Fluid Mechanics 100 Questions with Answers
1.
An ideal fluid is defined as the fluid which
A. Is compressible
B. Is
incompressible
C. Is
incompressible and non- viscous (inviscid)
D. Has
negligible surface tension
Answer: Option C
2. Netwton’s
law of viscosity states that
A.
Shear stress is
directly proportional to the velocity
B. Shear
stress is directly proportional to the velocity gradient
C. Shear
stress is directly proportional to shear strain
D. Shear
stress is directly proportional to the viscosity
Answer: Option B
3. A
Newtonian fluid is defined as the fluid which
A.
Is incompressible and non-viscous
B. Obeys
Newton’s law of viscosity
C. Is highly
viscous
D. Is
compressible and non-viscous
Answer: Option B
4. Kinematic
viscosity is defined as equal to
A.
Dynamic viscosity x density
B. Dynamic
viscosity /density
C. Dynamic viscosity
x pressure
D. Pressure
x density
Answer: Option B
5. Poise
is the unit of
A.
Mass density B. Kinematic viscosity
C.
Viscosity D. Velocity gradient
Answer: Option D
6. Stoke
is the unit of
A.
Surface tension
B. Viscosity
C.
Kinematic viscosity D. None of the above
Answer: Option C
7.
Surface
tension has the units of
A.
Force per unit area
B. Force per
unit length
C. Force per
unit volume
D. None of
the above
Answer: Option B
8.
Pascal’s
law states that pressure at a point is equal in all directions
A.
In a liquid at rest
B. In a
fluid at rest
C. In a
laminar flow
D. In a
turbulent flow
Answer: Option B
9.
The
relation between surface tension (σ) and difference of pressure (Δp) between
the inside and outside of a liquid is given as
A.
ΔP=σ/4d B.
ΔP=σ/2d
C.
ΔP=4σ/d D.
ΔP=σ/d
Answer: Option C
10.
For a soap bubble, the surface tension (σ) and
difference of pressure (Δ P) are related as
A.
ΔP=σ/4d B.
ΔP=σ/2d
C.
ΔP=4σ/d D.
ΔP=8σ/d
Answer: Option D
11.
For a liquid jet, the surface tension (σ) and
difference of pressure (Δ P) are related as
A.
ΔP=σ/4d B.
ΔP=σ/2d
C.
ΔP=4σ/d D.
ΔP=2σ/d
Answer: Option D
12. The
capillary rise or fall of a liquid is given by
A.
h=σcosθ/4ρ gd B. h=4σcosθ/ρ
gd
C.
h=8σcosθ/ρ gd D. None
Answer: Option B
13. Study of fluid motion with the force causing
the flow is known as
A. Kinematics of fluid flow
B. Dynamics of fluid flow
C. Statics of fluid flow
D. Kinetics of fluid flow
Answer: Option B
14. Study of fluid motion without considering the
forces causing the flow is known as
A. Kinematics
of fluid flow
B. Dynamics
of fluid flow
C. Statics
of fluid flow
D. None
Answer: Option A
15.
Study of fluid at rest, is known as
A.
Kinematics B.
Dynamics
C.
Statics D.
None
Answer: Option C
16. The stress-strain relation of the Newtonian
fluids are
A.
Linear B.
Parabolic
C.
Hyperbolic D.
Involutic
Answer: Option A
17. Capillarity is due to
A. Cohesion only
B. Adhesion only
C. Both cohesion and adhesion
D. None
Answer: Option C
18. Unit of viscosity in C.G.S system is
A.
Dyne B.
Newton
C.
Poise D.
Stoke
Answer: Option C
19. The necessary condition for the flow to be
steady is that
A. The velocity does not change
from place to place
B. The velocity is constant at a
point with respect to time
C. The velocity change at a point
with respect to time
D. None of the above
Answer: Option B
20. The necessary condition for the flow to be
uniform is that
A. The velocity is constant at a point with respect
to time
B. The velocity is constant in
the flow filed with respect to space
C. The velocity change at a point
with respect to time
D. None of the above
Answer: Option B
21. The flow in the pipe is laminar when
A. Reynold number is equal to
2500
B. Reynold number is equal to
4000
C. Reynold number is more than
2500
D. Reynold number is less than
2000
Answer: Option D
22. The flow in the pipe is turbulent if
A. Reynold number is more than
4000
B. Reynold number is less than
2000
C. Reynold number is equal to
4000
D. Reynold number is equal to
2000
Answer: Option A
23. Reynolds
number (Re) is given by
A.
Re=ρ Vµ/D B. Re=VD/ρµ
C.
