# Fluid Mechanics(FM) MCQs Practice Set-1

1.The mass per unit volume of a liquid at a standard temperature and pressure is called

- Specific weight
- Mass density (Ans)
- Specific gravity
- None of these

2.The weight per unit volume of a liquid at a standard temperature and pressure is called

- Specific weight (Ans)
- Mass density
- Specific gravity
- None of these

3.The specific weight of water in S.I. units is taken as

- 81 kN/m
^{3} - 81*10
^{3 }N/m^{3} - 81*10
^{-6}N/mm^{3} - Any one of these (Ans)

4.The ratio of specific weight of a liquid to the specific weight of pure water at a standard temperature is called

- Density of liquid
- Specific gravity of liquid (Ans)
- Compressibility of liquid
- Surface tension of liquid

5.The specific gravity of water is taken as

- 001
- 01
- 1
- 1 (Ans)

6.The property of a liquid which offers resistance to the movement of one layer of liquid over another adjacent layer of liquid, is called

- Surface tension
- Compressibility
- Capillarity
- Viscosity (Ans)

7.The force per unit length is the unit of

- Surface tension (Ans)
- Compressibility
- Capillarity
- Viscosity

8.The variation in the volume of a liquid with the variation of pressure is called its

- Surface tension
- Compressibility (Ans)
- Capillarity
- Viscosity

9.When a tube of smaller diameter is dipped in water, the water rises in the tube with an upward ………………… surface.

- Concave (Ans)
- Convex

10.A glass tube of smaller diameter is used while performing an experiment for the capillary rise of water because

- It is easier to see through the glass tube (Ans)
- Glass tube is cheaper than a metallic tube
- It is not possible to conduct this experiment with any other tube
- All of the above

11.The mercury does not wet the glass. This is due to the property of the liquid known as

- Cohesion
- Adhesion
- Viscosity
- Surface tension (Ans)

12.With an increase in size of tube, the rise or depression of liquid in the tube due to surface tension will

- Decrease (Ans)
- Increase
- Remain unchanged
- Depend upon the characteristics of liquid

13.The surface tension of mercury at normal temperature is ………… that of water

- Same as
- Lower than
- Higher than (Ans)

14.The unit of surface tension is

- N/m (Ans)
- N/m
^{2} - N/m
^{3} - N-m

15.Falling drops of water become spheres due to the property of

- Surface tension of water (Ans)
- Compressibility of water
- Capillarity of water
- Viscosity of water

16.The intensity of pressure at any point, in a liquid, is

- Directly proportional to the area of the vessel containing liquid
- Directly proportional to the depth of liquid from the surface (Ans)
- Directly proportional to the length of the vessel containing liquid
- Inversely proportional to the depth of liquid from the surface

17.The pressure intensity in kN/m^{2}(or kPa) at any point in a liquid is

- w
- wh (Ans)
- w/h
- h/w

where w= Specific weight of liquid, and

h= Depth of liquid from the surface

18.The pressure at a point 4 m below the free surface of water is

- 24 kPa
- 24 kPa
- 24 kPa (Ans)
- 24 kPa

19.The height of a water column equivalent to a pressure of 0.15 MPa is

- 3 m (Ans)
- 3 m
- 3 m
- 3 m

20.The intensity of pressure at any point, in a liquid, is ………………. To the depth of liquid from the surface.

- Equal
- Directly proportional (Ans)
- Inversely proportional

21.The pressure measured with the help of a pressure gauge is called

- Atmospheric pressure
- Gauge pressure (Ans)
- Absolute pressure
- Mean pressure

22.The Atmospheric pressure at sea level is

- 103 KN/m
^{2} - 3 m of water
- 760 mm of mercury
- All of these (Ans)

23.When the pressure intensity at a point is more than the local atmospheric pressure, then the difference of these two pressures is called

- Gauge pressure
- Absolute pressure
- Positive Gauge pressure (Ans)
- vacuum pressure

24.The absolute pressure is equal to

- Gauge pressure + atmospheric pressure (Ans)
- Gauge pressure – atmospheric pressure
- Atmospheric pressure – Gauge pressure
- Gauge pressure – vacuum pressure

