A 30% (by volume) suspension of spherical sand particles in a viscous oil has a hindered settling velocity of 4.44 μm/s. If the Richardson Zaki hindered settling index is 4.5, then the terminal velocity of a sand grain is_________________?

Related Mcqs:

1. A suspension of glass beads in ethylene glycol has a hindered settling velocity of 1.7 mm/s, while the terminal settling velocity of a single glass bead in ethylene glycol is 17 mm/s. If the Richardson-Zaki hindered settling index is 4.5, the volume fraction of solids in the suspension is_____________?

   A. 0.1
   B. 0.4
   C. 0.6
   D. None of these

2. In classification, particles are said to be equal settling, if they have the same terminal velocities in the_______________?

   A. Different fluids
   B. Same fluid
   C. Same field of force
   D. Both B. and C.

3. Number of particles in a crushed solid sample is given by (where, m = mass of particles in a sample, Vp = volume of one particle, ρ= density of particles) ?

   A. m/ρ . Vp
   B. m . ρ/Vp
   C. m . Vp/ρ
   D. Vp/m . ρ

4. The capacity of a classifier in ‘tons of solid/hr’ is given by (where, A = cross-sectional area in m2, V = rising velocity of fluid in m/sec, S = percentage of solids in the suspension by volume, ρ = density of solids in kg/m3)_________________?

   A. 3.6 AVS.ρ
   B. 3.6 A.V.ρ
   C. 3.6 A.S. ρ
   D. 3.6 AVS/ρ
   Answer: Option

5. Short distance transportation of grain, gravel, sand, ash, asphalt etc. is done by using a ______________ conveyor?

   A. Flight
   B. Slat or drag
   C. Ribbon
   D. Screw

6. Two particles are called to be equal settling, if they are having the same ?

   A. Size
   B. Specific gravity
   C. Terminal velocities in the same fluid & in the same field of force
   D. None of these

7. Sorting classifiers employing differential settling methods for separation of particles make use of the differences in their_________________?

   A. Particle sizes
   B. Densities
   C. Terminal velocities
   D. None of these

8. Separation of a suspension or slurry into a supernatant clear liquid (free from particles) and a thick sludge containing a high concentration of solid is called__________________?

   A. Classification
   B. Sedimentation
   C. Clarification
   D. Decantation

9. Work index is the gross energy (kWh/tonne of feed) necessary to reduce a very large feed to such a size that 80% of product particles will pass through a 0.1 mm screen. The value of work index determined for wet grinding should be multiplied with ______________ to get the same for dry grinding?

   A. 1.0
   B. 0.5
   C. 1.34
   D. 4.34

10. The specific surface of spherical particles is proportional to (where, Dp = diameter of particle)?

    A. D2
    B. Dp
    C. 1/Dp
    D. 1/D2p