Important MCQ on Hydraulics
1) The mass per unit volume of a liquid at a standard temperature and pressure is called
(a) specific weight
(b) mass density✓
(c) specific gravity
(d) none of these
2) The weight per unit volume of a liquid at a standard temperature and pressure is called
(a) specific weight✓
(b) mass density
(c) specific gravity
(d) none of these
3) The specific weight of water in S.I. units is taken as
(a) 9.81 kN/m3
(b) 9.81 x 103 N/m3
(c) 9.81 x 10-6 N/mm3
(d) any of these✓
4)The ratio of specific weight of a liquid to the specific weight of pure water at a standard temperature is called
(a) density of liquid
(b) specific gravity of liquid✓
(c) compressibility of liquid
(d) surface tension of liquid
5) The specific gravity of water is taken as
(a) 0.001
(b) 0.01
(c) 0.1
(d) 1✓
6) The mass of 2.5 m3 of a certain liquid is 2 tonnes. Its mass density is
(a) 200 kg / m3
(b) 400 kg / m3
(c) 600 kg / m3
(d) 800 kg / m3✓
7) The specific gravity of an oil whose specific weight is 7.85 kN / m3, is
(a) 0.8✓
(b) 1
(c) 1.2
(d) 1.6
8) The force per unit length is the unit of
(a) surface tension✓
(b) compressibility
(c) capillarity
(d) viscosity
9) The variation in the volume of a liquid with the variation of pressure is called its
(a) surface tension
(b) compressibility✓
(c) capillarity
(d) viscosity
10) The mercuty does not wet the glass. This is due to the property of the liquid known as
(a) cohesion
(b) adhesion
(c) viscosity
(d) surface tension ✓
11) With an increase in size of tube, the rise or depression of liquid in the tube due to surface tension will
(a) decrease
(b) increase
(c) remain unchanged
(d) depend upon the characteristics of liquid✓
12) The unit of surface tension is
(a) N / m✓
(b) N / m2
(c) N / m3
(d) N - m
13) Falling drops of water become spheres due to the property of
(a) surface tension of water✓
(b) compressibility of water
(c) capillarity of water
(d) viscosity of water
14) The pressure at a point 4 m below the free surface of water is
(a) 19.24 kPa
(b) 29.24 kPa
(c) 39.24 kPa✓
(d) 49.24 kPa
15) The height of a water column equivalent to a pressure of 0.15 MPa is
(a) 15.3 m✓
(b) 25.3 m
(c) 35.3 m
(d) 45.3 m
16) The pressure measured with the help of a pressure gauge is called
(a) atmospheric pressure
(b) gauge pressure✓
(c) absolute pressure
(d) mean pressure
17) The atmospheric pressure at sea level is
(a) 103 kN / m3
(b) 10.3 m of water
(c) 760 mm of mercury
(d) all of the above✓
18) The absolute pressure is equal to
(a) gauge pressure + atmospheric pressure✓
(b) gauge pressure - atmospheric pressure
(c) atmospheric pessure - gauge pressure
(d) gauge pressure - vacuum pressure
19) The pressure less than atmospheric pressure is known as
(a) suction pressure
(b) vacuum pressure
(c) negative gauge pressure
(d) all of these✓
20) The pressure of a liquid measured with the help of a piezometer tube is
(a) vacuum pressure
(b) gauge pressure✓
(c) absolute pressure
(d) atmospheric pressure
21) The pressure measured with the help of a piezometer tube is in
(a) N / mm2
(b) N / m2
(c) head of liquid✓
(d) all of these
22) A piezometer tube is used only for measuring
(a) low pressure
(b) high pressure
(c) moderate pressure✓
(d) vacuum pressure
23) The liquid used in manometers should have
(a) low density
(b) high density
(c) low surface tension
(d) high surface tension✓
24) A manometer is used to measure
(a) atmospheric pressure
(b) pressure in pipes and channels✓
(c) pressure in venturimeter
(d) difference of pressures between two points in a pipe
25) A manometer is used to measure
(a) low pressure
(b) moderate pressure
(c) high pressure✓
(d) atomospheric pressure
26) The point at which the resultant pressure on an immersed surface acts, is known as
(a) centre of gravity
(b) centre of depth
(c) centre of pressure✓
(d) centre of immersed surface
27) A water tank contains 1.3 m deep water. The pressure exerted by the water per metre length of the tank is
(a) 2.89 kM
