UKPSC Regional Inspector (Technical) 2022: Mechanical Engineering 2
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Mechanical Engineering-II
1. Compressibility of a liquid is expressed by its –
(a) Density (b) Volume
(c) Pressure (d) Bulk modulus of elasticity
2. The velocity gradient in the transverse direction for a fluid flow equals
(a) The pressure gradient in the flow (b) The rate of shear strain
(c) The stress at that point (d) The strain at that point
3. For a laminar flow through a pipe, the discharge varies
(a) as the square of diameter (b) as the inverse of viscosity
(c) inversely as the pressure gradient (d) as the square of viscosity
4. The frictional resistance in case of turbulent flow is independent of
(a) pressure of flow (b) density of fluid
(c) temperature of fluid (d) area of surface in contact
5. In case of frictionless flow of an incompressible fluid, the summation of kinetic energy,
potential energy and pressure energy per unit weight of fluid
(a) gradually increases (b) remains the same
(c) decreases (d) first increases then decreases
6. For turbulent flow in rough pipes, the coefficient of friction depends only on
(a) centre line velocity (b) length of the pipe
(c) wetted perimeter of pipe (d) relative roughness
7. If v = average velocity of flow, D = diameter of pipe, then in case of turbulent flow through
rough pipe, the head loss in friction is proportional to
(a) v/D (b) v2/D (c) v/D2 (d) v2/D2
8. If v = velocity, f = coefficient of friction and = density for turbulent flow through rough
pipe, then wall shear stress is given by
1 1
(a) 2 f v2 (b) f v2 (c) 4 f v2 (d) f v2
2 4
9. In a flow through tube, the flow is generally assumed to be turbulent when –
(a) Re < 1000 (b) 1000 < Re < 2300 (c) Re > 5 × 105 (d) Re > 2300
(Where Re is Reynold’s number.)
10. For a sudden expansion in pipe flow, if D1 and D2 are respectively diameters of smaller and
D1
larger pipe, then the pressure rise will be maximum when is equal to
D2
1 1 1 1
(a) (b) (c) (d)
2 2 3 3
11. The U = velocity of fluid stream, L = Characteristic length and g = gravitational acceleration,
then Froude number is expressed as
U 2U 1 U 1 U
(a) (b) (c) (d)
gL gL 2 gL 2 gL
12. During a fluid flow around a sphere, if FD = total drag, then skin friction drag is
1 1 2 3
(a) FD (b) FD (c) FD (d) FD
2 3 3 2
Series-A 2 MEN-02
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13. According to Stokes’ law, the relationship between drag coefficient (CD) and Reynold’s
number (Re) is expressed as
12 16 20 24
(a) CD = (b) CD = (c) CD = (d) CD =
Re Re Re Re
14. If P1 and P2 are respectively upstream and downstream pressure, then strength of shock is
given as
P1 P1 P2 P2
(a) +1 (b) –1 (c) +1 (d) –1
P2 P2 P1 P1
15. Impingement of a jet on a flat plate may be idealized by following :
(a) = xy (b) = x2 – y2 (c) = x2 + y2 (d) = x/y
(Where the symbols have their usual meaning.)
16. Which one of the following is a characteristic of laminar flow ?
(a) Movement of fluid particles in layers parallel to boundary surface
(b) Presence of eddies
(c) Irregular motion of fluid particles
(d) Random motion of fluid particles
17. A 20 cm diameter pipe 30 km long transports oil at a rate of 0.01 m3/s. If = 0.1 N-s/m2
and = 900 kg/m3 for oil, the flow will be
(a) laminar or turbulent, cannot be predicted
(b) in transition
(c) turbulent
(d) laminar
18. For a circular pipe, the value of momentum correction factor is
(a) 3/4 (b) 4/3 (c) 2/3 (d) 3/2
19. The Mach number for an isentropic flow is defined as the ratio of
(a) pressure to density (b) pressure to the speed of sound
(c) flow velocity to the density (d) flow velocity to the speed of sound
20. Which of the following boundary conditions exist at the wall (y = 0) in a boundary layer ?
dp
(a) u = U (b) = –ve (c) 0 = O (d) u = 0, v = 0
dx
(Symbols have their usual meaning.)
21. If a body floating in a liquid returns back to its original position when given a small angular
displacement; the body is
(a) in neutral equilibrium (b) in stable equilibrium
(c) in unstable equilibrium (d) None of these
22. A 1 : 20 model of a submarine is to be tested in a tank containing sea water. If the submarine
velocity is 6 m/s, at what velocity should the model be towed for dynamic similarity ?
(a) 60 m/s (b) 120 m/s (c) 180 m/s (d) 240 m/s
23. Calculate the power required to tow a smooth flat plate 2 m wide, 20 m long through still
water at 10 m/s. Given : coefficient of drag = 0.002 and density of water = 1000 kg/m3.
(a) 120 kW (b) 80 kW (c) 40 kW (d) None of these
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13. () (CD) (Re) :
12 16 20 24
(a) CD = (b) CD = (c) CD = (d) CD =
Re Re Re Re
14. P1 P2 ,
P1 P1 P2 P2
(a) +1 (b) –1 (c) +1 (d) –1
P2 P2 P1 P1
15.
(a) = xy (b) = x2 – y2 (c) = x2 + y2 (d) = x/y
( )
16. ?
(a)
(b)
(c)
(d)
17. 20 cm 30 km 0.01 3/. ,
= 0.1 N-s/m2 = 900 kg/m3 ,
(a) , (b)
(c) (d)
18. :
(a) 3/4 (b) 4/3 (c) 2/3 (d) 3/2
19.