25.The pressure less than atmospheric pressure is known as

- Suction pressure
- Vacuum pressure
- Negative gauge pressure
- All of these (Ans)

26.The pressure of a liquid measured with the help of a piezometer tube is

- Vacuum pressure
- Gauge pressure (Ans)
- Absolute pressure
- Atmospheric pressure

27.The pressure measured with the help of a piezometer tube is in

- N/mm
^{2} - N/m
^{2} - Head of liquid (Ans)
- All of these

28.A piezometer tube is used only for measuring

- Low pressure
- High pressure
- Moderate pressure (Ans)
- Vacuum pressure

29.The liquid used in manometers should have

- Low density
- High density
- Low surface tension
- High surface tension (Ans)
- A manometer is used to measure
- Atmospheric pressure
- Pressure in pipes and channels (Ans)
- Pressure in venturimeter
- Difference of pressures between two points in a pipe

- A manometer is used to measure

- Low pressure
- Moderate pressure
- High pressure (Ans)
- Atmospheric pressure

32.A differential manometer is used to measure

- Atmospheric pressure
- Pressure in pipes and channels
- Pressure in venturimeter
- Difference of pressures between two points in a pipe (Ans)

33.The intensity of pressure on an immersed surface…………….with the increase in depth.

- Does not change
- Increases (Ans)
- Decreases

34.The power transmitted through the pipe is maximum when the head lost due to friction is equal to

- One-fourth of the total supply head
- One-third of the total supply head (Ans)
- One-half of the total supply head
- two-third of the total supply head

35.The maximum efficiency of transmission through a pipe is

- 50%
- 7%
- 67% (Ans)
- 66%

36.The point at which the resultant pressure on an immersed surface acts, is known as

- Centre of gravity
- Centre of depth
- Centre of pressure (Ans)
- Centre of immersed surface

37.A compound pipe is required to be replaced by a new pipe. The two pipes are said to be equivalent, if

- Length of both the pipes is same
- Diameter of both the pipes is same
- Loss of head and discharge of both the pipes is same (Ans)
- Loss of head and velocity of flow in both the pipes is same

38.In case of flow through parallel pipes,

- The head loss for all the pipes is same (Ans)
- The total discharge is equal to the sum of discharges in the various pipes (Ans)
- The total head loss is the sum of head losses in the varies pipes
- All of the above

39.A vertical wall is subjected to a pressure due to one kind of liquid, on one of its sides. The total pressure on the wall per unit length is

- wH
- wH /2
- wH
^{2}/2 (Ans) - wH
^{2}/3

Where w= Specific weight of liquid, and

H= Height of liquid

40.A water tank contains 1.3 m deep water. The pressure exerted by the water per metre length of the tank is

- 89 kN
- 29 kN (Ans)
- 28 kN
- 9 kN

- A vertical wall is subjected to a pressure due to one kind of liquid, on one of its sides. The total pressure on the wall acts at a distance………………..from the liquid surface.

- H/3
- H/2
- 2H/3 (Ans)
- 3H/4

42.When a vertical wall is subjected to a pressures due to liquid on both sides, the resultant pressure is the …………………………. Of the two pressures.

- Sum
- Difference (Ans)
- Arithmetic mean
- Geometric mean

43.The water pressure per metre length on a vertical masonry wall of dam is

- wH
- wH /2
- wH
^{2}/2 (Ans) - wH
^{2}/4

Where w= Specific weight of the liquid, and

H= Height of the liquid.

44.The stability of a dam is checked for

- tension at the base
- overturning of the wall or dam
- sliding of the wall or dam
- all of these (Ans)

45.When a body is placed over a liquid, it will sink down if

- gravitational force is equal to the upthrust of the liquid
- gravitational force is less than the upthrust of the liquid
- gravitational force is more than the upthrust of the liquid (Ans)
- none of the above

- When a body is placed over a liquid, it will float if

- gravitational force is equal to the upthrust of the liquid
- gravitational force is less than the upthrust of the liquid(Ans)
- gravitational force is more than the upthrust of the liquid
- none of the above

47.When a body is immersed wholly or partially in a liquid, it is lifted up by a force equal to the weight of liquid displaced by the body. This statement is called

- Pascal’s law
- Archimede’s principle (Ans)
- Principle of floatation
- Bernoulli’s theorem

48.The force of buoyancy is always …….. the weight of the liquid displaced by the body.

