MCQ fluid mechanics

MCQ fluid mechanics

Q1. The SI unit of viscosity is:

N/m² Pa·s kg/m³ m/s

Q2. A fluid which has no viscosity is called:

Ideal fluid Real fluid Newtonian fluid Non-Newtonian fluid

Q3. The ratio of inertial force to viscous force is known as:

Mach number Reynolds number Froude number Weber number

Q4. Bernoulli’s equation is based on the conservation of:

Mass Energy Momentum Volume

Q5. The dimension of pressure is:

ML⁻¹T⁻² ML²T⁻² MLT⁻² ML⁻²T⁻¹

Q6. Which device is used to measure the flow rate of a liquid in a pipe?

Pitot tube Venturimeter Manometer Barometer

Q7. In fluid mechanics, continuity equation is derived from conservation of:

Energy Momentum Mass Volume

Q8. Which type of flow has Reynolds number less than 2000?

Turbulent flow Laminar flow Transitional flow Uniform flow

Q9. Pascal’s law states that pressure at a point in a fluid is:

Equal in all directions Greater at depth Dependent on velocity None of these

Q10. The device used to measure atmospheric pressure is:

Manometer Piezometer Barometer Venturimeter

Q16. The property of a fluid which enables it to resist tensile stress is:

Compressibility Surface tension Viscosity Density

Q17. A streamline is a line which is:

Tangent to the velocity vector at every point Perpendicular to velocity vector Along pressure gradient None of these

Q18. Which of the following has the highest bulk modulus?

Air Water Mercury Oil

Q19. In dimensional analysis, which of these is a derived dimension?

Length Time Force Mass

Q20. Which of the following is used to measure small pressure differences?

U-tube manometer Piezometer Inclined manometer Barometer

Q21. Specific gravity is the ratio of:

Mass of fluid to mass of water Density of fluid to density of water Weight of fluid to weight of air None of these

Q22. Critical velocity occurs when:

Reynolds number exceeds 4000 Reynolds number falls below 2000 Flow transitions from laminar to turbulent None of these

Q23. Hydraulic grade line represents:

Total head Pressure head Piezometric head Velocity head

Q24. Cavitation in pumps occurs when:

Pressure falls below vapor pressure Pressure increases suddenly Velocity decreases None of these

Q25. Mach number is defined as:

Velocity of object / speed of light Velocity of object / speed of sound Velocity of fluid / acceleration due to gravity None of these

Q26. The center of pressure on a plane surface immersed vertically in a liquid lies:

At the centroid Above the centroid Below the centroid At the liquid surface

Q27. Hydraulic jump is a phenomenon seen in:

Open channel flow Pipe flow Laminar flow Compressible flow

Q28. A venturimeter works on the principle of:

Conservation of momentum Conservation of mass Bernoulli’s theorem Hydrostatic law

Q29. Specific speed of a pump is defined as speed of a geometrically similar pump that would deliver unit discharge at:

Unit head Maximum efficiency No head Unit speed

Q30. Bernoulli’s equation can be applied between two points in a fluid flow when:

The flow is steady The fluid is incompressible No energy losses All of the above

Q31. For turbulent flow in pipes, the velocity distribution follows:

Linear law Logarithmic law Exponential law Parabolic law

Q32. In fluid statics, the pressure intensity increases with:

Increase in depth Decrease in density Decrease in depth None of these

Q33. The term used for flow in which velocity at a point changes with time is:

Steady flow Unsteady flow Uniform flow Compressible flow

Q34. A device used to measure high fluid velocities is:

Piezometer Pitot tube Manometer Venturimeter

Q35. If Mach number is less than 1, the flow is called:

Supersonic Sonic Subsonic Hypersonic

Q36. The ratio of specific weight to specific volume is equal to:

Pressure Density Specific gravity Kinematic viscosity

Q37. In a venturimeter, the pressure is minimum at:

Inlet section Throat section Outlet section None of these

Q38. Kinematic viscosity is the ratio of:

Dynamic viscosity to pressure Dynamic viscosity to density Pressure to density Pressure to viscosity

Q39. Bernoulli’s theorem assumes:

Compressible fluid Non-viscous fluid Unsteady flow All of these

Q40. Which one is not a dimensionless number?