(a) (b) (c) (d)
20. (y = 0) ?
dp
(a) u = U (b) = –ve (c) 0 = O (d) u = 0, v = 0
dx
( )
21. ,
(a) (b) (c) (d)
22. 1 : 20 ,
6 m/s , ?
(a) 60 m/s (b) 120 m/s (c) 180 m/s (d) 240 m/s
23. 2 m 20 m 10 m/s
= 0.002 = 1000 kg/m3
(a) 120 kW (b) 80 kW (c) 40 kW (d)
MEN-02 5 Series-A
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24. The Buckingham theorem is based on the following principle :
(a) Newton’s law of motion (b) Bernoulli’s equation
(c) Conservation of mass (d) Dimensional homogeneity
25. The force of surface tension is
(a) point force (b) surface force (c) volume force (d) line force
26. When the velocity of flow has same direction at all points, it is known as
(a) one dimensional flow (b) two dimensional flow
(c) three dimensional flow (d) steady flow
27. The main reason for occurrence of shear in turbulent flow is
(a) pressure transfer (b) heat transfer
(c) momentum transfer (d) mass transfer
28. If a thin plate is held parallel to a fluid stream, the pressure drag on it is
(a) maximum (b) minimum (c) zero (d) average
29. The total drag on a plate held normal to the flow is equal to
(a) pressure drag (b) viscous drag
viscous drag
(c) pressure drag × viscous drag (d)
pressure drag
30. The coefficient of drag and lift are functions of
(a) Froude number (b) Reynold’s number
(c) Weber number (d) Euler’s number
31. If A1 and A2 are surface areas of two bodies, F12 = fraction of energy that leaves the black
surface 1 and incident on the black surface 2, F21 = fraction of energy that leaves the black
surface 2 and incident on the black surface 1, then which of the following relation among
the following is true ?
(a) A1A2 = F12F21 (b) A1F12 = A2F21
(c) A1F21 = A2F12 (d) (A1+A2) = (F12+ F21)
2T 2T 2T
32. The equation + + = 0 is known as
x2 y2 z2
(a) Fourier equation (b) Newton’s equation
(c) Laplace equation (d) Stefan Boltzmann equation
33. If Nu = Nusselt number, Re = Reynold’s number and Pr = Prandtl number, then the Stanton
number is expressed as
Nu Re Pr RePr
(a) (b) (c) (d)
RePr NuPr NuRe Nu
34. An insulating material (k = 0.16 W/m-k) is wrapped on a pipe which is exposed to air at
25 C (h = 4.0 W/m2-k). The critical thickness of insulation will be
(a) 4.0 cm (b) 4.0 mm (c) 4.0 m (d) 25 m
35. The emissivity of a surface averaged over all direction is known as
(a) total emissivity (b) hemispherical emissivity
(c) spectral or monochromatic emissivity (d) spectral or radiation intensity
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36. If c1 and c2 are constant, is wavelength and T is absolute temperature, then monochromatic
emissive power of a black body is expressed as
c λ 5 c λ5 c λ 5 c λ5
(a) c1 (b) c 1 (c) c1 (d) c 1
2 2 2 2
e λT 1 e λT 1 e λT 1 e λT 1
37. Total radiant energy leaving a surface per unit time and per unit surface area is indicated by
(a) emissivity (b) reflectivity (c) radiosity (d) diffusivity
38. What is the average flow velocity in a pipe if the centre line velocity in pipe is 4 m/s and
Reynold’s number is 800 ?
(a) 2 m/s (b) 2.5 m/s (c) 4 m/s (d) 1 m/s
39. If L = length of hollow cylinder, R2 = outside radius, R1 = inside radius, k = thermal
conductivity; then thermal resistance of hollow cylinder is given as
1 R2 1 R1 Lk R2 Lk R1
(a) loge (b) loge (c) loge (d) loge
2Lk R1 2Lk R2 2 R1 2 R2
40. Consider that Rconv and Rcond are convective and conductive resistances, respectively in case
of heat transfer through fins. The use of fin will not be effective when –
(a) Rcond and Rconv both are more significant. (b) Rcond and Rconv both are negligible.
(c) Rconv is more and Rcond is negligible. (d) Rcond is more and Rconv is negligible.
41. If L = characteristic length, then Grashoff number is proportional to
(a) L (b) L2 (c) L3 (d) L4
42. If two plates of infinite length having emissivity 1 and 2 respectively are arranged in
parallel manner, then interchange factor will be equal to
1 1 1 1 – 1 1
(a) + (b) + 1 (c) (d)
1 2 1 2 1 1 – 1 1
+ 1 + +1
1 2 1 2
43. A plane wall is 25 cm thick with an area of 1 m2 and has a thermal conductivity of
0.5 W/ m-k. If a temperature difference of 60 C is imposed across it, then what will be the
heat flow ?
(a) 120 W (b) 140 W (c) 160 W (d) 180 W
44. The NTU in a heat exchanger is given by following :
UA UA UA Cmax
(a) (b) (c) (d)
Cmax Cmin Cmin
(Where symbols have their usual meanings.)
45. In a balanced counter flow heat exchanger with mh ch = mc cc, the NTU is 1.0. What will be
effectiveness of the heat exchanger ? (Here the symbols have usual meaning.)
(a) 0.5 (b) 1.5 (c) 0.33 (d) 0.20
46. In case of unsteady state heat conduction, lumped capacity analysis is applicable when Biot
number (Bi) is
(a) < 1.0 (b) < 0.1 (c) > 1.0 (d) > 0.1
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36. c1 c2 , T ,
c1λ 5 c1λ 5 c1λ 5 c1λ 5
(a) c2
(b) c2
(c) c2
(d) c2
e λT 1 e λT 1 e λT 1 e λT 1
37.
(a) (b) (c) (d)
38. 4 m/s 800 , ?
