Quiznetik

Hydraulics and Fluid Mechanics | Set 4

1. Whenever a plate is held immersed at some angle with the direction of flow of the liquid, it is subjected to some pressure. The component of this pressure, in the direction of flow of the liquid, is known as

Correct : B. Drag

2. Which of the following is dimensionless?

Correct : D. Specific gravity

3. Coefficient of resistance is the ratio of

Correct : C. Loss of head in the orifice to the head of water available at the exit of the orifice

4. Mercury does not wet glass. This is due to property of liquid known as

Correct : C. Surface tension

5. A flow in which __________ force is dominating over the viscosity is called turbulent flow.

Correct : D. Inertia

6. Specific weight of sea water is more that of pure water because it contains

Correct : D. All of the above

7. In an internal mouthpiece, the absolute pressure head at vena contracta is __________ the atmospheric pressure head by an amount equal to height of the liquid above the vena contracta.

Correct : A. Less than

8. An odd shaped body weighing 7.5 kg and occupying 0.01 m3 volume will be completely submerged in a fluid having specific gravity of

Correct : D. 0.75

9. The factional resistance of a pipe varies approximately with __________ of the liquid.

Correct : C. Square of velocity

10. For measuring flow by a Venturimeter, if should be installed in

Correct : D. In any direction and in any location

11. The ratio of the inertia force to the elastic force is called

Correct : D. Mach number

12. All the terms of energy in Bernoulli's equation have dimension of

Correct : D. Length

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

Correct : C. 39.24 kPa

14. Specific weight of water in S.I. units is equal to

Correct : C. 9.81 × 103 N/m3

15. In an external mouthpiece, the absolute pressure head at vena contracta is __________ the atmospheric pressure head by an amount equal to 0.89 times the height of the liquid, above the vena contracta.

Correct : A. Less than

16. Poise is the unit of

Correct : C. Viscosity

17. Viscous force is the __________ of shear stress due to viscosity and cross-section area of flow.

Correct : C. Product

18. The siphon will work satisfactorily, if the minimum pressure in the pipe is __________ vapour pressure of liquid.

Correct : C. More than

19. The tangential velocity of the water element having a free vortex is

Correct : B. Inversely proportional to its distance from the centre

20. The horizontal component of buoyant force is

Correct : C. Zero

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

Correct : A. Steady

22. The divergent portion of a Venturimeter is made longer than convergent portion in order to

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

23. According to Chezy's formula, the discharge through an open channel is (where A = Area of flow, C = Chezy's constant, m = Hydraulic mean depth, and i = Uniform slope in bed)

Correct : C. AC × m × i)

24. In a free vortex motion, the radial component of velocity everywhere is

Correct : C. Zero

25. Coefficient of contraction is the ratio of

Correct : D. Area of jet at vena-contracta to the area of orifice

26. The Bernoulli's equation is based on the assumption that

Correct : D. All of the above

27. The flow in a pipe is turbulent when Reynold number is

Correct : C. More than 2800

28. When the flow parameters at any given instant remain same at every point, then flow is said to be

Correct : D. Uniform

29. Rain drops are spherical because of

Correct : C. Surface tension forces

30. The discharge over the trapezoidal notch is equal to the discharge over the rectangular notch __________ the discharge over the triangular notch.

Correct : A. Plus

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

Correct : B. Nappe or vein

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

Correct : C. Weir

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

Correct : A. Coincides with its centre of gravity

34. General energy equation holds for

Correct : D. Non-uniform flow

35. The buoyancy depends on

Correct : A. Mass of liquid displaced

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

Correct : B. Centre of buoyancy

37. The Reynold's number of a ship is __________ to its velocity and length.

Correct : A. Directly proportional

38. In the above question, if the angular velocity ? is doubled, then the depth of parabola will be

Correct : C. four times

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

Correct : C. directly proportional to (radius)4

40. The discharge over the trapezoidal notch is equal to the discharge over the rectangular notch

Correct : A. plus

41. The coefficient of discharge for an external mouthpiece is

Correct : D. 0.855

42. A fluid having no viscosity is known as

Correct : B. ideal fluid

43. A wwir is said to be broad crested weir. If the width of the crest of the weir is

Correct : C. more than

44. The velocity through a channel of circular section will be maximum when the depth of water is

Correct : C. 0.81 times

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

Correct : C. decreases

46. An error of 1% in measureing head over the crest of the notch (H) will produce an error of

Correct : B. 1.50%

47. In a broad-crested weir, the discharge is maximum if the head of water on the downstream side of weir is

Correct : C. two-third

48. To force present in a moving liquid is

Correct : D. all of these

49. If an incompressible liquid is continuously flowing through a pipe, the quantity of liquid passing per second is different at different sections.

