Answer to Question #73114 in Physics for Adnan rafi

Question

Why the entropy of the universe is always iincrease?

Answer 1

The entropy of the isolated system is the measure of the irreversibility undergone by the system. More is the irreversibility more increase is the entropy of the system. As such the reversible process is an ideal process and it never really occurs. This means the certain amount of the irreversibility is always there in the system, this also means that the entropy of the isolated system always goes on increasing, it never reduces. Here let us keep in mind that isolated system can always be formed by including any system and surroundings within a single boundary.
Summarizing the first and second law of thermodynamics, Clausius made two statements:
1) The energy of the world (universe) is constant.
2) The entropy of the world tends towards a maximum.
Thus the entropy of the isolated system tends to go on increasing and reaches maximum value at the state of equilibrium. When the system reaches equilibrium the increase in entropy becomes zero.