MCQOPTIONS
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MCQOPTIONS
This section includes 552 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
Theoretical capacity of crushing rolls in tons/hr is given by (where, V = peripherial velocity, m/sec. W = width of rolls, m Dr = distance between rolls ρ = density of material to be crushed, kg/m³ here, V =πN.D where, N = speed of the rolls in rotation per second (rps) D = diameter of rolls, m) |
| A. | 3.6 V.W.Dr.ρ |
| B. | 3.6 V.W. ρ |
| C. | 3.6 W.Dr.ρ |
| D. | 3.6 V.W.Dr/ρ |
| Answer» B. 3.6 V.W. ρ | |
| 52. |
Filtrate flow rate in case of a rotary drum vacuum filter (in which Rm < < Rc) is proportional to __________ and the cycle time (where, μ = filtrate viscosity Rm = filter medium resistance Rc = cake resistance ). |
| A. | √μ |
| B. | 1/√μ |
| C. | 1/μ |
| D. | 1/μ² |
| Answer» C. 1/μ | |
| 53. |
At low Reynold's number, the power (P) required for agitating a fluid in a stirred tank becomes independent of inertial forces. In this limit, indicate which of the following relations is satisfied: P₀ = ρ/ρN³ D⁵ : Power number Re = ρ N D²/μ: Reynold's number N is the impeller rotational speed, and D is the impeller diameter. |
| A. | P₀ ∝ Re^-1.0 |
| B. | P₀ ∝ Re^0.0 |
| C. | P₀ ∝ Re^0.5 |
| D. | P₀ ∝ Re^1.0 |
| Answer» C. P₀ ∝ Re^0.5 | |
| 54. |
In a mixer, the quantity, (v. L/D) is termed as __________ number (where, v = longitudinal velocity of material, L = length of the mixer, D = diffusivity in axial mixing). |
| A. | Weber |
| B. | Peclet |
| C. | Brinkman |
| D. | Schmidt |
| Answer» C. Brinkman | |
| 55. |
The specific surface of sherical particles is proportional to (where, Dₚ = diameter of particle). |
| A. | D²ₚ |
| B. | Dp |
| C. | 1/Dₚ |
| D. | 1/D²ₚ |
| Answer» D. 1/D²ₚ | |
| 56. |
For a turbine agitated and baffled tank, operating at low Reynold's number (based on impeller diameter), the power number (Nₚ) varies with Nʀₑ as |
| A. | Nₚ ∝ Nʀₑ |
| B. | Nₚ ∝ √Nʀₑ |
| C. | Nₚ → constant |
| D. | Nₚ ∝ 1/Nʀₑ |
| Answer» E. | |
| 57. |
Capacity of flight conveyor in tons/hr is given by (where, W & D = width and depth of flight respectively in metre, V = speed of the conveyor in metre/second, ρ = bulk density of material in kg/m³) |
| A. | 3.6 W.D.V.ρ |
| B. | 3.6 W.D.V. |
| C. | 3.6 W.V.ρ |
| D. | 3.6 D.V.ρ |
| Answer» B. 3.6 W.D.V. | |
| 58. |
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 |
| Answer» C. fine | |
| 59. |
Number of particles in a crushed solid sample is given by (where, m = mass of particles in a sample, Vₚ = volume of one particle, ρ= density of particles) |
| A. | m/ρ . Vₚ |
| B. | m . ρ/Vₚ |
| C. | m . Vₚ/ρ |
| D. | Vₚ/m . ρ |
| Answer» B. m . ρ/Vₚ | |
| 60. |
If dₚ is the equivalent diameter of a non-spherical particle, Vₚ its volume and sₚ its surface area, then its sphericity is Φₛ is defined by |
| A. | Φₛ = 6 Vₚ/dₚ sₚ |
| B. | Φₛ = Vₚ/dₚ sₚ |
| C. | Φₛ = 6 dₚ Sₚ/Vₚ |
| D. | Φₛ = dₚ Sₚ/Vₚ |
| Answer» B. Φₛ = Vₚ/dₚ sₚ | |
| 61. |
The cummulative mass fraction of particles smaller than size dⱼ for a collection of Nᵢ particles of diameter dᵢ and mass mi (i = 1, 2, 3, ...... ∞) is given by |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 62. |
Pick out the correct statement. |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 63. |
Velocity of a small particle of diameter 'Dₚ' at a distance 'r' from the rotational axis of a cyclone rotating at an angular speed 'ω' is given by (the other symbols are as per standard notation) |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 64. |
The basic filtration equation is given as in the below figure, where, V is volume of the filtrate ; A is the filtration area, a is specific cake resistance, μ is viscosity of the filtrate, and C is the concentration of the solids in the feed slurry. In a 20 minutes constant rate filtration, 5 m³ of filtrate was obtained. If this is followed by a constant pressure filtration, how much more time in minutes, it will take for another 5 m³ of filtrate to be produced ? Neglect filter medium resistance, Rm ; assume incompressible cake. |
