Selected MCQ

Current Question
Which thermodynamic potential is minimized at constant temperature and pressure?
  • A. Internal energy
  • B. Helmholtz free energy
  • C. Gibbs free energy
  • D. Enthalpy
Correct Answer: C
Explanation:
Gibbs free energy reaches minimum at equilibrium under constant T and P.
Related Question 1
In thermodynamics, the Helmholtz free energy is minimized at constant:
  • A. Pressure and temperature
  • B. Volume and temperature
  • C. Volume and entropy
  • D. Pressure and entropy
Correct Answer: B
Explanation:
Helmholtz free energy applies to constant T and V systems.
Related Question 2
Which thermodynamic quantity remains constant in adiabatic process?
  • A. Temperature
  • B. Pressure
  • C. Entropy (reversible case)
  • D. Volume
Correct Answer: C
Explanation:
Reversible adiabatic process is isentropic.
Related Question 3
Which gas deviates most from ideal behavior at high pressure and low temperature?
  • A. One with negligible intermolecular attraction and molecular volume
  • B. One with significant intermolecular attractions and finite molecular volume
  • C. A hypothetical point-particle gas
  • D. Any gas behaves ideally under all conditions
Correct Answer: B
Explanation:
Real-gas deviations become strong when attractions and excluded volume matter.
Related Question 4
Which instrument measures air pressure?
  • A. Hygrometer
  • B. Barometer
  • C. Thermometer
  • D. Anemometer
Correct Answer: B
Explanation:
Barometer measures pressure.
Related Question 5
Which atmospheric layer has lowest temperature?
  • A. Troposphere
  • B. Stratosphere
  • C. Mesosphere
  • D. Thermosphere
Correct Answer: C
Explanation:
Mesosphere is coldest.