321. In an ideal refrigeration cycle, the change in internal energy of the fluid is
A. +ve
B. -ve
C. 0
D. Either of the above three ; depends on the nature of refrigerant
✅ The correct answer is option C.
Thermodynamics MCQs
322. Thermal efficiency of a Carnot engine can approach 100%, only when the temperature of the
A. Cold reservoir approaches zero
B. Hot reservoir approaches infinity
C. Either A or B
D. Neither A nor B
✅ The correct answer is option C.
323. __________ explains the equilibrium constant for any chemical reaction.
A. Henry’s law
B. Law of mass action
C. Hess’s law
D. None of these
✅ The correct answer is option B.
324. The unity of Planck’s constant ‘h’ in the equation, E = hv is
A. J/s
B. J.S
C. J/kmol
D. Kmol/J
✅ The correct answer is option B.
325. Which of the following is an extensive property of a system?
A. Heat capacity
B. Molal heat capacity
C. Pressure
D. Concentration
✅ The correct answer is option A.
326. High pressure steam is expanded adiabati-cally and reversibly through a well insulated turbine, which produces some shaft work. If the enthalpy change and entropy change across the turbine are represented by ΔH and ΔS respectively for this process:
A. Δ H = 0 and ΔS = 0
B. Δ H ≠ 0 and ΔS = 0
C. Δ H ≠ 0 and ΔS ≠ 0
D. Δ H = 0 and ΔS ≠ 0
✅ The correct answer is option B.
327. Which of the following units is not present in both the vapor compression refrigeration system and absorption refrigeration system ?
A. Expansion valve
B. Condenser
C. Refrigerator
D. Compressor
✅ The correct answer is option D.
328. The equation, Cp – Cv = R, is true for __________ gas.
A. No
B. Any real
C. Only ideal
D. Both B and C
✅ The correct answer is option C.
329. In an ideal solution, the activity of a component equals its
A. Mole fraction
B. Fugacity at the same temperature and pressure
C. Partial pressure
D. None of these
✅ The correct answer is option A.
330. Which of the following is not a common refrigerant?
A. Freon-12
B. Ethylene
C. Ammonia
D. Carbon dioxide
✅ The correct answer is option B.