Fluid Properties
1. An ideal fluid is defined as the fluid which
(a) is compressible
(b) is incompressible
(c) is incompressible and non-viscous (inviscid)
(d) has negligible surface tension.
2. Newton’s law of viscosity states that
(a) shear stress is directly proportional to the velocity
(b) shear stress is directly proportional to velocity gradient
(c) shear stress is directly proportional to shear strain
(d) shear stress is directly proportional to the viscosity.
3. A Newtonian fluid is defined as the fluid which
(a) is incompressible and non-viscous (b) obeys Newton’s law of viscosity
(c) is highly viscous (d) is compressible and non-viscous.
4. Kinematic viscosity is defined as equal to
(a) dynamic viscosity × density (b) dynamic viscosity/density
(c) dynamic viscosity × pressure (d) pressure × density.
5. Dynamic viscosity (P) has the dimensions as
(a) MLT–2 (b) ML–1T–1
(c) ML–1T–2 (d) M–1L–1T–1.
6. Poise is the unit of
(a) mass density (b) kinematic viscosity
(c) viscosity (d) velocity gradient.
7. The increase of temperature
(a) increases the viscosity of a liquid (b) decreases the viscosity of a liquid
(c) decreases the viscosity of a gas (d) increases the viscosity of a gas.
8. Stoke is the unit of
(a) surface tension (b) viscosity
(c) kinematic viscosity (d) none of the above.
9. The multiplying factor for converting one poise into MKS unit of dynamic viscosity is
(a) 9.81 (b) 98.1
(c) 981 (d) 0.981.
10. Surface tension has the units of
(a) force per unit area (b) force per unit length
(c) force per unit volume (d) none of the above.
11. The gases are considered incompressible when mach number
(a) is equal to 1.0 (b) is equal to 0.50
(c) is more than 0.3 (d) is less than 0.2.
12. Kinematic viscosity (Q) is equal to
(a) P × U (b) P U
(c) U P (d) none.
13. Compressibility is equal to
(a) dVVdp
(b) dp dVV
(c) dpdU
(d) dpdU .
14. Hydrostatic law of pressure is given as
(a) wwpz= Ug
(b) wwpz= 0
(c) wwpz= z (d) wwpz= constant.
15. Four curves are shown in Fig. 1.2 with velocity gradient wwuy along x-axis and viscous shear stress (W) along y-axis. Curve A corresponds to
(a) ideal fluid
(b) newtonian fluid
(c) non-newtonian fluid
(d) ideal solid.
16. Curve B in Fig. 1.2 corresponds to
(a) ideal fluid
(b) newtonian fluid
(c) non-newtonian fluid
(d) ideal-solid.
17. Curve C in Fig. 1.2 corresponds to
(a) ideal fluid (b) newtonian fluid
(c) non-newtonian fluid (d) ideal solid.
18. Curve D in Fig. 1.2 corresponds to
(a) ideal fluid (b) newtonian fluid
(c) non-newtonian fluid (d) ideal solid.
19. The relation between surface tension (V) and difference of pressure ('p) between the inside
and outside of a liquid droplet is given as
(a) 'p = V4d (b) 'p = V2d
(c) 'p = 4Vd (d) 'p = Vd
20. For a soap bubble, the surface tension (V) and difference of pressure ('p) are related as
(a) 'p = V4d (b) 'p = V 2d
(c) 'p = 4Vd (d) 'p = 8Vd .
21. For a liquid jet, the surface tension (V) and difference of pressure ('p) are related as
(a) 'p = V4d
(b) 'p = V2d
(c) 'p = 4Vd
(d) 'p = 2Vd .
22. The capillary rise or fall of a liquid is given by
(a) h = V TUcos4 gd
(b) h = 4V TUcosgd
(c) h = 8V TUcosgd
(d) none of the above.
23. Pascal’s law states that pressure at a point is equal in all direction
(a) in a liquid at rest (b) in a fluid at rest
(c) in a laminar flow (d) in a turbulent flow.
24. The hydrostatic law states that rate of increase of pressure in a vertical direction
(a) is equal to density of the fluid (b) is equal to specific weight of the fluid
(c) is equal to weight of the fluid (d) none of the above.
