increasing the capacity of a screen _______________ the screen effectiveness?

Related Mcqs:

1. 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_________________?

   A. 0.50
   B. 0.58
   C. 0.68
   D. 0.62

2. 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.

3. Screen capacity is proportional to (where, S = screen aperture)____________________?

   A. S
   B. 1/S
   C. S2
   D. √S

4. 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

5. 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

6. Screen capacity is expressed in terms of____________________?

   A. tons/hr
   B. tons/ft2
   C. Both A. & B.
   D. tons/hr-ft2

7. With increase in the capacity of screens, the screen effectiveness__________________?

   A. Remains unchanged
   B. Increases
   C. Decreases
   D. Decreases exponentially

8. Screen capacity is not a function of__________________?

   A. Its openings size
   B. Screening mechanism
   C. Screening surface
   D. Atmospheric humidity

9. A _______________ employs a set of screen across a flow channel for the separation of dirt/rust from a flowing liquid stream?

   A. Thickener
   B. Classifier
   C. Strainer
   D. Clarifier

10. A screen is said to be blinded, when the___________________?

    A. Over-sizes are present in undersize fraction
    B. Under-sizes are retained in oversize fraction
    C. Screen is plugged with solid particles
    D. Screen capacity is abruptly increased