Top 250+ Solved Engineering Thermodynamics MCQ Questions Answer
Q. During a polytropic expansion 25% of heat is converted into work while temperature of gas rises by 30 K, the specific heat of gas at constant volume is
a. a) 10% w
b. b) 12 % w
c. c) 15% w
d. d) 20% w
Q. During a constant pressure expansion of a gas 33.3 % heat is converted into work while the temperature rises by 20K. The specific heat of gas at constant pressureis
a. a) 10% w
b. b) 12 % w
c. c) 15% w
d. d) 20% w
Q. During an adiabatic compression when temperature increase by 100% the pressure increases by 1000%. The ratio ofspecific heats, ? is
a. a) 1.3
b. b) 1.35
c. c) 1.4
d. d) 1.45
Q. In an constant pressure heating certain fraction of heat supplied is converted into work. If ?=1.4 this fraction is
a. a) 0.25
b. b) 0.286
c. c) 0.3
d. d) 0.327
Q. The area under the curve on temperature entropy diagram represents
a. a) work done during the process
b. b) heat exchanged during the process
c. c) change in internal energy during the process
d. d) change in entropy during the process
Q. The change in entropy is zero during
a. a) hyperbolic process
b. b) constant pressureprocess
c. c) adiabatic processes
d. d) polytropic process
Q. Choose incorrect statement
a. a) isentropic process is adiabatic
b. b) adiabatic process has no heat exchange
c. c) hyperbolic process is isothermal
d. d) no work is done in constant pressure process
Q. Choose the correct statement
a. a) there is no change of entropy in an adiabatic expansion
b. b) entropy is an extensive property of gas derived from first law of thermodynamics
c. c) the area under the curve in a temp.-entropy diagram gives the change of entropy
d. d) the change of entropy during a constant pressure process is always negative
Q. Entropy at absolute zero temperature iszero for a
a. a) perfect gas
b. b) perfect substance
c. c) perfect crystal
d. d) glass
Q. The third law of thermodynamics
a. a) defines entropy
b. b) provides a base from which entropy is measured
c. c) defines change of entropy
d. d) gives availability of heat for conversion into work
Q. Entropy is called the property of a system because
a. a) it has same value at any two equilibrium states
b. b) it depends upon the process path
c. c) it has a unique value at each equilibrium state
d. d) it does not change between two equilibriumstates
Q. Entropy of mixture of two gases aftersudden mixing is
a. a) greater than
b. b) less than its inputtemperature
c. c) same as sum of entropy ofindividual gases
d. d) unpredictable
Q. If a substance goes though a cycle of changes returning back to original state,the change in entropy is
a. a) positive
b. b) negative
c. c) zero
d. d) positive or negative depending upon originalstate
Q. A sequence of operations which a gas undergoes in such a way that final state issame as original state, mahe a
a. a) reversible cycle
b. b) irreversible cycle
c. c) thermal cycle
d. d) thermodynamic cycle