- Equal to (Ans)
- Less than
- More than

49.The body will float if the force of buoyancy is …………….. the weight of the liquid displaced.

- Equal to
- Less than
- More than (Ans)

50.The body will sink down if the force of buoyancy is …………. the weight of the liquid displaced.

- Equal to
- Less than (Ans)
- More than

- The centre of gravity of the volume of the liquid displaced is called.

- Centre of pressure
- Centre of buoyancy (Ans)
- Metacentre
- None of these

52.The buoyancy depends upon the

- Weight of the liquid displaced (Ans)
- Pressure with which the liquid is displaced
- Viscosity of the liquid
- Compressibility of the liquid

53.When a body, floating in a liquid, is given a small angular displacement, it starts oscillating about a point known as

- Centre of pressure
- Centre of buoyancy (Ans)
- Metacentre (Ans)
- Centre of gravity

54.The metacentric height is the distance between the

- Centre of gravity of the floating body and the centre of buoyancy
- Centre of gravity of the floating body and the metacentre (Ans)
- Metacentre and centre of buoyancy
- Original centre of buoyancy and new centre of buoyancy

55.If a body floating in a liquid returns back to its original position, when given a small angular displacement, the body is said to be in

- Neutral equilibrium
- Stable equilibrium (Ans)
- Unstable equilibrium
- None of these

- If a body floating in a liquid occupies a new position and remains at rest in this new position, when given a small angular displacement, the body is said to be in …… equilibrium.

- Neutral (Ans)
- Stable
- Unstable

57.A body floating in a liquid is said to be in neutral equilibrium, if its metacentre

- Coincides with its centre of gravity (Ans)
- Lies above its centre of gravity
- Lies below its centre of gravity
- Lies between the centre of buoyancy and centre of gravity

58.A submerged body is said to be in a stable equilibrium, if its centre of gravity ……………… the centre of buoyancy.

- Coincides with
- Lies below (Ans)
- Lies above

59.The time of oscillation (T) of a floating body is given by

- 2π√k
^{2}/h.g (Ans) - 2π√h.g/k
^{2} - 1/2π√ k
^{2}/h.g - 1/2π√ h.g/k
^{2}

60.One cubic metre of water weighs

- 100 litres
- 250 litres
- 500 litres
- 1000 litres (Ans)

61.One litre of water occupies a volume of

- 100 cm
^{3} - 250 cm
^{3} - 500 cm
^{3} - 1000 cm
^{3 }(Ans)

62.When a liquid is flowing through a pipe, the velocity of the liquid is

- Maximum at the centre and minimum near the walls (Ans)
- Minimum at the centre and maximum near the walls
- Zero at the centre and maximum near the walls
- Maximum at the centre and zero near the walls

63.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

- Path line
- Stream line (Ans)
- Steak line
- Potential line

64.The flow in a pipe or channel is said to be uniform when

- The liquid particles at all sections have the same velocities (Ans)
- The liquid particles at different sections have different velocities
- The quantity of liquid flowing per second is constant
- Each liquid particle has a definite path

65.The flow in a pipe or channel is said to be non-uniform when

- The liquid particles at all sections have the same velocities
- The liquid particles at different sections have different velocities(Ans)
- The quantity of liquid flowing per second is constant
- Each liquid particle has a definite path

66.A flow in which each liquid particle has a definite path, and the paths of individual particles do not cross each other, is called

- Steady flow
- Uniform flow
- Streamline flow (Ans)
- Turbulent flow

67.A flow in which the quantity of liquid flowing per second is constant, is called …………… flow.

- Steady (Ans)
- Streamline
- Turbulent
- Unsteady

- A flow in which the quantity of liquid flowing per second is constant, is called

- Steady flow
- Streamline flow
- Turbulent flow
- Unsteady flow (Ans)

69.which of the following statement is correct?

