RRB JE MIXED QUESTIONS
1. Which of the following laws states that the volume of a gas is inversely proportional to the pressure of a gas?
1. Boyle’s law
2. Gay – Lussac’s law
3. Charles law
4. Avogadro’s law
Answer: A
2. In a polytropic process , if the value of n = 1 , the process
(a) An isothermal process
(b) An irreversible process
(c) An adiabatic process
(d) A reversible process
Answer: A
3. The internal energy of a perfect gas does not change during the
(a) Isobaric process
(b) Isochoric process
(c) Adiabatic process
(d) Isothermal process
Answer: D
4. Which of the following is an extensive property?
(a) Pressure
(b) Heat capacity
(c) Temperature
(d) Specific volume
Answer: B
5. Kelvin Planck’s law deals with
(a) Conversion of work
(b) Conversion of heat
(c) Conversation of heat into work
(d) Conservation of work into heat
Answer: C
6. A system and its environment put together constitute
(a) An adiabatic system
(b) An isolated system
(c) A segregated system
(d) A homogeneous system
Answer: B
7. Slope of constant volume line on temperature entropy diagram is given by
(a) Cp/T
(b) T/Cp
(c) Cv/T
(d) T/Cv
ย Answer: D
8. Zeroth law of thermodynamics forms the basis of measurement ofย
(a) Pressure
(b) Temperature
(c) Heat exchange
(d) Work
Answer: B
9. Internal energy is defined by
(a) Zeroth law of thermodynamics
(b) First law of thermodynamics
(c) Second law of thermodynamics
(d) Law of entropy
Answer: B
10. Control volume refers to
(a) A fixed region in space
(b) A specified mass
(c) An isolated system
(d) A reversible process only
Answer: A
11. All of the following are intensive properties except
(a) Mass
(b) Density
(c) Pressure
(d) Temperature
Answer: A
12. Kinematic viscosity of gases on increase of temperature
(a) Decrease
(b) Increases
(c) Remains the same
(d) First decreases then increases
Answer: B
13. First law of thermodynamics deals withย
(a) Conservation of heat
(b) Conservation of momentum
(c) Conservation of mass
(d) Conservation of energy
Answer: D
14. An isothermal process is governed by
(a) Boyle’s law
(b) Charle’s law
(c) Gay – lussac’a law
(d) Avogadro’s law
Answer: A
15. Heat is closely related with
(a) Energy
(b) Temperature
(c) Entropy
(d) Enthalpy
Answer: B
16. An engine operates between temperature limits of 900 K and T2 and another between T2 and 400K . For both the engines to be equally efficient . T2 should be equal toย
