A. T
B. T and P
C. T, P and Z
D. T and Z
✅ The correct answer is option B.
Thermodynamics MCQs
42. Gases are cooled in Joule-Thomson expansion, when it is __________ inversion temperature.
A. Below
B. At
C. Above
D. Either B or C
✅ The correct answer is option A.
43. In vapour compression refrigeration system, if the evaporator temperature and the condenser temperatures are -13°C and 37°C respetively, the Carnot COP will be
A. 5.2
B. 6.2
C. 0.168
D. Data insufficient, can’t be found out
✅ The correct answer is option A.
44. When dilute aqueous solutions of two salts are mixed, the process is associated with
A. Decrease in temperature
B. Increase in temperature
C. No change in temperature
D. Change in temperature which is a function of composition
✅ The correct answer is option B.
45. What is the degree of freedom for a system comprising liquid water equilibrium with its vapour?
A. 0
B. 1
C. 2
D. 3
✅ The correct answer is option B.
46. The absolute entropy for all crystalline substances at absolute zero temperature is
A. Zero
B. Negative
C. More than zero
D. Indeterminate
✅ The correct answer is option A.
47. First law of thermodynamics deals with the
A. Direction of energy transfer
B. Reversible processes only
C. Irreversible processes only
D. None of these
✅ The correct answer is option A.
48. Melting of ice is an example of an __________ process.
A. Adiabatic
B. Isothermal
C. Isometric
D. None of these
✅ The correct answer is option B.
49. Number of components (C), phase (P) and degrees of freedom (F) are related by Gibbs phase rule as
A. P + F – C = 2
B. C = P – F + 2
C. F = C – P – 2
D. P = F – C – 2
✅ The correct answer is option A.
50. Critical temperature is defined as the temperature above which a gas will
A. Not liquify (barring exceptions)
B. Immediately liquify
C. Never liquify however high the pressure may be
D. None of these
✅ The correct answer is option C.