Practice Test: Question Set - 44
1. Choking in case of pipe flow means that a
- (A) Specified mass flow rate cannot be achieved
- (B) Valve is closed in the line
- (C) Restriction in flow cross-section area occurs
- (D) None of these
2. Viscosity of water is about __________ times that of air at room temperature.
- (A) 15
- (B) 55
- (C) 155
- (D) 1050
3. Sewage sludge is an example of the __________ fluid.
- (A) Bingham plastic
- (B) Newtonian
- (C) Pseudo plastic
- (D) Dilatent
4. The ratio of width to depth for the most economical rectangular section in open channel flow is
- (A) 0.5
- (B) 1
- (C) 1.5
- (D) 2
5. The ratio of hydrodynamic boundary layer to thermal boundary layer thickness in case of liquid metals is
- (A) < 1
- (B) 1
- (C) > 1
- (D) 2
6. The pipe wall thickness is minimum for a pipe of given nominal size having schedule number
- (A) 160
- (B) 120
- (C) 80
- (D) 40
7. High specific speed of a pump implies that, it is a/an __________ pump.
- (A) Centrifugal
- (B) Mixed flow
- (C) Axial flow
- (D) None of these
8. Air vessel provided in a reciprocating pump
- (A) Smoothens the flow by avoiding pulsations
- (B) Increases the volumetric efficiency of the pump
- (C) Saves the pump from the danger of cavitation
- (D) None of these
9. Velocity of liquid hydrocarbon fuels in a pipeline cannot be measured by magnetic flow-meters, because their __________ is very low/small.
- (A) Thermal conductivity
- (B) Electrical conductivity
- (C) Specific gravity
- (D) Electrical resistivity
10. Volute type of casing is provided in a centrifugal pump to
- (A) Convert velocity head to pressure head
- (B) Convert pressure head to velocity head
- (C) Reduce the discharge fluctuation
- (D) Increase the discharge
11. The friction factor is
- (A) Always inversely proportional to the Reynolds number
- (B) Not dimensionless
- (C) Not dependent on the roughness of the pipe
- (D) None of these
12. The ratio of the hydraulic radius to the diameter of the channel, for maximum mean velocity of flow in a circular channel, in open channel flow is
- (A) 0.3
- (B) 0.9
- (C) 0.03
- (D) 0.66
13. What is the ratio of the velocity at the axis of the pipe to the mean velocity of flow in case of pipe flow under viscous condition?
- (A) 0.5
- (B) 0.67
- (C) 1
- (D) 2
14. Net positive suction head (NPSH) of a centrifugal pump must be
- (A) Greater than the vapor pressure of the liquid
- (B) Less than the vapor pressure of the liquid
- (C) Equal to the vapor pressure of the liquid
- (D) Less than barometric pressure
15. Turbine impeller
- (A) Produces only radial current
- (B) Produces only tangential current
- (C) Is effective over wide range of viscosities
- (D) Does not produce tangential current
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