(a) 600 K
(b) 650 K
(c) 625 K
(d) 700 K
Answer: A
17. Work done in a free expansion process is
(a) Zeroย
(b) Positive
(c) Negative
(d) Maximum
Answer: A
18. The internal energy of an ideal gas is
(a) A function of temperature only
(b) A function of pressure
(c) A function of volume
(d) Both pressure and volume
Answer: A
19. The process in which no heat enters or leaves the system is called
(a) Isobaric
(b) Isothermal
(c) Isentropic
(d) Isochoric
Answer: C
20. Economiser used in power plants is used to heat
(a) Flue gases
(b) Intake air
(c) Steam
(d) Feed water
Answer: D
21. Which one of the following expression is true for Tds equation .
(a) dU – PdV
(b) dU + PdV
(c) dU – VdP
(d) dU + VdP
Answer: B
22. PMMI is closely related with
(a) First law of thermodynamics
(b) Second law of thermodynamics
(c) Third law of thermodynamics
(d) Zeroth law of thermodynamics
Answer: A
23. Isolated system indicates
(a) Mass of substance cross the boundary
(b) Energy of substance cross the boundary
(c) Both mass and energy of substance cross the boundary
(d) Both mass and energy substance does not cross the boundary
Answer: D
24. Air preheater is a part of
(a) Thermal power plant
(b) Wind power plant
(c) Nuclear power plant
(d) Hydro power plant
Answer: A
25. For an ideal gas the value of Joule Thomson coefficient is
(a) Zero
(b) 0.5
(c) Unity
(d) Infinity
Answer: A
26. Perpetual motion machine of second kind violates the
(a) First law of thermodynamics
(b) Kelvin – plank statement
(c) Clausius statement
(d) Third law of thermodynamics
Answer: B
27. The cyclic integral of (ยงQ – ยงW) for a process is
(a) Positiveย
(b) Negative
(c) Zero
(d) Unpredictable
Answer: C
28. Triple point temperature of water is
(a) 273 K
(b) 273.14 K
(c) 273.15 K
(d) 273.16 K
Answer: D
29. Which of the following law of thermodynamics is responsible for heat transferย
(a) Zeroth law of thermodynamics
(b) First law of thermodynamics
(c) Second law of thermodynamics
(d) Third law of thermodynamics
Answer: C
30. Which one of the following thermodynamics process approximates the steaming of food in a pressure cooker?
(a) Isenthalpic
(b) Isobaric
(c) Isochoric
(d) Isothermal
Answer: C
31. Ice kept in a well insulated thermo flask is an example of which system?
(a) Closed system
(b) Isolated system
(c) Open system
(d)ย Non – flow adiabatic system
Answer: B
32. In which of the following processes , the heat is fully converted into work?
(a) Reversible adiabatic process
(b) Reversible isobaric process
(c) Reversible isometric process
(d) Reversible isothermal process
Answer: D
33. Which one of the following represents open thermodynamics system?
(a) Manual ice cream freezer
(b) Centrifugal pump
(c) Pressure cooker
(d) Bomb calorimeter
Answer: B
34. An adiabatic wall is one which
(a) Prevents thermal interaction
(b) Permits thermal interaction
(c) Encourage thermal interaction
(d) Discourage thermal interaction
Answer: B
35. An ideal gas at 27ยฐC is heated at constant pressure till the volume becomes three times . The temperature of the gas will then be
(a) 81ยฐC
(b) 900ยฐC
(c) 627ยฐC
(d) 927ยฐC
Answer: C
36. Increase in entropy of a system represents
(a) Increase in availability of energy
(b) Increase in temperature
(c) Decrease in pressure
(d) Degradation of energy
Answer: D
37. A closed system receives 60 kJ heat but its internal energy decreases by 30kJ . Then the work done by the system is
(a) 90 kJ
(b) 30 kJ
(c) -30 kJ
(d) -90 kJ
Answer: A
38. At critical point , the enthalpy of vapourization is
(a) Depend on temperature only
(b) Maximum
(c) Minimum
(d) Zero
Answer: D
39. Which thermodynamics law predicts correctly , the degree of completion of chemical reaction?
(a) Zeroth law
(b) First law
(c) Second law
(d) Third law
Answer: C
40. Zeroth law of thermodynamics is the basis of
(a) Pressure measurement
(b) Temperature measurement
(c) Density measurement
(d) Viscosity measurement
Answer: B
41. A process in which no heat crosses the boundary of the system is called
(a) Ideal process
(b) Adiabatic process
(c) Isothermal process
(d) Isobaric process
Answer: B
42. The enthalpy of a substance is defined as
(a) h = pv + RT
(b) h = u + pT
(c) h = u + pv
(d) h = u . pv
Answer: C
43. Cyclic integral of any property isย
(a) Zero