- In a compressible flow, the volume of the flowing liquid changes during the flow
- A flow in which the volume of the flowing liquid does not change, is called incompressible flow
- When the particles rotate about their own axes while flowing, the flow is said to be rotational flow
- All of the above (Ans)

70.According to equation of continuity

- w
_{1}a_{1 }= w_{2}a_{2} - w
_{1}v_{1}= w_{2}v_{2} - a
_{1}v_{1 }= a_{2}v_{2}(Ans) - a
_{1 }/v_{1}= a_{2 }/v_{2}

71.A flow through a long pipe at constant rate is called

- steady uniform flow (Ans)
- steady non-uniform flow
- unsteady uniform flow
- unsteady non-uniform flow

- A flow through a long pipe at decreasing rate is called ………………….. uniform flow.

- Steady
- Unsteady (Ans)

73.A flow through an expending tube at constant rate is called

- steady uniform flow
- steady non-uniform flow (Ans)
- unsteady uniform flow
- unsteady non-uniform flow

74.A flow whose streamline is represented by a curve, is called

- one-dimensional flow
- two- dimensional flow (Ans)
- three-dimensional flow
- four-dimensional flow

75.A flow in which the volume of a fluid and its density does not change during the flow is called …………… flow.

- Incompressible (Ans)
- Compressible

- A flow whose streamline is represented by a straight line, is called ……….. dimensional flow.

- One (Ans)
- Two
- Three
- Four

77.In one dimensional flow, the flow

- Is steady and uniform
- Takes place in straight line (Ans)
- Takes place in curve
- Takes place in one direction

78.The total energy of a liquid particle in motion is equal to

- Pressure energy + kinetic energy + potential energy(Ans)
- Pressure energy – (kinetic energy + potential energy)
- Potential energy – (pressure energy + kinetic energy)
- kinetic energy – (pressure energy + potential energy)

79.The total head of a liquid particle in motion is equal to

- Pressure head + kinetic head + potential head (Ans)
- Pressure head – (kinetic head + potential head)
- Potential head – (pressure head + kinetic head)
- kinetic head – (pressure head + potential head)

80.For a perfect incompressible liquid, flowing in a continuous stream, the total energy of a particle remains the same, while the particle moves from one point a another. This statement is called

- Continuity equation
- Bernoulli’s eqution (Ans)
- Pascal’s law
- Archimede’s principle

81.According to Bernoulli’s equation

- Z + p/w + v
^{2}/2g = constant (Ans) - Z + p/w – v
^{2}/2g = constant - Z – p/w + v
^{2}/2g = constant - Z – p/w – v
^{2}/2g = constant

82.Euler’s equation in the differential from for the motion of liquids is given by

- dp/p + g.dz + v.dv = 0 (Ans)
- dp/p – g.dz + v.dv = 0
- dp + g.dz + v.dv = 0
- dp – g.dz + v.dv = 0

83.The Bernoulli’s equation is based on the assumption that

- there is no loss of energy of the liquid flowing
- the velocity of flow is uniform across any cross-section of the pipe
- no force except gravity acts on the fluid
- all of the above (Ans)

84.The Euler’s equation for the motion of liquids is based upon the assumption that

- the fluid is non-viscous, homogeneous and incompressible
- the velocity of flow is uniform over the section
- the flow is continuous, steady and along the stream line
- all of the above (Ans)

85.Bernoulli’s equation is applied to

- venturimeter
- orifice meter
- pitot tube
- all of these (Ans)

86.Barometer is used to measure

- velocity of liquid
- atmospheric pressure (Ans)
- pressure in pipes and channels
- difference of pressure between two points in a pipe

87.Venturimeter is used to

- measure the velocity of a flowing liquid
- measure the pressure of a flowing liquid
- measure the discharge of liquid flowing in a pipe (Ans)
- measure the pressure difference of liquid flowing in a pipe line

- The length of the divergent cone in a venturimeter is …………… that of the convergent cone.

- Equal to
- Double
- Three to four times (Ans)
- Five to six times

89.In a venturimeter, the velocity of liquid at throat is ……….. than at inlet.

