Practice Test: Question Set - 31
1. The pressure head of a flow meter remains constant for
- (A) Venturimeter
- (B) Orificemeter
- (C) Rotameter
- (D) Pitot tube
2. Hydraulic mean depth (Dm) for a circular pipe of diameter 'D' flowing full is 0.25 D. For a circular channel, at Dm = 0.3 D, gives the condition for the maximum
- (A) Flow rate
- (B) Mean velocity
- (C) Both 'a' & 'b'
- (D) Neither 'a' nor 'b'
3. Which of the following quantities are computed by using the hydraulic radius for non-circular ducts?
- (A) Velocity and relative roughness
- (B) Head loss and velocity
- (C) Reynold number, relative roughness and head loss
- (D) Reynolds number and friction factor
4. A 0.5 m high bed made up of a 1 mm dia glass sphere (density 2500 kg/m3 ) is to be fluidized by water (density 1000 kg/m3 ). If at the point of incipient fluidization, the bed voidage is 40%, the pressure drop across the bed is
- (A) 4.4 KPa
- (B) 2.94 KPa
- (C) 3.7 KPa
- (D) None of these
5. A pressure head of 320 metres of water in meters of CCl4 (sp.gr = 1.6) will be
- (A) 100
- (B) 200
- (C) 320
- (D) 160
6. Which of the following denotes the effect of compressibility in fluid flow?
- (A) Weber number
- (B) Mach number
- (C) Euler number
- (D) Reynolds number
7. For pipe flows, head is proportional to __________ at constant capacity(where, D = pipe diameter).
- (A) 1/D
- (B) 1/D2
- (C) 1/D5
- (D) D2
8. Reynolds number for water flow through a tube of I.D. 5 cm is 1500. If a liquid of 5 centipoise viscosity and 0.8 specific gravity flows in the same pipe at the same velocity, then the pressure drop will
- (A) Increase
- (B) Decrease
- (C) Remain same
- (D) Data insufficient to predict pressure drop
9. A perfect gas
- (A) Does not satisfy PV = nRT
- (B) Is incompressible and has zero viscosity
- (C) Has constant specific heat
- (D) Can’t develop shear stresses
10. The ratio of the depth of flow to the hydraulic radius for the most economical trapezoidal section, in open channel flow is
- (A) 0.5
- (B) 1
- (C) 1.5
- (D) 2
11. Check in a centrifugal pump is
- (A) Provided in the discharge line
- (B) Generally a globe valve
- (C) Provided to prevent liquid from backing up through the pump when the
pump is turned off or accidently stops running
- (D) All (a), (b) and (c)
12. Which of the following equations as suggested by Colebrook and White gives the increase in roughness of a new surface (ε0) with age/time (t) (where, ε = roughness of the surface after time 't'. α = a co-efficient to be experimentally determined)?
- (A) ε = ε0 + α.t
- (B) ε = ε0 + α.t2
- (C) ε = ε0 + α.t3
- (D) ε = ε0 + α.t4
13. Reciprocating pumps are not able to compete with the centrifugal pump for industrial use, mainly because these pumps have
- (A) Very low speeds
- (B) Smaller discharge
- (C) Higher capital &maintenance cost
- (D) High vibrations
14. __________ pumps are axial flow pumps.
- (A) Turbine
- (B) Propeller
- (C) Diffuser
- (D) None of these
15. In an incompressible fluid, the density is
- (A) Greatly affected by moderate changes in pressure
- (B) Greatly affected only by moderate changes in temperature
- (C) Not affected with moderate change in temperature
& pressure
- (D) Sensible to changes in both temperature & pressure
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