25. Fluid statics deals with the following forces
(a) viscous and gravity forces (b) viscous and gravity forces
(c) gravity and pressure forces (d) surface tension and gravity forces.
26. Gauge pressure at a point is equal to
(a) absolute pressure plus atmospheric pressure
(b) absolute pressure minus atmospheric pressure
(c) vacuum pressure plus absolute pressure
(d) none of the above.
27. Atmospheric pressure head in terms of water column is
(a) 7.5 m (b) 8.5 m
(c) 9.81 m (d) 10.30 m.
28. The hydrostatic pressure on a plane surface is equal to
(a) UgAh (b) UgAh sin2 T
(c) 14 UgAh (d) UgAh sin T
where A = Area of plane surface and h = Depth of centroid of the plane area below the
liquid free surface.
29. Centre of pressure of a plane surface immersed in a liquid is
(a) above the centre of gravity of the plane surface
(b) at the centre of gravity of the plane surface
(c) below the centre of gravity of the plane surface
(d) none of the above.
30. The resultant hydrostatic force acts through a point known as
(a) centre of gravity (b) centre of buoyancy
(c) centre of pressure (d) none of the above.
31. For submerged curved surface, the vertical component of the hydrostatic force is
(a) mass of the liquid supported by the curved surface
(b) weight of the liquid supported by the curved surface
(c) the force of the projected area of the curved surface on vertical plane
(d) none of the above.
32. Manometer is a device used for measuring
(a) velocity at a point in a fluid (b) pressure at a point in a fluid
(c) discharge of a fluid (d) none of the above.
33. Differential manometers are used for measuring
(a) velocity at a point in a fluid
(b) pressure at a point in a fluid
(c) difference of pressure between two points
(d) none of the above.
34. The pressure at a height Z in a static compressible fluid undergoing isothermal compression
is given as
(a) p = p0 egRZT
(b) p = p0 egTRZ
(c) p = p0 eRTgZ
(d) p = p0 egZRT
where p0 = Pressure at ground level, R = Gas constant, T = Absolute temperature.
35. The pressure at a height Z in a static compressible fluid undergoing adiabatic compression
is given by
(a) p = p0 1 1 0 1 J JJRT JgZ
(b) p = p0 110 1 J JJRT JgZ
(c) p = p0 1 101J JJgZ JRT
(d) none of the above.
36. The temperature at a height Z in a static compressible fluid undergoing adiabatic compression
is given as
(a) T = T0 1 1 0 JJRTgZ
(b) T = T0 1 10JJgZRT
(c) T = T0 110 JJRTgZ
(d) none of the above.
37. Temperature lapse-rate is given by
38. When the fluid is at rest, the shear stress is
(a) maximum (b) zero
(c) unpredictable (d) none of the above.
39. The depth of centre of pressure of an inclined immersed surface from free surface of liquid
is equal to
.
40. The depth of centre of pressure of a vertical immersed surface from free surface of liquid is
equal to
41. The centre of pressure for a plane vertical surface lies at a depth of
(a) half the height of the immersed surface
(b) one-third the height of the immersed surface
(c) two-third the height of the immersed surface
(d) none of the above.
42. The inlet length of a venturimeter
(a) is equal to the outlet length (b) is more than the outlet length
(c) is less than the outlet length (d) none of the above.
43. Flow of a fluid in a pipe takes place from
(a) higher level to lower level (b) higher pressure to lower pressure
(c) higher energy to lower energy (d) none of the above.
Buoyancy and Flotation
44. For a floating body, the buoyant force passes through the
(a) centre of gravity of the body
(b) centre of gravity of the submerged part of the body
(c) metacentre of the body
(d) centroid of the liquid displaced by the body.
45. The condition of stable equilibrium for a floating body is
(a) the metacentre M coincides with the centre of gravity G
(b) the metacentre M is below centre of gravity G
(c) the metacentre M is above centre of gravity G
(d) the centre of buoyancy B is above centre of gravity G.
46. A submerged body will be in stable equilibrium if
(a) the centre of buoyancy B is below the centre of gravity G
(b) the centre of buoyancy B coincides with G
(c) the centre of buoyancy B is above the metacentre M
(d) the centre of buoyancy B is above G.
