Chemical Fluid Mechanics Problems for Qualifying Exam Questions - Set 36 - ObjectiveBooks
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# Practice Test: Question Set - 36

1. For one dimensional flow of an incompressible fluid in unsteady state in x-direction, the continuity equation is given by
(A) ∂u/∂x = 0
(B) ∂(ρu)/∂x = 0
(C) (∂u/∂x) = - (∂ρ/∂t)
(D) ∂ρ/∂t = 0

2. The specific speed of a pump is defined as the speed of a unit of such a size, that it
(A) Delivers unit discharge at unit head
(B) Requires unit power for unit head
(C) Delivers unit discharge at unit power
(D) None of these

3. Pick out the wrong statement.
(A) The shear stress at the pipe (dia = D, length = L) wall in case of laminar flow of Newtonian fluids is (D/4L). ∆p
(B) In the equation, T. gc = k. (du/dy)n the value of 'n' for pseudoplastic and Dilatant fluid are < 1 and >1 respectively
(C) Shear stress for Newtonian fluid is proportional to the rate of shear in the direction perpendicular to motion
(D) With increase in the Mach number >0.6, the drag co-efficient decreases in case of compressible fluids

4. For ideally incompressible fluid, the Mach number will be
(A) 1.5
(B) 1
(C) 0
(D) 5

5. Absolute viscosity of a fluid is a function of the __________ of the fluid.
(A) Motion
(B) Pressure & temperature
(C) Shearing stress
(D) Both (b) & (c)

6. Various efficiencies of a centrifugal pump are related as (where, ηm = mechanical efficiency ηv = volumetric efficiency. ηma = manometric efficiency ηo = overall efficiency)
(A) ηma × ηm × ηv = ηo
(B) ηm = ηv . ηma
(C) ηma = ηm × ηv
(D) ηv = ηm × ηma

7. Three piping networks as shown in the figure are placed horizontally. They are made using identical pipe segments and are subjected to the same pressure drop across them. Assuming no pressure losses at junctions, the flow rates across the three networks are related as Q1 : Q2 : Q3.
(A) 1 : √3 : 2
(B) 1 : 2 : 3
(C) 1 : 2 : 2
(D) 1 : √2 : √2

(A) Less power than
(B) More power than
(C) Same power as
(D) Data insufficient to predict

9. For flow of fluids through packed bed, the superficial velocity is
(A) Less than the average velocity through channels
(B) More than the average velocity through channels
(C) Dependent on the pressure drop across the bed
(D) Same as the average velocity through channels

10. A fluid is pumped at the rate of 10 lb/sec to a height of 55 ft. The horse power required is __________ hp.
(A) 1
(B) 10/55
(C) 5.5
(D) 1/55

11. Unsteady uniform flow is represented by flow through a/an
(A) Long pipe at constant rate
(B) Long pipe at decreasing rate
(C) Expanding tube at increasing rate
(D) Expanding tube at constant rate

12. In turbulent flow, a rough pipe has the same friction factor as a smooth pipe
(A) In the zone of complete turbulence
(B) When the roughness projections are much smaller than the thickness of the laminar film
(C) Everywhere in the transition zone
(D) When the friction factor is independent of the Reynold's number

13. The speed of sound in an ideal gas varies as the
(A) Temperature
(B) Pressure
(C) Density
(D) None of these

14. What is the pipe called which lifts water from a reservoir to a greater height than the initial level in the supply reservoir?
(A) Penstock
(B) Siphon
(C) Tunnel
(D) Pressure pipeline

15. Velocity at a certain point in case of streamline flow is
(A) Constant
(B) Independent of time
(C) Both (a) & (b)
(D) Neither (a) nor (b)

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