Specific heats for an ideal gas: compare cp and cv State how the specific heat at constant pressure (cp) compares to the specific heat at constant volume (cv). Choose the correct comparison.
Mechanical Engineering
Thermodynamics
Difficulty: Easy
Choose an option
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Acp is greater than cv
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Bcp equals cv
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Ccp is less than cv
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DNo definite relation
Answer
Correct Answer: cp is greater than cv
Explanation
Concept/Approach
- At constant pressure, part of the heat goes into doing boundary work during expansion; hence more heat per kelvin is required.
- For an ideal gas: cp − cv = R and the ratio γ = cp/cv > 1.
Final Answercp is greater than cv.