##### Q61. A jet of water issues from a Nozzle with a velocity 20 m/s and it impinges normally on a flat plate moving away from it at 10 m/s. The cross-sectional area of the jet is 0.01 m2, and the density of water = 1000 kg/m3. The force developed on the plate is

(a) 1000 N
(b) 100 N
(c) 10 N
(d) 2000 N.                                                                                             (GATE-ME-2010)

Ans: (a) 1000 N

##### Q62. The stream function in a two dimensional flow field is given by ψ = x2 – y2. The magnitude of the velocity at point (1, 1) is

(a) 2

$\text { (b) } 2 \sqrt{2}$

(c) 4
(d) 8.                                                                                                                        (GATE-ME-1989)

Ans: $\text { (b) } 2 \sqrt{2}$

##### Q63. The specific speed of a turbine is given by

$(a) N_{s}=\frac{N \sqrt{P}}{H^{3 / 4}}$

$(b) N_{s}=\frac{N \sqrt{Q}}{H^{3 / 4}}$

$(c) N_{s}=\frac{N \sqrt{P}}{H^{5 / 4}}$

$(d) N_{s}=\frac{N \sqrt{P}}{H^{3 / 2}}$

Ans: $(c) N_{s}=\frac{N \sqrt{P}}{H^{5 / 4}}$

##### Q64. The velocity distribution in laminar flow through circular pipe, follows the

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

Ans: (a) parabolic law

##### Q65. The wetted perimeter P in the above question is given by

(a) P = 2d sec (θ/2)
(b) P = d/2sec θ
(c) P = d sec 2θ
(d) P = 2d sec θ.

Ans: (a) P = 2d sec (θ/2)

##### Q66. The wetted perimeter in a trapezoidal is given by

$\text { (a) } P=b+d \sqrt{n^{2}+1}$

$\text { (b) } P=2b+d \sqrt{n^{2}+1}$

$\text { (c) } P=b+2d \sqrt{n^{2}+1}$

$\text { (d) } P=2b+d \sqrt{n^{2}-1}$

Ans: $\text { (c) } P=b+2d \sqrt{n^{2}+1}$

##### Q67. The expressionb (b×d/ b+2d)represents the hydraulic mean depth for

(a) triangular channel
(b) rectangular channel
(c) trapezoidal channel
(d) circular channel
where b = Width of channel and d = Depth of flow.

Ans: (b) rectangular channel

#### Q68. Chezy’s formula is given by

$\text { (a) } V=\sqrt{C m i}$

$\text { (b) } Q=A C \sqrt{m i}$

$\text { (C) } Q=C \sqrt{m i}$

(d) m =A/P

where V = Velocity of flow, C = Chezy’s constant,
m = Hydraulic mean depth, and i = Slope of the bed of channel.

$\text { (C) } Q=C \sqrt{m i}$

##### Q69. The unit discharge (Qu) is given by the expression

$\text { (a) } Q_{u}=\frac{Q}{\sqrt{H}}$

(b) Qu =Q/H3/2

(c) Qu = Q/H3/4

(d) Qu = Q/H5/4

Ans: $\text { (a) } Q_{u}=\frac{Q}{\sqrt{H}}$

##### Q70. Unit power (Pu) is given by the expression

$\text { (a) } P_{u}=\frac{P}{\sqrt{H}}$

(b) Pu =PH/3/2

(c) Pu =P/H3/4

(d) Pu =P/H5/4 .

Ans: (b) Pu =PH/3/2

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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