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Second Law of Thermodynamics

"The second law of thermodynamics states that the entropy of an isolated system never decreases due to the fact that isolated systems spontaneously evolve towards thermodynamic equilibrium"¹. Thermodynamic equilibrium is the state of maximum entropy. 

The second law of thermodynamics can be understood and explained using the underlying quantum statistical mechanics with the assumption of low-entropy initial conditions in the distance past. In statistical mechanics, entropy is the measure of the number of microscopic configurations corresponding to a macroscopic state.

The second law of thermodynamics has been expressed in many ways. The following at the most predominantly used.

Clausius Statement
Heat can never pass from a colder to a warmer body without some other change.

Kelvin Statement
It is impossible to cool matter in a system below the temperature of the coolest of the surround objects

Principle of Caratheodory
In every neighborhood of any state S of an adiabatically isolated system there are states inaccessible from S.

 

References 

1. Planck, Max. "Vom Relativen Zum Absoluten."Die Naturwissenschaften 13.3 (1925): 463-64. Print.

Categories within Second Law of Thermodynamics

Entropy

Postings: 20

Entropy is a measure of the number of specific ways in which a system may be arranged.

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