Pick out the wrong statement: (A) Magnetic separation method can be employed to treat both dry & wet ores (B) Reduction ratio in crushing operation is defined as the ratio of minimum feed size to the maximum product size (C) Gyratory crusher is used for coarse crushing (D) Screens are of stationary, moving and vibratory types

Pick out the wrong statement:
(A) Magnetic separation method can be employed to treat both dry & wet
ores
(B) Reduction ratio in crushing operation is defined as the ratio of minimum
feed size to the maximum product size
(C) Gyratory crusher is used for coarse crushing
(D) Screens are of stationary, moving and vibratory types
by

1 Answer

Answer :

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

Related questions

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

Description : 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 ... Crushing of explosive materials are done by employing dry-grinding (D) Gyratory crusher is a coarse crusher

Last Answer : (B) Cake resistance is independent of the pressure drop

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

Description : 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 ... a pipeline which permits the solids to settle down due to reduction in velocity of the dust laden gas

Last Answer : (C) Size enlargement (opposite of size reduction) is not a mechanical operation

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

Description : 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 ... ratio and differential roll speed affect production rate & energy consumed per unit of surface produced

Last Answer : (C) Both the rolls run necessarily at the same speed

Energy consumption in a crusher decreases with increase in the (A) Size of the product (at constant feed size) (B) Capacity of the crushing machine (C) Size of feed (at constant reduction ratio) (D) All (A), (B) & (C)

Description : Energy consumption in a crusher decreases with increase in the (A) Size of the product (at constant feed size) (B) Capacity of the crushing machine (C) Size of feed (at constant reduction ratio) (D) All (A), (B) & (C)

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

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

Which of the following achieves the least reduction ratio for a given feed size? (A) Jaw crusher (B) Roll crusher (C) Cone crusher (D) Gyratory crusher

Description : Which of the following achieves the least reduction ratio for a given feed size? (A) Jaw crusher (B) Roll crusher (C) Cone crusher (D) Gyratory crusher

Last Answer : (B) Roll crusher

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)

Description : 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)

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

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

Description : 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 ... Dry chemicals (C) Heavy tonnages of rocks or gravel (D) Powdered food & granular materials

Last Answer : (C) Heavy tonnages of rocks or gravel

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

Description : 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

Last Answer : (B) 2.5 times

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

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

Last Answer : (B) Gyratory crusher

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

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

Last Answer : (C) Gyratory crusher

Size reduction of ice and gypsum can be accomplished suitably by a __________ crusher. (A) Blake jaw (B) Toothed roll (C) Gyratory (D) None of these

Description : Size reduction of ice and gypsum can be accomplished suitably by a __________ crusher. (A) Blake jaw (B) Toothed roll (C) Gyratory (D) None of these

Last Answer : (B) Toothed roll

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

Description : 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 ... upon the specific gravity of the minerals (D) Asphalt is best crushed using toothed roll crusher

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

In a size reduction crushing operation, the feed size is 10 to 50 mm, while the product size is 2 to 10 mm. This is a case of __________ crushing. (A) Primary (B) Secondary (C) Fine

Description : In a size reduction crushing operation, the feed size is 10 to 50 mm, while the product size is 2 to 10 mm. This is a case of __________ crushing. (A) Primary (B) Secondary (C) Fine

Last Answer : (C) Fine

In a size reduction crushing operation, feed size is 100 to 300 mm. while the product size is 10 to 50 mm. This is a case of the __________ crushing. (A) Primary (B) Secondary (C) Fine (D) Ultrafine

Description : In a size reduction crushing operation, feed size is 100 to 300 mm. while the product size is 10 to 50 mm. This is a case of the __________ crushing. (A) Primary (B) Secondary (C) Fine (D) Ultrafine

Last Answer : (B) Secondary

In a size reduction crushing operation, feed size is 300 to 1500 mm while the product size is 100 to 300 mm. This is a case of the __________ crushing. (A) Secondary (B) Fine (C) Primary (D) Ultrafine

Description : In a size reduction crushing operation, feed size is 300 to 1500 mm while the product size is 100 to 300 mm. This is a case of the __________ crushing. (A) Secondary (B) Fine (C) Primary (D) Ultrafine

Last Answer : (C) Primary

Size reduction of asbestos and mica is done by (A) Hammer mills (B) Rod mills (C) Gyratory crushers (D) Crushing rolls

