Quiznetik

Fluid Mechanics and Machinery | Set 1

1. The specific gravity of a liquid has

Correct : D. no unit

2. The specific volume of a liquid is the reciprocal of

Correct : B. mass density

3. Which one of the following is the unit of specific weight?

Correct : A. n = m3

4. [p] = [m]/[v] = [m] /[L3] = [ML-3].

Correct : D. [m0 l0 t0].

5. Which one of the following is the

Correct : B. [m-1 l3 t0].

6. the relation between their specific volumes v1 and v2?

Correct : B. v1 < v2

7. mark of one litre and weighed. The weight of the liquid is found to be 6.5 N. The specific weight of the liquid will be

Correct : A. 6:5 kn = m3

8. A beaker is filled with a liquid up to the mark of one litre and weighed. The weight of the liquid is found to be 6.5 N. The specific gravity of the liquid will be

Correct : A. 0.65

9. mark of one litre and weighed. The weight of the liquid is found to be 6.5 N. The specific volume of the liquid will be

Correct : B. 1:5 l =kg

10. continuity equation is

Correct : A. mass conservation

11. equation of mass conservation into the conservative integral form, which of these theorems is used?

Correct : D. gauss divergence theorem

12. ρV→. dS→ is positive when

Correct : A. the mass flow is outward

13. Hydraulic gradient line takes into consideration

Correct : B. potential and pressure heads only

14. Which of the following is true?

Correct : A. egl always drops in the direction of c

15. Which of the following is true?

Correct : D. hgl may or may not in the direction of flow

16. Which of the following is true?

Correct : A. hgl will never be above egl

17. The slope of HGL will be

Correct : C. equal than that of egl for a pipe of uniform cross-section

18. For a nozzle, the vertical intercept between EGL and HGL

Correct : A. increases

19. between EGL and HGL

Correct : B. decreases

20. Which of the following is true?

Correct : D. the slope of egl will always be independent of that of the axis of the pipe

21. the pressure vary with the length of the pipe?

Correct : A. linearly

22. When a problem states “The velocity of the water flow in a pipe is 20 m/s”, which of the following velocities is it talking about?

Correct : B. average velocity

23. Which of the factors primarily decide whether the flow in a circular pipe is laminar or turbulent?

Correct : D. the reynolds number

24. How is Reynolds number defined as?

Correct : D. ratio of inertia force to viscous force

25. A circular pipe of radius 7 cm is used for water flow transmission. This pipe is moulded into another pipe with a square cross-section keeping the length same. (Ignore the thickness of the pipe). Calculate the hydraulic diameter of the moulded pipe. (Take π = 22/7).

Correct : A. 11 cm

26. The Reynolds number is found out for a flow in a circular pipe. This circular pipe is moulded into a square pipe, keeping length of the pipe same. Ignore the thickness of the pipe. The Reynolds number changes by

Correct : B. 57% increase

27. The flow through a circular pipe is laminar. Now, the fluid through the pipe is replaced with a more viscous fluid and passed through the pipe again with the same velocity. What can we say about the nature of this flow?

Correct : C. the flow will remain laminar

28. What can be the maximum diameter of the pipe for the water flow of velocity 1 m/s (ν = 10-6) to be laminar in nature? Assume Lower critical Reynolds number to be 2100.

Correct : A. 2.1 mm

29. Which of the following flows have the highest critical Reynolds number (lower)?

Correct : A. flow in a pipe

30. The flow separation occurs when the fluid travels away from the

Correct : C. adverse pressure gradient

31. The swirl caused due to eddies are called as

Correct : A. vortices

32. Eddy viscosity is a turbulent transfer of

Correct : C. momentum

33. Which among the following is a device that converts a laminar flow into a turbulent flow?

Correct : C. turbulator

34. Boundary layer separation does not undergo detachment.

Correct : B. false

35. With the boundary layer separation, displacement thickness

Correct : A. increases

36. automatic control scheme during the fluid flow?

Correct : D. pilot static tube

37. What is D’Alembert’s Paradox?

Correct : B. drag force= 0

38. The steady- state flow must satisfy

Correct : A. kirchhoff’s law

39. depend on the friction factor?