(b) 8.29 kN✓
(c) 9.28 kN
(d) 28.9 kN
28) When a vertical wall is subjected to pressures due to liquid on both sides, the resultant pressure is the
(a) sum
(b) difference✓
(c) arithmatic mean
(d) geometric mean
29) The stability of a dam is checked for
(a) tension at the base
(b) overturning of the wall or dam
(c) sliding of the wall or dam
(d) all of these✓
30) The force of buoyancy is always
(a) equal to✓
(b) less than
(c) more than
31) The centre of gravity of the volume of the liquid displaced is called
(a) centre of pressure
(b) centre of buoyancy✓
(c) metacentre
(d) none of these
32) The buoyancydepends upon the
(a) weight of the liquid displaced✓
(b) pressure with which the liquid is displaced
(c) viscosity of the liquid
(d) compressibility of the liquid
33) The metacentric height of a ship is 0.6 m and the radius of gyration is 4 m. The time of rolling of a ship is
(a) 4.1s
(b) 5.2s
(c) 10.4s✓
(d) 14.1s
34) One litre of water occupies a volume of
(a) 100 cm3
(b) 250 cm3
(c) 500 cm3
(d) 1000 cm3✓
35) One cubic metre of water weighs
(a) 100 Liters
(b) 500 Liters
(c) 250Liters
(d) 1000 Liters✓
36) A flow in hich the quantity of liquid flowing per second is constant, is called
(a) steady ✓
(b) stream line
(c) turbulent
(d) unsteady
37) A flow in which the quantity of liquid flowing per second is not constant, is called
(a) streamline flow
(b) turbulent flow
(c) steady flow
(d) unsteady flow✓
38) According to equation of continuity,
(a) w1a1 = w2a2
(b) w1v1 = w2v2
(c) a1v1 = a2v2✓
(d) a1/v1 = a2/v2
39) A flow through a long pipe at constant rate is called
(a) steady uniform flow✓
(b) steady non-uniform flow
(c) unsteady uniform flow
(d) unsteady non-uniform flow
40) A flow through an expanding tube at constant rate is called
(a) steady uniform flow
(b) steady non-uniform flow✓
(c) unsteady uniform flow
(d) unsteady non-uniform flow
41) A flow whose streamline is represented by a curve, is called
(a) one-dimensional flow
(b) two-dimensional flow✓
(c) three-dimensional flow
(d) four-dimensional flow
42) A flow whose streamline is represented by a straight line, is called
(a) one ✓
(b) Two
(c) Three
(d) Four
43) In one dimensional flow, the flow
(a) is steady and uniform
(b) takes place in straight line✓
(c) takes place in curve
(d) takes place in one direction
44) The total head of a liquid particle in motion is equal to
(a) pressure head + kinetic head + potential head✓
(b) pressure head - (kinetic head + potential head)
(c) potential head - (pressure head + kinetic head)
(d) kinetic head - (pressure hed + potential head)
45) The Bernoulli's equation is based on the assumption that
(a) there is no loss of energy of the liquid flowing
(b) the velocity of flow is uniform across any cross-section of the pipe
(c) no force except gravity acts on the fluid
(d) all of the above✓
46) Bernoulli's equation is applied to
(a) venturimeter
(b) orifice meter
(c) pitot tube
(d) all of these✓
47) Barometer is used to measure
(a) velocity of liquid
(b) atmospheric pressure✓
(c) pressure in pipes and channels
(d) difference of pressure between two points in a pipe
48) Venturimeter is used to
(a) measure the velocity of a flowing liquid
(b) measure the pressure of a flowing liquid
(c) measure the discharge of liquid flowing in a pipe✓
(d) measure the pressure difference of liquid flowing between two points in a pipe line
49) The length of the divergent cone in a venturimeter is
(a) equal to
(b) double
(c) three to four times✓
(d) five to six times
50) In order to measure the flow with a venturimeter, it is installed in
(a) horizontal line
(b) inclined line with flow upwards
(c) inclined line with flow downwards
(d) any direction and in any location✓
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| Important MCQ on Hydraulics |
51) A pitot tube is used to measure the
(a) velocity of flow at the required point in a pipe
(b) pressure difference between two points in a pipe
(c) total pressure of liquid flowing in a a pipe