(b) One
(c) Infinite
(d) Two
Answer: A
44. The machine which voilates the first law of thermodynamics is known as
(a) PMM-I
(b) PMM-II
(c) PMM-III
(d) Heat engine
Answer: A
45. The device in which the work is done by the fluid at the expense of its enthalpy is known as
(a) Compressor
(b) Throttling device
(c) Turbine
(d) Heat exchange
Answer: C
46. A device which increases the velocity of a fluid at the expense of its pressure drop is known as
(a) Diffuser
(b) Nozzle
(c) Throttling device
(d) Heat transfer
Answer: B
47. A fluid flow in which the density of the fluid does not change during flowing is called as
(a) Incompressible
(b) Uniform
(c) Compressible
(d) Non – Linear
Answer: A
48. A large body of infinite heat capacity is known as
(a) Thermal Energy Reservoir (TER)
(b) Mechanical Energy Reservoir (MER)
(c) Thermodynamics
(d) Heat pump
Answer: A
49. “Heat transfer flows from a body at a higher temperature to a body at a lower temperature” is the statement of
(a) First law of thermodynamics
(b) Second law of thermodynamics
(c) Third law of thermodynamics
(d) Zeroth law of thermodynamics
Answer: B
50. The network output for any heat engine is given by
(a) QL – QH
(b) QL + QH
(c) QH – QL
(d) 2QL
Answer: C
51. A cyclic device which produces work continuously at the expense of heat input is known as
(a) Refrigerator
(b) Heat pump
(c) Heat engine
(d) Throttling
Answer: C
52. The efficiency of perpetual motion machine-II (PMM-II) is
(a) 0%
(b) 50%
(c) 75%
(d) 100%
Answer: D
53. A thermal energy reservoir that supplies the heat is known as
(a) Refrigerator
(b) Source
(c) Sink
(d) Heat engine
Answer: B
54. Thermal efficiency of heat energy may be defined as
(a) 1 – (Q2 / Q1)
(b) 1 – (Q1 / Q2)
(c) (Q1 – Q2)
(d) (Q2 / Q1) – 1
Answer: A
55. “Theoretical limits” for the performance of commonly used engineering systems is determined by
(a) Zeroth law of thrmodynamics
(b) First law of thermodynamics
(c) Second law of thermodynamics
(d) Third law of thermodynamics
Answer: C
56. When two bodies are in thermal equilibrium with a third body they are also in thermal equilibrium with each other . This statement is called
(a) Zeroth law of thermodynamics
(b) First law of thermodynamics
(c) Second law of thermodynamics
(d) Kelvin’s Plank’s law
Answer: A
57. Which of the following are intensive properties?
1. Kinetic energy
2. Specific Enthalpy
3. Pressure
4. Entropy
Select the correct answer using the code given below .
(a) 1 and 3
(b) 2 and 3
(c) 1 , 3 and 4
(d) 2 and 4
Answer: B
58. A real gas having positive Joule Thomson coefficient , when throttled will
(a) Become warmer
(b) Become cooler
(c) Remains at same temperature
(d) Either be warmer or cooler depending upon composition of gas
Answer: B
59. An isolated system
(a) Is a specified region where transfer of energy and or mass takes place .
(b) Is a region of constant mass and only energy is allowed to cross the boundaries .
(c) Cannot transfer either energy or mass to or from the surroundings
(d) Is one in which mass within the system is not necessarily constant .
Answer: C
60. If a heat source at temperature T1 transfers heat to a system at temperature T2(T1 > T2) ; then which of the following statements is not true?
(a) ฮSsystem DECREASES
(b) ฮSsource DECREASES
(c) (ฮSsystem + ฮSsource)
(d) ฮ(Ssystem + ฮSsource)
Answer: D
61. Enthalpy of formation is defined as enthalpy of compounds at
(a) 25ยฐC and 10 atmosphere
(b) 25ยฐC and 1 atmosphere
(c) 0ยฐC and 1 atmosphere
(d) 100ยฐC and 1 atmosphere
Answer: B
62. In a Carnot engine , when the working substance gives heat to the sink
(a) The temperature of the sink increases
(b) The temperature of the sink remains the same
(c) The temperature of the source decreases
(d) The temperatures of both the sink and the source decrease
Answer: B
63. Availability function is expressed as
(a) ฮฆ = (u + Po V – To s)
(b) ฮฆ = (u + Po dv + To ds)
(c) ฮฆ = (du + Po dv – To ds)
(d) ฮฆ = (u + Po v + To s)
Answer: A
64. Which one of the following statements is correct?
(a) The slope of vaporisation curve is always negative
(b) The slope of vaporisation curve is always positive
(c) The slope of sublimation curve is negative for all
(d) The slope of fusion curve is positive for all pure substances .
