Hydraulics And Fluid Mechanics MCQ Questions & Answers

61

Which of the following statement is correct?

A) The centrifugal pump is suitable for large discharge and smaller heads B) The centrifugal pump requires less floor area and simple foundation as compared to reciprocating pump C) The efficiency of centrifugal pump is less as compared to reciprocating pump D) All of the above

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Answer & Solution

Answer: Option D

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62

Which of the following statement is correct?

A) In an impulse turbine, the water impinges on the buckets with pressure energy. B) In a reaction turbine, the water glides over the moving vanes with kinetic energy. C) In an impulse turbine, the pressure of the flowing water remains unchanged and is equal to atmospheric pressure. D) In a reaction turbine, the pressure of the flowing water increases after gliding over the vanes.

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Answer: Option C

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63

The length AB of a pipe ABC in which the liquid is flowing has diameter (d₁) and is suddenly enlarged to diameter (d₂) at B which is constant for the length BC. The loss of head due to sudden enlargement is

A) $$\frac{{{{\left( {{{\text{v}}_1} - {{\text{v}}_2}} \right)}^2}}}{{\text{g}}}$$ B) $$\frac{{{\text{v}}_1^2 - {\text{v}}_2^2}}{{\text{g}}}$$ C) $$\frac{{{{\left( {{{\text{v}}_1} - {{\text{v}}_2}} \right)}^2}}}{{2{\text{g}}}}$$ D) $$\frac{{{\text{v}}_1^2 - {\text{v}}_2^2}}{{2{\text{g}}}}$$

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Answer & Solution

Answer: Option C

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64

In centrifugal pumps, maximum efficiency is obtained when the blades are

A) Straight B) Bent forward C) Bent backward D) Radial

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Answer & Solution

Answer: Option C

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65

The specific speed of a turbine is the speed of an imaginary turbine, identical with the given turbine, which

A) Delivers unit discharge under unit head B) Delivers unit discharge under unit speed C) Develops unit power under unit head D) Develops unit power under unit speed

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Answer: Option C

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66

Power required (in watts) to drive a centrifugal pump is (where H_m = Manometric head in metres, w = Specific weight in N/m³, Q = Discharge of the pump in m³/s and $${\eta _{\text{o}}}$$ = Overall efficiency of the pump)

A) $$\frac{{{\text{w}}{{\text{H}}_{\text{m}}}}}{{{\text{Q}} \times {\eta _{\text{o}}}}}$$ B) $$\frac{{{\text{wQ}}{{\text{H}}_{\text{m}}}}}{{{\eta _{\text{o}}}}}$$ C) $$\frac{{{\text{wQ}}}}{{{{\text{H}}_{\text{m}}} \times {\eta _{\text{o}}}}}$$ D) $$\frac{{{\text{wQ}} \times {\eta _{\text{o}}}}}{{{{\text{H}}_{\text{m}}}}}$$

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Answer & Solution

Answer: Option B

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67

According to Francis formula, the discharge over a rectangular weir is (where n = Number of end contractions)

A) $$\frac{2}{3} \times {{\text{C}}_{\text{d}}}\left( {{\text{L}} - {\text{nH}}} \right) \times \sqrt {2{\text{gh}}} $$ B) $$\frac{2}{3} \times {{\text{C}}_{\text{d}}}\left( {{\text{L}} - 0.1{\text{nH}}} \right) \times \sqrt {2{\text{g}}} \times {{\text{H}}^{\frac{3}{2}}}$$ C) $$\frac{2}{3} \times {{\text{C}}_{\text{d}}}\left( {{\text{L}} - {\text{nH}}} \right) \times \sqrt {2{\text{g}}} \times {{\text{H}}^2}$$ D) $$\frac{2}{3} \times {{\text{C}}_{\text{d}}}\left( {{\text{L}} - {\text{nH}}} \right) \times \sqrt {2{\text{g}}} \times {{\text{H}}^{\frac{5}{2}}}$$

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Answer & Solution

Answer: Option B

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68

The length of a liquid stream while flowing over a weir __________ at the ends of the sill.

A) Expands B) Does not change C) Contracts D) None of these

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Answer & Solution

Answer: Option C

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69

The discharge through a large rectangular orifice is given by (where H₁ = Height of the liquid above the top of the orifice, H₂ = Height of the liquid above the bottom of the orifice, b = Breadth of the orifice and C_d = Coefficient of discharge)

A) $${\text{Q}} = \frac{2}{3} \times {{\text{C}}_{\text{d}}} \times {\text{b}}\sqrt {2{\text{g}}} \left( {{{\text{H}}_2} - {{\text{H}}_1}} \right)$$ B) $${\text{Q}} = \frac{2}{3} \times {{\text{C}}_{\text{d}}} \times {\text{b}}\sqrt {2{\text{g}}} \left( {{\text{H}}_2^{\frac{1}{2}} - {\text{H}}_1^{\frac{1}{2}}} \right)$$ C) $${\text{Q}} = \frac{2}{3} \times {{\text{C}}_{\text{d}}} \times {\text{b}}\sqrt {2{\text{g}}} \left( {{\text{H}}_2^{\frac{3}{2}} - {\text{H}}_1^{\frac{3}{2}}} \right)$$ D) $${\text{Q}} = \frac{2}{3} \times {{\text{C}}_{\text{d}}} \times {\text{b}}\sqrt {2{\text{g}}} \left( {{\text{H}}_2^2 - {\text{H}}_1^2} \right)$$

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Answer: Option C

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70

The depth of center of pressure of an immersed surface, inclined at an angle $$\theta $$ with the liquid surface lies at a distance equal to __________ the center of gravity.

A) $$\frac{{{I_{\text{G}}}{{\sin }^2}\theta }}{{{\text{A}}\overline {\text{x}} }}{\text{ below}}$$ B) $$\frac{{{I_{\text{G}}}{{\sin }^2}\theta }}{{{\text{A}}\overline {\text{x}} }}{\text{ above}}$$ C) $$\frac{{{I_{\text{G}}}\sin \theta }}{{{\text{A}}\overline {\text{x}} }}{\text{ below}}$$ D) $$\frac{{{I_{\text{G}}}\sin \theta }}{{{\text{A}}\overline {\text{x}} }}{\text{ above}}$$

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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