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1) _____________ mills are termed as disintegrators? a. Cage b. Compartment c. Pebble d. All tumbling
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2) Vibrating screens have capacity in the range of ______________ tons/ft2 .mm mesh size? a. 0.2 to 0.8 b. 5 to 25 c. 50 to 100 d. 100 to 250
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3) The speed of a rotary drum vacuum filter may be about _____________ rpm? a. 1 b. 50 c. 100 d. 500
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4) ______________ is used for producing a thick suspension from a thin slurry? a. Cartridge filter b. Rotary drum vacuum filter c. Pressure filter thickener d. Plate and frame filter press
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5) The study on washability of coal is done by using the _____________ technique? a. Tabling b. Elutriation c. Heavy media separation d. None of these
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6) In the cyclone separator used for separation of dust from dust laden gas, the gas ? a. Enters the cyclone from the top b. Is admitted tangentially at high velocity c. Develops a helical motion inside the chamber d. Both B. and C.
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7) Which of the following represents the plot of filtrate volume versus time for constant pressure filtration ? a. Parabola b. Straight line c. Hyperbola d. Exponential curve
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8) Colloidal mills are used for ______________ grinding? a. Coarse b. Intermediate c. Fine d. Ultrafine
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9) The unit of specific cake resistance is______________________? a. gm/cm2 b. cm/gm c. cm/gm2 d. gm/gm
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10) Weber number is significant and is concerned with the_________________? a. Solid-liquid mixing b. Liquid-liquid mixing c. Dispersion of liquid in liquid d. Suspension of solid in liquid
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11) Horsepower required for a roll crusher is directly proportional to its__________________? a. Reduction ratio b. Capacity c. Both A. & B. d. Neither A. nor B.
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12) ______________ mean diameter of particles is given by Σ (xi/Dpi ⃗)? a. Mass b. Volume c. Arithmetic d. Volume surface
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13) The constants (Kb, Kr and Kk) used in the laws of crushing (i.e., Bond’s law, Rittinger’s law and Kick’s law) depend upon the_________________? a. Feed material b. Type of crushing machine c. Both A. & B. d. Neither A. nor B.
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14) What is the selectivity index, if the grade of tailings & concentrate is the same ? a. 0 b. ∞ c. 1 d. 0.5
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15) Hot, lumpy & abrasive materials are best transported by using a/an ___________ conveyor ? a. Apron b. Belt c. Screw d. Flight
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16) Moisture can be removed from lubricating oil using_________________? a. Tubular centrifuge b. Clarifier c. Sparkler filter d. Vacuum leaf filter
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17) Cartridge filters are termed as ‘edge’ filters, because of the fact that the_________________? a. Disks have very sharp edge b. Solids are not deposited at the edge of the disk c. Bulk of the solids are removed at the periphery of the disks d. None of these
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18) Fick’s law relates to_________________? a. Energy consumption b. Final particle size c. Feed size d. None of these
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19) Production rate _____________ with increased fineness, with a given energy input to the size reduction machine? a. Decreases b. Increases c. Remains unchanged d. May increase or decrease; depends on the machine
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20) The material is crushed in a gyratory crusher by the action of__________________? a. Impact b. Compression c. Attrition d. Cutting
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21) Trommels employ _____________ for screening of materials? a. Fibrous cloth b. Woven wire screen c. Punched plate d. None of these
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22) For classification of potable (drinking) water, we use a _______________ filter? a. Gravity sand b. Plate and frame c. Vacuum leaf d. Rotary vacuum
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23) The value of ‘angle of nip’ is generally about__________________? a. 16° b. 32° c. 52° d. 64°
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24) In a roll crusher, the specific power consumption and the production rate is affected by the_________________? a. Reduction ratio b. Differential roll speed c. Both A. and B. d. Neither A. nor B.
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25) Filter aid is used to____________________? a. Increase the rate of filtration b. Decrease the pressure drop c. Increase the porosity of the cake d. Act as a support base for the septum
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26) Sedimentation on commercial scale occurs in____________________? a. Classifiers b. Thickeners c. Rotary drum filters d. Cyclones
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27) Diatomaceous earth is a/an_________________? a. Explosive b. Filter aid c. Filter medium d. Catalyst
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28) Filter medium resistance is important during the ______________ of filtration? a. Early stages b. Final stages c. Entire process d. None of these
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29) A compressible cake has the_________________? a. Maximum porosity at the upstream side b. Maximum porosity at the filter medium c. Same porosity throughout the cake thickness d. None of these
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30) Crushing of mineral particles is accomplished in a ‘cage mill’, when one or more alloy steel bars are revolved in opposite directions. It is a type of ______________ mill? a. Impact b. Roll c. Vibratory d. None of these
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