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

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
by

1 Answer

Answer :

(B) √(S/V)
by

Related questions

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

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

. Which of the following equations is Rittinger's crushing law? (Where P = power required by the machine, m = feed rate, k = a constant, Ds̅a & D̅sb = volume surface mean diameter of feed & product respectively.) (A) P/m = K/ √Dp (B) P/m = K . ln D̅sa /D̅sb (C) P/m = K . (1/ D̅sb - 1/Ds̅a ) (D) None of these

Description : . Which of the following equations is Rittinger's crushing law? (Where P = power required by the machine, m = feed rate, k = a constant, Ds̅a & D̅sb = volume surface mean diameter of feed & product respectively.) (A) P/m = K/ ... K . ln D̅sa /D̅sb (C) P/m = K . (1/ D̅sb - 1/Ds̅a ) (D) None of these

Last Answer : (C) P/m = K . (1/ D̅sb - 1/Ds̅a )

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

For crushing of solids, the Rittinger's law states that the work required for crushing is proportional to(A) The new surface created(B) The size reduction ratio(C) The change in volume due to crushing(D) None of these

Description : For crushing of solids, the Rittinger's law states that the work required for crushing is proportional to (A) The new surface created (B) The size reduction ratio (C) The change in volume due to crushing (D) None of these

Last Answer : (A) The new surface created

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

General crushing equation is given by d(P/m) = -K (dD̅S /D̅ n S ). Bond's crushing law is obtained by solving this equation for n = __________ and feed of infinite size. (A) 1 (B) 1.5 (C) 2 (D) 2.5

Description : General crushing equation is given by d(P/m) = -K (dD̅S /D̅ n S ). Bond's crushing law is obtained by solving this equation for n = __________ and feed of infinite size. (A) 1 (B) 1.5 (C) 2 (D) 2.5

Last Answer : (B) 1.5

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 )

Sphericity for a non-spherical particle is given by (where, V and S are volume and surface area respectively of one particle. and, D = equivalent diameter of particle). (A) 6.V/D.S(B) V/6D.S (C) D.S/V (D) V/D.S

Description : Sphericity for a non-spherical particle is given by (where, V and S are volume and surface area respectively of one particle. and, D = equivalent diameter of particle). (A) 6.V/D.S (B) V/6D.S (C) D.S/V (D) V/D.S

Last Answer : (B) V/6D.S (C) D.S/V (D) V/D.S

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) 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

Description : 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 ... ) Gyratory crusher is used for coarse crushing (D) Screens are of stationary, moving and vibratory types

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

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)

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

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Angle of nip of the crushing rolls does not depend upon the (A) Diameter of the rolls (B) Speed of the rolls (C) Product size (D) Feed size

Description : Angle of nip of the crushing rolls does not depend upon the (A) Diameter of the rolls (B) Speed of the rolls (C) Product size (D) Feed size

Last Answer : (B) Speed of the rolls

The ratio of volume of mixed reactor to the volume of P.F.R. (for identical flow rate, feed composition and conversion) for zero order reaction is: (A) ∞(B) 0 (C) 1 (D) > 1

Description : The ratio of volume of mixed reactor to the volume of P.F.R. (for identical flow rate, feed composition and conversion) for zero order reaction is: (A) ∞ (B) 0 (C) 1 (D) > 1

Last Answer : (C) 1

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)

Which of the following is not a dimension-less group used in catalysis? (Where, D = dispersion co-efficient, cm2 /sec.D1 = diffusion co-efficient; cm2 /sec L = length of the reactor, cm t = time, sec, v = volumetric flow rate, cm3 /sec. V = volume, cm3 .) (A) Reactor dispersion number (D/vL) (B) Reduced time (vt/V) (C) Thiele modulus L √(k/D1 ) (D) None of these

Description : Which of the following is not a dimension-less group used in catalysis? (Where, D = dispersion co-efficient, cm2 /sec.D1 = diffusion co-efficient; cm2 /sec L = length of the reactor, cm t = time, sec, v = volumetric ... (D/vL) (B) Reduced time (vt/V) (C) Thiele modulus L √(k/D1 ) (D) None of these

Last Answer : (D) None of these

Which of the following gives the crushing energy required to create new surface ? (A) Taggarts rule (B) Fick's law (C) Rittinger's Law (D) None of these

Description : Which of the following gives the crushing energy required to create new surface ? (A) Taggarts rule (B) Fick's law (C) Rittinger's Law (D) None of these