Description : Size reduction of asbestos and mica is done by (A) Hammer mills (B) Rod mills (C) Gyratory crushers (D) Crushing rolls

Last Answer : (A) Hammer mills

During size reduction by a jaw crusher, the energy consumed decreases with the (A) Decreasing size of product at constant size of feed (B) Decreasing machine capacity (C) Increasing size of feed at constant reduction ratio (D) None of these

Description : During size reduction by a jaw crusher, the energy consumed decreases with the (A) Decreasing size of product at constant size of feed (B) Decreasing machine capacity (C) Increasing size of feed at constant reduction ratio (D) None of these

Last Answer : (C) Increasing size of feed at constant reduction ratio

Size reduction of the __________ can be suitably done by ball mills, crushing rolls and rod mills. (A) Metalliferous ores (B) Non-metallic ores (C) Basic slags (D) Asbestos & mica

Description : Size reduction of the __________ can be suitably done by ball mills, crushing rolls and rod mills. (A) Metalliferous ores (B) Non-metallic ores (C) Basic slags (D) Asbestos & mica

Last Answer : (A) Metalliferous ores

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

Description : 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 ... Operating principles of Dodge and Blake jaw crushers are combined in the working of universal jaw crushers

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

. In case of a hammer crusher, the (A) Feed may be highly abrasive (Moh's scale >5) (B) Minimum product size is 3 mm (C) Maximum feed size may be 50 mm (D) Rotor shaft carrying hammers can be vertical or horizontal

Description : . In case of a hammer crusher, the (A) Feed may be highly abrasive (Moh's scale >5) (B) Minimum product size is 3 mm (C) Maximum feed size may be 50 mm (D) Rotor shaft carrying hammers can be vertical or horizontal

Last Answer : (D) Rotor shaft carrying hammers can be vertical or horizontal

Out of the following size reduction equipments, the maximum feed size can be accepted by the (A) Tube mill (B) Ball mill (C) Jaw crusher (D) Jet pulveriser

Description : Out of the following size reduction equipments, the maximum feed size can be accepted by the (A) Tube mill (B) Ball mill (C) Jaw crusher (D) Jet pulveriser

Last Answer : (C) Jaw crusher

Pick out the correct statement. (A) Plastic chips are called non-cohesive solids (B) Kick's crushing law is, P/m = K . ln (D̅sa /Ds̅b ) (C) Communition is a generic term for size enlargement operation (D) Energy required in kwh per ton of product, such that 80% of it passes through a 200 mesh screen, is called 'Work index'

Description : Pick out the correct statement. (A) Plastic chips are called non-cohesive solids (B) Kick's crushing law is, P/m = K . ln (D̅sa /Ds̅b ) (C) Communition is a generic term for size enlargement ... per ton of product, such that 80% of it passes through a 200 mesh screen, is called 'Work index'

Last Answer : (B) Kick's crushing law is, P/m = K . ln (D̅sa /Ds̅b )

Rittinger's crushing law states that (A) Work required to form a particle of any size is proportional to the square of the surface to volume ratio of the product (B) Work required to form a particle of a particular size is proportional to the square root of the surface to volume ratio of the product (C) Work required in crushing is proportional to the new surface created (D) For a given machine and feed, crushing efficiency is dependent on the size of the feed & product

Description : Rittinger's crushing law states that (A) Work required to form a particle of any size is proportional to the square of the surface to volume ratio of the product (B) Work required to form a ... ) For a given machine and feed, crushing efficiency is dependent on the size of the feed & product

Last Answer : (C) Work required in crushing is proportional to the new surface created

Coal is finally pulverised to 200 mesh size for burning in boilers by a (A) Hammer crusher(B) Ball mill(C) Roll crusher(D) Gyratory crusher

Description : Coal is finally pulverised to 200 mesh size for burning in boilers by a (A) Hammer crusher (B) Ball mill (C) Roll crusher (D) Gyratory crusher

Last Answer : (B) Ball mill

Wet sieving is employed, when the product contains __________ materials. (A) Abrasive (B) Large quantity of very fine (C) Coarse (D) Non-sticky

Description : Wet sieving is employed, when the product contains __________ materials. (A) Abrasive (B) Large quantity of very fine (C) Coarse (D) Non-sticky

Last Answer : (B) Large quantity of very fine

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)

