Fluid Mechanics MCQ Solved Paper for NEET
Thursday 9th of March 2023
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1. A fluid in equilibrium can't sustain
A. Tensile stress
B. Compressive stress
C. Shear stress
D. Bending stress
Answer : C
A. Tensile stress
B. Compressive stress
C. Shear stress
D. Bending stress
Answer : C
2. When a body is placed over a liquid, it will sink down if
A. Gravitational force is equal to the up-thrust of the liquid
B. Gravitational force is less than the up-thrust of the liquid
C. Gravitational force is more than the up-thrust of the liquid
D. None of the above
Answer : C
A. Gravitational force is equal to the up-thrust of the liquid
B. Gravitational force is less than the up-thrust of the liquid
C. Gravitational force is more than the up-thrust of the liquid
D. None of the above
Answer : C
3. The weight per unit volume of a liquid at a standard temperature and pressure is called
A. Specific weight
B. Mass density
C. Specific gravity
D. None of these
Answer : A
A. Specific weight
B. Mass density
C. Specific gravity
D. None of these
Answer : A
4. The property of fluid by virtue of which it offers resistance to shear is called
A. Surface tension
B. Adhesion
C. Cohesion
D. Viscosity
Answer : D
A. Surface tension
B. Adhesion
C. Cohesion
D. Viscosity
Answer : D
5. If the depth of water in an open channel is greater than the critical depth, the flow is called
A. Critical flow
B. Turbulent flow
C. Tranquil flow
D. Torrential flow
Answer : C
A. Critical flow
B. Turbulent flow
C. Tranquil flow
D. Torrential flow
Answer : C
6. The force exerted by a moving fluid on an immersed body is directly proportional to the rate of change of momentum due to the presence of the body. This statement is called
A. Newton's law of motion
B. Newton's law of cooling
C. Newton's law of viscosity
D. Newton's law of resistance
Answer : D
A. Newton's law of motion
B. Newton's law of cooling
C. Newton's law of viscosity
D. Newton's law of resistance
Answer : D
7. Hot wire anemometer is used to measure
A. Pressure in gases
B. Liquid discharge
C. Pressure in liquids
D. Gas velocities
Answer : D
A. Pressure in gases
B. Liquid discharge
C. Pressure in liquids
D. Gas velocities
Answer : D
8. The centre of gravity of the volume of the liquid displaced is called
A. Centre of pressure
B. Centre of buoyancy
C. Metacentre
D. None of these
Answer : B
A. Centre of pressure
B. Centre of buoyancy
C. Metacentre
D. None of these
Answer : B
9. According to Bazin's formula, the discharge over a rectangular weir is mL2g x H3/2where m is equal to
A. 0.405 + (0.003/H)
B. 0.003 + (0.405/H)
C. 0.405 + (H/0.003)
D. 0.003 + (H/0.405)
Answer : A
A. 0.405 + (0.003/H)
B. 0.003 + (0.405/H)
C. 0.405 + (H/0.003)
D. 0.003 + (H/0.405)
Answer : A
10. Euler's number is the ratio of __________ force to pressure force.
A. Inertia
B. Gravity
C. Viscous
D. None of these
Answer : A
A. Inertia
B. Gravity
C. Viscous
D. None of these
Answer : A
11. In a lock-gate, the reaction between two gates is (where P = Resultant pressure on the lock gate, and ? = Inclination of the gate with the normal to the side of the lock)
A. p/sin?
B. 2p/sin?
C. p/2sin?
D. 2p/sin (?/2)
Answer : C
A. p/sin?
B. 2p/sin?
C. p/2sin?
D. 2p/sin (?/2)
Answer : C
12. The discharge over a rectangular notch is (where b = Width of notch, and H = Height of liquid, above the sill of the notch)
A. (2/3) Cd × b × ?(2gH)
B. (2/3) Cd × b × ?(2g) × H
C. (2/3) Cd × b × ?(2g) × H3/2
D. (2/3) Cd × b × ?(2g) × H2
Answer : C
A. (2/3) Cd × b × ?(2gH)
B. (2/3) Cd × b × ?(2g) × H
C. (2/3) Cd × b × ?(2g) × H3/2
D. (2/3) Cd × b × ?(2g) × H2
Answer : C
13. General energy equation holds for
A. Steady flow
B. Turbulent flow
C. Laminar flow
D. Non-uniform flow
Answer : D
A. Steady flow
B. Turbulent flow
C. Laminar flow
D. Non-uniform flow
Answer : D
14. The velocity through a channel of circular section will be maximum when the depth of water is __________ the diameter of the circular channel.