(d) discharge through a pipe✓
52) A jet of water discharging from a 40 mm diameter orifice has a diameter of 32 mm at its vena contract(a) The coefficient f contraction is
(a) 0.46
(b) 0.64✓
(c) 0.78
(d) 0.87
53) Coefficient of velocity is defined a the ratio of
(a) actual velocity of jet at vena contracta to the theoretical velocity✓
(b) area of jet at vena contracta to the area of orifice
(c) actual discharge through an orifice to the theoretical discharge
(d) none of the above
54) An average value of coefficient of velocity is
(a) 0.62
(b) 0.76
(c) 0.84
(d) 0.97✓
55) An orifice is said to be large, if
(a) the size of orifice is large
(b) the velocity of flow is large
(c) the available head of liquid is more than 5 times the height of orifice
(d) the available head of liquid is les than 5 times the height of orifice✓
56) A pipe of length more than double the diameter of orifice fitted externally or internally to the orifice is called a
(a) notch
(b) weir
(c) mouthpiece✓
(d) nozzle
57) In a short cylindrical external mouthpiece, the vena contracta occurs at a distance
(a) equal to
(b) one-fourth✓
(c) one-third
(d) one-half
58) The coefficient of discharge for an external mouthpiece depends upon
(a) velocity of liquid
(b) pressure of liquid
(c) area of outhpiece
(d) length of mouthpiece✓
59) The coefficient of discharge for an external mouthpiece is
(a) 0.375
(b) 0.5
(c) 0.707
(d) 0.855✓
60) An internal mouthpiece is said to be running free if the length of the mouthpiece is
(a) less than twice
(b) more than twice
(c) less than three times✓
(d) more than three times
61) The discharge through a convergent mouthpiece is
(a) equal to
(b) one-half
(c) three fourth
(d) double✓
62) A notch is used to measure
(a) pressure
(b) Disagree✓
(c) velocity
(d) volume
63) If the coefficient of discharge is 0.6, then the discharge over a right angled notch is
(a) 0.417 H5/2
(b) 1.417 H5/2✓
(c) 4.171 H5/2
(d) 7.141 H5/2
64) The discharge over a rectangular notch is
(a) inversely proportional to H3/2
(b) directly proportional to H3/2✓
(c) inversely proportional to H5/2
(d) directly proportional to H5/2
65) The discharge over a triangular notch is
(a) inversely proportional to H3/2
(b) directly proportional to H3/2
(c) inversely proportional to H5/2
(d) directly proportional to H5/2✓
66) An error of 1% in measureing head over the crest of the notch (H) will produce an error of
(a) 1%
(b) 1.50%✓
(c) 2%
(d) 2.5%
67) An error of 1% in measuring head over the apex of the notch (H) will produce an error of
(a) 1%
(b) 1.50%
(c) 2%
(d) 2.50%✓
68) A structure used to dam up a stream or river over which the water flows is called
(a) orifice
(b) notch
(c) weir✓
(d) dam
69) The sheet of water flowing over a notch or a weir is known as
(a) sill or crest
(b) nappe or vein✓
(c) orifice
(d) none of these
70) To to of the weir over whch the water flows in known as
(a) sill or crest✓
(b) nappe or vein
(c) oriffice
(d) none of thes
71) When the corfficient of discharge (Cd) is 0.623, then the general equation for discharge over a rectangular weir is
(a) 1.84 (L-0.1 nH) H3/2✓
(b) 1.84 (L-nH) H2
(c) 1.84 (L-0.1 nH) H5/2
(d) 1.84 (L-nH) H3
72) The Cippoletti weir is a
(a) rectangular
(b) triangular
(c) trapezoidal✓
(d) circular
73) The Francis formula for the discharge over Cippoletti weir is
(a) 1.84 LH1/2
(b) 1.84 LH
(c) 1.84 LH3/2✓
(d) 1.84 LH5/2
74) The maximum discharge over a broad crested eir is
(a) 0.384 Cd x L x H1/2
(b) 0.384 Cdx L x H3/2
(c) 1.71 Cd x L x H1/2
(d) 1.71 Cd x L x H3/2✓
75) A weir, generally, used as a spillway of a dam is
(a) narrow crested weir
(b) broad crested weir
(c) Ogee weir✓
(d) submerged weir
76) In a free nappe,
(a) the pressure below the nappe is atmospheric✓
(b) the pressure below the nappe is negative
(c) the pressure above the nappe is atmospheric
(d) the presure above the nappe is negative
77) In a depressed nappe
(a) the pressure below the nappe is atmospheric