Correct : B. False

50. Which of the following is an example of maninar flow?

Correct : D. all of these

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

Correct : C. gravitational force is more than the upthrust of the liquid

52. The pressure of air

Correct : B. decreases

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

Correct : B. 1.417 H5/2

54. The velocity corresponding to Reynold number of 2000 is called

Correct : C. lower critical velocity

55. The unit of surface tension is

Correct : A. N / m

56. The velocity at which the turbulent flow starts is known as higher critical velocity.

Correct : A. Yes

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

Correct : D. any direction and in any location

58. The shear stress-strain graph for a non-newtonian fluid is a curve.

Correct : A. Correct

59. The velocity of liquid flowing through an orifice varies with the available head of the liquid.

Correct : A. Agree

60. The D-Alembert's principle is used for changing the dynamic equilibrium of a fluid mass, into a static equilibrium.

Correct : A. Agree

61. When the Mach number is between

Correct : D. 1 and 6

62. The hoss of hed due to an obstruction in a pipe is twice the loss of head at its entrance.

Correct : A. Agree

63. The dynamic viscosity of gases

Correct : B. increases

64. A fluid whose viscosity does not change with the rate of deformation or shear strain is known as

Correct : C. newtonian fluid

65. 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

Correct : B. stable equilibrium

66. The property of a liquid which controls its rate of flow is called viscosity.

Correct : A. True

67. Reyold's number is the ratio of the inertia force to the

Correct : B. viscous force

68. When the end contractions of the weir are suppressed, then number of end contractions (n) are taken as zero

Correct : A. Agree

69. The specific gravity has no units.

Correct : A. Agree

70. A vertical wall is subjected to a pressure due to one kind of liquid, on one of its sides. Which of the following statement is correct?

Correct : C. The pressure on the wall at the liquid level is zero, and on the bottom of the wall is maximum

71. The stability of a dam is checked for

Correct : D. all of these

72. The centre of buoyancy is the centre of area of the immersed body.

Correct : A. Correct

73. The shear stress between the two liquid layers is

Correct : B. indirectly

74. The kinematic viscosity of an oil (in stokes) whose specific gravity is 0.95 and viscosity 0.011 poise, is

Correct : A. 0.0116 stoke

75. A nozzle placed at the end of a water pipe line discharges water at a

Correct : D. high velocity

76. Bernoulli's equation is applied to

Correct : D. all of these

77. The flow in a pipe is laminar, when Reynold number is less than 2000.

Correct : A. True

78. Select the wrong statement

Correct : D. Weber's number is the ratio of inertia force to surface tension force.

79. A vessel of 4 m3 contains an oil which weighs 30 kN. The specific weight of the oil is

Correct : C. 7.5 kN / m3

80. The quantity of a liquid flowing per second through a section of a pipe or a channel is called discharge and is measured in cumecs (m3/s).

Correct : A. True

81. Water is

Correct : B. an incompressible

82. The specific weight of sea water is

Correct : C. more than

83. The separation of flow occurs when the hydrodynamic boundary layer thickness is reduced to zero.

Correct : A. Agree

84. The specific weight of compressible fluids does not remain constant.

Correct : A. True

85. An internal mouthpiece is said to be runing

Correct : C. full

86. Turbulent flow takes place at high velocities.

Correct : A. Agree

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

Correct : D. viscosity

88. The ratio of the inertia force to the surface tension force is called Weber's number.

Correct : A. Correct

89. A venturiflume is used to measure

Correct : B. discharge of liquid

90. A fluid whose viscosity changes with the rate of deformation or shear strain is known as non-newtonian fluid.

Correct : A. True

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

Correct : A. surface tension of water

92. A flow in which the quantity of liquid flowing per second is not constant, is called

Correct : D. unsteady flow

93. A flow whose streamline is represented by a straight line, is called

Correct : A. one

94. The rise of liquid along the walls of a revolving cylinder about the initial level is

Correct : A. same as

95. A nirform 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

96. A point, in a compressible flow where the velocity of fluid is zero, is called

Correct : C. stagnation point

97. The coefficient of viscosity may be determined by

Correct : D. all of these

98. Coefficient of contraction is the ratio of

Correct : D. area of jet at vena contracta to the area of orifice

99. In an external or internal mouthpiece, the absolute pressure head at vena contracta is zero when atmospheric pressure head is 10.3 m of water.

Correct : A. Correct

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

Correct : A. Agree