Re=ρ VD/µ D.
Re=µVD/ρ
Answer: Option C
24. A stream line is a line
A. Which is along the path of a
particle
B. Which is always parallel to
the main direction of flow
C. Across which there is no flow
D. On which tangent drawn at any
point gives the magnitude of velocity
Answer: Option C
25.
Continuity equation can be take the form
A.
A1 V1=A2 V2 B. ρ1
A1=ρ2 A2
C.
ρ1 A1 V1=ρ2 A2 V2 D. p A1
V1=p2 A2 V2
Answer: Option C
26. Bernoulli’s theorem deals with the law of
conservation of
A.
Mass B.
Momentum
C.
Energy D. None of the above
Answer: Option C
27. Pitot tube is used for measurement of
A.
Pressure B. Flow
C.
Velocity at a point D.
Discharge
Answer: Option C
28. Continuity equation deals with the law of
conservation of
A.
Mass B. Momentum
C.
Energy D.
None of the above
Answer: Option A
29. Irrotational flow means
A. The fluid does not rotate
while moving
B. The fluid moves in straight
line
C. The net rotation of fluid
particles about their mass center is zero
Answer: Option C
30. Bernoulli’s equation is derived making
assumption that
A. The flow is uniform, steady
and incompressible
B. The flow in non viscous,
uniform and steady
C. The flow is steady, non
viscous, incompressible and irrotational
D. None of the above
Answer: Option C
31. The flow
rate through a circular pipe is measured by
A.
Pitot-tube B. Venturi-meter
C.
Orifice meter D.
(b) and (c)
Answer: Option D
32. One cumec is equivalent to
A.1
m3/sec B. 1000
m3/sec
C.100
m3/sec D.
1000 liters/sec
Answer: Option A
33.
The Bernoulli’s theorem depends on
A. Principle of conservation of
mass
B. Principle of conservation of
energy
C. Principle of conservation of
momentum
D. None of the above
Answer: Option B
34. Laminar flow occurs at
A.
low velocity B. High
velocity
C.
High viscosity D. low
viscosity
Answer: Option A
35.
Pitot tube is used for measurement of
A.
Pressure
B. Flow
C.
Velocity at a point D. Discharge
Answer: Option C
36. Pitot-tube is used to measure
A.
Discharge B.
Average velocity
C.
Velocity at a point D.
Pressure at a point
Answer: Option C
37. Venturimeter
is used to measure
A.
Discharge B.
Average velocity
C.
Velocity at a point D.
Pressure at a point
Answer: Option A
38. Orifice meter is used to measure
A. Discharge B.
Average velocity
C. Velocity at a point D. Pressure at a point
Answer: Option A
39. The angle of convergent cone is
A.
200 B. 400
C.
50 D. 70
Answer: Option A
40. The length of the convergent cone is equal to
A.
7.5 d B. 5d
C.
2.5 d D. 8 d
Answer: Option C
41. An average value of co-efficient of velocity
is
A.
0.62 B. 0.76
C.0.84 D. 0.97
Answer: Option D
42. Theoretical discharge is given by
A.
CC a√2gh B. Cd
a√2gh
C.
Cr a√2gh D. a√2gh
Answer: Option D
43. The discharge over a rectangular notch is
A. Inversly proportional to H3/2
B. Directly proportional to H3/2
C. Inversly proportional to H5/2
D. Directly proportional to H5/2
Answer: Option B
44. The discharge over a triangular notch is
A. Directly proportional to H5/2
B. Inversly proportional to H5/2
C. Directly proportional to H3/2
D. Inversly proportional to H3/2
Answer: Option A
45.
The
discharge through a rectangular weir is proportional to
A.
H B. H3/2
C.H1/2 D. H2
E. H5/2
Answer: Option B
46. The discharge through a V-notch weir varies as
A.
H1/2 B.
H3/2
C.
H5/2 D. H1/2
E. H
Answer: Option C
47. The horizontal to vertical side slopes in case
of cippoletiweir is
A.
1:1 B. 1:4
C.
4:1 D. 1:√2
E.
1:2
Answer: Option B
48.
For the laminar flow through a circular pipe
A. The max. velocity=1.5 times
the average velocity
B. The max. velocity=2.0 times
the average velocity
C. The max. velocity=2.5 times
the average velocity
D. None of the above
Answer: Option B
49.
Hydraulic gradient line (H.G.L) represents the
sum of
A. Pressure head and kinetic head
B. Kinetic head and datum head
C. Pressure head, kinetic head
and datum head
D. Pressure head and datum head
Answer: Option D
50.
