781. 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’

782. Which of the following denotes the effect of compressibility in fluid flow ?
A. Weber number
B. Mach number
C. Euler number
D. Reynolds number

783. 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

784. ______________ pumps are axial flow pumps?
A. Turbine
B. Propeller
C. Diffuser
D. None of these

785. For a particle settling in water at its terminal settling velocity, which of the following is true ?
A. Buoyancy = weight + drag
B. Weight = buoyancy + drag
C. Drag = buoyancy + weight
D. Drag = weight

786. Sewage sludge is ______________ type of non-Newtonian fluid?
A. Dilatant
B. Bingham plastic
C. Pseudo plastic
D. None of these

787. For the transfer of solution of thick slurry, the pump used is a _____________ pump?
A. Reciprocating
B. Gear
C. Diaphragm
D. Centrifugal

788. A particle A of diameter 10 microns settles in an oil of specific gravity 0.9 and viscosity 10 poise under Stoke’s law. A particle B with diameter 20 microns settling in the same oil will have a settling velocity ?
A. Same as that of A
B. One fourth as that of A
C. Twice as that of A
D. Four times as that of A

789. A piezometer opening measures the _____________ fluid pressure?
A. Static
B. Undisturbed
C. Total
D. Dynamic

790. The drag co-efficient for a bacterium moving in water at 1 mm/s, will be of the following order of magnitude (assume size of the bacterium to be 1 micron and kinematic viscosity of water to be 10-6m2/s) ?
A. 24000
B. 24
C. 0.24
D. 0.44

NOTE
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