Question

The second law of thermodynamics states that:

• A. Energy is always conserved
• B. Heat can be completely converted into work
• C. Entropy of an isolated system always increases
• D. Pressure is proportional to temperature

Hint:

Logic Tip: The First Law says you can't get something for nothing (Energy is conserved). The Second Law says you can't even break even (Entropy/disorder always increases in the universe).

Answer 1

The Correct Option is C

Concept:
The Second Law of Thermodynamics governs the directionality of processes and the concept of irreversibility, introducing the property of entropy ($S$).

Step 1: This describes the First Law of Thermodynamics, not the Second.

Step 2: The Kelvin-Planck statement of the Second Law explicitly declares it is impossible to construct an engine that completely converts all absorbed heat into work; some waste heat must always be rejected.

Step 3: This relationship relates to ideal gas laws (Gay-Lussac's law), not the fundamental laws of macroscopic thermodynamics.

Step 4: The principle of increase of entropy states that for any spontaneous, real-world process occurring in an isolated system, the total entropy (disorder) must always increase.