Total energy line (T.E.L) represents the sum
of
A. Pressure head and kinetic head
B. Kinetic head and datum head
C. Pressure head and datum head
D. Pressure head, kinetic head
and datum head
Answer: Option D
51. The value closure is said to be gradual if the
time required to close the value
A.
P/A B. A/P
C.A*P D. 1/A*P
Where
A= Area and P= Wetted perimeter
Answer: Option B
52. The hydraulic mean depth for a circular pipe
of diameter (d) is
A.
d/6 B. d/4
C.
d/2 D. d
Answer: Option B
53. According to Darcy’s formula, the loss of head
due to friction in the pipe is
A.
f lv2/gd B. f lv2/2gd
C.
3f lv2/gd D.
4f lv2/gd
Answer: Option B
54. The purpose of surge tank is
A. To control the pressure
variations due to rapid changes in the pipe line flow
B. To eliminate water hammer
possibilities
C. To regulate flow of water to
turbines by providing necessary regarding head of water
D. All of the above
E. None of the above
Answer: Option D
55. A pipe is said to be a long pipe, if l/D is
A. Less than 500
B. Greater than 500
C. Equal to 500
D. Greater than or equal to 500
Answer: Option D
56. Darcy’s equation is valid for
A. laminar
flow only
B. Turbulent
flow only
C. Both
laminar and turbulent flow
D. None
Answer: Option C
57. The pressure rise due to sudden rise of value
is called
A.
Cavitation B. Knocking
C.
Uplift D. Water hammer
Answer: Option D
58. Syphon is a device by which water runs up hill
due to
A.
Static pressure B. Atmospheric pressure
C.
Total head D.
None of the above
Answer: Option B
59. In circular pipes of laminar flow, velocity
varies
A.
Curved path B.
Straight line
C.
zero D.
Parabolically
Answer: Option D
60. The most economical section of rectangular
channel is one which has hydraulic radius equal to
A.
Half the depth B. Half the breadth
C.
Twice the depth D. Twice the breadth
Answer: Option A
61. The most economical section of a trapezoidal
channel is one which has hydraulic means depth equal to
A.
½ depth B. ½ dreadth
C.1/2
sloping side D. ¼
(depth+breadth)
Answer: Option A
62. Kinetic energy in a rectangular channel is
equal to
A.
2/3 Emin B. 1/3 Emin
C.
3/2 Emin D.
3 Emin
Answer: Option B
63. The max. suction head provided to avoid the
separation of water is
A.
2.5m B. 7.5m
C.
5.2m D. 7m
Answer: Option B
64. The specific speed (Ns) of a
centrifugal pump is given by
A.
N√Q/H2/3 B.
N√Q/H3/4
C.
N√Q/H D. N√Q/H5/4
Answer: Option B
65.
A pelton wheel is an
A. Axial flow impulse turbine
B. Inward flow impulse turbine
C. Outward flow impulse turbine
D. Outward flow reaction
turbine
Answer: Option A
66. The number of buckets on the periphery of a
pelton wheel is given by
A.
D/2d+5 B.
D/2d+10
C.
D/2d+15 D. D/2d+20
Answer: Option C
67.
In a flancis turbine runner, the number of
blades are generally between
A.
2 to 4 B. 4 to
8
C. 8 to 16 D.
16 to 24
Answer: Option D
68. In a Kaplan turbine runner, the number of
blades are generally between
A.2
to 4 B. 4 to
8
C.
8 to 16 D. 16 to 24
Answer: Option B
69. The power developed by a turbine is
A. Directly proportional to H1/2
B. Inversely proportional to H1/2
C. Directly proportional to H3/2
D. Inversely proportional to H3/2
Answer: Option C
70. The specific speed of a turbine is given by
the equation
A.
N√P/H3/2 B.
N√P/H2
C.
N√P/H5/4 D.
N√P/H3
Answer: Option C
71. A
draft tube is used with
A. Reaction turbines
B. Impulse turbines
C. Both of the above
D. None of the above
Answer: Option A
72. The cavitation in a hydraulic machine is
mainly due to
A.
Low velocity B. High
velocity
C.
low pressure D. High pressure
Answer: Option C
73. A
turbine is a hydraulic machine where in
A. Hydraulic energy is converted
into mechanical energy
B. Hydraulic energy is converted
into electrical energy
C. Mechanical energy is converted
into hydraulic energy
D. Electrical energy is converted
into hydraulic energy
Answer: Option A
74. Flow
in pipes is turbulent, if the Reynold’s number is
A. Less than 2100
B. Between 2100 and 4000
C. More than 4000
D. Equal to 2500 only
Answer: Option C
75.