- Higher (Ans)
- Lower

90.The velocity of the liquid flowing through the divergent portion of a ventrimeter

- Remains constant
- Increases
- Decreases (Ans)
- Depends upon mass of liquid

91.In order to avid tendency of separate at throat in a venturimeter, the ratio of the diameter at throat to the diameter of pipe should be

- 1/16 to 1/8
- 1/8 to 1/4
- 1/4 to 1/3
- 1/3 to 1/2 (Ans)

92.The pressure of the liquid flowing through the divergent portion of a venturimeter

- Remains constant
- Increases
- Decreases (Ans)
- Depends upon mass of liquid

93.The divergent portion of a venturimeter is made longer than convergent portion in order to

- Avoid the tendency of breaking away the stream of liquid
- To minimise frictional losses
- Both (a) and (b) (Ans)
- None of these

94.In order to measure the flow with a venturimeter, it is installed in

- Horizontal line
- Inclined line with flow upwards
- Inclined line with flow downwards
- Any direction and in any location (Ans)

95.A pitot tube is used to measure the

- Velocity of flow at the required point in a pipe (Ans)
- Pressure difference between two points in a pipe
- Total pressure of liquid flowing in a pipe
- Discharge through a pipe

96.When the venturimeter is inclined, then for a given flow it will show ………….. reading.

- Same (Ans)
- More
- Less

97.Coefficient of contraction is the ratio of

- Actual velocity of jet at vena contracta to the theoretical velocity
- Loss of head in the orifice to the head of water available at the exit of the orifice
- Actual discharge through an orifice to the theoretical discharge
- Area of jet at vena contracta to the area of orifice (Ans)

98.Coefficient of resistance is the ratio of

- Actual velocity of jet at vena contracta to the theoretical velocity
- Loss of head in the orifice to the head of water available at the exit of the orifice (Ans)
- Actual discharge through an orifice to the theoretical discharge
- Area of jet at vena contracta to the area of orifice

99.Coefficient of velocity is defined as the ratio of

- Actual velocity of jet at vena contracta to the theoretical velocity (Ans)
- Area of jet at vena contracta to the area of orifice
- Actual discharge through an orifice to the theoretical discharge
- None of the above

100.The theoretical velocity of jet at vena contracta is

- 2 gH
- H √2g
- 2g √H
- √2gH (Ans)

Where H = Head of water at vena contracta.

101.Coefficient of discharge C_{d }is equal to

- C
_{c }* C_{v }(Ans) - C
_{c }* C_{r} - C
_{v }* C_{r} - C
_{c }/C_{r}

Where C_{c} = Coefficient of contraction

C_{v }= Coefficient of velocity, and

C_{r} = Coefficient of resistance.

102.An average value of coefficient of velocity is

- 0.62
- 0.76
- 0.84
- 0.97 (Ans)

103.The value of coefficient of discharge is …………….. the value of coefficient of velocity.

- Less than (Ans)
- Same as
- More than

104.An orifice is said to be large, if

- The size of orifice is large
- The velocity of flow is large
- The available head of liquid is more than 5 times the height of orifice
- The available head of liquid is less than 5 times the height of orifice (Ans)

105.The discharge through a small rectangular orifice is given by

- Q = C
_{d }* a * √2gh (Ans) - Q = 2/3 C
_{d }* a * h - Q = C
_{d }* a / √2gh - Q = 3C
_{d }* a / √2h

Where C_{d }= Coefficient of discharge of the orifice

a = Cross- sectional area of the orifice

h = Height of the liquid above the centre of the orifice

- The discharge through a small rectangular orifice is given by

- Q = 2/3 C
_{d }* b√2g (H_{2 – }H_{1}) - Q = 2/3 C
_{d }* b√2g (H^{1/2}_{2 – }H^{1/2}_{1}) - Q = 2/3 C
_{d }* b√2g (H^{3/2}_{2 – }H^{3/2}_{1}) (Ans) - Q = 2/3 C
_{d }* b√2g (H^{2}_{2 – }H^{2}_{1})

Where H_{1}= Height of the liquid above the top of the orifice

H_{2}= Height of the liquid above the bottom of the orifice

b= Breadth of the orifice, and

C_{d}= Coefficient of discharge.

