Quiznetik

Hydraulics and Fluid Mechanics | Set 3

1. The velocity of the liquid flowing through the divergent portion of a Venturimeter

Correct : C. Decreases

2. The volumetric change of the fluid caused by a resistance is known as

Correct : C. Compressibility

3. If the depth of water in an open channel is less than the critical depth, the flow is called

Correct : D. Torrential flow

4. Choose the wrong statement

Correct : D. When in equilibrium, fluids can sustain shear forces

5. An orifice is said to be large, if

Correct : D. The available head of liquid is less than 5 times the height of orifice

6. A piece of metal of specific gravity 13.6 is placed in mercury of specific gravity 13.6, what fraction of it volume is under mercury?

Correct : C. Whole of the metal piece will be immersed with its top surface just at mercury level

7. The centre of pressure acts __________ the centre of gravity of immersed surface.

Correct : C. Below

8. Dynamic viscosity of most of the liquids with rise in temperature

Correct : B. Decreases

9. The discharge over a right angled notch is (where H = Height of liquid above the apex of notch)

Correct : D. (8/15) Cd. 2g. H5/2

10. A square surface 3 m × 3 m lies in a vertical line in water pipe its upper edge at water surface. The hydrostatic force on square surface is

Correct : B. 13,500 kg

11. Select the correct statement

Correct : B. Standard atmospheric pressure is the mean local atmospheric pressure a* sea level

12. The shear stress-strain graph for a Newtonian fluid is a

Correct : A. Straight line

13. The flow in which the particles of a fluid attain such velocities that varies from point to point in magnitude and direction as well as from instant to instant, is known as

Correct : D. Turbulent flow

14. Uniform flow occurs when

Correct : C. The magnitude and direction of the velocity do not change from point to point in the fluid

15. At the center line of a pipe flowing under pressure where the velocity gradient is zero, the shear stress will be

Correct : D. Could be any value

16. The discharge through a channel of trapezoidal section is maximum when

Correct : C. The sloping side is equal to half the width at the top

17. Piezometer is used to measure

Correct : C. Very low pressures

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

Correct : C. Centre of pressure

19. Choose the wrong statement

Correct : D. Center of buoyancy is located above the center of gravity of the displaced liquid

20. The pressure in the air space above an oil (sp. gr. 0.8) surface in a tank is 0.1 kg/cm". The pressure at 2.5 m below the oil surface will be

Correct : B. 3 metres of water column

21. The total pressure on the top of a closed cylindrical vessel completely filled up with a liquid is

Correct : C. Directly proportional to (radius)4

22. The flow which neglects changes in a transverse direction is known as

Correct : A. One dimensional flow

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

Correct : B. Mass density

24. A large Reynold number is indication of

Correct : D. Highly turbulent flow

25. Which of the following statement is wrong?

Correct : C. The length of divergent portion in a Venturimeter is equal to the convergent portion.

26. 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.

Correct : C. More than

27. The bulk modulus of elasticity

Correct : B. Increases with pressure

28. Kinematic viscosity is equal to

Correct : A. Dynamic viscosity/density

29. The atmospheric pressure at sea level is

Correct : D. All of these

30. The conditions for the stable equilibrium of a floating body are

Correct : D. All the above are correct

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

Correct : A. It is easier to see through the glass tube

32. To avoid an interruption in the flow of a siphon, an air vessel is provided

Correct : C. At the summit

33. When the coefficient of discharge (Cd) is 0.623, then the general equation for discharge over a rectangular weir is

Correct : A. 1.84(L - 0.1nH)H3/2

34. In an isothermal atmosphere, the pressure

Correct : C. Varies in the same way as the density

35. If the atmospheric pressure on the surface of an oil tank (sp. gr. 0.8) is 0.2 kg/cm", the pressure at a depth of 50 m below the oil surface will be

Correct : D. 6 meters of water Column

36. The pressure intensity in kN/m2 (or kPa) at any point in a liquid is (where w = Specific weight of liquid, and h = Depth of liquid from the surface)

Correct : B. wh

37. The resultant upward pressure of a fluid on a floating body is equal to the weight of the fluid displaced by the body. This definition is according to

Correct : C. Archimedes' principle

38. The liquid used in manometers should have

Correct : D. High surface tension

39. Which of the following instrument can be used for measuring speed of an aeroplane?

Correct : C. Pitot tube

40. A jet of water discharging from a 40 mm diameter orifice has a diameter of 32 mm at its vena contracta. The coefficient of contraction is

Correct : B. 0.64

41. Buoyant force is

Correct : D. The resultant force on a body due to the fluid surrounding it

42. In case of flow through parallel pipes,

Correct : D. Both (A) and (B)

43. Rotameter is a device used to measure

Correct : C. Flow

44. In a broad-crested 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.

Correct : C. Two-third

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

Correct : D. Metacentre

46. A nozzle is generally made of

Correct : B. Convergent shape

47. Pitot tube is used for measurement of

Correct : C. Velocity

48. The value of mass density in kg-sec-V-

Correct : D. 101.9

49. The shear stress between the two liquid layers is __________ proportional to the distance between two layers.

Correct : B. Inversely

50. Viscosity of water in comparison to mercury is

Correct : A. Higher

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

Correct : B. One-third of the total supply head

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

Correct : C. Surface tension

53. The difference of pressure between the inside and outside of a liquid drop is

Correct : D. p = 2T/r

54. A venturi -flume is used to measure

Correct : B. Discharge of liquid

55. Working principle of dead weight pressure gauge tester is based on

Correct : A. Pascal's law

56. The meatcentric height of a ship is 0.6 m and the radius of gyration is 4 m. The time of rolling of a ship is

Correct : C. 10.4 s

57. The discharge through a channel of rectangular section will be maximum, if

Correct : B. Its breadth is twice the depth

58. The discharge through a channel of circular section will be maximum when the depth of water is __________ the diameter of the circular channel.