Specific speed of a turbine is
A.
N√P/H3/2 B.
N√Q/H3/4
C.
N√P/H5/4 D.
N√Q/H5/4
Answer: Option C
76.
A draft tube
A. Reduces mechanical losses in
turbines
B. Reduces cavitation in turbines
C. Increases effective head on
the turbine
D. Increases discharge in the
turbine
Answer: Option C
77. Piezo
metric head is
A.
P/W+z B. P/W
C.
P+wz D. P+z
Answer: Option A
78. Relation between Cc, Cv and
Cd is
A.
Cc=Cd*Cv B. Cd=Cv/Cc
C.
Cd=Cc*Cv D.
Cd=(Cc*Cv)2
Answer: Option C
79. Head
loss due to sudden expansion is
A.
(v1-v2)/2g B. (v1-v2)2/2g
C.
(v1-v2)3/2g D.
v(v1-v2)2g
Answer: Option B
80. The relation between chezy’s constant (c) and
mannings (n) is
A. C=R2/3/n B. C=R1/6/n
C. C=R1/3/n D. C=R1/2/n
Answer: Option B
81. The conditions for critical flow in open
channel is
A.Q2/g=A2/T2 B. Q2/g=A2/T
C.
Q3/g=A/T D.
Q2/g=A3/T
Answer: Option D
82. The
head over a crippoletti weir is H. The discharge is proportional to
A.
H2.5 B. H1.5
C.
H0.75 D.
H0.5
Answer: Option B
83. Spherical
shape of droplet of mercury is due to
A.
high density B. high surface tension
C.
high adhesion D. water
Answer: Option B
84. The
liquid used in manometer should have
A.
low density B. high density
C.
low surface tension D. high surface
tension
Answer: Option B
85. For
a fluid, the shear stress was found to be directly proportional to the rate of
angular deformation. The fluid is classified as
A.
Newtonian B. Non Newtonian
C.
Dilatant fluid D. thixotropic
Answer: Option A
86. 1
bar =------- N/m2
A.
102 B. 103
C.
104 D.
105
Answer: Option D
87. Mercury
is considered as a superior barometric fluid chiefly due to its
A.
Negligible small vapour pressure B. high specific heat
C.
high specific gravity D. convex meniscus
Answer: Option C
88. Surface
tension of water
A.
increase with decrease in temperature
B.
decrease with decrease in temperature
C.
independent of temperature
D. none
of these
Answer: Option C
89. If
angle of contact of a drop of liquid is acute, the
A.
adhesion is more than cohesion
B.
cohesion is more than adhesion
C.
cohesion is equal to adhesion
D.
adhesion and cohesion have no bearing with angle of contact
Answer: Option A
90. The
pressure in meters of oil (G =0.8), equivalent to 80m of water is
A.
64 B. 80
C.
100 D. 88
Answer: Option C
91. Stagnation
point is when
A.
pressure is zero B. total energy is zero
C.
velocity of reduce to zero D. Total
energy is maximum
Answer: Option C
92. For
laminar flow in pipes, the momentum correction factor is
A.
1 B. 1.15
C.
1.33 D. 2.0
Answer: Option C
93. For
turbulent flow in pipes, the momentum correction factor is
A.
1.02 to 1.05 B. 1.15
C.
1.33 D. 2.0
Answer: Option A
94. In
a free vortex, velocity
A.
decreases with radius B. increase
with radius
C.
is constant D. varies inversely as the
square of the radius
Answer: Option A
95. The
range of coefficient of discharge of a venturimeter is
A.
0.5 to 0.6 B. 0.62 to 0.73
C.
0.7 to 0.8 D. 0.95 to
0.99
Answer: Option D
96. The
kinetic energy correction factor for laminar flow through a circular pipe is
A.
1 B. 1.15
C.
1.33 D. 2.0
Answer: Option D
97. The
kinetic energy correction factor for turbulent flow through a circular pipe is
A.
1.01 to 1.20 B. 1.15
C.
1.33 D. 2.0
Answer: Option A
98. In
a flow field, the streamlines and equipotential lines are
A.
Parallel B. perpendicular
C.
cut at any angle D.
none of these
Answer: Option B
99. Stream
lines, streak lines, path lines are all identical in case of
A.
uniform flow B. non uniform flow
C.
steady flow D. unsteady flow
Answer: Option C
100. The difference in elevation between
a H.G.L and total gradient line at a point is equal to
A.
datum head B. velocity head
C.
pressure head D. Piezometric
head
Answer: Option B
No comments:
Post a Comment