Selected MCQ

Current Question
Which thermodynamic law introduces entropy?
  • A. First law
  • B. Second law
  • C. Third law
  • D. Zeroth law
Correct Answer: B
Explanation:
Second law defines entropy and direction of processes.
Related Question 1
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 2
Which law defines entropy change in irreversible processes?
  • A. First law
  • B. Second law
  • C. Third law
  • D. Zeroth law
Correct Answer: B
Explanation:
Entropy increases in irreversible processes.
Related Question 3
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 4
Which process increases entropy most?
  • A. Freezing water
  • B. Mixing gases
  • C. Crystallization
  • D. Condensation
Correct Answer: B
Explanation:
Mixing increases randomness.
Related Question 5
The entropy at absolute zero for perfect crystal is:
  • A. Maximum
  • B. Infinite
  • C. Zero
  • D. Undefined
Correct Answer: C
Explanation:
Third law states entropy approaches zero.