(b) the pressure below the nappe is negative✓
(c) the pressure above the nappe is atmospheric
(d) the pressure above the nappe is negative
78) The frictional resistance of a pipe varies approximately with
(a) pressure
(b) velocity
(c) square of velocity✓
(d) cube of velocity
79) The hydraulic mean depth or the hydaulic radius is the ratio of
(a) area of flow and wetted perimeter✓
(b) wtted perimeter and diameter of pipe
(c) velocity of flow and aea of flow
(d) none of these
80) The hydraulic mean depth for a circular pipe of diameter (d) is
(a) d / 6
(b) d / 4✓
(c) d / 2
(d) d
81) The total energy line lies over the hydraulic gradient line by an amount equal to the
(a) pressure head
(b) velocity head✓
(c) pressure head + velocity head
(d) pressure head - velocity head
82) The hydraulic gradient line lies over the centre line f the pipe by an amount equal to the
(a) pressure head✓
(b) velocity head
(c) pressure head + velocity head
(d) pressure head - velocity head
83) The total energy line lies over the centre line of the pipe by an amount equal to
(a) pressure head
(b) velocity head
(c) pressure head + velocity head✓
(d) pressure head - velocity head
84) The maximum efficiency of transmission through a pipe is
(a) 50%
(b) 56.70%
(c) 66.67%✓
(d) 76.66%
85) An air vessel is provided at the summit in a syphon to
(a) avoid interruption in the flow✓
(b) increase discharge
(c) increase velocity
(d) maintain pressure difference
86) A nozzle is generally made of
(a) cylindrical shape
(b) convergent shape✓
(c) divergent shape
(d) convergent-divergent shape
87) A nozzle placed at the end of a water pipe line discharges water at a
(a) low pressure
(b) high pressure
(c) low velocity
(d) High velocity✓
88) The velocity through a channel of circular section will be maximum when the depth of water is
(a) 0.34 times
(b) 0.67 times
(c) 0.81 times✓
(d) 0.95 times
89) The highest efficiency is obtained with a channel of
(a) circular
(b) square
(c) rectangular
(d) trapezoidal✓
90) If the depth of water in an open channel is greater than the critical depth, the flow is called
(a) critical flow
(b) turbulent flow
(c) tranquil flow✓
(d) torrential flow
91) If the depth of water in an open channel is less than the critical depth, the flow is called
(a) critical flow
(b) turbulent flow
(c) tranquil flow
(d) torrential flow✓
92) The most efficient section of a channel is
(a) triangular
(b) rectangular
(c) square
(d) trapezoidal✓
93) The critical depth meter is used to measure
(a) velocity of flow in an open channel
(b) depth of flow in an open channel
(c) hydraulic jump✓
(d) depth of channel
94) The coefficient of venturiflume, generally lies between
(a) 0.3 to 0.45
(b) 0.50 to 0.75
(c) 0.75 to 0.95
(d) 0.95 to 1.0✓
95) The unit of dynamic viscosity in S.I. units is
(a) N-m/s2
(b) N-s/m2✓
(c) poise
(d) stoke
96) One poise is equal to
(a) 0.1 N-s/m2✓
(b) 1 N-s/m2
(c) 10 N-s/m2
(d) 100 N-s/m2
97) The kinematic viscosity is the
(a) ratio of absolute viscosity to the density of the liquid✓
(b) ratio of density of the liquid to the absolute viscosity
(c) product of absolute viscosity and density of the liquid
(d) product of absolute viscosity and mass of the liquid
98) Stoke is the unit of
(a) kinematic viscosity in (c) G.S. units✓
(b) kinematic viscosity in M.K.S. units
(c) dynamic viscosity in M.K.S. units
(d) dynamic viscosity in S.I. units
99) One stoke is equal to
(a) 10-2m2/s
(b) 10-3m2/s
(c) 10-4m2/s✓
(d) 10-6m2/s
100) The unit of kinematic viscosity in S. I. units is
(a) N-m/s
(b) N-s/m2
(c) m2/s✓
(d) N - m
101) The viscosity of water at 20? C is
(a) one stoke
(b) one centistroke
(c) on poise
(d) one centipoise✓
102) A fluid having no viscosity is known as
(a) real fluid
(b) ideal fluid✓
(c) newtonian fluid
(d) non-newtonian fluid
103) A fluid which obeys the Newton's law of viscosity is termed as
(a) real fluid
(b) ideal fluid
(c) newtonian fluid✓
(d) non-newtonian fluid
104) Water is a
(a) real
(b) ideal
(c) newtonian ✓
