Thermodynamic principle: which law dictates the direction of heat transfer? Identify the correct fundamental law governing heat flow from high temperature to low temperature. Choose the correct option.
Mechanical Engineering
Heat Transfer, Refrigeration and Air Conditioning
Difficulty: Easy
Choose an option
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AZeroth law of thermodynamics
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BFirst law of thermodynamics
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CSecond law of thermodynamics
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DKirchhoff's law
Answer
Correct Answer: Second law of thermodynamics
Explanation
ConceptThe second law sets the direction of spontaneous processes: heat flows spontaneously from higher to lower temperature.
Why others are wrongZeroth law: defines thermal equilibrium/temperature.First law: energy conservation; no directionality.Kirchhoff's law: electrical circuits, not thermodynamic direction of heat flow.
Final AnswerSecond law of thermodynamics.