##### 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.

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

Ans:  (c) 2.0

(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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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