Thermodynamics MCQs for MDCAT Practice

Physics section, Thermodynamics chapter. Sample questions from past PMC papers.

1. Question 1
   Substances A and B have the same freezing and boiling points. If solid samples of bothsubstances are heated in the exact same way, substance A boils before substance B.Which of the following would NOT explain this phenomenon?
   • A.Substance B has a higher specific heat.
   • B.Substance B has a higher heat of vaporization.
   • C.Substance B has a higher heat of fusion.
   • D.Substance B has a higher internal energy.
   Sign up free to see the explanation, distractor analysis, and add this to your spaced repetition deck.
2. Question 2
   The efficiency of a Carnot engine increases when:
   • A.The temperature of the cold reservoir increases
   • B.The temperature of the hot reservoir decreases
   • C.The temperature difference between reservoirs increases
   • D.The pressure of the gas increases
   Sign up free to see the explanation, distractor analysis, and add this to your spaced repetition deck.
3. Question 3
   Choose the correct statement?
   • A.Adiabat is steeper than isotherm
   • B.Isotherm is steeper than isochor
   • C.Isobar is steeper than isotherm
   • D.Adiabat is steeper than isochor
   Sign up free to see the explanation, distractor analysis, and add this to your spaced repetition deck.
4. Question 4
   The internal energy change of a gas in an isobaric process is given by:
   • A.nCvΔT
   • B.nCpΔT
   • C.PΔV
   • D.Zero
   Sign up free to see the explanation, distractor analysis, and add this to your spaced repetition deck.
5. Question 5
   In which of the following conditions, does the thermodynamic system DOES NOT perform any work?
   • A.Adiabatic condition
   • B.Isochoric condition
   • C.Isobaric condition
   • D.Isothermal condition
   Sign up free to see the explanation, distractor analysis, and add this to your spaced repetition deck.
6. Question 6
   A Cu rod and a steel rod maintain a constant difference in their lengths constant = 10 cm at all temperatures. If their coefficients of expansion are 1.6 × 10–5 K–1 and 1.2 × 10–5 K–1, then the length of the Cu rod is:
   • A.40 cm
   • B.30 cm
   • C.32 cm
   • D.24 cm
   Sign up free to see the explanation, distractor analysis, and add this to your spaced repetition deck.
7. Question 7
   During adiabatic compression work done is equal to 200 J. What will be the change in internal energy?
   • A.-200 J
   • B.+200 J
   • C.100 J
   • D.0 J
   Sign up free to see the explanation, distractor analysis, and add this to your spaced repetition deck.
8. Question 8
   A gas expands adiabatically, and its temperature decreases. The work done is:
   • A.Zero
   • B.Positive
   • C.Negative
   • D.Equal to heat supplied
   Sign up free to see the explanation, distractor analysis, and add this to your spaced repetition deck.