Last Answer : (C) Rittinger's Law

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

Work index is defined as the (A) Gross energy (kWh/ton of feed) needed to reduce very large feed to such a size that 80% of the product passes through a 100 micron screen (B) Energy needed to crush one tonne of feed to 200 microns (C) Energy (kWh/ton of feed) needed to crush small feed to such a size that 80% of the product passes a 200 mesh screen (D) Energy needed to crush one ton of feed to 100 microns

Description : Work index is defined as the (A) Gross energy (kWh/ton of feed) needed to reduce very large feed to such a size that 80% of the product passes through a 100 micron screen (B) Energy needed to crush ... of the product passes a 200 mesh screen (D) Energy needed to crush one ton of feed to 100 microns

Last Answer : (A) Gross energy (kWh/ton of feed) needed to reduce very large feed to such a size that 80% of the product passes through a 100 micron screen

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

Description : 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 ... to get the same for dry grinding. (A) 1.0 (B) 0.5 (C) 1.34 (D) 4.34

Last Answer : (C) 1.34

For spheres, the specific surface shape factor is given by (A) AD/V (B) D/V (C) A/V (D) √(AD/V)

Description : For spheres, the specific surface shape factor is given by (A) AD/V (B) D/V (C) A/V (D) √(AD/V)

Last Answer : (A) AD/V

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)

Description : 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)

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

Fick's law relates to (A) Energy consumption (B) Final particle size (C) Feed size (D) None of these

Description : Fick's law relates to (A) Energy consumption (B) Final particle size (C) Feed size (D) None of these

Last Answer : (A) Energy consumption

For a perfect gas, according to Boyle’s law (where p = Absolute pressure, v = Volume, and T = Absolute temperature)  A. p v = constant, if T is kept constant  B. v/T = constant, if p is kept constant  C. p/T = constant, if v is kept constant  D. T/p = constant, if v is kept constant

Description : For a perfect gas, according to Boyle’s law (where p = Absolute pressure, v = Volume, and T = Absolute temperature)  A. p v = constant, if T is kept constant  B. v/T = constant, if p is kept constant  C. p/T = constant, if v is kept constant  D. T/p = constant, if v is kept constant

Last Answer : Answer: A

A particle is settling in a liquid under Stokesian conditions. The free falling velocity of the particle is proportional to (A) √(Particle diameter) (B) Particle diameter (C) (Particle diameter)2 (D) (Particle diameter)3

Description : A particle is settling in a liquid under Stokesian conditions. The free falling velocity of the particle is proportional to (A) √(Particle diameter) (B) Particle diameter (C) (Particle diameter)2 (D) (Particle diameter)3

Last Answer : B) Particle diameter

In a single stage extraction process, 10 kg of pure solvent S (containing no solute A) is mixed with 30 kg of feed F containing A at a mass fraction xf = 0.2. The mixture splits into an extract phase E and a raffinate phase R containing A at xB = 0.5 and xR = 0.05 respectively. The total mass of the extract phase is (in Kg) (A) 6.89 (B) 8.89 (C) 10 (D) 8.25

Description : In a single stage extraction process, 10 kg of pure solvent S (containing no solute A) is mixed with 30 kg of feed F containing A at a mass fraction xf = 0.2. The mixture splits into an extract phase E and a raffinate ... phase is (in Kg) (A) 6.89 (B) 8.89 (C) 10 (D) 8.25

Last Answer : (B) 8.89

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

Critical Speed (Nc ) of a ball mill is given by (where R1 and R2 are radii of ball mill and the ball respectively). (A) Nc = (1/4π). √(g/R1 - R2 ) (B) Nc = (1/2π). √(g/R1 - R2 ) (C) Nc = (1/π). √(g/R1 - R2 ) (D) Nc = (1/2π). √(R1 - R2 /g)

Description : Critical Speed (Nc ) of a ball mill is given by (where R1 and R2 are radii of ball mill and the ball respectively). (A) Nc = (1/4π). √(g/R1 - R2 ) (B) Nc = (1/2π). √(g/R1 - R2 ) (C) Nc = (1/π). √(g/R1 - R2 ) (D) Nc = (1/2π). √(R1 - R2 /g)

Last Answer : (B) Nc = (1/2π). √(g/R1 - R2 )

For a non-spherical particle, the sphericity (A) Is defined as the ratio of surface area of a sphere having the same volume as the particle to the actual surface area of the particle (B) Has the dimension of length (C) Is always less than 1 (D) Is the ratio of volume of a sphere having the same surface area as the particle to the actual volume of the particle