(d) non-newtonian
105) A flow in which the viscosity of fluid is dominating over the inertia force is called
(a) steady flow
(b) unsteady flow
(c) laminar flow✓
(d) turbulent flow
106) A flow in which
(a) elastic
(b) surface tension
(c) viscous
(d) inertia✓
107) The velocity at which the flow changes from laminar flow to turbulent flow is called
(a) critical velocity✓
(b) velocity of approach
(c) sub-sonic velocity
(d) super-sonic velocity
108) Reyold's number is the ratio of the inertia force to the
(a) surface tension force
(b) viscous force
(c) gravity force
(d) elastic force✓
109) The flow in a pipe is turbulent when Reynold number is
(a) less than 2000
(b) between 2000 and 2800
(c) more than 2800✓
(d) none of these
110) The vlow in a pipe is neither laminar nor turbulent when Reynold number is
(a) less than 2000
(b) between 2000 and 2800✓
(c) more than 2800
(d) none of these
111) The velocity corresponding to Reynold number of 2000 is called
(a) sub-sonic velocity
(b) super-sonic velocity
(c) lower critical velocity✓
(d) higher critical velocity
112) The velocity corresponding to Reynold number of 2800, is called
(a) sub-sonic velocity
(b) super-son velocity
(c) lower critical velocity
(d) higher critical velocity✓
113) The loss of pressure head in case of laminar flow is proportional to
(a) velocity✓
(b) (velocity)2
(c) (velocity)3
(d) (velocity)4
114) The coefficient of viscosity may be determined by
(a) capillary tube method
(b) orifice type viscometer
(c) rotating cylinder method
(d) all of these✓
115) Bulk modulus of a fluid is the ratio of
(a) shear stress to shear strain
(b) increase in volume to the viscosity of fluid
(c) increase in pressure to the volumetric strain✓
(d) critical veloity to the viscosity of fluid
116) When the Mach number is less than unity, the flow is called
(a) sub-sonic flow✓
(b) sonic flow
(c) super-sonic flow
(d) hyper-sonic flow
117) When the Mach number is between
(a) 1 and 2.5
(b) 2.5 and 4
(c) 4 and 6
(d) 1 and 6✓
118) When the Mach number is more than 6, the flow is called
(a) sub-sonic flow
(b) sonic flow
(c) super-sonic flow
(d) hyper-sonic flow✓
119) A flow is called sub-sonic, if the Mach number is
(a) less than unity✓
(b) unity
(c) between 1 and 6
(d) more than 6
120) A flow is called super-sonic if the
(a) velocity of flow is very high
(b) discharge is difficult to measure
(c) Mach number is between 1 and 6✓
(d) none of these
121) A flow is called hyper-sonic, if the Mach number is
(a) less than unity
(b) unity
(c) between 1 and 6
(d) none of these✓
122) A point, in a compressible flow where the velocity of fluid is zero, is called
(a) critical point
(b) vena contracta
(c) stagnation point✓
(d) none of these
123) To force present in a moving liquid is
(a) inertia force
(b) viscous force
(c) gravity force
(d) all of these✓
124) To product of mass and accelaration of flowing liquid is called
(a) inertia force✓
(b) viscous force
(c) gravity force
(d) pressure force
125) Viscous force is the
(a) sum
(b) different
(c) product ✓
(d) ratio
126) The ratio of the inertia force to the viscous force is called
(a) Reynold's number✓
(b) Froude's number
(c) Weber's number
(d) Euler's number
127) The ratio of the inertia force to the
(a) pressure force✓
(b) elastic force
(c) surface tension force
(d) viscous force
128) The ratio of the inertia force to the elastic force is called
(a) Reynold's number
(b) Froude's number
(c) Weber's number
(d) Mach number✓
129) Froude's number is the ratio of inertia force to
(a) pressure force
(b) elastic force
(c) gravity force✓
(d) surface tension force
130) Euler's number is the ratio of _____force to pressure force.
(a) inertia ✓
(b) gravity
(c) viscous
131) Reynold's number is the ratio of inertia force to
(a) pressure force
(b) elastic force
(c) gravity force
(d) viscous force✓
132) The value of bulk modulus of a fluid is required to determine
(a) Reynold's number
(b) Froude's number
(c) Mach number ✓
(d) Euler's number
