Objective of civil engineering fuild mechanics

MULTIPLE-CHOICE QUESTIONS

I. Select correct options from the list given below each item.

1. Mass per unit volume is known as

(a) density

(b) specific gravity

(d) specific volume.

2. The reciprocal of the density is known as

(a) specific gravity

(b) specific weight

(d) none of these

3. The most important property which influences the fluid motion to a great extent is

(a) density

(b) specific weight

(d) viscocity

4. The rate of shear strain of fluid is known as

(a) shear modulus

(b) hydraulic gradient

(d) all the above

5. Newton’s law of viscocity states that shear stress is directly proportional to

(a) velocity

(b) shear strain

(d) viscocity

6. A Newtonian fluid is defined as the fluid which

(a) is highly viscous

(b) is compressible and non-viscous

(d) obeys Newton’s law of viscocity

7. A general relationship between shear stress and velocity gradient for non-Newtonian fluid may be

written as

t = A + B

If in the above relation, n > 1, the fluid is classified as

(a) dilatant

(b) Bingham plastic

(d) none of these.

8. An ideal fluid is defined as the fluid which is

(a) compressible

(b) incompressible

(d) incompressible and non-viscous

9. Kinematic viscocity is equal to

(a) dynamic viscocity × density

(b) dynamic viscocity × pressure

(d) dynamic viscocity/pressure

10. Dimension of dynamic viscocity is

(a) MLT

–1

(b) ML

–1T

–1

–2

(d) ML

–1

11. The viscocity of a fluid is considered to be composed of

(a) intermolecular cohesion

(b) transfer of molecular momentum

(d) none of (a) and (b)

12. The viscocity of gases

(a) changes with temperature but is practically unaffected by pressure.

(b) practically unaffected by temperature but very much affected by pressure.

(d) unaffected by temperature and pressure.

13. Stoke is the unit of

(a) dynamic viscocity

(b) kinematic viscocity

(d) specific weight

14. 1 stoke is equal to

(a) 1 m2

/sec

(b) 1 × 10

–2 m2

/sec

–3 m2

/sec

(d) 1 × 10

–4 m2

/sec

15. Which one of the following is the wrong statement about capillarity?

Magnitude depends upon

(a) the diameter of tube

(b) the specific weight of the liquid

(d) its viscocity.

16. Surface tension is a

(a) line force

(b) force per unit surface area

(d) all the above

17. The unit of surface tension is

(a) N

(b) N/m

(d) N/m3

18. The property of water to wet a solid surface when it comes in contact is known as

(a) surface tension

(b) viscocity

(d) vapour pressure.

19. The angle of contact q between water and solid surfaces is equal to

(a) 0°

(b) 30°

(d) 90°

20. The angle of contact between mercury and solid surface is

(a) 0°

(b) 45°

(d) more than 90°

21. Boiling of liquid can be achieved by either

(a) raising the temperature

(b) lowering the pressure of overlaying air below the vapour pressure

(d) none of the above.

22. 1 pascal pressure is equal to

(a) 1 m water pressure

(b) 10.01 m water pressure

(d) None of the above

23. The reciprocal of coefficient of compressibility is known as

(a) viscocity

(b) capillary action

(d) bulk modulus of elasticity

24. Falling drops of water become spherical due to

(a) surface tension

(b) capillary action of water

(d) viscocity of water

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

(a) w

(b) wh

(c)

(d) h/w

where w = specific weight

h = depth of liquid from the surface.

26. The ratio of the velocity of flow V to the velocity of sound in the fluid medium is known as

(a) Fraude number

(b) Mach number

(d) coefficient of viscocity

27. The atmospheric pressure at sea level is

(a) 360 mm of mercury

(b) 600 mm of mercury

(d) 960 mm of mercury.

28. Gauge pressure is

(a) pressure measured above complete vacuum

(b) absolute pressure + local atmospheric pressure

(d) none of the above.

