The first rigorous definition of the second law based on the concept of entropy came from German scientist Rudolph Clausius in the 1850s including his statement that heat can never pass from a colder to a warmer body without some other change, connected therewith, occurring at the same time. Its first formulation, which preceded the proper definition of entropy and was based on caloric theory, is Carnot's theorem, credited to the French scientist Sadi Carnot, who in 1824 showed that the efficiency of conversion of heat to work in a heat engine has an upper limit. The second law has been expressed in many ways. Statistical mechanics provides a microscopic explanation of the law in terms of probability distributions of the states of large assemblies of atoms or molecules. Historically, the second law was an empirical finding that was accepted as an axiom of thermodynamic theory.

The second law of thermodynamics is one of the most famous physics laws we have, and it states that the total entropy of an isolated system. If all processes in the system are reversible, the entropy is constant.Р”Р„n increase in entropy accounts for the irreversibility of natural processes, often referred to in the concept of the arrow of time. Submitted by Julius Juego on Febru5:44am. The second law may be formulated by the observation that the entropy of isolated systems left to spontaneous evolution cannot decrease, as they always arrive at a state of thermodynamic equilibrium, where the entropy is highest. Entropy predicts the direction of spontaneous processes, and determines whether they are irreversible or impossible, despite obeying the requirement of conservation of energy, which is established in the first law of thermodynamics. delta S delta Q / T For a given physical process, the combined entropy of the system and the environment remains a constant if the process can be reversed. The change in entropy delta S is equal to the heat transfer delta Q divided by the temperature T.

The second law of thermodynamics establishes the concept of entropy as a physical property of a thermodynamic system. The second law states that there exists a useful state variable called entropy S.

State the second law of thermodynamics