| A. | 10 |
| B. | 20 |
| C. | 25 |
| D. | 30 |
| Answer» C. 25 | |
| 65. |
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. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 66. |
Critical speed of rotation, N (in rps - rotation per second) of a trammel is equal to (where, g = acceleration due to gravity = 9.81 m/sec² and, r = radius of trammel, metre. ) |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 67. |
Which of the following equations is Rittinger's crushing law ?(where P = power required by the machine, m = feed rate, k = a constant, D̅sa & D̅sb = volume surface mean diameter of feed & product respectively.) |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» D. D | |
| 68. |
Critical Speed (Nc) of a ball mill is given by(where R₁ and R₂ are radii of ball mill and the ball respectively). |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 69. |
About 2-3 hp, power per gallon of a thin liquid provides vigrous agitation in an agitator. 'Power number' in agitation is given by |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 70. |
General crushing equation is given by following equation. 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 |
| Answer» C. 2 | |
| 71. |
Filtration rate through a filter cake is proportional to (where, S = filtering surface R = specific cake resistance μ = viscosity of the filtrate) |
| A. | S |
| B. | 1/R |
| C. | 1/μ |
| D. | All of the above |
| Answer» E. | |
| 72. |
Which of the following is not a wet classifier? |
| A. | Sharpies supercentrifuge |
| B. | Hydrocyclones |
| C. | Dorr Oliver rake classifier |
| D. | None of these |
| Answer» E. | |
| 73. |
Which one is a filter aid? |
| A. | Convas fabric |
| B. | Diatomaceous earth |
| C. | Calcined lime |
| D. | None of these |
| Answer» C. Calcined lime | |
| 74. |
Which of the following is the most suitable for cleaning of fine coal dust (<0.5 mm)? |
| A. | Trough washer |
| B. | Baum jig washer |
| C. | Spiral separator |
| D. | Froth floatation |
| Answer» E. | |
| 75. |
Which of the following conveyors cannot be recommended for transportation of abrasive materials? |
| A. | Belt conveyor |
| B. | Apron conveyor |
| C. | Flight conveyor |
| D. | Chain conveyor |
| Answer» D. Chain conveyor | |
| 76. |
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 meshsize |
| B. | Dry chemicals |
| C. | Heavy tonnages of rocks or gravel |
| D. | Powdered food & granular materials |
| Answer» D. Powdered food & granular materials | |
| 77. |
A centrifugal filtration unit operating at a rotational speed of w has inner surface of the liquid (density ρL) located at a radial distance R from the axis of rotation. The thickness of the liquid film is δ and no cake is formed. The initial pressure drop during filtration is |
| A. | ½w² . R² . ρL |
| B. | ½w² . δ² . ρL |
| C. | ½w² . δρL (2R + δ) |
| D. | ½w² . R . ρL(R + 2δ) |
| Answer» D. ½w² . R . ρL(R + 2δ) | |
| 78. |
If dp is the equivalent diameter of a non-spherical particle, Vp its volume and sp its surface area, then its sphericity is Φs is defined by |
| A. | Φs = 6 Vp/dp sp |
| B. | Φs = Vp/dp sp |
| C. | Φs = 6 dp Sp/Vp |
| D. | Φs = dp Sp/Vp |
| Answer» B. Φs = Vp/dp sp | |
| 79. |
Dry powdery solid materials are transported by a __________ conveyor. |
| A. | Belt |
| B. | Bucket |
| C. | Screw |
| D. | None of these |
| Answer» D. None of these | |
| 80. |
Theoretical capacity of crushing rolls in tons/hr is given by (where, V = peripherial velocity, m/sec. W = width of rolls, m Dr = distance between rolls ρ = density of material to be crushed, kg/m³ here, V =πN.D where, N = speed of the rolls in rotation per second (rps) D = diameter of rolls, m) |
| A. | 3.6 V.W.Dr.ρ |
| B. | 3.6 V.W. ρ |
| C. | 3.6 W.Dr.ρ |
| D. | 3.6 V.W.Dr/ρ |
| Answer» B. 3.6 V.W. ρ | |
| 81. |
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)²p |
| D. | (S/V)f |
| Answer» C. (S/V)²p | |
| 82. |
Which of the following may prove unsuitable for filtering volatile liquids? |