107.The discharge through a wholly drowned orifice is given by

- Q = C
_{d}* bH_{1}√2gH - Q = C
_{d}* bH_{2}√2gH - Q = C
_{d}* b(H_{2}-H_{1})√2gH (Ans) - Q = C
_{d}* bH√2gH

Where H_{1} = Height of water (on the upstream side) above the top of the orifice,

H_{2} = Height of water (on the downstream side) above the bottom of the orifice, and

H = Difference between two water levels on either side of the orifice.

108.A pipe of length more than double the diameter of orifice fitted externally or internally to the orifice is called a

- Notch
- Weir
- Mouthpiece (Ans)
- Nozzle

109.In a short cylindrical external mouthpiece, the vena contracta occurs at a distance …………. The diameter of the orifice from the outlet of orifice

- Equal to
- One-fourth (Ans)
- One-third
- One-half

110.The length AB of a pipe ABC in which the liquid is flowing has diameter (d_{1}) and is suddenly enlarged to diameter (d_{2}) at B which is constant for the length BC. The loss of head due to sudden enlargement is

- (v
_{1 }– v_{2})^{2}/g - (v
^{2}_{1 }– v^{2}_{2})^{2}/g - (v
_{1 }– v_{2})^{2}/2g (Ans) - (v
^{2}_{1 }– v^{2}_{2})^{2}/2g

- The length AB of a pipe ABC in which the liquid is flowing has diameter (d
_{1}) and is suddenly contracted to diameter (d_{2}) at B which is constant for the length BC. The loss of head due to sudden contraction, assuming coefficient of contraction as 0.62, is

- v
^{2}_{1}/2g - v
^{2}_{2}/2g - 5v
^{2}_{1 }/2g - 375v
^{2}_{2}/2g (Ans)

112.The loss of head at entrance in a pipe is

- v
^{2}/2g - 5 v
^{2}/2g (Ans) - 375v
^{2}/2g - 75v
^{2}/2g

Where v = Velocity of liquid in the pipe.

- The loss of head at exit of a pipe is

- v
^{2}/2g (Ans) - 5 v
^{2}/2g - 375v
^{2}/2g - 75v
^{2}/2g

114.The discharge through an external mouthpiece is given by

- 0.855 a√2Gh (Ans)
- 1.855aH√2g
- 1.585a√2gH
- 5.85aH√2g

Where a = Cross-sectional area of the mouthpiece, and

H = Height of liquid above the mouthpiece.

115.The coefficient of discharge for an external mouthpiece depends upon

- Velocity of liquid
- Pressure of liquid
- Area of mouthpiece
- Length of mouthpiece (Ans)

116.In an internal mouthpiece, if the jet after contraction does not touch the sides of the mouthpiece, then the mouthpiece is said to be

- Running full
- Running free (Ans)
- Partially running full
- Partially running free

117.An internal mouthpiece is said to be running ……………. If the length of the mouthpiece of more than three times the diameter of the orifice.

- Free
- Partially
- Full (Ans)

118.The coefficient of discharge in case of internal mputhpiece is ……… that of external mouthpiece.

- Less than (Ans)
- More than

- The coefficient of discharge for an external mouthpiece is

- 0.375
- 0.5
- 0.707
- 0.855 (Ans)

- An internal mouthpiece is said to be running free If the length of the mouthpiece is …………. The diameter of the orifice

- Less than twice
- More than twice
- Less than three times (Ans)
- More than three times

121.When an external mouthpiece is running free, the discharge through the mouthpiece is

- 0.5 a√2gH (Ans)
- 0.707a√2gH
- 0.855a√2gH
- a√2gH

Where a = Area of mouthpiece, and

H = Height of liquid above the mouthpiece.

