Top 350+ Solved Thermodynamics MCQ Questions Answer
Q. In a reversible polytropic process
a. The entropy remains constant
b. Enthalpy remains constant
c. Internal energy remains constant
d. Some heat transfer occurs
e. Temperature remains constant
Q. Entropy of the universe tends to
a. Approximately zero
b. A minimum
c. A maximum
d. No particular value as it remains constant
e. Zero
Q. Isothermals are curves obtained by drawing
a. P against T
b. P against V
c. V against T
d. PV against T
e. PV against V
Q. In an isothermal expansion of gases
a. Temperature is lowered
b. Temperature shows the extent of expansion
c. Temperature becomes zero
d. Temperature is unaltered
e. Temperature is raised
Q. A machine that continuously creates its own energy is known as
a. Perpetual motion machine of second kind
b. Self-propelled machine
c. 100% efficient machine
d. Perpetual motion machine of first kind
e. Reversible machine
Q. When a direct current is passed through a junction of two dissimilar metals, the junction becomes either cold or hot. The phenomenon is known as
a. Faraday's law
b. Peltier's effect
c. Thompson effect
d. Maxwell's effect
e. Seeback's effect
Q. Brayton cycle cannot be used in reciprocating engines even for same adiabatic compression ratio and work output because
a. Brayton cycle is for slow speed engines
b. Brayton cycle is less efficient
c. Brayton cycle requires large air-fuel ratio
d. Otto cycle is more efficient
e. Large volume of low pressure air cannot be efficiently handled in reciprocating engines
Q. Which of the following relations is not valid during throttling process?
a. External work done = Zero
b. Total heat = Constant
c. Pressure drop = Zero
d. Change in enthalpy = Zero
e. Change in internal energy = Zero
Q. Two ideal engines A and B have their sources at 600 k and 400 k and their sinks at 300 k and 250 k respectively. What inference can be drawn about their efficiency
a. A is more efficient than B
b. A is less efficient than B
c. The information given is incomplete
d. Both are equally efficient
e. Pulsejet
Q. A law which is applicable only to ideal vapours and liquids, that equates the equilibrium partial pressures of a solution component in the coexisting phases, is known as
a. Maxwell's equation
b. Roult's law
c. Henry's law
d. Fick's law
e. Joule's law
Q. A barn is
a. A unit of area
b. A unit of length
c. A unit of time
d. A unit of mass
e. None of the above
Q. Highly polished surfaces of a thermosflask prevent heat by
b. Convection
c. Radiation
d. Conduction
e. microns
Q. As we go up in air the temperature of air decreases because
a. Pulsejet
b. winds help in heat transfer by convection
c. of low pressure of air
d. oxygen content of air decreases sharply
e. heating effect due to infra red radiations from the surface of the earth is reduced