Correct : D. 0.95 times

59. Uniform flow occurs when

Correct : C. Size and shape of the cross section in a particular length remain constant

60. Bulk modulus of a fluid is the ratio of

Correct : C. Increase in pressure to the volumetric strain

61. An average value of coefficient of velocity is

Correct : D. 0.97

62. A liquid would wet the solid, if adhesion forces as compared to cohesion forces are

Correct : B. More

63. When a cylindrical vessel containing liquid is revolved about its vertical axis at a constant angular velocity, the pressure

Correct : A. Varies as the square of the radial distance

64. Which of the following is the unit of kinematic viscosity?

Correct : C. Stoke

65. Reynold's number is the ratio of the inertia force to the

Correct : B. Viscous force

66. A piece weighing 3 kg in air was found to weigh 2.5 kg when submerged in water. Its specific gravity is

Correct : D. 6

67. A differential manometer is used to measure

Correct : D. Difference of pressures between two points in a pipe

68. In a venturi-flume, the flow takes place at

Correct : A. Atmospheric pressure

69. The normal stress is same in all directions at a point in a fluid

Correct : C. When there is no motion of one fluid layer relative to an adjacent layer

70. The highest efficiency is obtained with a channel of __________ section.

Correct : D. Trapezoidal

71. 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 (where w = Specific weight of liquid, and H = Height of liquid)

Correct : C. wH2/2

72. Which of the following manometer has highest sensitivity?

Correct : D. Micro-manometer with water

73. The velocity corresponding to Reynold number of 2800, is called

Correct : D. Higher critical velocity

74. For a floating body to be in equilibrium

Correct : D. All of the above

75. When an internal mouthpiece is running free, the discharge through the mouthpiece is (where a = Area of mouthpiece, and H = Height of liquid above the mouthpiece)

Correct : A. 0.5 a. gH

76. A uniform body 3 m long, 2 m wide and 1 m deep floats in water. If the depth of immersion is 0.6 m, then the weight of the body is

Correct : C. 35.3 kN

77. The force per unit length is the unit of

Correct : A. Surface tension

78. When the Mach number is more than 6, the flow is called

Correct : D. Hyper-sonic flow

79. The upper surface of a weir over which water flows is known is

Correct : C. Sill

80. One cubic metre of water weighs

Correct : D. 1000 litres

81. Kinematic viscosity is dependent upon

Correct : C. Density

82. The discharge through a large rectangular orifice is given by (where H1 = Height of the liquid above the top of the orifice, H2 = Height of the liquid above the bottom of the orifice, b = Breadth of the orifice, and Cd = Coefficient of discharge)

Correct : C. Q = (2/3) Cd × b × (2g) × (H2 3/2 - H1 3/2)

83. 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.

Correct : D. 2.5 %

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

Correct : D. All of the above

85. The ratio of the inertia force to the viscous force is called

Correct : A. Reynold's number

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

Correct : A. Pressure energy + kinetic energy + potential energy

87. Which of the following instrument can be used for measuring speed of a submarine moving in deep sea?

Correct : D. Pitot tube

88. The force present in a moving liquid is

Correct : D. All of these

89. A ship whose hull length is 100 m is to travel at 10 m/sec. For dynamic similarity, at what velocity should a 1:25 model be towed through water?

Correct : C. 2 m/sec

90. The flow in which the velocity vector is identical in magnitude and direction at every point, for any given instant, is known as

Correct : B. Uniform flow

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

Correct : D. Length of mouthpiece

92. The specific weight of water is 1000 kg/m3

Correct : D. All the above

93. If the depth of water in an open channel is greater than the critical depth, the flow is called

Correct : C. Tranquil flow

94. When a cylindrical vessel, containing some liquid, is rotated about its vertical axis, the liquid surface is depressed down at the axis of its rotation and rises up near the walls of the vessel on all sides. This type of flow is known as

Correct : C. Vortex flow

95. The body will sink down if the force of buoyancy is __________ the weight of the liquid displaced.

Correct : B. Less than

96. The total pressure on the surface of a vertical sluice gate 2 m x 1 m with its top 2 m surface being 0.5 m below the water level will be

Correct : D. 2000 kg

97. The velocity at which the laminar flow stops, is known as

Correct : B. Lower critical velocity

98. The line of action of the buoyant force acts through the

Correct : D. Centroid of the displaced volume of fluid

99. The buoyancy depends upon the

Correct : A. Weight of the liquid displaced

100. Two dimensional flows occurs when

Correct : D. The fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane