Thermodynamics second law Definition and 14 Threads

For the first part, I got the answer pretty easily, it is a well known fact that the change in the entropy of the system does not matter about the process taken, so its the same for both reversible and irreversible processes, i.e nR ln(Vf/Vi). To derive this, I have assumed that the temperature...

Hi, as follow up to this thread I believe for any substance/thermodynamic system there exists actually a set of 3 state equations between the 5 variables ##(U,T,S,p,V)##. For example in the case of ideal gas which are the 3 equations ? Thanks.

Hi all, recently I started following the MIT course "Statistical Mechanics I: Statistical Mechanics Of Particles" by MIT (here). In the second lesson Prof. Kardar introduces the concept of thermodynamic temperature analyzing the behavior of two Carnot engines that share a thermal reservour at...

Einstein famously said “{Thermodynamics} is the only physical theory of universal content, which I am convinced, that within the framework of applicability of its basic concepts will never be overthrown.” I don't think any of us want to argue with Einstein, but it's worth noting the "within the...

Help! Hi, I need in the secodn law of thermodynamic, we have the ENTROPY "S". Well, I need help for this: We have dS ≈ dQ Then we have dS = λ *dQ where we have λ = λ (T, ... ) I have to demostrate that : λ = 1/T , where T = temperature. Thanks for the advices and help!

Recently read this article on Physorg: https://phys.org/news/2018-01-efficiency.html My questions are: 1. If "converting" information into energy requires a system (the demon I suppose) having a photodiode, processor, laser (light trap) all expending energy in order to cause the conversion...

Thermodynamics is stated in different ways. E.g. In isolated systems entropy never decreases Heat never spontaneously pass from colder to warmer body Total energy quality decreases in all processes. Energy disperses But what is it exactly? What is the correct description of the 2nd law of...

Ecosystems are open systems, they receive solar energy and other materials from outside the ecosystem and migration of animals is also witnessed. I read Physics uptil class XII and have done a bit of research on google books and have come across these three books: 1.Towards a Thermodynamic...

I guess there would be no flow in case 2; case 3 seems easy to me applying fluid mechanics principle; flow will be 1 to 2. But I doubt case 1; it is not in thermal equilibrium ? Pls help

Homework Statement In an ideal refrigeration cycle, the temperature of the condensing vapour is 40oC and the temperature during evaporation is -20oC. Determine the coefficient of performance of this cycle for the working fluids; R12 and ammonia. Homework Equations C.O.Pc = TL/(TH-TL) The...

Homework Statement A steam power plant consists of a boiler, a turbine, a condenser and a pump. The temperature of the inner walls of the boiler is 350oC and the temperature of the condenser cooling water is 20oC. During a certain interval of time, the heat added to the boiler is 2.9x106 kJ and...

I have a quick question concerning the 2nd law of thermodynamics. So my textbook uses an illustration to explain how the violation of the Clausius statement of the 2nd law implies a violation of the Kelvin-Plank. But while looking over the diagram I stated thinking about a certain situation. In...

I have a small confusion that can an irreversible engine have greater efficiency than reversible engine if both have different source and sink temperatures?I know that under same conditions reversible engines are more efficient but what can be concluded under different conditions like both...

Is Hydroelectric power plant a perpetual motion machine of second kind from this classification https://en.wikipedia.org/wiki/Perpetual_motion#Classification ? or not? If not which kind of perpetual motion machine is it? :)