| A. | Pressure filter |
| B. | Gravity filter |
| C. | Centrifugal filter |
| D. | Vacuum filter |
| Answer» E. | |
| 83. |
Which is the most suitable conveyor for transportation of sticky material? |
| A. | Apron conveyor |
| B. | Belt conveyor |
| C. | Screw conveyor |
| D. | Pneumatic conveyor |
| Answer» D. Pneumatic conveyor | |
| 84. |
Which of the following is used for primary crushing of very hard lumpy materials? |
| A. | Toothed roll crusher |
| B. | Gyratory crusher |
| C. | Ball mill |
| D. | Tube mill |
| Answer» C. Ball mill | |
| 85. |
Feed size of ≥ 25 cms can be accepted by |
| A. | Ball mill |
| B. | Rod mill |
| C. | Fluid energy mill |
| D. | Jaw crusher |
| Answer» E. | |
| 86. |
Which of the follwoing mechanical conveyors does not come under the division 'scrapers'? |
| A. | Ribbon conveyor |
| B. | Flight conveyor |
| C. | Bucket elevators |
| D. | Drag conveyor |
| Answer» D. Drag conveyor | |
| 87. |
Which of the following mechanical conveyors does not come under the division 'carriers'? |
| A. | Belt conveyor |
| B. | Bucket elevator |
| C. | Screw conveyor |
| D. | Apron conveyor |
| Answer» D. Apron conveyor | |
| 88. |
At low Reynold's number, the power (P) required for agitating a fluid in a stirred tank becomes independent of inertial forces. In this limit, indicate which of the following relations is satisfied: Po = ρ/ρN3 D5 : Power number Re = ρ N D2/μ: Reynold's number N is the impeller rotational speed, and D is the impeller diameter. |
| A. | Po ∝ Re-1.0 |
| B. | Po ∝ Re0.0 |
| C. | Po ∝ Re0.5 |
| D. | Po ∝ Re1.0 |
| Answer» C. Po ∝ Re0.5 | |
| 89. |
Which of the following must be stored in silos and not in open yard? |
| A. | Coke breeze |
| B. | High V.M. bituminous coal |
| C. | Sand |
| D. | None of these |
| Answer» C. Sand | |
| 90. |
Which of the following is a pressure filter? |
| A. | Leaf filter (Moore filter) |
| B. | Plate and flame filter |
| C. | Rotary drum filter |
| D. | Sand filter |
| Answer» C. Rotary drum filter | |
| 91. |
Capacity of flight conveyor in tons/hr is given by (where, W & D = width and depth of flight respectively in metre V = speed of the conveyor, metre/second ρ = bulk density of material, kg/m³) |
| A. | 3.6 W.D.V.ρ |
| B. | 3.6 W.D.V. |
| C. | 3.6 W.V.ρ |
| D. | 3.6 D.V.ρ |
| Answer» B. 3.6 W.D.V. | |
| 92. |
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 |
| Answer» B. V/6D.S | |
| 93. |
Which of the following size reduction equipments employs mainly attrition for ultrafine grinding? |
| A. | Jet mills |
| B. | Fluid energy mill |
| C. | Micronizer |
| D. | All of the above |
| Answer» E. | |
| 94. |
Which of the following is not used as a filter medium in case of corrosive liquids? |
| A. | Nylon |
| B. | Glass cloth |
| C. | Metal cloth of monel or stainless steel |
| D. | Cotton fabric |
| Answer» E. | |
| 95. |
Number of particles in a crushed solid sample is given by (where, m = mass of particles in a sample, Vp = volume of one particle, ρ= density of particles) |
| A. | M/ρ . Vp |
| B. | M . ρ/Vp |
| C. | M . Vp/ρ |
| D. | Vp/m . ρ |
| Answer» B. M . ρ/Vp | |
| 96. |
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 |
| Answer» B. Cone crusher | |
| 97. |
Which is a secondary crusher for a hard & tough stone? |
| A. | Jaw crusher |
| B. | Cone crusher |
| C. | Impact crusher |
| D. | Toothed roll crusher |
| Answer» C. Impact crusher | |
| 98. |
What is the selectivity index, if the grade of tailings & concentrate is the same? |
| A. | 0 |
| B. | ∞ |
| C. | 1 |
| D. | 0.5 |
| Answer» D. 0.5 | |
| 99. |
Which of the following is the most suitable for handling fibrous and dense slurries? |
| A. | Propeller agitator |
| B. | Cone type agitator |
| C. | Turbine agitator |
| D. | Radial propeller agitator |
| Answer» C. Turbine agitator | |
| 100. |
Which of the following is a vacuum filter? |
| A. | Filter press |
| B. | Rotary disc filter |
| C. | Batch basket centrifuge |
| D. | Tank filter (Nutsch filter) |
| Answer» C. Batch basket centrifuge | |