______________ mean diameter of particles is given by Σ (xi/Dpi ⃗)?

Related Mcqs:

1. Sauter mean diameter is the same as the ______________ mean diameter?

   A. Mass
   B. Arithmetic
   C. Volume-surface
   D. Geometric

2. 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

3. ______________ are used for the separation of coarse particles from a slurry of fine particles?

   A. Thickeners
   B. Classifiers
   C. Hydrocyclones
   D. Decanters

4. The specific surface of spherical particles is given by (where D and ρ are diameter and density of particle) ?

   A. 6/D.ρ
   B. 2/D.ρ
   C. 4/D.ρ
   D. 12/D.ρ

5. The energy required per unit mass to grind limestone particles of very large size to 100 μm is 12.7 kWh/ton. An estimate (using Bond’s law) of the energy to grind the particles from a very large size to 50 μm is________________?

   A. 6.35 kWh/ton
   B. 9.0 kWh/ton
   C. 18 kWh/ton
   D. 25.4 kWh/ton

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

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

7. Which of the following equations is Rittinger’s crushing law? (Where P = power required by the machine, m = feed rate, k = a constant, D̅ sa & D̅ sb = volume surface mean diameter of feed & product respectively) ?

   A. P/m = K/ √Dp
   B. P/m = K . ln D̅ sa/D̅ sb
   C. P/m = K . (1/ D̅ sb – 1/D̅ sa)
   D. None of these

8. Height of liquid in agitation tank is normally maintained equal to the tank diameter. However, if the tank is too tall and a large liquid hold up is desired, then two or more impellers mounted on the same shaft may be used. The clearance between the tank bottom and the bottom most impeller should be about (where, D = impeller diameter) ?

   A. 0.5 D
   B. D
   C. 1.5 D
   D. 2 D

9. Equivalent diameter of a particle is the diameter of the sphere having the same __________________?

   A. Ratio of surface to volume as the actual volume
   B. Ratio of volume to surface as the particle
   C. Volume as the particle
   D. None of these

10. Half the angle of nip, (α), for a roll crusher is given by (where, dr, dp and df are diameters of crushing rolls, feed particles and rolls gap respectively) ?

    A. cos α = (dr + dp)/(dr + df)
    B. cos α = (dr + df)/(dr + dp)
    C. tan α = (dr + dp)/(dr + df)
    D. sin α = (dr + dp)/(dr + df)