Description : For a non-spherical particle, the sphericity (A) Is defined as the ratio of surface area of a sphere having the same volume as the particle to the actual surface area of the particle (B) Has ... of volume of a sphere having the same surface area as the particle to the actual volume of the particle

Last Answer : (A) Is defined as the ratio of surface area of a sphere having the same volume as the particle to the actual surface area of the particle

. Equivalent diameter of a particle is the diameter of the sphere having the same (A) Ratio of surface to volume as the actual volume (B) Ratio of volume to surface as the particle (C) Volume as the particle (D) None of these

Description : . Equivalent diameter of a particle is the diameter of the sphere having the same (A) Ratio of surface to volume as the actual volume (B) Ratio of volume to surface as the particle (C) Volume as the particle (D) None of these

Last Answer : (A) Ratio of surface to volume as the actual volume

Sphericity is the ratio of the surface area of a spherical particle having the same volume as the particle to the surface area of the particle. Which of the following has the maximum value of sphericity? (A) Sphere(B) Cube(C) Cylinder (L/D = 1)(D) Raschig rings

Description : Sphericity is the ratio of the surface area of a spherical particle having the same volume as the particle to the surface area of the particle. Which of the following has the maximum value of sphericity? (A) Sphere (B) Cube (C) Cylinder (L/D = 1) (D) Raschig rings

Last Answer : (A) Sphere

Pick out the wrong statement. (A) With decrease in feed temperature, the number of plates required for binary distillation decreases for a given ‘L/V’ ratio (B) The extraction per unit of total height for a short packed column is more effective than for a tall column, in case of liquid-liquid extraction(C) Natural draft cooling towers are made of ferroconcrete and its cross￾section is wider at the bottom(D) Vander wall adsorption is also called chemisorption

Description : Pick out the wrong statement. (A) With decrease in feed temperature, the number of plates required for binary distillation decreases for a given L/V' ratio (B) The extraction per unit ... and its cross￾section is wider at the bottom (D) Vander wall adsorption is also called chemisorption

Last Answer : (D) Vander wall adsorption is also called chemisorption

For calculating the evaporation rate over a reservoir surface E = 0.771 (1.465 - 0.00732B) (0.44 - 0.007375 V) (pe - pa), the equation is given by (A) Roohwer's, formula in M.K.S. (B) Roohwer's formula in F.P.S. (C) Dalton's formula in F.P.S. (D) Dalton's formula in M.K.S

Description : For calculating the evaporation rate over a reservoir surface E = 0.771 (1.465 - 0.00732B) (0.44 - 0.007375 V) (pe - pa), the equation is given by (A) Roohwer's, formula in M.K.S. (B) Roohwer's formula in F.P.S. (C) Dalton's formula in F.P.S. (D) Dalton's formula in M.K.S

Last Answer : Answer: Option A

Crushing efficiency is the ratio of the (A) Surface energy created by crushing to the energy absorbed by the solid (B) Energy absorbed by the solid to that fed to the machine (C) Energy fed to the machine to the surface energy created by crushing (D) Energy absorbed by the solid to the surface energy created by crushing

Description : Crushing efficiency is the ratio of the (A) Surface energy created by crushing to the energy absorbed by the solid (B) Energy absorbed by the solid to that fed to the machine (C) Energy ... surface energy created by crushing (D) Energy absorbed by the solid to the surface energy created by crushing

Last Answer : (A) Surface energy created by crushing to the energy absorbed by the solid

The equation, Nst = (f/2)/[1 + 5 (Npr - 1) √(f/2)], corresponds to __________ analogy. (A) Von-Karman (B) Reynolds (C) Colburn (D) Prandtl

Description : The equation, Nst = (f/2)/[1 + 5 (Npr - 1) √(f/2)], corresponds to __________ analogy. (A) Von-Karman (B) Reynolds (C) Colburn (D) Prandtl

Last Answer : (D) Prandtl

The energy required per unit mass to grind limestone particles of very large size to 100 μm is 12.7 kWh/ton. An estimate (using Bond's law) of the energy to grind the particles from a very large size to 50 μm is (A) 6.35 kWh/ton (B) 9.0 kWh/ton (C) 18 kWh/ton (D) 25.4 kWh/ton

Description : The energy required per unit mass to grind limestone particles of very large size to 100 μm is 12.7 kWh/ton. An estimate (using Bond's law) of the energy to grind the particles from a very large size to 50 μm is (A) 6.35 kWh/ton (B) 9.0 kWh/ton (C) 18 kWh/ton (D) 25.4 kWh/ton