(a) 2 m/s (b) 2.5 m/s (c) 4 m/s (d) 1 m/s
39. L = , R2 = , R1 = , k = ,
1 R2 1 R1 Lk R2 Lk R1
(a) loge (b) loge (c) loge (d) loge
2Lk R1 2Lk R2 2 R1 2 R2
40. Rconv Rcond
(a) Rcond Rconv (b) Rcond Rconv
(c) Rconv Rcond (d) Rcond Rconv
41. L = ,
(a) L (b) L2 (c) L3 (d) L4
42. , 1 2 ,
, :
1 1 1 1 – 1 1
(a) + (b) + 1 (c) (d)
1 2 1 2 1 1 – 1 1
+ 1 + +1
1 2 1 2
43. 1 25 0.5 W/ m-k
60 C , ?
(a) 120 (b) 140 (c) 160 (d) 180
44. ‘NTU’ :
UA UA UA Cmax
(a) (b) (c) (d)
Cmax Cmin Cmin
( )
45. mh ch = mc cc NTU = 1.0
? ( )
(a) 0.5 (b) 1.5 (c) 0.33 (d) 0.20
46. (Bi)
(a) < 1.0 (b) < 0.1 (c) > 1.0 (d) > 0.1
MEN-02 9 Series-A
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47. With the usual meaning of the symbols, the Fourier’s law of conduction is expressed as
follows :
dT dx d2x dA
(a) Q = – kA (b) Q = – kA (c) Q = – kA 2 (d) Q = – kT
dx dT dT dx
48. A body which transmits all the incident radiation is known as
(a) Black body (b) Gray body (c) Opaque body (d) Diathermanous body
49. If in a double pipe heat exchanger, U = overall heat transfer coefficient, A = Area through
which heat is transferred, and LMTD = log-mean temperature difference; then the total heat
flow is given by
U × (LMTD) (LMTD)
(a) (b) 2UA × (LMTD) (c) UA (LMTD) (d)
A UA
50. In which of the following materials, the heat energy transfer will be minimum due to
conduction ?
(a) Lead (b) Copper (c) Water (d) Air
51. The critical thickness of insulation refers to
(a) The minimum thickness required to prevent heat transfer.
(b) The maximum thickness that can be used for insulation.
(c) The thickness at which adding more insulation increases heat transfer instead of
decreasing it.
(d) The thickness where thermal conductivity reaches its maximum.
52. Grashoff number in natural convection is defined as
(a) buoyancy force/viscous force (b) viscous force/buoyancy force
(c) buoyancy force × viscous force (d) viscous force/inertia force
53. The wall of a furnace is constructed from 15 cm thick fire brick having thermal conductivity
of 1.6 W/m-k. If the wall is having an area of 1.5 m2, how much temperature difference
between the two sides of the wall should be maintained under steady state conditions for
maintaining a heat loss of 4800 W ?
(a) 300 C (b) 350 K (c) 26.86 K (d) 273 K
hA
54. Addition of fin to the surface increases the heat transfer if is
kp
(The symbols have usual meanings.)
(a) equal to unity (b) greater than unity
(c) less than unity (d) greater than one but less than two
55. A composite wall consists of two layers of different materials having conductivities k1 and
k2 respectively. For equal thickness of the two layers, the equivalent thermal conductivity
of the wall will be
2k1k2 k1k2 k1 + k2
(a) k1 + k2 (b) (c) (d)
k1 + k 2 k1+ k2 k1k2
56. If the temperature of a solid surface changes from 27 C to 627 C, then its emissive power
will increase by
(a) 3 times (b) 9 times (c) 27 times (d) 81 times
57. The value of transmissivity of a body varies from
(a) –1 to 0 (b) 0 to 1 (c) –1 to – (d) +1 to +
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58. The sum of absorptivity, reflectivity and transmissivity of a metal body is
(a) Always less than 1 (b) Always more than 1
(c) Equal to 1 (d) Lies between –1 to +1
59. For infinitely long fin, if P = perimeter, k = thermal conductivity, h = convective heat transfer
coefficient, Ac = area; then fin effectiveness is given by
Pk Ph PAc hk
(a) (b) (c) (d)
hAc kAc kh PAc
60. If = thickness, h = convective heat transfer coefficient and k = thermal conductivity; then
Biot number is expressed as
h k k h
(a) (b) (c) (d)
2k h 2h k
61. The unit of convective heat transfer coefficient is
W W W Wm2
(a) (b) (c) 2 (d)
m-C m-k m -C k
62. The relative thickness of hydrodynamic and thermal boundary layer depends upon
(a) Mach number (b) Nusselt number (c) Reynold’s number (d) Prandtl number
63. If heat transfer takes place between two concentric spheres, the shape factor is equal to
(a) 0 (b) 1 (c) 1/2 (d)
64. If ‘n’ is the number of radiation shields present between two parallel surfaces which
exchange radiation, the ratio of heat transfer with shield to the heat transfer without shields
is given by the following :
1 1 1 (n + 1)
(a) (b) (c) (d)
n (n + 1) (n – 1) n
65. Which among the following expresses the momentum equation for a two-dimensional
flow ?
