**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**

**NOTEIF YOU THINK ANY OF THE MCQ ABOVE IS WRONG.PLEASE COMMENT WITH CORRECT ANSWER AND ITS DETAIL EXPLANATION IN COMMENT BOX.THANK YOU**