A. Is defined as the ratio of surface area of a sphere having the same volume as the particle to the
actual surface area of the particle
B. Has the dimension of length
C. Is always less than 1
D. Is the ratio of volume of a sphere having the same surface area as the particle to the actual
volume of the particle
Related Mcqs:
- Sphericity for a non-spherical particle is given by (where, V and S are volume and surface area respectively of one particle. and, D = equivalent diameter of particle)?
A. 6.V/D.S
B. V/6D.S
C. D.S/V
D. V/D.S - Sphericity is the ratio of the surface area of a spherical particle having the same volume as the particle to the surface area of the particle. Which of the following has the maximum value of sphericity ?
A. Sphere
B. Cube
C. Cylinder (L/D = 1)
D. Raschig rings - If dp is the equivalent diameter of a non-spherical particle, Vp its volume and sp its surface area, then its sphericity is φs is defined by________________?
A. φs = 6 Vp/dpsp
B. φs = Vp/dpsp
C. φs = 6 dpSp/Vp
D. φs = dpSp/Vp - The specific surface of spherical particles is proportional to (where, Dp = diameter of particle)?
A. D2
B. Dp
C. 1/Dp
D. 1/D2p - 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 - In a grinding operation, the limiting particle size is the size of the _______________ particle in the sample?
A. Smallest
B. Largest
C. Either A. or B.
D. Neither A. nor B. - 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_________________?
A. 0.90 μm/s
B. 1 μm/s
C. 22.1 μm/s
D. 0.02 μm/s - Particle size range in which dust catcher (gravity settling chamber) works most effectively and efficiently is ______________ microns?
A. < 5
B. 10 to 25
C. < 74
D. > 1000 - As particle size is reduced__________________?
A. Screening becomes progressively more difficult
B. Screening becomes progressively easier
C. Capacity and effectiveness of the screen is increased
D. None of these - Which of the following relationships between co-efficient of friction (μ) between rock & roll and a (half of the angle of nip) of the particle to be crushed is correct ?
A. μ > tan α
B. μ ≥ tan α
C. μ > tan 2α
D. μ ≤ tan α
