Pick out the wrong statement. (A) For the compressible cake, voidage & the specific resistance of the cake can be assumed to be constant (B) Cake resistance is independent of the pressure drop (C) Crushing of explosive materials are done by employing dry-grinding (D) Gyratory crusher is a coarse crusher

Pick out the wrong statement.
(A) For the compressible cake, voidage & the specific resistance of the cake
can be assumed to be constant
(B) Cake resistance is independent of the pressure drop
(C) Crushing of explosive materials are done by employing dry-grinding
(D) Gyratory crusher is a coarse crusher
by

1 Answer

Answer :

(B) Cake resistance is independent of the pressure drop
by

Related questions

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Last Answer : (B) Reduction ratio in crushing operation is defined as the ratio of minimum feed size to the maximum product size

Pick out the wrong statement. (A) Recycled coarse material to the grinder by a classifier is termed as circulating load (B) Wear and tear in wet crushing is more than that in dry crushing of materials (C) Size enlargement (opposite of size reduction) is not a mechanical operation (D) A 'dust catcher' is simply an enlargement in a pipeline which permits the solids to settle down due to reduction in velocity of the dust laden gas

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Which of the following is used for primary crushing of very hard lumpy materials? (A) Toothed roll crusher (B) Gyratory crusher

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With increase in the pressure drop across the cake, the specific cake resistance for the compressible sludge (A) Increases (B) Decreases (C) Remains constant (D) Increases linearly

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The specific cake resistance for compressible sludges is a function of the pressure drop (A) Over cake (B) Over medium (C) Overall (D) None of these

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Which of the following is a coarse crusher? (A) Smooth roll crusher (B) Toothed roll crusher (C) Gyratory crusher (D) Tube mill

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Pick out the wrong statement pertaining to the roll crushers. (A) Maximum feed size determines the required roll diameter (B) For hard material's crushing, the reduction ratio should not exceed 4 (C) Both the rolls run necessarily at the same speed (D) Reduction ratio and differential roll speed affect production rate & energy consumed per unit of surface produced

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Gyratory crushers compared to the reciprocating jaw crushers (A) Have greater capacity per unit of discharge area (B) Crush intermittently (C) Are less suitable for coarse materials (D) Have less steady power consumption

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The capacity of a gyratory crusher is __________ that of a jaw crusher with the same gape, handling the same feed & for the same product size range. (A) Same as (B) 2.5 times (C) 5 times (D) 10 times

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. A 0.5 m high bed made up of a 1 mm dia glass sphere (density 2500 kg/m3 ) is to be fluidised by water (density 1000 kg/m3 ). If at the point of incipient fluidisation, the bed voidage is 40%, the pressure drop across the bed is (A) 4.4 KPa (B) 2.94 KPa (C) 3.7 KPa (D) None of these

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Reciprocating screens are normally inclined at an angle of 5° with the horizontal and employ gyratory motion at feed end & reciprocating motion at the discharge end. They are not suitable for the screening of the (A) Light metal powder down upto 4 mesh size (B) Dry chemicals (C) Heavy tonnages of rocks or gravel (D) Powdered food & granular materials

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Which of the following crushing laws is most accurately applicable to the fine grinding of materials? (A) Bond's crushing law (B) Kick's law (C) Rittinger's law (D) None of these

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According to Taggart's rule for selecting between a gyratory crusher and a jaw crusher; the later should be used, if the hourly tonnage to be crushed divided by the square of the gape expressed in cm is less than (A) 0.00184 (B) 0.0184 (C) 0.184 (D) 1.84

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Which of the following is a fine crusher? (A) Blake jaw crusher (B) Gyratory crusher (C) Toothed roll crusher (D) Dodge jaw crusher

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Pick up wrong statement about friction force for dry surfaces. Friction force is (A) Proportional to normal load between the surfaces (B) Dependent on the materials of contact surface (C) Proportional to velocity of sliding (D) Independent of the area of contact surfaces

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Pick out the wrong statement. (A) Enthalpies of all elements in their standard states are assumed to be zero (B) Combustion reactions are never endothermic in nature (C) Heat of reaction at constant volume is equal to the change in internal energy (D) Clausius-Clapeyron equation is not applicable to melting process

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In case of a hammer crusher, the final product size depends on the (A) Feed rate (B) Rotor speed(C) Clearance between hammer & grinding plates(D) All (A), (B) and (C

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Pick out the wrong statement. (A) The shear stress at the pipe (dia = D, length = L) wall in case of laminar flow of Newtonian fluids is (D/4L). ∆p (B) In the equation, T. gc = k. (du/dy) n the value of 'n' for pseudoplastic and Dilatant fluid are < 1 and >1 respectively (C) Shear stress for Newtonian fluid is proportional to the rate of shear in the direction perpendicular to motion (D) With increase in the Mach number >0.6, the drag co-efficient decreases in case of compressible fluids

