In hindered settling, the particles are_________________________?

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

   A. Less than
   B. Equal to
   C. Not necessarily greater than
   D. Always greater than

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. Umf is the minimum fluidisation velocity for a bed of particles. An increase in the superficial gas velocity from 2 Umf to 2.5 Umf results in (all velocities are smaller than the entrainment velocity of the particles) no change in the_______________?

   A. Drag on particles
   B. Drag on column walls
   C. Bed height
   D. Bed voidage

6. Forces acting on a particle settling in fluid are _____________ forces?

   A. Gravitational & buoyant
   B. Centrifugal & drag
   C. Gravitational or centrifugal buoyant drag
   D. External, drag & viscous

7. Brownian movement is prominent in the particle size range of _____________ microns in case of settling of a particle in a fluid?

   A. 2 to 3
   B. 0.01 to 0.10
   C. 200 to 300
   D. 100 to 1000

8. The terminal velocity of a small sphere settling in a viscous fluid varies as the___________________?

   A. First power of its diameter
   B. Inverse of the fluid viscosity
   C. Inverse square of the diameter
   D. Square of the difference in specific weights of solid & fluid

9. For the free settling of a spherical particle through a fluid, the slope of, CD-log NRe, plot is____________________?

   A. 1
   B. -1
   C. 0.5
   D. -0.5

10. Drag co-efficient for motion of spherical particles in a stationary fluid in the stoke’s law range is_________________?

    A. 24/NRe,P
    B. 16/NRe,P
    C. 64/NRe,P
    D. 48/NRe,P