The law of increasing entropy is the law of thermodynamics proposed by Clausius, who introduced the concept of entropy to describe this irreversible process, that is, heat flow from a hot body to a cold body is irreversible, and its physical expression is: S =∫dQ/T or ds = dQ/T.
Law content:
Clausius introduced the concept of entropy to describe this irreversible process.
In thermodynamics, entropy is the state variable of a system, and its physical expression is:
S =∫dQ/T or ds = dQ/T
Where S stands for entropy, Q for heat, and T for temperature.
The physical meaning of this expression is: the entropy of a system is equal to the heat absorbed (or dissipated) by the system in a given process divided by its absolute temperature. It can be shown that the entropy of the system increases whenever heat flows from a hot body to a cold body:
S = ∫ dQ1 / T1 + ∫ dQ2 / T2
Suppose dQ1 is the heat increment of a hot body and T1 is its absolute temperature.
dQ2 is the change in heat of a cold object, T2 is its absolute temperature,
Then: dQ1 = -dQ2, T1> T2
So on type inference is: S = | Q2 / T2 | - | Q1 / T1 | & gt; 0
This increase in entropy is a spontaneous irreversible process, and the total entropy change is always greater than zero.