Hydraulics and Fluid Mechanics MCQ – Set 22

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Q1. The force of buoyancy is always __ the weight of the liquid displaced by the body.

(A) Equal to
(B) Less than
(C) More than
(D) None of these

Answer: (A) Equal to


Q2. The specific gravity of an oil whose specific weight is 7.85 kN/m3, is

(A) 0.8
(B) 1
(C) 1.2
(D) 1.6

Answer: (A) 0.8


Q3. A flow in which the viscosity of fluid is dominating over the inertia force is called

(A) Steady flow
(B) Unsteady flow
(C) Laminar flow
(D) Turbulent flow

Answer: (C) Laminar flow


Q4. The total pressure on the top of a closed cylindrical vessel completely filled up with a liquid is

(A) Directly proportional to (radius)2
(B) Inversely proportional to (radius)2
(C) Directly proportional to (radius)4
(D) Inversely proportional to (radius)4

Answer: (C) Directly proportional to (radius)4


Q5. 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) At the summit


Q6. A nozzle is generally made of

(A) Cylindrical shape
(B) Convergent shape
(C) Divergent shape
(D) Convergent-divergent shape

Answer: (B) Convergent shape


Q7. Uniform flow occurs when

(A) The flow is steady
(B) The flow is streamline
(C) Size and shape of the cross section in a particular length remain constant
(D) Size and cross section change uniformly along length

Answer: (C) Size and shape of the cross section in a particular length remain constant


Q8. In a venturi-flume, the flow takes place at

(A) Atmospheric pressure
(B) Gauge pressure
(C) Absolute pressure
(D) None of these

Answer: (A) Atmospheric pressure


Q9. An error of 1% in measuring head over the apex of the notch (H) will produce an error of _ in discharge over a triangular notch.

(A) 1 %
(B) 1.5 %
(C) 2 %
(D) 2.5 %

Answer: (D) 2.5 %


Q10. The velocity at which the laminar flow stops, is known as

(A) Velocity of approach
(B) Lower critical velocity
(C) Higher critical velocity
(D) None of these

Answer: (B) Lower critical velocity


Q11. The ratio of the inertia force to the elastic force is called

(A) Reynold’s number
(B) Froude’s number
(C) Weber’s number
(D) Mach number

Answer: (D) Mach number


Q12. Coefficient of contraction is the ratio of

(A) Actual velocity of jet at vena contracta to the theoretical velocity
(B) Loss of head in the orifice to the head of water available at the exit of the orifice
(C) Loss of head in the orifice to the head of water available at the exit of the orifice
(D) Area of jet at vena-contracta to the area of orifice

Answer: (D) Area of jet at vena-contracta to the area of orifice


Q13. With an increase in size of tube, the rise or depression of liquid in the tube due to surface tension will

(A) Decrease
(B) Increase
(C) Remain unchanged
(D) Depend upon the characteristics of liquid

Answer: (A) Decrease


Q14. 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
(C) Streamline flow
(D) Turbulent flow

Answer: (C) Streamline flow


Q15. When a vertical wall is subjected to pressures due to liquid on both sides, the resultant pressure is the __ of the two pressures.

(A) Sum
(B) Difference
(C) Arithmetic mean
(D) Geometric mean

Answer:(B) Difference


Q16. Froude’s number is the ratio of inertia force to

(A) Pressure force
(B) Elastic force
(C) Gravity force
(D) Surface tension force

Answer: (C) Gravity force


Q17. The property of a liquid which offers resistance to the movement of one layer of liquid over another adjacent layer of liquid, is called

(A) Surface tension
(B) Compressibility
(C) Capillarity
(D) Viscosity

Answer: (D) Viscosity


Q18. The density of water is 1000 kg/m3 at

(A) 0° C
(B) 0° K
(C) 4° C
(D) 20° C

Answer:(C) 4° C


Q19. The length of the divergent cone in a Venturimeter is __ that of the convergent cone.

(A) Equal to
(B) Double
(C) Three to four times
(D) Five to six times

Answer: (C) Three to four times


Q20. The hydraulic mean depth or the hydraulic radius is the ratio of

(A) Area of flow and wetted perimeter
(B) Wetted perimeter and diameter of pipe
(C) Velocity of flow and area of flow
(D) None of these

Answer: (A) Area of flow and wetted perimeter


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