U V 2U T T 2T
(a) U + V = V 2 (b) U + V = 2
x y y x y y
U V U – V
(c) + =0 (d) =0
x y x y
66. The function of a carburettor is
(a) to atomise the fuel
(b) to vapourise the fuel
(c) to inject petrol in the cylinder
(d) to atomise and vapourise the fuel, and to mix it with air in proper ratio
67. The ignition of fuel-air mixture under certain conditions of temperature, pressure and density
without the assistance of an initiating flame or spark is known as
(a) pre-ignition (b) auto ignition (c) ignition delay (d) normal combustion
68. The head of water required for Pelton wheel is
(a) low (b) medium
(c) high (d) suitable for any head of water
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69. Pelton wheel is a
(a) tangential flow turbine (b) radial flow turbine
(c) axial flow turbine (d) mixed flow turbine
70. In S.I. engines, detonation occurs
(a) before starting of ignition (b) at the starting of ignition
(c) near the end of combustion (d) in the middle of combustion
71. Kaplan turbine is
(a) an axial flow reaction turbine (b) an axial flow impulse turbine
(c) an inward radial flow impulse turbine (d) an outward radial flow reaction turbine
72. Constant volume gas turbine works on which of the following cycles ?
(a) Joule cycle (b) Otto cycle (c) Carnot cycle (d) Atkinson cycle
73. The division of heavy nucleus into small atoms is called
(a) fusion (b) fission (c) vapourisation (d) addition
74. 1 kg of Uranium will produce energy equivalent to approximately
(a) 30,000 tonnes of coal (b) 30 tonnes of coal
(c) 3,000 tonnes of coal (d) 300 tonnes of coal
75. The material used for reactor vessel is
(a) Cast Iron (b) Stainless Steel (c) Mild Steel (d) Copper
76. The coolant used in a nuclear power plant is
(a) Heavy water (b) Freon (c) Carbon dioxide (d) Sulphur dioxide
77. The term PWR stands for
(a) Power water reactor (b) Pressurised water reactor
(c) Power welding rod (d) Power work reaction
78. Flat plate solar collectors are used for achieving temperatures in the following range :
(a) 200 C to 300 C (b) 100 C to 200 C
(c) below 100 C (d) above 300 C
79. Steam expands isentropically in a nozzle such that its enthalpy reduces to half of its initial
value. If the initial enthalpy of the steam is 160 kJ/kg, its exit velocity will be
(a) 400 m/s (b) 566.6 m/s (c) 282.8 m/s (d) None of these
80. In the context of solar energy, air mass is
(a) mass of air in the atmosphere.
(b) mass of air above solar collector.
(c) the path length of radiation through the atmosphere.
(d) mass of air below solar collector.
81. The specific speed of a turbine is
(a) its maximum speed
(b) its minimum speed
(c) its speed at maximum output
(d) speed of a geometrically similar turbine that would develop unit power under unit head
82. If P1 = initial pressure; P2 = pressure after first stage and P3 = pressure after second stage,
then the efficiency of a two-stage compressor will be maximum when
P1
(a) P2 = P1 × P3 (b) P2 = (c) P2 = P1P3 (d) P2 = P1+ P3
P3
Series-A 14 MEN-02
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69. :
(a) (b)
v
(c) (d)
70. .. :
(a) (b)
(c) (d)
71. :
(a) (b)
(c) (d)
72. ?
(a) (b) (c) (d)
73. :
(a) (b) (c) (d)
74. , :
(a) 30,000 (b) 30
(c) 3,000 (d) 300
75. :
(a) (b) (c) (d)
76. :
(a) (b) (c) (d)
77. ‘PWR’
(a) (b)
(c) (d)
78.
(a) 200 C 300 C (b) 100 C 200 C
(c) 100 C (d) 300 C
79.
160 kJ/kg ,
(a) 400 ./. (b) 566.6 ./. (c) 282.8 ./. (d)
80. ‘ ’
(a) (b)
(c) (d)
81.
(a)
(b)
(c)
(d)
82. P1 = , P2 = P3 = , -
,
P1
(a) P2 = P1 × P3 (b) P2 = (c) P2 = P1P3 (d) P2 = P1+ P3
P3
MEN-02 15 Series-A
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83. Which energy is the ultimate source for generation of wind energy on the earth ?
(a) Solar energy (b) Rotational energy of earth
(c) Magnetic field of earth (d) Gravitational energy of the earth
84. In a four stroke S.I. engine, during the suction stroke
(a) only air is sucked (b) only fuel is sucked
(c) fuel-air mixture is sucked (d) only coolant is sucked
85. When the throttle is suddenly opened, the air-fuel mixture from the simple carburettor, for a
short time, tends to become
(a) rich (b) lean (c) stoichiometric (d) not affected
86. The major loss in a C.I. engine is
(a) direct heat loss (b) loss due to incomplete combustion
(c) pumping loss (d) friction loss
87. Which number is a useful measure of knock tendency of diesel ?
(a) Cetane number (b) Performance number
(c) Octane number (d) Fuel number
88. An internal combustion engine gives power output of 3 kW when the input is 10000 J/s. The
thermal efficiency of the engine is
(a) 33.3% (b) 30% (c) 60% (d) 60.6%
89. Which of the following is not an advantage of gas turbine over I.C. engines ?
(a) High mechanical efficiency (b) High driving speed
(c) Less weight per unit power (d) High thermal efficiency
90. The compression ratio in diesel engines is of the order of –
(a) 5 – 7 (b) 7 – 10 (c) 10 – 12 (d) 14 – 20
91. Stoichiometric air-fuel ratio of petrol is approximately
(a) 15 : 1 (b) 25 : 1 (c) 50 : 1 (d) 100 : 1
92. Brayton cycle is used for
(a) ramjet engines (b) gas turbines (c) C.I. engines (d) S.I. engines
93. The efficiency of Otto cycle
(a) decreases with compression ratio.
(b) increases with compression ratio.
(c) is not affected by compression ratio.
(d) first decreases and then increases with compression ratio.
94. In Rankine cycle the work output from the turbine is given by :
(a) change in internal energy between inlet and outlet
(b) change in enthalpy between inlet and outlet
(c) change in entropy between inlet and outlet
(d) change of temperature between inlet and outlet
95. Stage efficiency of steam turbine is (with usual meaning of symbols) given by –
(a) blade / nozzle (b) nozzle × blade (c) nozzle / blade (d) blade
96. The work input for running an air compressor is minimum if the compression law followed
is
(a) PV1.35 = C (b) PV1.2 = C (c) PVr = C (d) PV = C
Series-A 16 MEN-02
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83. ?
