second law statements

Question

Which statement correctly expresses the Second Law of Thermodynamics?

RankGuru · Accepted Answer

1. **Clausius/Planck Statement**: Heat cannot spontaneously flow from a colder body to a hotter body.
2. **Entropy Interpretation**: The total entropy of an **isolated system** (or the universe as a whole) always increases over time for any spontaneous process.
3. **Mathematical form**: $\Delta S_{	ext{total}} \ge 0$.
4. **Directionality**: This law defines the 'arrow of time' and explains why natural processes are irreversible.
5. **Comparison**: Option 2 is the First Law. Option 3 is a misunderstanding of the Third Law.

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second law statements

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