Answer: B
65. If a process can be stopped at any stage and reversed so that the system and surroundings are exactly restored to their initial states , it is know as :
(a) Adiabatic process
(b) Isothermal process
(c) Ideal process
(d) Frictionless process
Answer: C
66. The work ratio of closed cycle gas turbine plant depends upon :
(a) Pressure ratio of the cycle and specific heat ratioย
(b) Temperature ratio of the cycle and specific heat
(c) Pressure ratio , temperature ration and specific heat ratio
(d) Only on pressure ratio
Answer: C
67. The area under the T-s diagram curve at any thermodynamics process represents
(a) Heat rejected only
(b) Heat absorbedย
(c) Work done during the process
(d) Heat absorbed and rejectedย
Answer: D
68. Which one of the following is correct?
The cyclic integral of (๐ฟQ – ๐ฟW) for a process is:
(a) Positive
(b) Negative
(c) Zero
(d) Unpredictable
Answer: C
69. The fundamental unit of enthalpy is
(a) MLTยฒ
(b) MLยฒTยน
(c) MLยฒTยฒ
(d) MLยณTยฒ
Answer: C
70. For a simple closed system of constant composition , the difference between the heat and work interactions is identifiable as change in
(a) Enthalpy
(b) Entropy
(c) Flow energy
(d) Internal energy
Answer: D
71. This process is one in which there is only work interaction between the system and the surroundings
(a) Diabatic process
(b) Adiabatic process
(c) Isothermal process
(d) Quasi-static process
Answer: B
72. Isentropic flow is
(a) Irreversible adiabatic flow
(b) Reversible adiabatic flow
(c) Ideal fluid flow
(d) Frictionless reversible flow
Answer: B
73. In a thermodynamics system , a process in which volume remains constant is called _____ process .
(a) Isobaric
(b) Isometric
(c) Adiabatic
(d) Isentropic
Answer: B
74. In a thermodynamic system , thermal equilibrium is achieved when two bodies reach
(a) Same thermal energy
(b) Same entropy
(c) Same temperature
(d) Same molecular energy
Answer: C
75. Efficiency of Carnot cycle is :
(a) 1 – Q1/Q1 + Q3
(b) 1 – T1/T2
(c) 1 – T1/T1 + T2
(d) 1 – Q1/Q2
Answer: B
76. If a system in equilibrium is subjected to a change of concentration ; temperature or pressure , the equilibrium shifts in a direction that tends to undo the effect of the change imposed . This is known as
(a) Le Chatelier’s Principle
(b) Law of Mass Action
(c) Van der Walls Principle
(d) None of these
Answer: A
77. Zeroth law of thermodynamics state that
(a) Two thermodynamic systems are always in thermal equilibrium with each other
(b) If two systems are in thermal equilibrium , then the third system will also be in thermal equilibrium .
(c) Two systems not in thermal equilibrium with a third system will also not be in thermal equilibrium with each other .
(d)ย When two systems are in thermal equilibrium with a third system they are in thermal equilibrium with each other .
Answer: D
78. Which of the following does not sublimate?
(a) Ice
(b) Ammonium Chloride
(c) Naphthalene
(d) Camphor
Answer: A
79. The pressure exerted on the walls of a container by a gas is due to the fact that Gas molecules :
(a) Stick to the walls of the container
(b) Lose their kinetic energy
(c) Get accelerated towards the wall
(d) Change the momentum due to collision with the wall
Answer: D
80. Zeroth law of thermodynamics forms the basis of measurement
(a) Pressure
(b) Temperature
(c) Work
(d) Momentum
Answer: B
81. Boyle’s law states that :
(a) The pressure of a gas varies directly with temperature at constant volume i.e. P โ T
(b) The product of pressure and volume of a given mass of a gas is constant at constant temperature i.e. PV = constant
(c) The volume of a gas varies directly with temperature at constant pressure i.e.
