initial and final temperatures of the water are 25 C and 90 C respectively. Calculate ...
21k views

### What is polytropic index?

What is polytropic index? What is the connection between it and work of an adiabatic system? I tried surfing but didn't able to find a proper answer for that.
886 views

### Specific heat capacity for Adiabatic process

We can define infinite number of specific heat capacities between two temperatures(e.g $c_p ,c_v$) . Could we do that for an adiabatic process. As for adiabatic process heat addition or removal is ...
460 views

### Is there a proof that adiabatic processes only occur in thermally isolated systems?

This question arose when I read somewhere that adiabatic processes can only be done in thermally isolated systems and isothermal processes can only be done in thermally non-isolated system. Now, let'...
2k views

### Adiabatically stretching a rubber band

When a rubber band is stretched it heats up, but how can this be explained (from the microscopic view) in the case of an adiabatic expansion (meaning that the entropy remains constant). Further more ...
180 views

### Are stationary quantum states attractors?

While explaining the quantum adiabatic theorem recently, I appealed to a thermodynamic analogy: when slowly contracting the walls containing a classical gas, the relaxation timescale can be taken to ...
206 views

### Why doesn't entropy get decreased in adiabatic expansion process?

I was reading the second step of Carnot cycle in which the system undergoes adiabatic expansion doing work & thus decreasing the internal energy of itself. The entropy didn't change as no further ...
964 views

### Adiabatic invariant and Liouville's theorem

It appears that many people have tried to show adiabatic theorem from Liouville's theorem, e.g., Li's note, or at least tried to find some relations, e.g., Rugh, Adib and Tong's lecture notes Sec. 4.6....
500 views

I was studying some basic thermodynamics concepts and I noticed that in reversible processes in my book always the adiabatic word is used. So are all reversible processes adiabatic? (ques 1) Or are ...
181 views

### Ordering of eigenstates in the quantum adiabatic theorem

Suppose we have an 'initial' Hamiltonian $H_{i}$ whose eigenvalues are all non-degenerate, which we order as follows: $E^{0}_{i} < E^{1}_{i} < \dots < E^{N-2}_{i} < E^{N-1}_{i}$ Suppose ...
59 views

### Why the air is more compressed near to the ground

I'm studying the adiabatic effect of the air on the atmosphere but i can't understand why the compression near to the ground is higher, is something relate to the higher pressure caused by the earth ...
244 views

In some lecture notes on thermodynamics there is a discussion as to whether by assuming the first law of thermodynamics alone we can prove the existence of a adiabatic surface in three dimensions. To ...
266 views

I recently went through Griffiths' Quantum Mechanics text and there is a chapter called the Adiabatic Theorem that includes Berry phase and the Aharonov-Bohm effect. As I found them very ...
384 views

### Adiabatic cooling in a closed system

Please forgive me ahead of time if something I say isn't correct, I've just started to read about thermodynamics ever since I developed a fascination for the anti-griddle (by the way does anyone know ...
114 views

### Determining the final state of the gas in the tank

Suppose there is air of mass m1 in an insulated tank at temperature T1 and pressure P1. 0.25m1 of air is released through a valve attached to the tank. Find the final temperature, T2 and pressure P2?...
532 views

### How can a reversible adiabatic expansion not increase entropy?

In the second stage of the Carnot cycle, a gas is thermally insulated and allowed to expand and do work on the piston. I understand the reason people give is that because entropy is $\,dS = \,dQ/T$ ...
1k views

### Show that change in internal energy equals zero for an adiabatic process with incompressible fluid

I have a problem when solving an exercise in thermodynamics. I am supposed to show that when we have an open system, where the process is adiabatic with an incompressible fluid, it follows that the ...
2k views

### Bernoulli Equation for isentropic ideal gas flow

If one derives the Bernoulli Equation for the isentropic ideal gas flow you get: $$\frac{1}{2}v^2 + g z + \left(\frac{\kappa}{\kappa -1} \right) \frac{p}{\rho} = const.$$ Two questions: Is ...
216 views

135 views

### What are the state variables like temperature after the system has done an adiabatic irreversible process? [closed]

Consider a system containing ideal gas which is initially at a volume $V_{1}$ and then suddenly its volume is increased to a volume $V_{2}$. What is the final temperature of the system if the initial ...
664 views

### Thermodynamics of expanding nitrogen bubble as it rises in water

Problem An air bubble is released from a nitrogen tank 20 meters under water. The bubble has a radius of 1 mm. What will be the radius of the bubble when it reaches the surface? My Questions Is it ...
221 views

