Hydraulics And Fluid Mechanics MCQ Questions & Answers

21

Coefficient of resistance is the ratio of

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

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Answer & Solution

Answer: Option C

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22

The mercury does not wet the glass. This is due to the property of the liquid known as

A) Cohesion B) Adhesion C) Viscosity D) Surface tension

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Answer & Solution

Answer: Option D

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23

The total pressure on a horizontally immersed surface is (where w = Specific weight of the liquid, A = Area of the immersed surface and x = Depth of the centre of gravity of the immersed surface from the liquid surface)

A) wA B) wx C) wAx D) $$\frac{{{\text{wA}}}}{{\text{x}}}$$

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Answer & Solution

Answer: Option C

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24

The depth of centre of pressure (h) for a vertically immersed surface from the liquid surface is given by (where $${I_{\text{G}}}$$ = 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) $$\frac{{{I_{\text{G}}}}}{{{\text{A}}\overline {\text{x}} }} - \overline {\text{x}} $$ B) $$\frac{{{I_{\text{G}}}}}{{\overline {\text{x}} }} - {\text{A}}\overline {\text{x}} $$ C) $$\frac{{{\text{A}}\overline {\text{x}} }}{{{I_{\text{G}}}}} + \overline {\text{x}} $$ D) $$\frac{{{I_{\text{G}}}}}{{{\text{A}}\overline {\text{x}} }} + \overline {\text{x}} $$

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Answer & Solution

Answer: Option D

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25

A vertical wall is subjected to a pressure due to one kind of liquid, on one of its sides. The total pressure on the wall acts at a distance __________ from the liquid surface.

A) $$\frac{{\text{H}}}{3}$$ B) $$\frac{{\text{H}}}{2}$$ C) $$\frac{{2{\text{H}}}}{3}$$ D) $$\frac{{3{\text{H}}}}{4}$$

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Answer & Solution

Answer: Option C

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26

The discharge through a wholly drowned orifice is given by (where H₁ = Height of water (on the upstream side) above the top of the orifice, H₂ = Height of water (on the downstream side) above the bottom of the orifice and H = Difference between two water levels on either side of the orifice)

A) $${\text{Q}} = {{\text{C}}_{\text{d}}} \times {\text{b}}{{\text{H}}_1}\sqrt {2{\text{gh}}} $$ B) $${\text{Q}} = {{\text{C}}_{\text{d}}} \times {\text{b}}{{\text{H}}_2}\sqrt {2{\text{gh}}} $$ C) $${\text{Q}} = {{\text{C}}_{\text{d}}} \times {\text{b}}\left( {{{\text{H}}_2} - {{\text{H}}_1}} \right)\sqrt {2{\text{gh}}} $$ D) $${\text{Q}} = {{\text{C}}_{\text{d}}} \times {\text{bH}}\sqrt {2{\text{gh}}} $$

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Answer & Solution

Answer: Option C

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27

The discharge through a small rectangular orifice is given by (where C_d = Coefficient of discharge for the orifice, a = Cross-sectional area of the orifice, h = Height of the liquid above the centre of the orifice)

A) $${\text{Q}} = {{\text{C}}_{\text{d}}} \times {\text{a}} \times \sqrt {2{\text{gh}}} $$ B) $${\text{Q}} = \frac{2}{3}{{\text{C}}_{\text{d}}} \times {\text{a}} \times {\text{h}}$$ C) $${\text{Q}} = \frac{{{{\text{C}}_{\text{d}}} \times {\text{a}}}}{{\sqrt {2{\text{gh}}} }}$$ D) $${\text{Q}} = \frac{{3{{\text{C}}_{\text{d}}} \times {\text{a}}}}{{\sqrt {2{\text{h}}} }}$$

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Answer & Solution

Answer: Option A

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28

One cubic metre of water weighs

A) 100 liters B) 250 liters C) 500 liters D) 1000 liters

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Answer & Solution

Answer: Option D

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29

According to fan laws, for fans having constant wheel diameter, the pressure varies

A) Directly as fan speed B) Square of fan speed C) Cube of fan speed D) Square root of fan speed

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Answer & Solution

Answer: Option B

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30

A turbine is required to develop 1500 kW at 300 r.p.m. under a head of 150 m. Which of the following turbine should be used?

A) Pelton wheel with one nozzle B) Pelton wheel with two or more nozzles C) Kaplan turbine D) Francis turbine

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Answer & Solution

Answer: Option A

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Hydraulics And Fluid Mechanics MCQ Questions &amp; Answers | Mechanical Engineering

Hydraulics And Fluid Mechanics MCQ Questions & Answers | Mechanical Engineering