Reynolds number Mach number Froude number Velocity

Q41. Capillary rise is more in:

Narrow tubes Wide tubes Large containers No dependence on size

Q42. A floating body is in stable equilibrium when its:

Center of gravity is above metacenter Metacenter is above center of gravity Center of gravity coincides with center of buoyancy None of these

Q43. The unit of dynamic viscosity in SI system is:

Poise Pa·s N·m kg/m²

Q44. The instrument used to measure absolute pressure is:

Bourdon gauge Piezometer Vacuum gauge Barometer

Q45. The pressure intensity at the base of a fluid column is independent of:

Height of liquid column Density of liquid Shape of container Acceleration due to gravity

Q46. The unit of kinematic viscosity in SI system is:

m²/s m/s² Pa·s N/m²

Q47. Continuity equation represents conservation of:

Energy Mass Momentum Force

Q48. Pressure in a moving liquid is measured by:

Manometer Pitot tube Barometer Piezometer

Q49. For a floating body to be stable:

Metacenter should be below center of gravity Metacenter should coincide with center of gravity Metacenter should be above center of gravity Center of buoyancy must be above metacenter

Q50. Reynold's number is the ratio of:

Inertial force to viscous force Viscous force to inertial force Pressure force to gravity force Inertial force to gravity force

Q51. Open channel flow is characterized by:

Free surface exposed to atmosphere No free surface Flow under pressure None of these

Q52. The pressure at a point in a static fluid:

Acts equally in all directions Is different in different directions Is maximum in vertical direction Is zero

Q53. The SI unit of pressure is:

Pascal Newton Bar kg/m²

Q54. Which instrument measures very small pressure differences?

Inclined manometer Barometer Piezometer Venturimeter

Q55. Cavitation occurs in a pump when:

Pressure at suction falls below vapor pressure Pressure increases suddenly Velocity decreases None of these

Q56. The main cause of major head loss in pipe flow is:

Sudden expansion Sudden contraction Friction Fittings

Q57. Hydraulic gradient line (HGL) represents:

Pressure head only Velocity head only Pressure head + datum head Total head

Q58. A stream line and equipotential line in a flow field are:

Parallel to each other Perpendicular to each other Inclined at 45° Overlapping

Q59. The slope of the energy grade line (EGL) in pipe flow represents:

Friction loss per unit length Velocity head Pressure intensity Pipe diameter

Q60. In open channel, critical flow occurs when:

Froude number is less than 1 Froude number equals 1 Froude number is greater than 1 Zero slope

Q61. The discharge in a venturimeter increases if:

Throat area decreases Upstream pressure decreases Throat pressure increases Throat area increases

Q62. A negative pressure head in a piezometer indicates:

Cavitation Steady flow Uniform flow Critical flow

Q63. Manometric head is the:

Sum of suction and delivery heads Static head only Discharge head only Suction head only

Q64. Unit of specific speed of a turbine in SI is:

rpm Dimensionless m³/s No unit

Q65. Flow rate through a pipe increases if:

Pipe diameter decreases Head loss increases Pipe length increases Pipe diameter increases

Q66. The velocity distribution in laminar flow through a circular pipe is:

Uniform Parabolic Linear None

Q67. The Mach number is defined as:

Velocity of fluid / speed of light Velocity of fluid / speed of sound Speed of sound / velocity of fluid None

Q68. Pressure drop in laminar flow is proportional to:

Square of velocity Velocity Inversely to velocity Cube of velocity

Q69. Hydraulic jump is commonly observed in:

Pipe flow Open channel flow No flow Gas flow

Q70. Which principle is used in venturimeter?

