Project ForgeThermodynamics
Entropy & Second Law
GATE 2010
Medium
One kilogram of water at room temperature is brought into contact with a high temperature thermal reservoir. The entropy change of the universe is
- Aequal to entropy change of the reservoir
- Bequal to entropy change of water
- Cequal to zero
- always positive
Explanation
Heat transfer across a finite temperature difference is inherently irreversible, so the total entropy of the universe (system + reservoir) must always increase — it cannot simply equal either individual entropy change or be zero.
Source: GATE ME 2010 (2010)
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