Hydro-cyclone is a (A) Crusher (B) wet classifier (C) Dry classifier (D) Magnetic separator

Description : Hydro-cyclone is a (A) Crusher (B) wet classifier (C) Dry classifier (D) Magnetic separator

Last Answer : (B) wet classifier

Pick out the wrong statement about cavitation. (A) Sudden reduction of pressure in a fluid flow system caused by flow separation, vortex formation or abrupt closing of valve leads to cavitation (B) Cavitation may be caused due to boiling of liquid by decreasing the pressure resulting in formation & collapse of vapor cavities (C) Cavitation begins at higher static pressure and lower velocity in larger diameter pipelines resulting in audible noise(D) Large scale cavitation cannot damage pipeline, restrict fluid flow anddamage steam turbine blades

Description : Pick out the wrong statement about cavitation. (A) Sudden reduction of pressure in a fluid flow system caused by flow separation, vortex formation or abrupt closing of valve leads to cavitation ... (D) Large scale cavitation cannot damage pipeline, restrict fluid flow and damage steam turbine blades

Last Answer : (D) Large scale cavitation cannot damage pipeline, restrict fluid flow and damage steam turbine blades

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

Description : 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

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

Pick out the wrong statement. (A) Denier is defined as weight in gm of 9000 metres length of a fibre, while tex is defined as weight in gm of 1000 metres length of fibre (B) Crimp is a measure of the difference between the length of the straightened and unstraightened fibre (C) Dacron fibres, acrylic fibres, viscose rayon fibres & cellulose acetate fibres are all prepared by wet spinning (D) Nylon fibres have greater water absorption capacity than polyester fibres

Description : Pick out the wrong statement. (A) Denier is defined as weight in gm of 9000 metres length of a fibre, while tex is defined as weight in gm of 1000 metres length of fibre (B) ... fibres are all prepared by wet spinning (D) Nylon fibres have greater water absorption capacity than polyester fibres

Last Answer : (C) Dacron fibres, acrylic fibres, viscose rayon fibres & cellulose acetate fibres are all prepared by wet spinning

Pick up the correct statement from the following: (A) The maximum size of a coarse aggregate, is 75 mm and minimum 4.75 mm (B) The maximum size of the fine aggregate, is 4.75 mm and minimum 0.075 mm (C) The material having particles of size varying from 0.06 mm to 0.002 mm, is known as silt (D) All the ab

Description : Pick up the correct statement from the following: (A) The maximum size of a coarse aggregate, is 75 mm and minimum 4.75 mm (B) The maximum size of the fine aggregate, is 4.75 mm and minimum 0.075 mm ( ... having particles of size varying from 0.06 mm to 0.002 mm, is known as silt (D) All the ab

Last Answer : Answer: Option D

According to Bond crushing law, the work required to form particle of size 'D' from very large feed is (where (S/V)p and (S/V) f are surface to volume ratio of the product and feed respectively). (A) (S/V)p (B) √(S/V)p (C) (S/V) 2 p (D) (S/V) f

Description : According to Bond crushing law, the work required to form particle of size 'D' from very large feed is (where (S/V)p and (S/V) f are surface to volume ratio of the product and feed respectively). (A) (S/V)p (B) √(S/V)p (C) (S/V) 2 p (D) (S/V) f

Last Answer : (B) √(S/V)

Bond crushing law (A) Calls for relatively less energy for the smaller product particles, than does the Rittinger law (B) Is less realistic in estimating the power requirements of commercial crushers (C) States that the work required to form particle of any size from very large feed is proportional to the square root of the volume to surface ratio of the product (D) States that the work required for the crushing is proportional to the new surface created

Description : Bond crushing law (A) Calls for relatively less energy for the smaller product particles, than does the Rittinger law (B) Is less realistic in estimating the power requirements of commercial crushers ( ... (D) States that the work required for the crushing is proportional to the new surface created

Last Answer : (A) Calls for relatively less energy for the smaller product particles, than does the Rittinger law

Pick out the correct statement. (A) The slope of the stripping line is always less than unity (B) For a given separation in a binary distillation column, with increase in reflux ratio (above the minimum reflux ratio), the fixed cost of the distillation column first increases and then decreases (C) In Ponchon-Savarit method of no. of theoretical plate determination, the stripping and rectifying operating lines are vertical at total reflux (D) Kremser-Brown-Souder's equation is used to calculate the efficiency of a plate tower