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Pick out the wrong statement. (A) Critical moisture content is not a property of the material itself (B) A sharp increase in pressure drop gives an indication of the flooding in a distillation column (C) Separation of components is not possible in liquid extraction, if selectivity is unity (D) Dehydration of ethyl alcohol is most economically done by molecular distillation at very high vacuum

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Pick out the wrong statement. (A) α-particle emission from a radioactive element makes it electrically negative (B) β-particle emission from a radioactive element makes it electrically positive (C) A radioactive element having a half life period of 20 years will completely disintegrated in 40 years (D) The disintegration constant of a radioactive isotope is independent of pressure, temperature or concentration

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Pick out the correct statement: (A) Removal of iron from ceramic material is necessitated (by magnetic separation method) so as to avoid discolouration of ceramic products (B) The operating cost of shaking screen is more than that of a vibrating screen (C) Screen capacity does not depend upon the specific gravity of the minerals (D) Asphalt is best crushed using toothed roll crusher

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Last Answer : (A) Removal of iron from ceramic material is necessitated (by magnetic separation method) so as to avoid discolouration of ceramic products

Pick out the wrong statement. (A) More commonly used jaw crusher between Dodge jaw crusher and Blake jaw crusher is the later one(B) There are only four methods namely compression, impact, attrition andcutting, which the size reduction equipments employ(C) Cutting machines mainly employ 'attrition' for size reduction of solids(D) Operating principles of Dodge and Blake jaw crushers are combined inthe working of universal jaw crushers

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Last Answer : (C) Cutting machines mainly employ 'attrition' for size reduction of solids

Pick up the incorrect statement from the following: (A) Compaction has no effect on the structure of a soil (B) Permeability decreases with increase in the dry density of a compacted soil (C) A wet side compacted soil is more compressible than a dry side compacted soil (D) Dry side compaction soils swell more when given access to moisture

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Last Answer : (A) Compaction has no effect on the structure of a soil

Filtration rate does not depend upon the (A) Pressure drop & area of filtering surface (B) Resistance of the cake & the septum (C) Properties of the cake & the filtrate (D) None of these

Description : Filtration rate does not depend upon the (A) Pressure drop & area of filtering surface (B) Resistance of the cake & the septum (C) Properties of the cake & the filtrate (D) None of these

Last Answer : (D) None of these

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)

Description : 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)

Last Answer : (A) cos α = (dr + dp)/(dr + df)

In case of a hammer crusher, (A) Crushing takes place by impact breaking (B) Maximum acceptable feed size is 30 cms (C) Reduction ratio can be varied by adjusting the distance from cage to hammers (D) All (A), (B) and (C)

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Last Answer : (D) All (A), (B) and (C)

Choke crushing (in case of a Jaw crusher) compared to free crushing (A) Results in increased capacity (B) Consumes less power (C) Consumes more power (D) Both (A) and (C)

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Last Answer : (C) Consumes more power

Pick out the wrong statement. (A) Packed towers are preferred for vacuum operation, because the pressure drop through the packing is less and they (packings) also lessen the possibility of tower wall collapse (B) Packed towers are preferred over plate towers for handling corrosive and foamy liquids (C) Diameter of randomly packed tower is normally more than 1.2 metres (D) Due to uneven supply and improper distribution of liquid, problem of channelling, loading & flooding is generally encountered in packed towers

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Last Answer : (C) Diameter of randomly packed tower is normally more than 1.2 metres

Pick out the wrong statement. (A) Low intensity explosives are also called propellants, whereas high intensity explosive are called detonators (B) Gun powder comprises of 75% salt petre, 15% charcoal and 10% sulphur (C) Lead azide is a popular military explosive (D) TNT is a hygroscopic explosive having very high melting point and is non-toxic to human being

Description : Pick out the wrong statement. (A) Low intensity explosives are also called propellants, whereas high intensity explosive are called detonators (B) Gun powder comprises of 75% salt petre, 15% charcoal ... TNT is a hygroscopic explosive having very high melting point and is non-toxic to human being

Last Answer : (D) TNT is a hygroscopic explosive having very high melting point and is non-toxic to human being

Pick out the wrong statement. (A) Gape is the greatest distance between the crushing surfaces or the jaws (B) The angle of nip (2α) is the angle between roll faces at the level where they will just take hold of a particle and draw it in the crushing zone (C) Crushing efficiency is the ratio of the energy absorbed by the solid to the surfaces energy created by crushing (D) Reduction ratio is the ratio of the maximum size of the particles in the feed to that in the product

Description : Pick out the wrong statement. (A) Gape is the greatest distance between the crushing surfaces or the jaws (B) The angle of nip (2α) is the angle between roll faces at the level where they will ... Reduction ratio is the ratio of the maximum size of the particles in the feed to that in the product

Last Answer : (C) Crushing efficiency is the ratio of the energy absorbed by the solid to the surfaces energy created by crushing