Last Answer : (C) 18 kWh/ton

The importance of diffusion in a catalyst are increased by (A) Large catalyst particle size (B) An active surface of the catalyst (C) Small pore diameter (D) All (A), (B) and (C)

Description : The importance of diffusion in a catalyst are increased by (A) Large catalyst particle size (B) An active surface of the catalyst (C) Small pore diameter (D) All (A), (B) and (C)

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

Slugging in a fluidised bed can be avoided by using (A) Tall narrow vessel (B) Deep bed of solids (C) Shallow beds of solids and proper choice of particle size (D) Very large particles

Description : Slugging in a fluidised bed can be avoided by using (A) Tall narrow vessel (B) Deep bed of solids (C) Shallow beds of solids and proper choice of particle size (D) Very large particles

Last Answer : (C) Shallow beds of solids and proper choice of particle size

An adsorption isotherm equation proposed by Langmuir is of the form `V = (V_(0)bPO)/((1 + bP))` where V is the volume of gas adsorbed at pressure P. F

Description : An adsorption isotherm equation proposed by Langmuir is of the form `V = (V_(0)bPO)/((1 + bP))` where V is the volume of gas adsorbed at pressure P. F

Last Answer : An adsorption isotherm equation proposed by Langmuir is of the form `V = (V_(0)bPO)/((1 + bP))` where V is ... of V on P can be depicted as B. C. D.

Calculate surface area to volume ratio of spherical particle.

Description : Calculate surface area to volume ratio of spherical particle.

Last Answer : Calculate surface area to volume ratio of spherical particle. See how the ratio increases with the ... particle. Plot the ratio against the radius.

Coulter counter is used in determination of (A) particle surface area (B) particle size (C) particle volume (D)all of A, B, C

Description : Coulter counter is used in determination of (A) particle surface area (B) particle size (C) particle volume (D)all of A, B, C

Last Answer : (D)all of A, B, C

One mole feed of a binary mixture of a given composition is flash vaporised at a fixed P and T. If Raoult's law is obeyed, then changing the feed composition would effect (A) The product composition but not the fraction vaporised (B) The product composition as well as the fraction vaporised (C) The fraction vaporised but not the product composition (D) Neither the product composition nor the fraction vaporised

Description : One mole feed of a binary mixture of a given composition is flash vaporised at a fixed P and T. If Raoult's law is obeyed, then changing the feed composition would effect (A) ... The fraction vaporised but not the product composition (D) Neither the product composition nor the fraction vaporised

Last Answer : (C) The fraction vaporised but not the product composition

The effectiveness factor for large value of Thiele modulus [L√(K/D1 )] of a solid catalysed first order reaction is equal to (where, L = length of the reactor, cm, D1 = diffusion co-efficient, cm2 /second). (A) L √(K/D1 ) (B) 1/[L√(K/D1 )] (C) 1 (D) ∞

Description : The effectiveness factor for large value of Thiele modulus [L√(K/D1 )] of a solid catalysed first order reaction is equal to (where, L = length of the reactor, cm, D1 = diffusion co-efficient, cm2 /second). (A) L √(K/D1 ) (B) 1/[L√(K/D1 )] (C) 1 (D) ∞

Last Answer : (B) 1/[L√(K/D1 )]

A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun's equation for the above fluid-particle system (in SI units) is given below : Δ P/L = 375 × 10 3 VOM + 10.94 × 10 6 V2 OM (SI units) If water is to be used as the fluidising medium, the minimum fluidisation velocity, VOM is (A) 12 mm/s (B) 16 mm/s (C) 24 mm/s (D) 28 mm/s

Description : A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun's equation for the above fluid-particle ... fluidisation velocity, VOM is (A) 12 mm/s (B) 16 mm/s (C) 24 mm/s (D) 28 mm/s

Last Answer : (B) 16 mm/s

The value of x and y which satisfy the equations : √ e) x=1,y=0 f) x=0,y=0 g) x=1,y=1 h) x=0,y=1

Description : The value of x and y which satisfy the equations : √ e) x=1,y=0 f) x=0,y=0 g) x=1,y=1 h) x=0,y=1

Last Answer : f) x=0,y=0

For small temperature difference, the heat transfer rate as per Newton's law of cooling is proportional to (where, Δt = excess temperature) (A) Δt (B) Δt 2 (C) Δt 3 (D) √(Δt)

Description : For small temperature difference, the heat transfer rate as per Newton's law of cooling is proportional to (where, Δt = excess temperature) (A) Δt (B) Δt 2 (C) Δt 3 (D) √(Δt)

Last Answer : (A) Δt