(a) (b)
(c) (d)
84. - ..
(a) (b)
(c) (d)
85. -
(a) (b) (c) (d)
86. .. (C.I.)
(a) (b)
(c) (d)
87. ?
(a) (b) (c) (d)
88. 3 kW 10000 J/s
(a) 33.3% (b) 30% (c) 60% (d) 60.6%
89. .. ?
(a) (b)
(c) (d)
90. ?
(a) 5 – 7 (b) 7 – 10 (c) 10 – 12 (d) 14 – 20
91. -
(a) 15 : 1 (b) 25 : 1 (c) 50 : 1 (d) 100 : 1
92.
(a) (b) (c) .. (d) ..
93. :
(a)
(b)
(c)
(d) ,
94.
(a)
(b)
(c)
(d)
95. ( )
(a) blade / nozzle (b) nozzle × blade (c) nozzle / blade (d) blade
96.
(a) PV1.35 = C (b) PV1.2 = C (c) PVr = C (d) PV = C
MEN-02 17 Series-A
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97. The phenomenon of chocking in air compressor means –
(a) no flow of air
(b) fixed mass flow rate regardless of pressure ratio
(c) reducing mass flow rate with increase in pressure ratio
(d) increased inclination of chord with air stream
98. Multistage centrifugal pumps are used to
(a) give high discharge (b) pump viscous fluids
(c) produce high heads (d) give low discharge
99. If the minimum and maximum temperatures in Brayton cycle are 300 K and 1200 K
respectively, the efficiency of the cycle for maximum output will be
(a) 50% (b) 47% (c) 43% (d) 38%
100. If P = power, Q = discharge and H = head; then the specific speed of a hydraulic turbine is
given by the relation –
N Q N Q N P N P
(a) Ns = 3/2 (b) Ns = 5/4 (c) Ns = 5/4 (d) Ns = 3/2
(H) H H H
101. The number of buckets in a Pelton wheel of runner diameter of 2 m and jet diameter of
10 cm will be
(a) 15 (b) 20 (c) 27 (d) 25
102. Consider the following turbines :
1. Kaplan 2. Pelton wheel 3. Francis
The correct sequence in increasing order of the specific speed of these turbines will be
(a) 2, 3, 1 (b) 2, 1, 3 (c) 3, 1, 2 (d) 1, 2, 3
103. In case of impulse steam turbine the enthalpy drop
(a) happens in both fixed and moving blades
(b) happens only in moving blades
(c) happens only in nozzles
(d) there is no enthalpy drop
104. For a gas turbine, the turbine isentropic efficiency is defined as
(a) actual work output/isentropic work output
(b) isentropic work input/actual work input
(c) work output/heat input
(d) isentropic work output/actual work output
105. Surge tank in a hydroelectric power plant is used to
(a) reduce water hammer in penstock
(b) avoid use of draft tube
(c) reduce the size of main dam
(d) reduce the head required for power generation
106. Supercharging of an engine is the process to
(a) increase the compression ratio
(b) remove the exhaust gases from the cylinder
(c) increase density of air-fuel mixture entering into cylinder
(d) run the engine at an optimum temperature
107. Centrifugal compressors are used for producing
(a) large quantities of air at high pressure (b) large quantities of air at low pressure
(c) small quantities of air at low pressure (d) small quantities of air at high pressure
Series-A 18 MEN-02
Text of page 19
97. :
(a)
(b)
(c)
(d)
98. :
(a) (b)
(c) (d)
99. 300 K 1200 K ,
(a) 50% (b) 47% (c) 43% (d) 38%
100. P = , Q = H = ,
N Q N Q N P N P
(a) Ns = 3/2 (b) Ns = 5/4 (c) Ns = 5/4 (d) Ns = 3/2
(H) H H H
101. 2 m 10 cm ,
(a) 15 (b) 20 (c) 27 (d) 25
102.
1. 2.
3.
(a) 2, 3, 1 (b) 2, 1, 3 (c) 3, 1, 2 (d) 1, 2, 3
103. :
(a) (b)
(c) (d)
104. :
(a) /
(b) /
(c) /
(d) /
105.
(a) (b)
(c) (d)
106. :
(a)
(b)
(c) -
(d)
107. ?
(a) (b)
(c) (d)
MEN-02 19 Series-A
Text of page 20
108. Which of the following method(s) is/are used for governing of steam turbines ?
(a) Throttle governing only (b) Nozzle governing only
(c) Capacity governing only (d) Both throttle governing and nozzle governing
109. The pressure range for a super critical boiler is
(a) 50 to 100 kg/cm2 (b) 100 to 150 kg/cm2
(c) 150 to 200 kg/cm 2 (d) 225 to 250 kg/cm2
110. A boiler produces superheated steam at 330 C (h = 3020 kJ/kg) from water at
100 C (Cp = 4.2 kJ/kg C). The steam is produced at a rate of 8.2 kg per kg of fuel burnt.
What will be the boiler efficiency if the calorific value of fuel is 26000 kJ/kg ?
(a) 79% (b) 82% (c) 84% (d) 86%
111. Which of the following is a secondary refrigerant ?
(a) Carbon dioxide (b) Brine solution (c) Sulphur dioxide (d) Ammonia
112. Which of the following refrigerants has the maximum latent heat ?
(a) Monochloro-difluoro-ethane (R22) (b) Carbon dioxide
(c) Ammonia (d) (R12)
113. Which of the following is known as dry ice ?
(a) Milky coloured ice (b) Solid carbon dioxide
(c) Liquid ammonia (d) Solid Sulphur dioxide
114. During which of the following processes the refrigerant changes phase from vapour to liquid
in a vapour-compression refrigeration cycle ?