47. The metacentric height of a floating body is
(a) the distance between metacentre and centre of buoyancy
(b) the distance between the centre of buoyancy and centre of gravity
(c) the distance between metacentre and centre of gravity
(d) none of the above.
48. The point, through which the buoyant force is acting, is called
(a) centre of pressure (b) centre of gravity
(c) centre of buoyancy (d) none of the above.
49. The point, through which the weight is acting, is called
(a) centre of pressure (b) centre of gravity
(c) centre of buoyancy (d) none of the above.
50. The point, about which a floating body, starts oscillating when the body is tilted is called
(a) centre of pressure (b) centre of buoyancy
(c) centre of gravity (d) meta-centre.
51. The meta-centric height (GM) is given by
52. For floating body, if the meta-centre is above the centre of gravity, the equilibrium is called
(a) stable (b) unstable
(c) neutral (d) none of the above.
53. For a floating body, if the meta-centre is below the centre of gravity, the equilibrium is
called
(a) stable (b) unstable
(c) neutral (d) none of the above.
54. For a floating body, if the meta-centre coincides with the centre of gravity, the equilibrium
is called
(a) stable (b) unstable
(c) neutral (d) none of the above.
55. For a floating body, if centre of buoyancy is above the centre of gravity, the equilibrium is
called
(a) stable (b) unstable
(c) neutral (d) none of the above.
56. For a submerged body, if the centre of buoyancy is above the centre of gravity, the equilibrium
is called
(a) stable (b) unstable
(c) neutral (d) none of the above.
57. For a submerged body, if the centre of buoyancy is below the centre of gravity, the equilibrium
is called
(a) stable (b) unstable
(c) neutral (d) none of the above.
58. For a submerged body, if the centre of buoyancy coincides with the centre of gravity, the
equilibrium is called
(a) stable (b) unstable
(c) neutral (d) none of the above.
59. For a submerged body, if the meta-centre is below the centre of gravity, the equilibrium is
called
(a) stable (b) unstable
(c) neutral (d) none of the above.
60. The meta-centric height (GM) experimentally is given as
where w = Movable weight, W = Weight of floating body including w, T = Angle of tilt.
61. The time period of oscillation of a floating body is given by
where k = Radius of gyration, GM = Meta-centric height and T = Time period.
Kinematics and Dynamics of Flow
62. The necessary condition for the flow to be steady is that
(a) the velocity does not change from place to place
(b) the velocity is constant at a point with respect to time
(c) the velocity changes at a point with respect to time
(d) none of the above.
63. The necessary condition for the flow to be uniform is that
(a) the velocity is constant at a point with respect to time
(b) the velocity is constant in the flow field with respect to space
(c) the velocity changes at a point with respect to time
(d) none of the above.
64. The flow in the pipe is laminar if
(a) Reynold number is equal to 2500 (b) Reynold number is equal to 4000
(c) Reynold number is more than 2500 (d) None of the above.
65. A stream line is a line
(a) which is along the path of a particle
(b) which is always parallel to the main direction of flow
(c) across which there is no flow
(d) on which tangent drawn at any point gives the direction of velocity.
66. Continuity equation can take the form
(a) A1V1 = A2V2 (b) U1A1 = U2A2
(c) U1A1V1 = U2A2V2 (d) p1A1V1 = p2A2V2.
67. Pitot-tube is used for measurement of
(a) pressure (b) flow
(c) velocity at a point (d) discharge.
68. Bernoulli’s theorem deals with the law of conservation of
(a) mass (b) momentum
(c) energy (d) none of the above.
69. Continuity equation deals with the law of conservation of
(a) mass (b) momentum
(c) energy (d) none of the above.
70. Irrotational flow means
(a) the fluid does not rotate while moving
(b) the fluid moves in straight lines
(c) the net rotation of fluid-particles about their mass centres is zero
(d) none of the above.
71. The velocity components in x and y-directions in terms of velocity potential (I) are
72. The velocity components in x and y-directions in terms of stream function (\) are
73. The relation between tangential velocity (v) and radius (r) is given by
(a) V × r = constant for forced vortex (b) V/r = constant for forced vortex
(c) V × r = constant for free vortex (d) V/r = constant for free vortex.
74. The pressure variation along the radial direction for vortex flow along a horizontal plane is
given as
75. For a forced vortex flow the height of paraboloid formed is equal to
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