##### Q51. For the most efficient trapezoidal channel, the hydraulic mean depth should be

(a) twice the depth of flow
(b) 1.5 times the depth of flow
(c) equal to the depth of flow
(d) half the depth of flow.

Ans:  (d) half the depth of flow.

##### Q52. The flow of water, leaving the impeller, in a centrifugal pump casing is

(a) forced vortex flow
(b) free vortex flow
(c) centrifugal flow
(d) none of the above.

Ans:  (b) free vortex flow

##### Q53. Rotameter is used for measuring

(a) density of fluids
(b) velocity of fluids in pipes
(c) discharge of fluids
(d) viscosity of fluids.

Ans:  (c) discharge of fluids

##### Q54. The work done by impeller of a centrifugal pump on water per second per unit weight of water is given by

(a) 1/gVw1u1
(b) 1/gVw2u2
(c) 1/g(Vw1u2 – Vw1u1
(d) none of the above.

Ans:  (b) 1/gVw2u

##### Q55. The manometer head (Hm) of a centrifugal pump is given by

(a) pressure head at outlet of pump—pressure head at inlet
(b) total head at inlet—total head at outlet
(c) total head at outlet—total head at inlet
(d) none of the above.

Ans:  (c) total head at outlet—total head at inlet

##### Q56. The manometric efficiency (ηman) of a centrifugal pump is given by

(a) Hm/gVw2 u2
(b) gHm/Vw2 u2
(c) Vw 2 u2 /gHm
(d)g× Vw2 u2/Hm

Ans:  (b) gHm/Vw2 u2

##### Q57. Efficiency of the jet of water having velocity V striking a series of vertical plates moving with a velocity u is given by

(a) η = 2V( V -u)/u2
(b) η =2u(V- u)/V2
(c) η = u2/V2( V- u)
(d) none of the above.

Ans:  (c) η = u2/V2( V- u)

##### Q58. The lift force (FL) produced on a rotating circular cylinder in a uniform flow is given by

(a) FL =LUT/ρ
(b) FL = ρLUT
(c) FL = ρρU/T
(d) FL =ρLU/Γ
where L = Length of the cylinder, U = Free stream velocity, Γ = Circulation.

Ans:  (a) FL =LUT/ρ

##### Q59. The lift coefficient (CL) for a rotating cylinder in a uniform flow is given by

(a) CL= ΓU/R
(b) CL =ΓR//U
(c) CL = Γ/RU
(d) CL =RU/Γ

Ans:  (c) CL = Γ/RU

##### Q60. The circulation developed on an airfoil is given by

(a) Γ = CU sin α/π
(b) Γ = πCU sin α
(c) Γ =πCU/sinα
(d) Γ = π sin α/CU
where C = Chord length, U = Velocity of airfoil, α = Angle of attack.

Ans:   (b) Γ = πCU sin α

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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