### What is the criterion for a change to be adiabatic?

I'm trying to understand whether the change of a parameter $\lambda$ of a Hamiltonian $H$ is adiabatic. Reading Landau and Lifshitz "Mechanics", I see ... let us suppose that $\lambda$ varies ...
5k views

### Are sound waves adiabatic or isothermal?

I am doing a presentation on sound waves and I need to know if they are adiabatic or isothermal. I know that they can generate heat, but is the amount of heat created so small that it can still be ...
2k views

### Is there a single Poisson constant for mixtures of gases?

Let's say air consists of 79% nitrogen and 21% diatomic gas. To perform calculations on $\Delta H$ on adiabatic expansions, instead of taking them as individual parts, can I take the air to be a ...
1k views

### Work done in adiabatic reversible process

I was solving a problem on turbine.the steam works on turbine adiabatic reversibly .Is change in enthalpy or is it change in internal energy which equal this work?
138 views

### scattering by weak potential and the adiabatic hypothesis

In Ryder QFT, regarding the calculation of the scattering amplitude by a weak potential $V$, the potential is assumed to be switched on and off slowly using the adiabatic hypothesis. But there is a ...
282 views

### Isentropic process and reversibility [duplicate]

I know that every adiabatic reversible process is an isentropic process. Can a process be isentropic but still not reversible adiabatic? Please provide me some examples.
57 views

### Does no variables change in an adiabatic + isothermal system?

Adiabatic + isothermal = no heat and temperature change. Does that mean the system will remain as it is? If it is adiabatic + isovolumetric or adiabatic + isobaric , is it as well no change in any ...
20k views

### What is the difference between reversible and irreversible adiabatic expansion?

What is the difference between reversible and irreversible adiabatic expansion? Is it true that the work done by the gas is the same but the pressure applied externally differ between two process? ...
12k views

### Comparison between isobaric, isothermal and adiabatic expansion

Please check if my understandings of these terms are right because they are a bit confusing to me. For all three types of expansions, a change in volume means work is done by the system to the ...
455 views

If an unsaturated air parcel ascends adiabatically in the atmosphere with an initial temperature, would the final temperature of the air parcel, when it reaches it's destination, be the same at the ...
4k views

The question is 2.10 taken from: Introductory Chemical Engineering Thermodynamics, 2E by Elliot,Lira Air at 30ºC and 2MPa flows ata steady state in a horizontal pipeline with a velocity of 25m/s. ...
229 views

### Eigenvalue of the adiabatic Hamiltonian of Farhi's three qubit 2-SAT problem

I was trying to reproduce example 3.3 of Quantum Computation by Adiabatic Evolution by Edward Farhi et. al. This is an adiabatic algorithm to solve an instance of three qubits 2-SAT problem. I think ...
72 views

### Is it possible to change one quantum state to another state by a cyclic adiabatic process?

An example is applying magnetic flux through the axis of a cylinder (2D system with periodic boundary condition). When changing flux from 0 to 1 flux quanta adiabatically, it seems that we can ...
7k views

### Does the entropy of an adiabatically isolated system stays the same after we decrease/increase the pressure?

Even if the system is isolated and there is no heat exchange with surroundings, shouldn't the decrease/increase of pressure result in increase/decrease of entropy? Does this property of an ...
118 views

### Different forms of the Adiabatic Theorem

I've been reading several papers on Adiabatic Quantum Computation, and I am confused by the form in which the adiabatic approximation condition is presented. For example (quant-ph/0001106 eq 2.8) \...
749 views

### How to understand the indeterminate process in thermodynamics?

Consider a closed composite system with an internal movable adiabatic wall. If we release the piston, thermodynamics cannot determine the final equilibrium state (the temperature cannot be determined)....
1k views

### Can we apply $pV^\gamma$=const only for quasistatic adiabatic process?

But If this is so, I have often seen people applying this formula for quick processes where no heat exchange is possible. Here is an example from where I am quoting the following: we will assume ...
781 views

### Schrodinger basis kets with Time-dependent Hamiltonian

I was reading through the proof of the Adiabatic Theorem (in Sakurai) and I realised I'm not quite sure how Schrodinger Basis kets behave when we have a time-dependent Hamiltonian. I know that with a ...
366 views

### Adiabatic expansion in the atmosphere

When an air parcel rises and cools adiabatically, it is said that there is no heat transfer as work is done on the surrounding atmosphere as the parcel expands. The parcel loses internal energy and ...
Suppose a paramagnetic solid is taken on the following cycle, where $B_1 > B_2$ (1)->(2)->(3) I'm trying to explain what happens to occupation numbers in magnetic levels. Step (1) As $B_1$ ...