A. 0.34 times
B. 0.67 times
C. 0.81 times
D. 0.95 times
Answer : C
A. 0.34 times
B. 0.67 times
C. 0.81 times
D. 0.95 times
Answer : C
15. A flow is called hyper-sonic, if the Mach number is
A. Less than unity
B. Unity
C. Between 1 and 6
D. None of these
Answer : D
A. Less than unity
B. Unity
C. Between 1 and 6
D. None of these
Answer : D
16. The normal stress is same in all directions at a point in a fluid
A. Only when the fluid is frictionless
B. Only when the fluid is incompressible and has zero viscosity
C. When there is no motion of one fluid layer relative to an adjacent layer
D. Irrespective of the motion of one fluid layer relative to an adjacent layer
Answer : C
A. Only when the fluid is frictionless
B. Only when the fluid is incompressible and has zero viscosity
C. When there is no motion of one fluid layer relative to an adjacent layer
D. Irrespective of the motion of one fluid layer relative to an adjacent layer
Answer : C
17. The velocity corresponding to Reynold number of 2000 is called
A. Sub-sonic velocity
B. Super-sonic velocity
C. Lower critical velocity
D. Higher critical velocity
Answer : C
A. Sub-sonic velocity
B. Super-sonic velocity
C. Lower critical velocity
D. Higher critical velocity
Answer : C
18. The continuity equation is connected with
A. Open channel/pipe flow
B. Compressibility of fluids
C. Conservation of mass
D. Steady/unsteady flow
Answer : C
A. Open channel/pipe flow
B. Compressibility of fluids
C. Conservation of mass
D. Steady/unsteady flow
Answer : C
19. The speed of sound in a ideal gas varies directly as its
A. Absolute temperature
B. Temperature
C. Density
D. Modulus of elasticity
Answer : A
A. Absolute temperature
B. Temperature
C. Density
D. Modulus of elasticity
Answer : A
20. In order that flow takes place between two points in a pipeline, the differential pressure between these points must be more than
A. Frictional force
B. Viscosity
C. Surface friction
D. All of the above
Answer : D
A. Frictional force
B. Viscosity
C. Surface friction
D. All of the above
Answer : D
21. Newton's law of viscosity is a relationship between
A. Pressure, velocity and temperature
B. Shear stress and rate of shear strain
C. Shear stress and velocity
D. Rate of shear strain and temperature
Answer : B
A. Pressure, velocity and temperature
B. Shear stress and rate of shear strain
C. Shear stress and velocity
D. Rate of shear strain and temperature
Answer : B
22. A flow is called super-sonic if the
A. Velocity of flow is very high
B. Discharge is difficult to measure
C. Mach number is between 1 and 6
D. None of these
Answer : C
A. Velocity of flow is very high
B. Discharge is difficult to measure
C. Mach number is between 1 and 6
D. None of these
Answer : C
23. In order to increase sensitivity of U-tube manometer, one leg is usually inclined by angle ?. Sensitivity of inclined tube to sensitivity of Utube is equal to
A. Sin?
B. 1/Sin?
C. Cos?
D. 1/Cos?
Answer : B
A. Sin?
B. 1/Sin?
C. Cos?
D. 1/Cos?
Answer : B
24. A liquid compressed in cylinder has a volume of 0.04 m3 at 50 kg/cm² and a volume of 0.039 m3 at 150 kg/cm². The bulk modulus of elasticity of liquid is
A. 400 kg/cm²
B. 4000 kg/cm²
C. 40 × 10? kg/cm²
D. 40 × 10? kg/cm²
Answer : B
A. 400 kg/cm²
B. 4000 kg/cm²
C. 40 × 10? kg/cm²
D. 40 × 10? kg/cm²
Answer : B
25. If a body floating in a liquid occupies a new position and remains at rest in this new position, when given a small angular displacement, the body is said to be in __________ equilibrium.
