Drag co-efficient in hindered settling is _____________ that in free settling?

Related Mcqs:

1. For motion of spherical particles in a stationary fluid, the drag co-efficient in hindered settling compared to that in free settling is _______________?

   A. More
   B. Less
   C. Equal
   D. More or less, depending on the type of particle

2. In hindered settling, the particles are_________________________?

   A. Placed farther from the wall
   B. Not affected by other particles and the wall
   C. Near each other
   D. None of these

3. 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

4. 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

5. In which of the following body shapes, the pressure drag is large compared to the friction drag ?

   A. Stream line body
   B. Two dimensional body
   C. Bluff body
   D. None of these

6. The ratio of wall drag to total drag in the Stoke’s law range is_________________?

   A. 0.5
   B. 1
   C. 1/3
   D. 2/3

7. The ratio of the wall drag to the form drag in the Stoke’s law range (for motion of spherical particles in a stationary fluid) is__________________?

   A. 0.5
   B. 1
   C. 2
   D. 0.33

8. Drag co-efficient for flow past immersed body is the ratio of _____________ to the product of velocity head and density?

   A. Shear stress
   B. Shear force
   C. Average drag per unit projected area
   D. None of these

9. 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

10. Cd, Cc and Cv are related (for flow through an orifice) as (where, Cd = discharge co-efficient, Cc = co-efficient of contraction = (area of jet at vena-contracta/area of opening), Cv = co-efficient of velocity = (actual velocity at vena-contracta/theoretical velocity)?

    A. Cd = Cc/Cv
    B. Cd = Cc.Cv
    C. Cd = Cv/ Cc
    D. None of these