Practice Test: Question Set - 23
1. Co-efficient of discharge (Cd) is defined as actual discharge/theoretical discharge and is equal to Cc . Cv; where Cc = Co-efficient of contraction and Cv = co-efficient of velocity. Cd of an orifice is usually about
- (A) 0.42
- (B) 0.62
- (C) 0.82
- (D) 0.98
2. Mach number is important in a fluid flow problem, when the inertia and __________ forces predominate.
- (A) Elastic
- (B) Viscous
- (C) Gravity
- (D) None of these
3. The head loss in turbulent flow in a pipe varies
- (A) As velocity
- (B) As (velocity)2
- (C) Inversely as the square of diameter
- (D) Inversely as the velocity
4. Boundary layer thickness in turbulent flow over a flat plate increases as(where, d = distance from the leading edge.)
- (A) √d
- (B) d2/3
- (C) d4/5
- (D) d1/3
5. The fluid property, due to which, mercury does not wet the glass is
- (A) Surface tension
- (B) Viscosity
- (C) Cohesion
- (D) Adhesion
6. The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the
- (A) Discharge
- (B) Suction
- (C) Suction minus vapor pressure of the liquid at suction temperature
- (D) Discharge minus vapor pressure of the liquid at the discharge
temperature
7. The ratio of inertial forces to elastic forces is called the __________ number.
- (A) Reynolds
- (B) Mach
- (C) Euler
- (D) Weber
8. Select the correct statement.
- (A) The discharge through a Venturimeter depends
upon Δp only and is independent of orientation of the meter
- (B) A Venturimeter with a given gage difference discharges at a greater
rate, when the flow is vertically downward through it, than when the flow is
vertically upward
- (C) For a given pressure difference, the discharge of gas is greater
through a Venturimeter, when compressibility is taken into account, than when
it is neglected
- (D) The overall pressure loss is the same in a given pipe line, whether
a Venturimeter or a nozzle with the same throat dia is used
9. Centrifugal compressors compared to reciprocating compressors
- (A) Require less space
- (B) Have quieter operation
- (C) Have lower operating costs
- (D) All (a), (b) and (c)
10. Nominal size of the discharge pipe of a pump is usually __________ the nominal size of the inlet pipe.
- (A) Smaller than
- (B) Larger than
- (C) Same as
- (D) Twice
11. A fluid element has a velocity V = -y2. xi + 2yx2 . j. The motion at (x, y) = (1/√2, 1) is
- (A) Rotational and incompressible
- (B) Rotational and compressible
- (C) Irrotational and compressible
- (D) Irrotational and incompressible
12. Which of the following has the minimum compressibility?
- (A) Water at room temperature
- (B) Air at room temperature
- (C) Oxygen at room temperature
- (D) Nitrogen at room temperature
13. A stream tube is that, which has __________ cross-section entirely bounded by stream lines.
- (A) A circular
- (B) Any convenient
- (C) A small
- (D) A large
14. Power loss in an orificemeter is __________ that in a Venturimeter.
- (A) Less than
- (B) Same as
- (C) More than
- (D) Data insufficient, cannot be predicted
15. Applying a pressure drop across a capillary results in a volumetric flow rate 'Q' under laminar flow conditions. The flow rate for the same pressure drop, in a capillary of the same length but half the radius is
- (A) Q/2
- (B) Q/4
- (C) Q/8
- (D) Q/16
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