Description : Pick out the correct statement. (A) The slope of the stripping line is always less than unity (B) For a given separation in a binary distillation column, with increase in reflux ratio ( ... (D) Kremser-Brown-Souder's equation is used to calculate the efficiency of a plate tower

Last Answer : C) In Ponchon-Savarit method of no. of theoretical plate determination, the stripping and rectifying operating lines are vertical at total reflux

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

Description : 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

Last Answer : (A) Impact

The material is crushed in a gyratory crusher by the action of (A) Impact (B) Compression (C) Attrition (D) Cutting

Description : The material is crushed in a gyratory crusher by the action of (A) Impact (B) Compression (C) Attrition (D) Cutting

Last Answer : (B) Compression

Which of the following comes in the category of primary crusher for hard and tough stone? (A) Jaw crusher (B) Cone crusher (C) Gyratory crusher (D) None of these

Description : Which of the following comes in the category of primary crusher for hard and tough stone? (A) Jaw crusher (B) Cone crusher (C) Gyratory crusher (D) None of these

Last Answer : (A) Jaw crusher

Which of the following crushers can be considered as a combination of a jaw crusher and a roller crusher? (A) Rod mill (B) Fluid energy mill (C) Gyratory crusher (D) Ball mill

Description : Which of the following crushers can be considered as a combination of a jaw crusher and a roller crusher? (A) Rod mill (B) Fluid energy mill (C) Gyratory crusher (D) Ball mill

Last Answer : (C) Gyratory crusher

For the preliminary breaking of hard rock, we use a (A) Gyratory crusher(B) Ball mill(C) Tube mill(D) Squirrel-cage disintegrator

Description : For the preliminary breaking of hard rock, we use a (A) Gyratory crusher (B) Ball mill (C) Tube mill (D) Squirrel-cage disintegrator

Last Answer : (A) Gyratory crusher

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

Description : 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

Last Answer : (B) 0.0184

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

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

Last Answer : (C) Toothed roll crusher

Capacity (in tons/hr) of jaw/gyratory crusher is equal to (where, L = length of the receiving opening, cm S = greater width of the discharge opening, cm). (A) 0.01 L.S (B) 0.087 L.S (C) L.S (D) L.S/0.087

Description : Capacity (in tons/hr) of jaw/gyratory crusher is equal to (where, L = length of the receiving opening, cm S = greater width of the discharge opening, cm). (A) 0.01 L.S (B) 0.087 L.S (C) L.S (D) L.S/0.087

Last Answer : (B) 0.087 L.S

Carbon black is pulverised in a (A) Hammer crusher (B) Ball mill (C) Roll crusher (D) Gyratory crusher

Description : Carbon black is pulverised in a (A) Hammer crusher (B) Ball mill (C) Roll crusher (D) Gyratory crusher

Last Answer : (B) Ball mill

To get a fine talc powder from its granules, the equipment used is (A) Roller crusher (B) Ball mill (C) Jaw crusher (D) Gyratory crusher

Description : To get a fine talc powder from its granules, the equipment used is (A) Roller crusher (B) Ball mill (C) Jaw crusher (D) Gyratory crusher

Last Answer : (B) Ball mill

As per Taggart's formula, the capacity (kg/hr) of Jaw & Gyratory crushers (for gapes of 10 to 60 cms) is equal to (where, L = Length of feed opening, cms S = Maximum width of discharge opening, cms). (A) LS (B) 93 LS (C) 250 LS (D) √(LS)

Description : As per Taggart's formula, the capacity (kg/hr) of Jaw & Gyratory crushers (for gapes of 10 to 60 cms) is equal to (where, L = Length of feed opening, cms S = Maximum width of discharge opening, cms). (A) LS (B) 93 LS (C) 250 LS (D) √(LS)

Last Answer : (B) 93 LS

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)

Description : 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)

Last Answer : (C) Both (A) & (B)

The reduction ratio for grinders is defined as (where, Df and Dp are average diameters of feed and product respectively). (A) Df /Dp (B) Dp /Df (C) Df - Dp (D) None of these

Description : The reduction ratio for grinders is defined as (where, Df and Dp are average diameters of feed and product respectively). (A) Df /Dp (B) Dp /Df (C) Df - Dp (D) None of these

Last Answer : (A) Df /Dp