Correct : D. weight

40. How do we calculate losses for a larger range of Reynolds number?

Correct : A. moody chart

41. Darcy- Weisbach equation gives relation between

Correct : C. head loss and pressure loss

42. Which among the following is formula for friction factor of circular pipes?

Correct : B. 64/re

43. Loss of head due to friction is

Correct : C. inversely proportional to hydraulic radius

44. The formula for hydraulic diameter is

Correct : A. 4a/p

45. What are the reasons for minor head loses in a pipe?

Correct : C. valves and bends

46. What happens to the head loss when the flow rate is doubled?

Correct : D. four times

47. Relative roughness is

Correct : A. ϵ/d

48. pipes can take up

Correct : A. pipes of different diameters

49. What is the total loss developed in a series of pipes?

Correct : C. sum of local losses plus the losses in each pipe

50. The total head loss for the system is equal to

Correct : D. height difference of reservoirs

51. that is developed in the pipe?

Correct : D. liquid velocity

52. Which among the following is the correct formula for head loss?

Correct : A. z1-z2

53. If the two reservoirs are kept at the same level, the head loss is

Correct : B. zero

54. How do we determine the total discharge through parallel pipes?

Correct : A. add them.

55. The pipe diameter is

Correct : B. directly proportional to mass flow rate

56. Define Viscosity.

Correct : C. resistance to flow of fluid

57. Coefficient of friction of a laminar flow is

Correct : C. 16/re

58. TOPIC 3.1 NEED FOR DIMENSIONAL ANALYSIS - METHODS OF DIMENSIONAL ANALYSIS

Correct : C. chemistry

59. Quantum physics deals with macroscopic phenomena.

Correct : B. false

60. Which of the following uses electromagnetic waves?

Correct : A. radio

61. Which is the universal attractive force?

Correct : D. gravitational force

62. Gravitational force is the weakest force in nature.

Correct : A. true

63. Which of the following is an example of electromagnetic force?

Correct : D. compression of spring

64. Why is climbing a lamp post harder than climbing up a tree?

Correct : A. because of parallel friction force

65. Gravitational force, despite being a weak force, governs the large scale motion.

Correct : A. true

66. When a body is falling freely under gravity, the total mechanical energy remains constant because of which of the following?

Correct : A. law of conservation of energy

67. What happens when a bullet is fired from a rifle?

Correct : C. rifle gives backward kick

68. Similitude is a concept applicable to the testing of

Correct : C. engineering models

69. Which among the following is the main application for Similitude?

Correct : C. hydraulics

70. A model of with same shape is

Correct : A. geometric similarity

71. Which among the following have similar fluid streamlines?

Correct : B. kinematic similarity

72. Which among the following have the same forces acting on them?

Correct : C. dynamic similarity

73. All the parameters in a similitude are described using

Correct : A. continuum mechanics

74. Physical similitude has exactly the same geometric shape of the prototype.

Correct : A. true

75. Which among the following is a standard scale for a similitude?

Correct : C. 1:25

76. In similitude, Fapplication=Fmodel*3.44

Correct : A. true

77. spread is called

Correct : B. diffusivity

78. Which among the following is the standard symbol for Archimedes number?

Correct : C. ar

79. symbol for Atwood number?

Correct : A. a

80. Which among the following is the standard symbol for Blake number?

Correct : B. ba

81. Which among the following is the standard symbol for Darcy friction factor?

Correct : B. fd

82. Fanning friction factor is

Correct : A. 0.25 times darcy friction factor

83. symbol for Froude number?

Correct : C. fr

84. Which among the following is the formula for Knudsen number?

Correct : A. λ⁄l

85. utilization of

Correct : C. work

86. fluid mechanics deals with heat transfer. It is

Correct : B. forward direction

87. The force analysis on a curved vane is understood using

Correct : A. velocity triangles

88. Jet propulsion works on the principle of

Correct : C. newton’s third law

89. How is absolute velocity at inlet denoted?

Correct : B. v1

90. The relative velocity is obtained by the equation

Correct : A. u – v1

91. If the friction is neglected, then

Correct : C. vr1 = vr2

92. If the pressure remains a constant, then

Correct : C. vr1 = vr2

93. from the sea can be taken by the pump.

Correct : A. true

94. Jet propulsion of ship is less efficient than screw propeller due to

Correct : C. frictional losses

95. A jet strikes a curved plate at its

Correct : C. centre

96. of jet engine?

Correct : D. propulsive jet

97. decelerates the flow, what increases?

Correct : A. pressure

98. while passing

Correct : A. pressure energy

99. The consequence of Newtons second law is

Correct : A. conservation of angular momentum

100. in centrifugal pumps.

Correct : A. true