Basic of Chemical Engineering Fluid Mechanics Questions & Answers - Set 25 - ObjectiveBooks

# Practice Test: Question Set - 25

1. A mercury (specific gravity = 13.6) manometer connected across an orificemeter fitted in a pipe shows a manometer reading of 2 cms. If the manometer liquid is changed to carbon tetrachloride (specific gravity = 1.6), then for the same flow rate of water the new manometer reading will be __________ cms.
(A) 17
(B) 42
(C) 84
(D) 1.8

2. The Prandtl Pitot tube measures the
(A) Velocity at a point in the flow
(B) Pressure at a point
(C) Average flow velocity
(D) Pressure difference in pipe flow

3. In centrifugal pump operation, the cavitation can be eliminated by maintaining suction pressure __________ the vapor pressure of the liquid at the suction temperature.
(A) Lower than
(B) Higher than
(C) Equal to
(D) None of these

4. A Bingham fluid of viscosity μ = 10 Pa.s and yield stress, τ0 = 10 KPa, is shared between flat parallel plates separated by a distance of 10-3 m. The top plate is moving with a velocity of 1 m/s. The shear stress on the plate is
(A) 10 KPa
(B) 20 KPa
(C) 30 KPa
(D) 40 KPa

5. A centrifugal pump is called a turbine pump, if it is having a
(A) Turbine type impeller
(B) Vaned diffusion casing
(C) Rotating vaned volute
(D) None of these

6. The equation f-0.5 = 4.07 loge (NRe f)-0.6 is called the __________.
(A) Colebrook formula
(B) Von-Karman equation
(C) Fanning equation
(D) None of these

7. The velocity profile exhibited by laminar flow of Newtonian fluids is such that the velocity distribution w.r.t. radius of the circular pipe is a/an __________ with the apex at the centre line of the pipe.
(A) Hyperbola
(B) Parabola
(C) Semi-circle
(D) Semi-ellipse

8. Laminar flow of a Newtonian fluid ceases to exist, when the Reynolds number exceeds
(A) 4000
(B) 2100
(C) 1500
(D) 3000

9. Pick out the wrong statement.
(A) The form drag is dependent upon the occurrence of a wake
(B) The shear stress at any given cross-section of a pipe for steady flow (either laminar or turbulent) varies linearly as the radial distance
(C) An ideal fluid is the one, which has negligible surface tension and obeys the Newton's law of viscosity
(D) Existence of the boundary layer in fluid flow is because of viscosity of the fluid

10. For an unstable equilibrium of a floating body (where, M = metacentre.)
(A) M is above G
(B) M is below G
(C) M & G coincide
(D) None of these

11. The hydrodynamic and thermal boundary layers will merge, when
(A) Prandtl number is one
(B) Schmidt number tends to infinity
(C) Nusselt number tends to infinity
(D) Archimedes number is greater than 10000

12. Schedule number of a pipe, which is a measure of its wall thickness, is given by
(A) 1000 P'/S
(B) 100 P'/S
(C) 1000 S/P'
(D) 10000 P'/S

13. The energy equation, E + (p/ρ) + (V2/2g) + gZ = constant (E = internal energy/mass), is applicable to
(A) Perfect gases only
(B) Isothermal flow of gases
(D) All compressible fluids

14. Steady fluid flow occurs, when the derivative of flow variables satisfy the following condition.
(A) ∂/∂s = 0
(B) ∂/∂t = 0
(C) ∂/∂s = constant
(D) ∂/∂t = constant

15. A Rotameter works on the principle of __________ pressure drop.
(A) Constant
(B) Variable
(C) Both (a) & (b)
(D) Neither (a) nor (b)

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