29. For measuring small difference of pressure

(a) simple manometer is preferred

(b) differential manometer is advantageous

(d) mercury manometers are used

30. Inclined manometer is used for precise measurement of small pressure in

(a) low velocity gas flow

(b) in high velocity gas flow

(d) in low velocity water flow

31. If l is inclined length of pressure difference and h is vertical depth of pressure difference the

amplification is

(a)

(b) h/l

–1

l/h

(d) tan

–1

32. A submerged body is subjected to a buoyancy equal to the weight of the fluid displaced by it. This

principle is known as

(a) Newton’s principle

(b) Archimedes’ principle

(d) none of the above

35. The intersection of line of action of buoyancy force with the axis of symmetry of floating body is

known as

(a) centre of buoyancy

(b) centre of gravity

(d) all the above

36. If centre of gravity G lies above the centre of buoyancy B, the submarine is in

(a) neutral equilibrium

(b) stable equilibrium

(d) dynamic equilibrium

37. For a floating cylinder metacentre is

(a) –ve

(b) zero

(d) both (a) or (b) depending

upon diameter.

38. A floating vessel has better stability if its sides.

(a) diverge upward

(b) straighten upward

(d) both (b) and (c).

39. In case of steady flow ______ change with time

(a) displacement

(b) velocity

(d) all the above

40. The flow is known as uniform if ______ is same at any instant.

(a) pressure

(b) velocity

(d) acceleration

41. Unsteady flow occurs when

(a) the velocity change from place to place.

(b) the velocity at a given point changes from time to time

(d) none of the above.

42. If the velocity vector varies from point to point at any instant of time the flow is known as

(a) unsteady flow

(b) non-uniform flow

(d) all of these

43. A flow in which the quantity of liquid flowing per second is constant is called

(a) steady flow

(b) streamline flow

(d) turbulent flow

44. A flow in which each liquid particle has a definite path and the paths of individual particles do

not cross each other is called

(a) steady flow

(b) uniform flow

(d) all the above

45. A flow in which streamline is represented by a straight line is called ______ dimensional flow.

(a) one

(b) two

(d) multi

46. The line that connects all particles passing through a point is known as

(a) streamline

(b) pathline

(d) all the above.

47. ______ can be traced by injecting a dye in the flowing liquid.

(a) Streamline

(b) Pathline

(d) all the above

49. Equipotential lines intersect streamlines at

(a) acute angles

(b) 90°

(d) any of the above

50. Using flownets

(a) uplift pressure on dam can be found.

(b) outlets can be designed for their streamlining.

(d) all the above.

51. In irrotational flow

(a) the fluid does not rotate as it moves along.

(b) the net rotation of fluid particles about their mass centre remains zero.

(d) none of the above

52. The science that considers the forces causing flow of fluids is known as

(a) statics of fluid

(b) kinematics of fluid

(d) none of these

53. The fundamental transport phenomenon associated with the motion of fluid

(a) is mass transport

(b) is heat transport

(d) all the above

54. In Reynolds equation

(a) no force is neglected.

(b) only force of compressibility is neglected.

(d) forces of compressibility, turbulence and velocity are neglected.

55. In Navier–Stroke equation

(a) no force is neglected.

(b) only force of compressibility is neglected.

(d) forces of compressibility, turbulence and velocity are neglected

56. In Euler’s equations

(a) no force is neglected.

(b) only force of compressibility is neglected.

(d) forces of compressibility, turbulence and velocity are neglected.