(a) Evaporation (b) Condensation (c) Compression (d) Expansion
115. Which of the following component is absent in vapour absorption refrigeration system ?
(a) Evaporator (b) Compressor (c) Condenser (d) Expander
116. Which of the following is not correct about sensible heating ?
(a) Dry bulb temperature increases (b) Wet bulb temperature increases
(c) Specific enthalpy increases (d) Specific humidity increases
117. Sensible Heat Factor (SHF) is expressed by the following :
(a) sensible heat/total heat (b) total heat/sensible heat
(c) sensible heat/latent heat (d) latent heat/sensible heat
118. If in the formula for the coefficient of performance of a refrigeration system
Q1
COP = , Q is heat absorbed in the evaporator, then Q2 stands for
Q2 – Q1 1
(a) heat rejected in the condenser (b) heat rejected in the evaporator
(c) heat absorbed in the evaporator (d) heat absorbed in the condenser
119. The main difference between a heat pump and refrigerating machine is in
(a) the cycle of operation (b) the working fluid used
(c) the purpose for which it is used (d) all of the above
120. Calculate the maximum possible COP of a refrigerator which absorbs heat from the
evaporator at –23 C and rejects heat to the environment at 52 C ?
(a) 2.92 (b) 3.33 (c) 3.0 (d) 1.91
121. Long copper tube with fins that is seen on the back side of a domestic refrigerator is
(a) capillary tube (b) evaporator tube (c) throttle tube (d) condenser tube
Series-A 20 MEN-02
Text of page 21
108. () / :
(a) (b)
(c) (d)
109.
(a) 50 100 kg/cm2 (b) 100 150 kg/cm2
(c) 150 200 kg/cm2 (d) 225 250 kg/cm2
110. 100 C (Cp = 4.2 kJ/kg C) 330 C (h = 3020 kJ/kg)
8.2 kg/kg 26000 kJ/kg , ?
(a) 79% (b) 82% (c) 84% (d) 86%
111. ?
(a) (b) (c) (d)
112. ?
(a) -- (R22) (b)
(c) (d) (R12)
113. ?
(a) (b)
(c) (d)
114. ?
(a) (b) (c) (d)
115. - ?
(a) (b) (c) (d)
116. ?
(a) (b)
(c) (d)
117. (SHF) :
(a) / (b) /
(c) / (d) /
Q1
118. COP = Q1
Q2 – Q1
, Q2 ?
(a) (b)
(c) (d)
119.
(a) (b)
(c) (d)
120. (COP) –23 C
52 C ?
(a) 2.92 (b) 3.33 (c) 3.0 (d) 1.91
121. , ,
(a) (b) (c) (d)
MEN-02 21 Series-A
Text of page 22
122. The capillary tube in a refrigeration system is used for
(a) only expansion of refrigerant
(b) only control the supply of refrigerant to evaporator
(c) both (a) and (b)
(d) overload protection
123. Which of the following are used in vapour absorption system ?
(a) NH3 as absorbent and H2O as refrigerant
(b) LiBr2 as absorbent and H2O as refrigerant
(c) NH3 as absorbent and LiBr2 as refrigerant
(d) NH3 and LiBr2 both as refrigerant
124. Which of the element present in CFC refrigerant is most potent for Ozone layer depletion ?
(a) Methane (b) Hydrogen (c) Chlorine (d) Fluorine
125. Which type of refrigeration system is used in jet aircrafts ?
(a) Air refrigeration (b) Vapour compression
(c) Vapour absorption (d) Peltier system
126. When the temperature shown by dry bulb thermometer and wet bulb thermometer are the
same, the relative humidity of air is –
(a) 25% (b) 50% (c) 75% (d) 100%
127. In air conditioning system the sensible heat loss due to air infiltration can be calculated
by which of the following equations when = density of air (kg/m3), V = rate of air
infiltration (m3/h), c = specific heat of air, to = outside air temperature, and ti = inside air
temperature ?
(a) Q = Vc (to – ti) (b) Q = V (to – ti)/c
V
(c) Q = (t – t ) c (d) Q = (t – t )
o i Vc o i
128. A refrigerant should have
(a) high specific heat (b) high specific volume
(c) high latent heat (d) high boiling point
129. The chemical formula for Freon-12 is
(a) CCl4 (b) CCl2F2 (c) CHCl2F (d) C2H5Cl
130. Superheating of vapours in evaporator of vapour compression system –
(a) increases net refrigeration effect
(b) decreases net refrigeration effect
(c) will not change net refrigeration effect
(d) increases C.O.P.
131. The dehumidification of air will change its
(a) dry bulb temperature (b) wet bulb temperature
(c) humidity ratio (d) (b) and (c) both
132. In vapour compression cycle the expansion process is assumed to be isenthalpic while in
actual process, the enthalpy –
(a) increases.
(b) first increases then decreases.
(c) first decreases then increases.
(d) decreases and the process is represented by Fanno line.