A. Neutral
B. Stable
C. Unstable
D. None of these
Answer : A
A. Neutral
B. Stable
C. Unstable
D. None of these
Answer : A
26. Normal depth in open channel flow is the depth of flow corresponding to
A. Steady flow
B. Unsteady flow
C. Laminar flow
D. Uniform flow
Answer : D
A. Steady flow
B. Unsteady flow
C. Laminar flow
D. Uniform flow
Answer : D
27. Choose the wrong statement
A. The horizontal component of the hydrostatic force on any surface is equal to the normal force on the vertical projection of the surface
B. The horizontal component acts through the center of pressure for the vertical projection
C. The vertical component of the hydrostatic force on any surface is equal to the weight of the volume of the liquid above the area
D. The vertical component passes through the center of pressure of the volume
Answer : D
A. The horizontal component of the hydrostatic force on any surface is equal to the normal force on the vertical projection of the surface
B. The horizontal component acts through the center of pressure for the vertical projection
C. The vertical component of the hydrostatic force on any surface is equal to the weight of the volume of the liquid above the area
D. The vertical component passes through the center of pressure of the volume
Answer : D
28. The depth of the centre of pressure on a vertical rectangular gate 8 m wide and 6 m high, when the water surface coincides with the top of the gate, is
A. 2.4 m
B. 3.0 m
C. 4.0 m
D. 5.0 m
Answer : B
A. 2.4 m
B. 3.0 m
C. 4.0 m
D. 5.0 m
Answer : B
29. The coefficient of venturi-flume, generally, lies between
A. 0.3 to 0.45
B. 0.50 to 0.75
C. 0.75 to 0.95
D. 0.95 to 1.0
Answer : D
A. 0.3 to 0.45
B. 0.50 to 0.75
C. 0.75 to 0.95
D. 0.95 to 1.0
Answer : D
30. When the Mach number is more than 6, the flow is called
A. Sub-sonic flow
B. Sonic flow
C. Super-sonic flow
D. Hyper-sonic flow
Answer : D
A. Sub-sonic flow
B. Sonic flow
C. Super-sonic flow
D. Hyper-sonic flow
Answer : D
31. All the terms of energy in Bernoulli's equation have dimension of
A. Energy
B. Work
C. Mass
D. Length
Answer : D
A. Energy
B. Work
C. Mass
D. Length
Answer : D
32. The flow in a pipe or channel is said to be uniform when
A. The liquid particles at all sections have the same velocities
B. The liquid particles at different sections have different velocities
C. The quantity of liquid flowing per second is constant
D. Each liquid particle has a definite path
Answer : A
A. The liquid particles at all sections have the same velocities
B. The liquid particles at different sections have different velocities
C. The quantity of liquid flowing per second is constant
D. Each liquid particle has a definite path
Answer : A
33. Specific weight of sea water is more that of pure water because it contains
A. Dissolved air
B. Dissolved salt
C. Suspended matter
D. All of the above
Answer : D
A. Dissolved air
B. Dissolved salt
C. Suspended matter
D. All of the above
Answer : D
34. The point in the immersed body through which the resultant pressure of the liquid may be taken to act is known as
A. Meta center
B. Center of pressure
C. Center of buoyancy
D. Center of gravity
Answer : B
A. Meta center
B. Center of pressure
C. Center of buoyancy
D. Center of gravity
Answer : B
35. Choose the wrong statement
A. The center of buoyancy is located at the center of gravity of the displaced liquid
B. For stability of a submerged body, the center of gravity of body must lie directly below the center of buoyancy
C. If C.G. and center of buoyancy coincide, the submerged body must lie at neutral equilibrium for all positions
D. All floating bodies are stable
Answer : D
A. The center of buoyancy is located at the center of gravity of the displaced liquid
B. For stability of a submerged body, the center of gravity of body must lie directly below the center of buoyancy
C. If C.G. and center of buoyancy coincide, the submerged body must lie at neutral equilibrium for all positions
D. All floating bodies are stable
Answer : D
36. The water pressure per metre length on a vertical masonry wall of dam is (where w = Specific weight of the liquid, and H = Height of the liquid)
A. wH/2
B. wH
