Mechanical Operations in Chemical Engineering MCQ - Set 02 - ObjectiveBooks

Mechanical Operations in Chemical Engineering MCQ - Set 02

Practice Test: Question Set - 02

1. 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

2. 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

3. Size measurement of ultrafine particles can be best expressed in terms of
    (A) Centimeter
    (B) Screen size
    (C) Micron
    (D) Surface area per unit mass

4. Which of the following agitators having a large blade area, rotating at slow speed is used for mixing high viscosity liquids (> 50000 centipoise)?
    (A) Propeller
    (B) Helical screw
    (C) Flat blade turbine
    (D) Curved blade turbine

5. Rittinger number which designates the new surface produced per unit of mechanical energy absorbed by the material being crushed, depends on the
    (A) State or manner of application of the crushing force
    (B) Ultimate strength of the material
    (C) Elastic constant of the material
    (D) All (a), (b) and (c)

6. The specific surface of spherical particles is proportional to (where, Dp = diameter of particle).
    (A) Dp2
    (B) Dp
    (C) 1/Dp
    (D) 1/D2p

7. During filtration operation, the filtrate encounters the resistance of the
    (A) Filter medium
    (B) Cake
    (C) Channel carrying the slurry to the upstream side of the cake and filtrate away from the filter medium
    (D) All (a), (b) and (c)

8. Separation of materials of the same density based on their sizes by using then-different rates of flow is called
    (A) Sorting
    (B) Sizing
    (C) Flocculation
    (D) Elutriation

9. __________ is the most suitable for compounding rubber and plastic solids.
    (A) Banbury mixer
    (B) Pan mixer
    (C) Pug mill
    (D) Charge can mixer

10. 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

11. What is the reduction ratio in a fine crushing operation having following feed and product sizes? 
Mechanical Operations - Set 02, Question No. 11
    (A) 0.5
    (B) 2
    (C) 5
    (D) 10

12. Dust collection efficiency of electrostatic precipitator can be as high as 99.9%. Maximum temperature and pressure of dust laden gas that can be cleaned in an electrostatic precipitator is respectively.
    (A) 200°C and 5 atm
    (B) 1000°C and 10 atm
    (C) 500°C and 50 atm
    (D) 1000°C and 500 atm

13. For a sphere falling in the constant drag co-efficient regime, its terminal velocity depends on its diameter (d) as
    (A) d
    (B) √d
    (C) d2
    (D) 1/d

14. Energy consumed for crushing one ton of material ranges from __________ kWh.
    (A) 0.01 to 0.1
    (B) 0.5 to 1.5
    (C) 2 to 3.5
    (D) 4 to 5

15. 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

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