(d) The pressure of a gas varies directly with volume at constant temperature i.e. PฮฑV
Answer: B
82. The entropy of universe tends to be:
(a) Minimum
(b) Zero
(c) Average
(d) Maximum
Answer: D
83. At what temperature , both Celcius and Fahrenheit scales will show the identical readings?
(a) 100ยฐ
(b) 0ยฐ
(c) -40ยฐ
(d) 40ยฐ
Answer: C
84. Which law of thermodynamics defines Entropy?
(a) Zeroth
(b) First
(c) Second
(d) Third
Answer: C
85. The value of โdQ/T for an irreversible process is :
(a) Less than zero
(b) Greater than zero
(c) Equal to zero
(d) Any one of these
Answer: A
86. The characteristic equation of Gases PV = nRT holds good for :
(a) Monoatomic Gases
(b) Diatomic Gases
(c) Ideal Gases
(d) Real Gases
Answer: C
87. For an Ideal Gas , the change in Enthaply (ฮH) for an elemental change in temperature (ฮT) is given by :
(where Cp = Heat capacity at Constant Pressure; Cv = Heat capacity at Constant Volume)
(a) CvฮT
(b) Cp/Cv. ฮT
(c) Cv/Cp. ฮT
(d) Cp. ฮT
Answer: D
88. A perfect gas at 27ยฐC is heated at constant pressure till its volume is double . The final temperature is :
(a) 54ยฐC
(b) 108ยฐC
(c) 327ยฐC
(d) 600ยฐC
Answer: C
89. A closed thermodynamic system is one in which
(a) There is no energy or mass transfer across the boundary .
(b) There is no mass transfer , but energy transfer exists .
(c) There is no energy transfer , but mass transfer exists .
(d) Both energy and mass transfer take place across the boundary , but mass transfer is controlled by valves .
Answer: B
90. Pressure reaches a value of absolute zero
(a) at a temperature of 273K
(b) Under vacuum condition
(c) At the earth’s centre
(d) When molecular momentum of system becomes zero
Answer: D
91. The imaginary line drawn in the fluid in such a way that the tangent to any point gives the direction of motion at that point , is known as
(a) Potential line
(b) Streak line
(c) Path line
(d) Stream line
Answer: D
92. Which of the following forces act(s) in a moving fluid?
(a) Inertia force
(b) Viscous force
(c) Gravity force
(d) All of the options
Answer: D
93. ______ is a small opening of any cross section on the side or bottom of the tank on which take on which fluid is flowing .
(a) Mouth piece
(b) Notch
(c) Weir
(d) Orifice
Answer: D
94. Continuity equation can take the form –
(where A = Area , V = Volume , ฯ = Density , v = velocity and P = Pressure)
(a) P1A1V1 = P2A2V2
(b) ฯ1A1 = ฯ2A1
(c) A1V1 = A2V2
(d) P1V1 = P2V2
Answer: C
95. Bernoulli’s theorem deals with the principle of conservation of
(a) Mass
(b) Energy
(c) Force
(d) Momentum
Answer: B
96. The coefficient of velocity is defined as the ratio of the
(a) Actual velocity of jet at vena contracta to the theoretical velocity
(b) Actual discharge through an orifice to the theorem discharge
(c) Area of jet at vena contracta to the area of orifice
(d) Actual discharge through an orifice to the area of orifice
Answer: A
97. Which of the following statements is true about the pitot tube?
(a) It is made up of a tapered tube and a float inside it
(b) It consists of a short converging part , throat and diverging part
(c) It consists of a thin metal sheet , having in it a square edged , a sharp edge or round edged circular hole
(d) It consists of a glass tube bent at right angles
Answer: D
98. Which of the following is used to measure the discharge ?
(a) Current meter
(b) Venturimeter
(c) Pitot tube
(d) Hot wire anemometer
Answer: B
99. The eddy viscosity for turbulent flow is
(a) A function of temperature only
(b) A physical property of the fluid
(c) Dependent of the flow
(d) Independent of the flow
Answer: C
100. The flow profile of a fluid depends upon
(a) Velocity of the fluid only
(b) The diameter of the tube only
(c) The Reynold number
(d) The surface roughness
Answer: C
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