C. wH2/2
D. wH2/4
Answer : C
A. wH/2
B. wH
C. wH2/2
D. wH2/4
Answer : C
37. To avoid an interruption in the flow of a siphon, an air vessel is provided
A. At the inlet
B. At the outlet
C. At the summit
D. At any point between inlet and outlet
Answer : C
A. At the inlet
B. At the outlet
C. At the summit
D. At any point between inlet and outlet
Answer : C
38. If the coefficient of discharge is 0.6, then the discharge over a right angled notch is
A. 0.417 H5/2
B. 1.417 H5/2
C. 4.171 H5/2
D. 7.141 H5/2
Answer : B
A. 0.417 H5/2
B. 1.417 H5/2
C. 4.171 H5/2
D. 7.141 H5/2
Answer : B
39. For a perfect incompressible liquid, flowing in a continuous stream, the total energy of a particle remains the same, while the particle moves from one point to another. This statement is called
A. Continuity equation
B. Bernoulli's equation
C. Pascal's law
D. Archimedess principle
Answer : B
A. Continuity equation
B. Bernoulli's equation
C. Pascal's law
D. Archimedess principle
Answer : B
40. The imaginary line drawn in the fluid in such a way that the tangent to any point gives the direction of motion at that point, is known as
A. Path line
B. Stream line
C. Steak line
D. Potential line
Answer : B
A. Path line
B. Stream line
C. Steak line
D. Potential line
Answer : B
41. Coefficient of discharge Cd is equal to (where Cc = Coefficient of contraction, Cv = Coefficient of velocity, and Cr = Coefficient of resistance)
A. Cc × Cv
B. Cc × Cr
C. Cv × Cr
D. Cc/Cr
Answer : A
A. Cc × Cv
B. Cc × Cr
C. Cv × Cr
D. Cc/Cr
Answer : A
42. The absolut pressure is equal to
A. Gauge pressure + atmospheric pressure
B. Gauge pressure - atmospheric pressure
C. Atmospheric pressure - gauge pressure
D. Gauge pressure - vacuum pressure
Answer : A
A. Gauge pressure + atmospheric pressure
B. Gauge pressure - atmospheric pressure
C. Atmospheric pressure - gauge pressure
D. Gauge pressure - vacuum pressure
Answer : A
43. Froude number is significant in
A. Supersonics, as with projectile and jet propulsion
B. Full immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc.
C. Simultaneous motion through two fluids where there is a surface of discontinuity, gravity forces, and wave making effect as with ship's hulls
D. All of the above
Answer : C
A. Supersonics, as with projectile and jet propulsion
B. Full immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc.
C. Simultaneous motion through two fluids where there is a surface of discontinuity, gravity forces, and wave making effect as with ship's hulls
D. All of the above
Answer : C
44. The most efficient section of a channel is
A. Triangular
B. Rectangular
C. Square
D. Trapezoidal
Answer : D
A. Triangular
B. Rectangular
C. Square
D. Trapezoidal
Answer : D
45. The pressure at a point 4 m below the free surface of water is
A. 19.24 kPa
B. 29.24 kPa
C. 39.24 kPa
D. 49.24 kPa
Answer : C
A. 19.24 kPa
B. 29.24 kPa
C. 39.24 kPa
D. 49.24 kPa
Answer : C
46. When a body floating in a liquid, is displaced slightly, it oscillates about
A. C.G. of body
B. Center of pressure
C. Center of buoyancy
D. Metacentre
Answer : D
A. C.G. of body
B. Center of pressure
C. Center of buoyancy
D. Metacentre
Answer : D
47. The discharge over the trapezoidal notch is equal to the discharge over the rectangular notch __________ the discharge over the triangular notch.
A. Plus
B. Minus
C. Divide
D. None of these
Answer : A
A. Plus
B. Minus
C. Divide
D. None of these
Answer : A
48. The region between the separation streamline and the boundary surface of the solid body is known as
A. Wake
B. Drag
C. Lift
D. Boundary layer
Answer : A
A. Wake
B. Drag
C. Lift
D. Boundary layer
Answer : A
49. Which of the following is an example of laminar flow?
A. Underground flow
B. Flow past tiny bodies
C. Flow of oil in measuring instruments
D. All of these
Answer : D
A. Underground flow
B. Flow past tiny bodies
C. Flow of oil in measuring instruments
D. All of these
Answer : D
50. The volume of a fluid __________ as the pressure increases.
A. Remains same
B. Decreases
C. Increases
D. None of these
Answer : B
A. Remains same
B. Decreases
C. Increases
D. None of these
Answer : B
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