Question

What is the principle of increase of entropy?

Answer 1

Entropy:

Entropy is defined as the property of the randomness or disorder in a system.

The principle of increase of entropy states that the entropy of the Universe also increases. It never decreases but remains constant only in a reversible process.

For an isolated system:

$$\mathrm{\Delta }S>0$$, for irreversible processes

$$\mathrm{\Delta }S=0$$, for reversible processes

$$\mathrm{\Delta }S<0$$, this is an impossible case

The entropy change of a system is given by the equation:

ΔS =$\frac{dQ}{T}$

Where, $$dQ$$ is the change of heat of the system and $$T$$ is the temperature of the system.

Therefore, the entropy of an isolated system either increases or in the limit, remains constant.