122.The discharge through a convergent mouthpiece is ……….. the discharge through an internal mouthpiece of the same diameter and head of water

- equal to
- one-half
- three-fourth
- double (Ans)

123.An opening in the side of a tank or vessel such that the liquid surface with the tank is below the top edge of the opening, is called

- weir
- notch (Ans)
- orifice
- none of these

124.A notch is used to measure …………. Of liquids

- pressure
- discharge (Ans)
- velocity
- volume

125.The discharge over a rectangular notch is

- 2/3 C
_{d}* b√2gH - 2/3 C
_{d}* b√2g * H - 2/3 C
_{d}* b√2g * H^{3/2 }(Ans) - 2/3 C
_{d}* b√2g *H^{2}

Where b= Width of notch, and

H= Height of liquid, above the sill of the notch

- The discharge over a right angled notch is

- 8/15 C
_{d}√2g * H - 8/15C
_{d}√2g * H^{3/2} - 8/15C
_{d}√2g * H^{2} - 8/15C
_{d}√2g * H^{5/2 }(Ans)

Where H= Height of liquid above the apex of notch

127.If the coefficient of discharge is 0.6, then the discharge over a right angled notch is

- 417 H
^{5/2} - 417 H
^{5/2 }(Ans) - 171 H
^{5/2} - 141 H
^{5/2}

128.The discharge over a rectangular notch is

- Inversely proportional to H
^{3/2} - Directly proportional to H
^{3/2 }(Ans) - Inversely proportional to H
^{5/2} - Directly proportional to H
^{5/2}

129.The discharge over a triangular notch is

- Inversely proportional to H
^{3/2} - Directly proportional to H
^{3/2} - Inversely proportional to H
^{5/2} - Directly proportional to H
^{5/2 }(Ans)

130.The error in discharge(dQ /Q) to the error in measurement of head (dH/H) over a rectangular notch is given by

- dQ /Q = 1/2 * dH/H
- dQ /Q = 3/4 * dH/H
- dQ /Q = dH/H
- dQ /Q = 3/2 * dH/H (Ans)

- The error in discharge(dQ /Q) to the error in measurement of head (dH/H) over a triangular notch is given by

- dQ /Q = 3/2 * dH/H
- dQ /Q = 2 * dH/H
- dQ /Q = 5/2 dH/H (Ans)
- 3 * dH/H

132.An error of 1% in measuring head over the crest of the notch (H) will produce an error of ……………. In discharge over a triangular notch,

- 1%
- 5%
- 2%
- 5%

- An error of 1% in measuring head over the apex of the notch (H) will produce an error of ……………. In discharge over a triangular notch.

- 1%
- 5%
- 2%
- 5% (Ans)

134.A structure used to dam up a stream or river over which the water flows is called

- Orifice
- Notch
- Weir (Ans)
- Dam

135.The sheet of water flowing over a notch or a weir is known as

- Sill or crest
- Nappe or vein (Ans)
- Orifice
- None of these

136.The top of the weir over which the water flows is known as

- Sill or crest (Ans)
- Nappe or vein
- Orifice
- None of these

137.The length of a liquid stream while flowing over a weir ……………. At the ends of the sill.

- Expands
- Does not change
- Contracts (Ans)

138.According to Francis formula, the discharge over a rectangular weir is

- 2/3 C
_{d }(L – nH)√2gH - 2/3 C
_{d }(L – 0.1nH)√2gH^{3/2}(Ans) - 2/3 C
_{d }(L – nH)√2gH^{2} - 2/3 C
_{d }(L – 0.2nH)√2gH^{5/2}

Where n= Number of end contractions.

139.When the coefficient of discharge (C_{d}) is 0.623, then the general equation for discharge over a rectangular weir is

- 84(L – 0.1nH)H
^{3/2}(Ans) - 84(L – 0.1nH)H
^{2} - 84(L – 0.1nH)√2gH
^{5/2} - 84(L – 0.1nH)H
^{3}

140.According to Bazin’s formula, the discharge over a rectangular weir is mL√2g *H^{3/2}, where m is equal to

- 405 + 0.003/H (Ans)
- 003 + 0.405/H
- 405 + H/0.003
- 003 + H/0.405

141.The Cippoletti weir is a ………… weir.

