HYDRAULICS AND FLUID MECHANICS OBJECTIVE AND MCQs
Section-4
 
Q61. The velocity distribution in laminar flow through a circular pipe follows the

(a) parabolic law 
(b) linear law 
(c) logarithmic law 
(d) none of the above. 

Ans:  (a) parabolic law

 

Q62. A boundary is known as hydrodynamically smooth, if

(a) k/δ′= 0.3 
(b)k/δ′> 0.3 
(c)k/δ′< 0.25 
(d)k/δ′= 6.0 
where k = Average height of the irregularities from the boundary and δ′ = Thickness of laminar sub-layer.

Ans:  (c)k/δ′< 0.25

 

Q63. The coefficient of friction for laminar flow through a circular pipe is given by

(a) f =0.0791/(Re )1 4 
(b) f = 16/Re
(c) f = 64/Re
(d) none of the above.

Ans: (b) f = 16/Re

 

Q64. For the laminar flow between two parallel plates

(a) the maximum velocity = 2.0 times the average velocity 
(b) the maximum velocity = 2.5 times of the average velocity 
(c) the maximum velocity = 1.33 times the average velocity 
(d) none of the above. 

Ans: (d) none of the above.

 

Q65. The valve of the kinetic energy correction factor (α) for the viscous flow through a circular pipe is

(a) 1.33 
(b) 1.50 
(c) 2.0 
(d) 1.25. 

Ans:  (c) 2.0

 

Q66. The valve of the momentum correction factor (β) for the viscous flow through a circular pipe is

(a) 1.33 
(b) 1.50 
(c) 2.0 
(d) 1.25.

Ans:  (a) 1.33

 

Q67. Francis’s formula for a rectangular weir with end contraction suppressed is given as

(a) Q = 1.84 LH5/2 
(b) Q = 2/3 L × H3/2 
(c) Q = 1.84 LH3/2 
(d) Q = 2/3 L × H5/2 

Ans:  (c) Q = 1.84 LH3/2 

 

Q68. Francis’s formula for a rectangular weir for two end contractions is given by

(a) Q = 1.84[L – 0.2 × 2H]H5/2 
(b) Q = 1.84[L – 0.2H]H3/2 
(c) Q = 1.84[L – 0.2H]H5/2 
(d) none of the above.

Ans:  (b) Q = 1.84[L – 0.2H]H3/2 

 

Q69. A flow is said to be laminar when

(a) the fluid particles move in a zigzag way 
(b) the Reynold number is high 
(c) the fluid particles move in layers parallel to the boundary 
(d) none of the above. 

Ans:  (c) the fluid particles move in layers parallel to the boundary

 

Q70. For the laminar flow through a circular pipe

(a) the maximum velocity = 1.5 times the average velocity 
(b) the maximum velocity = 2.0 times the average velocity 
(c) the maximum velocity = 2.5 times the average velocity 
(d) none of the above.

Ans:  (b) the maximum velocity = 2.0 times the average velocity

 

 

 

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Each section contains maximum 80 Questions. To practice more questions visit other sections.
 
Hydraulics and Fluid mechanics MCQ-Section-1

 

Hydraulics and Fluid mechanics MCQ-Section-2

 

Hydraulics and Fluid mechanics MCQ-Section-3

 

Hydraulics and Fluid mechanics MCQ-Section-4

 

Hydraulics and Fluid mechanics MCQ-Section-5

 

Hydraulics and Fluid mechanics MCQ-Section-6 

 


 

 

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