Series-A 22 MEN-02
Text of page 24
133. Fresh air at 40 C DBT and room air at 25 C DBT are mixed together in the ratio of 1 : 4
by weight. The DBT of the mixture will be –
(a) 32.5 C (b) 37 C (c) 28 C (d) 20 C
134. The degree of saturation is the ratio of the
(a) actual humidity and saturated specific humidity
(b) actual humidity and absolute humidity
(c) actual humidity and saturated specific humidity at same pressure
(d) actual specific humidity and saturated specific humidity at same temperature
135. Chemical dehumidification takes place with the help of the following absorbent :
(a) vaseline gel (b) activated silicate (c) activated alumina (d) sulphur silicate
136. Which of the following processes are used in summer air conditioning ?
(a) Only cooling (b) Only dehumidification
(c) Only humidification (d) Cooling and dehumidification
137. Halide torch is used to detect leaks of the following refrigerant(s) :
(a) Ammonia only (b) Chloro-Fluoro Carbon (CFC) refrigerants only
(c) CO2 only (d) Both ammonia and CO2
138. The refrigerant used for vapour absorption refrigeration working on heat from solar
collectors is a mixture of water and
(a) Carbon dioxide (b) Sulphur dioxide (c) Lithium bromide (d) Freon-12
139. For an ideal refrigerator working on reversed Carnot cycle, the condenser and evaporator
temperatures are 27 C and –13 C respectively. The COP of this refrigerator would be
(a) 6.5 (b) 7.5 (c) – 0.325 (d) 0.675
140. The combined effect of superheating of vapour in the evaporator and subcooling of
condensate in the condenser is –
(a) to decrease the COP
(b) to increase the COP
(c) that COP may increase, decrease or remain same
(d) None of the above
0.622 Pv
141. The expression is used to determine (where symbols have their usual meaning) :
Pt – Pv
(a) relative humidity (b) specific humidity
(c) degree of saturation (d) partial pressure
142. Input energy to the steam ejector refrigeration system is in the form of
(a) electric power (b) mechanical power (c) thermal power (d) pneumatic power
143. A valve fitted in the liquid line to start/stop the flow of refrigerant in vapour compression
system is called
(a) Solenoid valve (b) High pressure valve
(c) Low pressure valve (d) Main valve
144. Bulb and bellow element is used for control in a vapour compression system in the following
(a) automatic expansion valve (b) thermo-static expansion valve
(c) float valve (d) capillary tube
Series-A 24 MEN-02
Text of page 25
133. 40 C DBT 25 C DBT 1 : 4
DBT
(a) 32.5 C (b) 37 C (c) 28 C (d) 20 C
134.
(a)
(b)
(c)
(d)
135.
(a) (b) (c) (d)
136. ?
(a) (b) (c) (d)
137. :
(a)
(b) - (CFC)
(c)
(d)
138.
(a) (b) (c) (d) -12
139. 27 C –13 C
...
(a) 6.5 (b) 7.5 (c) – 0.325 (d) 0.675
140.
(a) ...
(b) ...
(c) ... ,
(d)
0.622 Pv
141. ( )
Pt – Pv
(a) (b) (c) (d)
142.
(a) (b) (c) (d)
143. /
(a) (b) (c) (d)
144.
(a) (b) -
(c) (d)
MEN-02 25 Series-A
Text of page 26
145. For a simple vapour compression cycle the following information is available :
(i) The enthalpy of the refrigerant increases from H to 4 H in the evaporator.
(ii) The enthalpy of the refrigerant increases from 4 H to 5 H in the compressor.
The coefficient of performance of the cycle will be
(a) 3 (b) 4
(c) 1 (d) cannot be calculated from given data
146. In actual vapour compression cycle, the compression process will be
(a) isentropic
(b) adiabatic
(c) polytropic with friction and heat transfer
(d) None of the above
147. The following compressor is not a positive displacement machine :
(a) reciprocating compressor (b) rotary compressor
(c) scroll compressor (d) centrifugal compressor
148. If heat transfer to refrigerant in evaporator takes place at a rate of 17.6 kW, then the capacity
of refrigeration plant will be approximately –
(a) 3 ton (b) 4 ton
(c) 5 ton (d) insufficient data to calculate
149. The limitation(s) of lithium bromide water vapour absorption system is/are that
(a) the mixture is corrosive (b) it cannot be used for freezing
(c) both (a) and (b) (d) None of these
150. In the determination of properties of moist air, which of the following law is applicable ?
(a) Gibb’s law (b) Raoult’s law (c) Fourier’s law (d) Dalton’s law
151. The instrument used for measuring the psychrometric properties is
(a) Psychrometer (b) Thermometer (c) Hydrometer (d) Pyrometer
152. The ratio of molecular weights of water vapour and air is
(a) 1.61 (b) 0.622 (c) 1.622 (d) 1.65
153. In ammonia-water vapour absorption system, following component(s) is/are used to prevent
water passing to condenser :
(a) only analyser (b) only rectifier (c) only dephlegmator (d) All of these
154. Which of the following is not true about air refrigeration system ?
(a) It has low COP.
(b) It has high operating cost.
(c) It can’t work on open cycle.
(d) Small amount of leakages of air are tolerable.
155. In milk chilling plant, the usual secondary refrigerant is –
(a) ammonia solution (b) sodium silicate
(c) glycol (d) brine
Series-A 26 MEN-02
Text of page 27
145. :
(i) H 4 H
(ii) 4 H 5 H
(a) 3 (b) 4
(c) 1 (d)
146.
(a)
(b)
(c)
(d)
147. :
(a) (b) (c) (d)
148. 17.6 kW , ,
(a) 3 (b) 4
(c) 5 (d)
149. () / -
(a)
(b)
(c) (a) (b)
(d)
150. ?
(a) (b) (c) (d)
151.
(a) (b) (c) (d)
152.
(a) 1.61 (b) 0.622 (c) 1.622 (d) 1.65
153. - /
-
(a) (b) (c) (d)
154. ?