- Rectangular
- Triangular
- Trapezoidal (Ans)
- Circular

142.The Francis formula for the discharge over Cippoletti weir is

- 84 LH
^{1/2} - 84 LH
- 84 LH
^{3/2}(Ans) - 84 LH
^{5/2}

143.The discharge over a rectangular weir, considering the velocity of approach, is

- 2/3 C
_{d }* L√2g [H_{1 }– H_{a}] - 2/3 C
_{d }* L√2g [H^{3/2}_{1 }– H^{3/2}_{a}] (Ans) - 2/3 C
_{d }* L√2g [H^{2}_{1 }– H^{2}_{a}] - 2/3 C
_{d }* L√2g [H^{5/2}_{1 }– H^{5/2}_{a}]

Where H_{1 }= Total height of water above the weir = H + H_{a}

H = Height of water, over the crest of the weir, and

H_{a}= Height of water, due to velocity of approach.

144.A weir is said to be narrow-crested weir, if the width of the crest of the weir is ……………. Half the height of water above the weir crest.

- Equal to
- Less than (Ans)
- More than

- A weir is said to be broad-crested weir, if the width of the crest of the weir is ……………. Half the height of water above the weir crest.

- Equal to
- Less than
- More than (Ans)

146.In a board crest weir, the discharge is maximum if the head of water on the downstream side of weir is ……………. The head of water on the upstream side of weir

- Equal to
- One-third
- Two-third (Ans)
- Three-fourth

147.The maximum discharge over a board crested weir is

- 384 C
_{d }* L * H^{1/2} - 384 C
_{d }* L * H^{3/2} - 71 C
_{d }* L * H^{1/2} - 71 C
_{d }* L * H^{3/2 }(Ans)

148.A weir, generally, used as a spillway of a dam is

- Narrow crested weir
- Broad crested weir
- Ogee weir (Ans)
- Submerged weir

149.When the water level on the downstream side of a weir is above the top surface of a weir, the weir is known as

- Narrow crested weir
- Broad crested weir
- Ogee weir
- Submerged weir (Ans)

150.In a free nappe,

- The pressure below the nappe is atmospheric (Ans)
- The pressure below the nappe is negative
- The pressure above the nappe is atmospheric
- The pressure above the nappe is negative

151.In a depressed nappe

- The pressure below the nappe is atmospheric
- The pressure below the nappe is negative (Ans)
- The pressure above the nappe is atmospheric
- The pressure above the nappe is negative

152.The discharge through a siphon spillway is

- C
_{d }* a√2gH (Ans) - C
_{d }* a√2g * H^{3/2} - C
_{d }* a√2g * H^{2} - C
_{d }* a√2g * H^{5/2}

153.The frictional resistance of a pipe varies approximately with …………….. of the liquid.

- Pressure
- Velocity
- Square of velocity (Ans)
- Cube of velocity

154.According to Darcy’s formula, the loss of head due to friction in the pipe is

- flv
^{2}/2gd - flv
^{2}/gd - 3flv
^{2}/2gd - 4flv
^{2}/2gd (Ans)

Where f= Darcy’s coefficient

L= Length of pipe

v= Velocity of liquid in pipe, and

d= Diameter of pipe

155.The hydraulic mean depth or the hydraulic radius is the ratio of

- Area of flow and wetted perimeter (Ans)
- Wetted perimeter and diameter of pipe
- Velocity of flow and area of flow
- None of these

- The hydraulic mean depth for a circular pipe of diameter(d) is

- d/6
- d/4 (Ans)
- d/2
- d

157.The total energy line lies over the hydraulic gradient line by an amount equal to the

- pressure head
- velocity head (Ans)
- pressure head + velocity head
- pressure head – velocity head

158.The hydraulic gradient line lies over the centre line of the pipe by an amount equal to the

- pressure head (Ans)
- velocity head
- pressure head + velocity head
- pressure head – velocity head

- The total energy line lies over the centre line of the pipe by an amount equal to

- pressure head
- velocity head
- pressure head + velocity head (Ans)
- pressure head – velocity head

160.The efficiency of power transmission through pipe is

- H – h
_{f}/H (Ans) - H/ H – h
_{f} - H + h
_{f}/H - H/ H + h
_{f}

Where H= Total supply head, and

h_{f}= Head lost due to friction in the pipe

161.The power transmitted through a pipe is

- w * Q * H
- w * Q * h
_{f} - w * Q (H – h
_{f}) (Ans) - w * Q * (H + h
_{f})

where w= Specific weight in N/m^{3}

Q= Discharge in m^{3}/s.