【Daily Question】Theoretical Foundation 2020.05.15
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Multiple-choice question: On a V–T diagram, an ideal gas undergoes the state change process as shown. Then, the internal energy of the ideal gas before and after this process ( ) A. decreases, as the ideal gas does positive work on the surroundings during the process B. decreases, as the ideal gas does negative work on the surroundings during the process C. increases, as the ideal gas does positive work on the surroundings during the process D. increases, as the ideal gas does negative work on the surroundings during the process Answer: A Hint: Extra rewards will be given to those who can explain the solution process; the answer can be found in the response!
A. The internal energy of an ideal gas is proportional to temperature; as the temperature decreases from a to b, the internal energy decreases. The volume increases, doing positive work on the outside.