Top 250+ Solved Engineering Thermodynamics MCQ Questions Answer
Q. In a reversible process
a. a) heat transfer takes place over finite temperaturedifference
b. b) heat transfer takes place over infinitesimaltemperature difference
c. c) heat transfer takes place from surrounding to thesystem
d. d) heat transfer takes place from the system tothe surrounding
Q. Which of the following processes is very close to reversible
a. a) lifting of a body above the ground
b. b) compression of a gas in the cylinder against a piston
c. c) flow of a fluid in a pipe
d. d) motion of a boat in water
Q. A perfect gas having p1= 0.1 M/mm², v1=0.18 m³, T1=20°C is compressed to 1/10 of volume in an isothermal process.The change in entropy is
a. a) -141.45 j/k
b. b) 141.45 j/k
c. c) -41446.23 j/k
d. d) 0
Q. The enthalpy of a system
a. a) i= internal energy + pv
b. b) i= internal energy + pdv
c. c) i= internal energy + vdp
d. d) i= change in internalenergy + pv
Q. During a polytropic expansion workobtained is 1.8 times the heat transferred. If ?=1.4, n will be
a. a) 1.2
b. b) 1.19
c. c) 1.178
d. d) 1.155
Q. Which statement is wrong for throttlingexpansion
a. a) pressure drop = 0
b. b) change in enthalpy = 0
c. c) work done = 0
d. d) change in internalenergy = 0
Q. Which statement is wrong for adiabaticexpansion
a. a) h = 0
b. b) w = 0
c. c) ds = 0
d. d) w+e = 0
Q. Maximum amount of work that can be converted into heat in any process
a. a) depends upon initial & final temperature
b. b) depends upon how much work is lost in friction
c. c) is 50%
d. d) is 100%
Q. The universal gas constant will be equal to difference between specific heats at constant pressure & constant volume for
a. 1 kg mass of gas
b. 1 molecule of gas
c. 1 kg molecule of gas
d. any mass of gas
Q. Air is compressed isothermally by performing work equal to 16 KJ upon it.The change in internal energy is
a. a) - 16 kj
b. b) zeroth law of thermodynamics
c. c) 16 kj
d. d) 32 kj
Q. The latent heat ofvapouristation at critical point is
a. a) less than zero
b. b) greater than zero
c. c) equal to zero
d. d) none of the above
Q. Choose the correct answer
a. a) critical point involves equilibrium of solid & vapour phases
b. b) critical point involves equilibrium of solid & liquid phases
c. c) critical point involves equilibrium of solid, liquid & vapour phases
d. d) triple point involves equilibrium of solid, liquid & vapour phases
Q. Examine follwing two statements & choosethe correct relationshipi) for a steam power plant Rankine cycle is preferred over Carnot cycleii) a pump which will handle the mixture of vapour & liquid is difficult to construct
a. a) both i) ii) are correct & i) is the consequence of ii)
b. b) both i) & ii) are independently correct
c. c) i) is correct but ii) is not
d. d) ii) is correct but i) is not
Q. Considerfollowing options for a simple Rankine cyclei) increasing pressure at exist of turbine ii) increasing average temperature of heat additioniii) decreasing pressure at exit of turbine iv) superheating of steamv) decreasing pressure during superheating. Which combination of above will increase Rankine efficiency?
a. i), ii) & iv)
b. i), ii) & v)
c. iii), iv) & v)
d. ii), iii) & iv)
Q. Higher dryness fraction of steam at turbine exit in aRankine cycle
a. a) will increase cycle efficiency
b. b) will increase turbine work
c. c) will protect turbine blading
d. d) will reduce pump work