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The statement that heat cannot spontaneously pass from a colder body to a hotter body is a direct expression of which principle?

1. Second law of thermodynamics
2. Conservation of momentum
3. Conservation of mass
4. First law of thermodynamics

Correct answer: Second law of thermodynamics

Solution

The second law of thermodynamics states that heat naturally flows from hot to cold, and it cannot spontaneously flow in the opposite direction without external work being done, highlighting the directionality of energy transfer.

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