Hydraulics and Fluid Mechanics MCQ - Set 01 - ObjectiveBooks

# Practice Test: Question Set - 01

1. 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

2. The property by virtue of which a liquid opposes relative motion between its different layers is called
(A) Surface tension
(B) Coefficient of viscosity
(C) Viscosity
(D) Osmosis

3. A weir is said to be narrow-crested weir, if the width of the crest of the weir is __________ half the height of water above the weir crest.
(A) Equal to
(B) Less than
(C) More than
(D) None of these

4. Euler's dimensionless number relates the following
(A) Inertial force and gravity
(B) Viscous force and inertial force
(C) Viscous force and buoyancy force
(D) Pressure force and inertial force

5. 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

6. The pressure of the liquid flowing through the divergent portion of a Venturimeter
(A) Remains constant
(B) Increases
(C) Decreases
(D) Depends upon mass of liquid

7. When the Mach number is between __________ the flow is called super-sonic flow.
(A) 1 and 2.5
(B) 2.5 and 4
(C) 4 and 6
(D) 1 and 6

8. In an immersed body, centre of pressure is
(A) At the centre of gravity
(B) Above the centre of gravity
(C) Below be centre of gravity
(D) Could be above or below e.g. depending on density of body and liquid

9. A vertically immersed surface is shown in the below figure. The distance of its centre of pressure from the water surface is
(A) (bd²/12) +
(B) (d²/12 ) +
(C) b²/12 +
(D) d²/12 +

10. The torque required to overcome viscous resistance of a collar bearing is              (where R1 and R2 = External and internal radius of collar)
(A) (Î¼Ï€²N/60t) × (R₁ - R₂)
(B) (Î¼Ï€²N/60t) × (R₁² - R₂²)
(C) Î¼Ï€²N/60t) × (R₁³ - R₂³)
(D) (Î¼Ï€²N/60t) × (R₁⁴ - R₂⁴)

(A) The direction and magnitude of the velocity at all points are identical
(B) The velocity of successive fluid particles, at any point, is the same at successive periods of time
(C) The magnitude and direction of the velocity do not change from point to point in the fluid
(D) The fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane

12. 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

13. In a forced vortex, the velocity of flow everywhere within the fluid is
(A) Maximum
(B) Minimum
(C) Zero
(D) Nonzero finite

14. The depth of centre of pressure (h) for a vertically immersed surface from the liquid surface is given by (where IG = Moment of inertia of the immersed surface about horizontal axis through its centre of gravity, A = Area of immersed surface, and x = Depth of centre of gravity of the immersed surface from the liquid surface)
(A) (IG/A) -
(B) (IG/x̅) - A
(C) (A/IG) +
(D) (IG/A) +

15. Mach number is significant in
(A) Supersonics, as with projectiles 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 force, and wave making effects, as with ship's hulls
(D) All of the above

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