Top 250+ Solved Engineering Thermodynamics MCQ Questions Answer
Q. If the temperature of the source is increased, the efficiency of the Carnotengine
a. a) decrease
b. b) increase
c. c) does not change
d. d) will be equal to the efficiency of a practicalengine
Q. The efficiency of an ideal Carnot engine depends on
a. a) working substance
b. b) on the temperature of the source only
c. c) on the temperature of the sink only
d. d) on the temperatures of both the source & the sink
Q. In a reversible cycle, the entropy of thesystem
a. a) increases
b. b) decreases
c. c) does not change
d. d) first increases & thendecreases
Q. Kelvin-Plank's law deals with
a. a) conservation of energy
b. b) conservation of heat
c. c) conservation of mass
d. d) conversion of heat intowork
Q. Which of the following statements is correct according to Clausius statement of second law of thermodynamics?
a. a) it is impossible to transfer heat from a body at a lower temperature to a body at a higher temperature
b. b) it is impossible to transfer heat from a body at a lower temperature to a body at a higher temperature, without the aid of an external source
c. c) it is possible to transfer heat from a body at a lower temperature to a body at a higher temperature by using refrigeration cycle
d. d) none of the above
Q. The property of a working substance which increases or decreases as the heat is supplied or removed in a reversiblemanner is known as
a. a) enthalpy
b. b) internal energy
c. c) entropy
d. d) external energy
Q. The entropy may be expressed as afunction of
a. a) pressure & temperature
b. b) temperature & volume
c. c) heat & work
d. d) all of the above
Q. The change of entropy when heat isabsorbed by the gas is
a. a) positive
b. b) negative
c. c) positive or negative
d. d) all of the above
Q. Which of the following statements is correct?
a. a) the increase in entropy is obtained from a given quantity of heat at a low temperature
b. b) the change in entropy may be regarded as a measure of the rate of the availability of heat fortransformation into work
c. c) the entropy represents the maximum amount of work obtainable per degree drop in temperature
d. d) all of the above
Q. In an irreversible process, there is a
a. a) loss of heat
b. b) no loss of work
c. c) gain of heat
d. d) no gain of heat
Q. The efficiency of the Carnot cycle may beincreased by
a. a) increasing the highesttemperature
b. b) decreasing the highesttemperature
c. c) increasing the lowesttemperature
d. d) decreasing the lowesttemperature
Q. Which of the following is the correct statement?
a. a) all the reversible engines have the same efficiency
b. b) all the reversible & irreversible engines have the same efficiency
c. c) irreversible engines have maximum efficiency
d. d) all engines are designed as reversible in order to obtain maximum efficiency
Q. The reversible engines are
a. a) least efficient
b. b) most efficient
c. c) having same efficiency asirreversible engines
d. d) none of the above
Q. Gases could have an infinite number ofspecific heats but only ……. Specific heats are defined
a. a) one
b. b) two
c. c) three
d. d) four
Q. The area under the T-s (temperature - entropy) curve of any thermodynamicprocess represents
a. a) heat rejected only
b. b) heat absorbed only
c. c) work done during the process
d. d) heat absorbed or rejected