(a) ... (b)
(c) (d)
155. :
(a) (b) (c) (d)
MEN-02 27 Series-A
Text of page 28
156. An isentropic process is always
(a) Irreversible and adiabatic (b) Reversible and isothermal
(c) Frictionless and irreversible (d) Internally reversible and adiabatic
157. If the temperature of the source is increased, the efficiency of the Carnot cycle –
(a) decreases (b) increases
(c) does not change (d) depends upon other factors
158. In isentropic non-flow process, the work done by the system is
(a) W = 2(u2 – u1) (b) W = Q (c) W = u1 – u2 (d) W = h2 – h1
159. When work is converted into internal energy by stirring a fluid in an insulated vessel, then
the process is
(a) reversible (b) irreversible (c) quasi-static (d) None of these
160. Steady flow process occurs when
(a) The thermodynamic conditions do not change with time at any point.
(b) The thermodynamic conditions are the same at all points at any instant.
(c) The thermodynamic conditions change steadily with time.
v
(d) = constant, where symbols have usual meaning.
t
161. A closed system implies that
(a) mass and energy cannot cross the system boundary.
(b) mass cannot cross the system boundary.
(c) size of system is constant.
(d) volume of the system is constant.
162. Examples of intensive properties are
(a) temperature, pressure and total mass (b) temperature and pressure
(c) pressure and total mass (d) temperature and total mass
163. When a process proceeds in such a manner that the system remains close to an equilibrium
state at all times, it is called
(a) quasi-static (b) quasi-dynamic (c) static (d) dynamic
164. The following remains constant during an isochoric process
(a) temperature (b) pressure (c) volume (d) enthalpy
165. The thermal efficiency of heat engine is defined as
(a) Net work output/total heat input (b) Total heat input/net work output
(c) Total work input/total heat output (d) Total heat output/total work input
166. Heat is transferred to a heat engine at a rate of 80 MW. If the heat rejection is 50 MW, then
the thermal efficiency will be
(a) 0.625 (b) 0.600 (c) 0.375 (d) 0.360
167. For an isolated system, change in entropy of the system must be
(a) (ds) < 0 (b) (ds) = negative (c) (ds) = (d) (ds) 0
(Where the notations have their usual meaning.)
168. An industrial heat pump operates between the temperatures of 27 C and – 13 C. The rates
of heat addition and heat rejection are 750 W and 1000 W respectively. The C.O.P. of the
heat pump is
(a) 7.5 (b) 6.5 (c) 4.0 (d) 3.0
Series-A 28 MEN-02
Text of page 29
156. :
(a) (b)
(c) (d)
157. ,
(a) (b)
(c) (d)
158.
(a) W = 2(u2–u1) (b) W = Q (c) W = u1 – u2 (d) W = h2 – h1
159. ,
(a) (b) (c) (d)
160. ,
(a)
(b)
(c)
v
(d) = ,
t
161. / :
(a)
(b)
(c)
(d)
162. - :
(a) , (b)
(c) (d)
163. ,
(a) (b) (c) (d)
164. ?
(a) (b) (c) (d)
165. :
(a) / (b) /
(c) / (d) /
166. 80 MW 50 MW ,
(a) 0.625 (b) 0.600 (c) 0.375 (d) 0.360
167.
(a) (ds) < 0 (b) (ds) = negative (c) (ds) = (d) (ds) 0
( )
168. 27 C – 13 C
750 W 1000 W ...
(a) 7.5 (b) 6.5 (c) 4.0 (d) 3.0
MEN-02 29 Series-A
Text of page 30
169. For a thermodynamic cycle to be reversible, it is necessary that
d d d d
(a) = 0 (b) <0 (c) >0 (d) 0
T T T T
(Where notations have their usual meaning.)
170. Perpetual motion machine of the second kind violates the
(a) First law of thermodynamics (b) Kelvin-Planck statement
(c) Zeroth law of thermodynamics (d) Third law of thermodynamics
171. The displacement work done by a system is given by pdv. It is valid for –
(a) any process (b) a quasi-static process
(c) a non-quasi-static process (d) an isentropic process
172. If the value of ‘n’ is infinitely large in the polytropic process PVn = constant, then the process
is known as
(a) constant volume process (b) constant temperature process
(c) constant pressure process (d) constant enthalpy process
173. Internal energy is defined by the
(a) Zeroth law of thermodynamics (b) First law of thermodynamics
(c) Second law of thermodynamics (d) Law of entropy
174. A cyclic heat engine with thermal efficiency of 70% operates between a source and sink.
which of the following is correct value of least rate of heat rejection per kW net output of
the engine ?
(a) 0.428 kW (b) 0.0428 kW (c) 1.428 kW (d) 2.428 kW
175. The total heat supplied at constant volume is given by the relation
(a) Q = mcp (T2 – T1) (b) Q = mR (T2 – T1)
(c) Q = mcv (T1 + T2) (d) Q = mcv (T2 – T1)
(Where symbols have their usual meaning.)
176. At the point of boundary layer separation –
(a) Shear stress is maximum (b) Shear stress is zero
(c) Velocity is negative (d) Density variation is maximum
177. The number which is interpreted as a ratio of inertial force per unit volume to gravitational
force per unit volume is known as –
(a) Reynold’s number (b) Froude number
(c) Mach number (d) Weber number
178. Which of the following sets of conditions clearly apply to an ideal fluid ?
(a) Non-viscous and incompressible (b) Viscous and compressible
(c) Non-viscous and compressible (d) Viscous and incompressible
179. Fluid is a substance which offers no resistance to change of
(a) Pressure (b) Volume (c) Flow (d) Shape
180. Newtonian fluids are the one which
(a) Obeys Hooke’s law (b) Obeys Newton’s law of viscosity
(c) Obeys power law (d) Obeys Bernoulli’s theorem
Series-A 30 MEN-02
Text of page 32
Space For Rough Work / Series-A 32 MEN-02
Official key not published for this paper.
Page 1 of 32
Source: Uttarakhand Public Service Commission. Question paper published by Uttarakhand Public Service Commission.