57. The term is known as

(a) kinematic energy

(b) kinetic energy

(d) none of the above

58. The term is known as

(a) potential energy

(b) pressure energy

(d) none of the above

59. The term z in total energy expression

+ z is

(a) potential energy

(b) pressure energy

(d) none of the above

60. Head lost between two points 1 and 2 in fluid flow is given by

(a)

(b)

(d) u2 – u1 + q

where u2

, u1 are velocities of flow, q is heat transfer

61. Bernoulli equation finds its application in

(a) pitot tube

(b) venturimeter

(d) all the above

(d)

63. In a venturimeter, entrance cone is having

(a) converging angle of 20°

(b) converging angle of 5° to 7°

(d) diverging angle of 5° to 7°

64. A venturimeter is having a exit cone of

(a) diverging angle 20°

(b) diverging angle of 5° to 7°

(d) converging angle of 5° to 7°

65. Venturimeter is a device based on

(a) Euler’s equation

(b) Reynolds equation

(d) Bernauli’s principle

67. Venturimeter should be preceded by a straight portion of the pipe of length ______ times the

diameter

(a) 25

(b) 50

(d) 100

68. The coefficient of discharge in a venturimeter depends upon

(a) roughness of inner portion of pipe

(b) diameter ratio d2

/d1

(d) all the above

69. The velocity of flow in a orifice is V = . This equation is known as

(a) Euler’s equation

(b) Bernoulli equation

(d) Torricelli’s equation

70. Trajectory of a free jet is

(a) circular curve

(b) parabola

(d) elliptic curve

72. The dynamics of fluid in which normal stresses and shear stresses in all the three mutually

perpendicular directions is considered is known as

(a) Navier-Stokes theory

(b) Reynolds theory

(d) Euler’s theory

73. The region within which the effect of viscocity is confined is known as

(a) cavitation

(b) stagnation layer

(d) free layer

74. The nominal thickness of boundary layer may be considered the distance between the solid

boundary and the layer where the velocity of fluid particles is ______ of free stream velocity.

(a) 90%

(b) 95%

(d) 100%

75. The ratio of displacement thickness to momentum thickness is called

(a) viscocity factor

(b) shape factor

(d) none of the above.

76. The conditions favourable for laminar flow are

(a) high viscocity

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(b) low mass density

(d) all the above

78. The flow is laminar if Reynolds number is less than

(a) 1000

(b) 1500

(d) 3000

79. In finding Reynolds number, the characteristic length of circular pipe is taken as

(a) d

(b) 2d

(d) 10d

where d is the diameter of pipe.

80. If b is the spacing of two parallel plates the characteristic length is usually taken as

(a) 0.1b

(b) 0.5b

(d) b

81. In case of flow about a sphere, the characteristic length is taken as

(a)

(b) D

(d) 5D

where D is the diameter of sphere

82. In case of flow in wide open channels, for finding Reynolds number, characteristic length taken is

(a) 0.5y

(b) y

(d) 5y

where y is the depth of flow.

83. The viscometer of ______ type may be used for measuring viscocity of fluids.

(a) capillary tube

(b) concentric cylinder

(d) any of the above

84. Industrial viscometers are

(a) Ostwald viscometer

(b) Saybolt viscometer

(d) both (a) and (b).

85. Porous media flow is characterized by

(a) low velocity

(b) high pressure drops

(d) all the above

86. In case of turbulent flow, the loss of pressure head is proportional to V

n where V is mean velocity

and n is from

(a) 1.0 to 1.5

(b) 1.75 to 2.0

(d) 2.75 to 3.0

87. The factors which affect the transition from laminar to turbulent flow are

(a) turbulence in the incoming fluid

(b) the pressure gradient

(d) all the above.

89. Maximum loss of head in flow through pipe is due to

(a) sudden enlargement

(b) sudden contraction

96. If the Froude number in open channel flow is less than 1.0, the flow is known as

(a) subcritical

(b) critical

(d) none of the above

97. If the Froude number in open channel is 1.0, this flow is known as

(a) subcritical

(b) critical

(d) none of the above

98. If the Froude number in open channel is more than 1.0, the flow is known as

(a) subcritical

(b) critical

(d) none of the above

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Objective of civil engineering of fluid mechanics

Objective of civil engineering fuild mechanics

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