Bernoulli's theorem Newton's law Pascal's law Hooke's law

Q71. The dimension of dynamic viscosity is:

MLT^-1 ML^-1T^-1 MLT^-2 None

Q72. The flow is said to be steady when:

Pressure changes with time Velocity changes with time Neither pressure nor velocity changes with time Density changes with time

Q73. The maximum efficiency of a centrifugal pump occurs at:

Shut-off condition Maximum flow rate At its design point Zero discharge

Q74. Surface tension is due to:

Cohesion Adhesion Viscosity Pressure

Q75. Reynolds number determines:

Energy loss Turbulence or laminarity of flow Pipe diameter Pressure loss

Q76. Bernoulli’s theorem is applicable to:

Viscous and compressible fluids Ideal, incompressible and non-viscous fluids Fluids with heat transfer Gaseous fluids

Q77. The continuity equation is based on the principle of conservation of:

Energy Momentum Mass Pressure

Q78. A Pitot tube is used to measure:

Pressure head Velocity head Total head Discharge

Q79. A venturimeter is preferred over an orifice meter because:

It is cheaper Head loss is less It can be used for gases It occupies less space

Q80. Absolute pressure is equal to:

Gauge pressure + atmospheric pressure Gauge pressure - atmospheric pressure Atmospheric pressure - gauge pressure None

Q81. The pressure of fluid measured above absolute zero pressure is known as:

Gauge pressure Absolute pressure Atmospheric pressure Vacuum pressure

Q82. The point in a submerged body through which buoyant force acts is called:

Metacentre Centre of gravity Centre of buoyancy None

Q83. Turbulent flow occurs when Reynolds number exceeds:

2000 4000 500 100

Q84. Capillarity is inversely proportional to:

Specific weight Viscosity Diameter of tube Temperature

Q85. Hydraulic jump is a phenomenon in:

Pipe flow Free surface open channel flow Gas flow Vapour flow

Q86. The unit of kinematic viscosity in SI system is:

m²/s N/m² m/s kg/m³

Q87. Centre of pressure on a submerged vertical plane surface is:

At centroid Above centroid Below centroid Cannot say

Q88. In a floating body, stability depends on:

Position of metacentre Centre of gravity Both A and B None

Q89. The total head line in pipe flow is called:

Hydraulic grade line Energy grade line Streamline Datum line

Q90. In venturimeter, minimum pressure occurs at:

Inlet Throat Outlet Everywhere equal

Q91. The Froude number is the ratio of:

Inertia force to viscous force Inertia force to gravity force Viscous force to gravity force Pressure force to inertia force

Q92. Absolute pressure below atmospheric pressure is called:

Gauge pressure Vacuum pressure Barometric pressure Atmospheric pressure

Q93. Cavitation in a hydraulic machine is caused by:

Excessive pressure Low pressure below vapour pressure High temperature High speed only

Q94. The pressure intensity at a point in a static fluid:

Is same in all directions Is maximum in vertical direction Is zero None of these

Q95. The dimension of surface tension is:

ML⁰T^-2 MT^-2 MLT^-2 M⁰L⁰T⁰

Q96. Which device measures discharge in open channels?

Pitot tube Notch or weir Orifice meter Manometer

Q97. The discharge equation of a rectangular weir is proportional to:

H^1/2 H^3/2 H² H

Q98. Specific gravity is the ratio of:

Density of fluid to density of water Mass of fluid to mass of water Volume of fluid to volume of water Viscosity of fluid to viscosity of water

Q99. Flow through a nozzle attached to a pipe is an example of:

Steady flow Unsteady flow Rotational flow Compressible flow

Q100. The pressure measured by a piezometer is:

Total pressure Static pressure Dynamic pressure Atmospheric pressure

Q101. The vena contracta is formed:

Before orifice At orifice Just after orifice Far away from orifice

Q102. Which statement about viscosity is true?

It decreases with temperature for liquids It increases with temperature for liquids Independent of temperature Same for all fluids

Q103. The hydraulic radius is defined as:

Wetted perimeter / Area Area / Wetted perimeter Diameter / 4 Length / Time

Q104. Capillarity is directly proportional to:

Specific weight Surface tension Diameter of tube Temperature

Q105. The discharge of a nozzle is maximum when:

Exit pressure equals critical pressure Exit pressure equals atmospheric pressure Back pressure is maximum Fluid is incompressible