Correct Answer - Option 3 : increasing
Explanation:
The universe is formed by the system and surrounding and considered an isolated system.
\(d{S_{univ}} \ge 0\) or \(d{S_{sys}} + d{S_{surr}} \ge 0\)
- The energy of the universe is constant. (First law of Thermodynamics)
- The entropy of the universe tends towards a maximum. (Second law of Thermodynamics)
- The entropy increase of an isolated system is a measure of the extent of the irreversibility of the process undergone by the system.
- In actual practice the reversible isentropic process never really occurs, it is only an ideal process. In actual practice whenever there is a change in the state of the system the entropy of the system increases. The entropy of the universe increases because energy never flows uphill spontaneously.
- If in any process, if the entropy of the universe decreases, then the process will be an impossible process, so for any process which exists the entropy of the universe is always increasing.
