A sand mixture was screened through a standard 10-mesh screen. The mass fraction of the oversize material in feed, overflow and underflow were found to be 0.38, 0.79 and 0.22 respectively. The screen effectiveness based on the oversize is_________________?

Related Mcqs:

1. Higher is the mesh number, smaller will be the aperture size of the screen. It means that the aperture size of a 200 mesh screen will be smaller than that of 20 mesh screen. This is valid for__________________?

   A. British standard screens
   B. German standard screens (DIN 1171) etc
   C. American standard screens (ASTM and Tyler standard screens)
   D. All A., B. and C.

2. Pulverised coal passing through 200 mesh screen has a diameter of 0.074 mm (74 micron). The same passing through 50 mesh screen will have a dia of ____________ mm?

   A. 0.007
   B. 0.30
   C. 50
   D. 0.014

3. For Indian standard (IS) screens, the mesh number is equal to its aperture size expressed to the nearest deca-micron (0.01 mm). Aperture width of IS screen of mesh number 50 will be approximately _____________ microns?

   A. 5
   B. 50
   C. 500
   D. 5000

4. increasing the capacity of a screen _______________ the screen effectiveness?

   A. Decreases
   B. Increases
   C. Does not effect
   D. None of these

5. 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

6. The ratio of the area of openings in one screen (Taylor series) to that of the openings in the next smaller screen is_________________?

   A. 1.5
   B. 1
   C. √2
   D. None of these

7. The opening of a 200 mesh screen (Taylor series) is__________________?

   A. 0.0074 cm
   B. 0.0074 mm
   C. 0.0047 cm
   D. 74 milli-microns

8. The ratio of the actual mesh dimension of Taylor series to that of the next smaller screen is_______________?

   A. 2
   B. √2
   C. 1.5
   D. √3

9. 200 mesh screen means 200 openings per_____________________?

   A. cm2
   B. cm
   C. inch
   D. inch2

10. 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