MCQOPTIONS
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MCQOPTIONS
This section includes 657 Mcqs, each offering curated multiple-choice questions to sharpen your Testing Subject knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Which of the following size reduction equipments employs mainly attrition for ultrafine grinding ? |
| A. | Jet mills |
| B. | Fluid energy mill |
| C. | Micronizer |
| D. | all (a), (b) and (c) |
| Answer» E. | |
| 2. |
Sphericity of pulverised coal is |
| A. | 1 |
| B. | <1 |
| C. | >1 |
| D. | |
| Answer» C. >1 | |
| 3. |
A __________ mixer resembles a ball mill without balls. |
| A. | banbery |
| B. | pug mill |
| C. | tumbling |
| D. | pan |
| Answer» D. pan | |
| 4. |
__________ conveyor is the most suitable for short distance transportation of non-abrasive loose materials like garbage, grain, food wastes etc. |
| A. | Flight |
| B. | Screw |
| C. | Drag |
| D. | Belt |
| Answer» B. Screw | |
| 5. |
As the product becomes finer, the energy required for grinding |
| A. | decreases |
| B. | increases |
| C. | is same as for coarser grinding |
| D. | is 1.5 times that for coarser grinding |
| Answer» C. is same as for coarser grinding | |
| 6. |
Gyratory crushers compared to the reciprocating jaw crushers |
| A. | have greater capacity per unit of discharge area. |
| B. | crush intermittantly. |
| C. | are less suitable for coarse materials. |
| D. | have less steady power consumption. |
| Answer» B. crush intermittantly. | |
| 7. |
The important dimensional group involved in the power requirement calculation in mixing operation is the __________ number. |
| A. | Reynold's |
| B. | Froude |
| C. | both (a) & (b) |
| D. | neither (a) nor (b) |
| Answer» D. neither (a) nor (b) | |
| 8. |
Colloid mills achieve size reduction mainly by |
| A. | impact |
| B. | attrition |
| C. | cutting |
| D. | compression |
| Answer» C. cutting | |
| 9. |
Mesh indicates the number of holes per |
| A. | square inch |
| B. | linear inch |
| C. | square foot |
| D. | linear foot |
| Answer» C. square foot | |
| 10. |
For achieving maximum capacity of the ball mill, the ball charge should be equal to about __________ percent of the ball mill volume. |
| A. | 10 |
| B. | 25 |
| C. | 50 |
| D. | 75 |
| Answer» D. 75 | |
| 11. |
The sphericity of a cylinder of 1 mm diameter and length 3 mm is |
| A. | 0.9 |
| B. | 0.78 |
| C. | 0.6 |
| D. | 0.5 |
| Answer» B. 0.78 | |
| 12. |
Pulverised coal passing through 200 mesh screen has a diameter of 0.074 mm (74 micron). The same passing through 50 mesh screen will have a dia of __________ mm. |
| A. | 0.007 |
| B. | 0.30 |
| C. | 50 |
| D. | 0.014 |
| Answer» C. 50 | |
| 13. |
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 | |
| 14. |
The most suitable equipment used to devulcanise rubber scrap and to make water dispersion & rubber solution is a |
| A. | boundary mixer. |
| B. | propeller agitator. |
| C. | sharpies centrifuge. |
| D. | none of these. |
| Answer» B. propeller agitator. | |
| 15. |
Traces of solids are removed from, liquid in a |
| A. | classifier |
| B. | clarifier |
| C. | sparkler filter |
| D. | rotary vacuum filter |
| Answer» C. sparkler filter | |
| 16. |
For efficient grinding, ball mills must be operated |
| A. | at a speed less than the critical speed. |
| B. | at a speed more than the critical speed. |
| C. | at a speed equal to the critical speed. |
| D. | with minimum possible small balls. |
| Answer» B. at a speed more than the critical speed. | |
| 17. |
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 |
| Answer» D. none of these | |
| 18. |
In filtration, the use of 'filter aid' helps in |
| A. | reducing the filtration pressure. |
| B. | accelerating the rate of filtration. |
| C. | deplugging the filter medium. |
| D. | enhancing the cake porosity in case of a dense impermeable cake. |
| Answer» D. enhancing the cake porosity in case of a dense impermeable cake. | |
| 19. |
Critical Speed (Nc) of a ball mill is given by(where R1 and R2 are radii of ball mill and the ball respectively). |
| A. | <img src="/_files/images/chemical-engineering/mechanical-operations/105-117-1.png"> |
| B. | <img src="/_files/images/chemical-engineering/mechanical-operations/105-117-2.png"> |
| C. | <img src="/_files/images/chemical-engineering/mechanical-operations/105-117-3.png"> |
| D. | <img src="/_files/images/chemical-engineering/mechanical-operations/105-117-4.png"> |
| Answer» C. <img src="/_files/images/chemical-engineering/mechanical-operations/105-117-3.png"> | |
| 20. |
Gizzlies are used for separating __________ solids. |
| A. | coarse |
| B. | fine |
| C. | any size |
| D. | none of these |
| Answer» C. any size | |
| 21. |
Which of the following clay mixing devices is vacuum operated for deairation of clay? |
| A. | Banbery mixer |
| B. | Pug mill |
| C. | Muller-mixer |
| D. | None of these |
| Answer» C. Muller-mixer | |
| 22. |
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 |
| Answer» D. jet pulveriser | |
| 23. |
Bucket elevators are not suitable for the vertical lifting of __________ materials. |
| A. | fine (e.g. - 200 mesh size coal) |
| B. | sticky (e.g. clay paste) |
| C. | small lumpy (e.g. grains and sand) |
| D. | free flowing |
| Answer» C. small lumpy (e.g. grains and sand) | |
| 24. |
The most common filter aid is |
| A. | diatomaceous earth |
| B. | calcium silicate |
| C. | sodium carbonate |
| D. | silica gel |
| Answer» B. calcium silicate | |
| 25. |
For removal of very small amounts of precipitate from large volume of water, the most suitable filter is the __________ filter. |
| A. | plate & frame |
| B. | shell & leaf |
| C. | sand |
| D. | rotary vacuum |
| Answer» D. rotary vacuum | |
| 26. |
For separation of sugar solution from settled out mud, we use a __________ filter. |
| A. | sparkler |
| B. | plate and frame |
| C. | centrifugal |
| D. | rotary drum vaccum |
| Answer» D. rotary drum vaccum | |
| 27. |
Maximum size reduction in a ball mill is done by the, __________ action. |
| A. | attrition |
| B. | compression |
| C. | impact |
| D. | cutting |
| Answer» D. cutting | |
| 28. |
increasing the capacity of a screen __________ the screen effectiveness. |
| A. | decreases. |
| B. | increases |
| C. | does not effect |
| D. | none of these |
| Answer» B. increases | |
| 29. |
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. |
| Answer» B. is less realistic in estimating the power requirements of commercial crushers. | |
| 30. |
Flow of filtrate through the cake in a plate and frame filter press is best described by the __________ equation. |
| A. | Kozney-Karman |
| B. | Hagen-Poiseulle's |
| C. | Fanning's |
| D. | Kremser |
| Answer» B. Hagen-Poiseulle's | |
| 31. |
Length/diameter ratio of a ball mill is |
| A. | 1.5 |
| B. | 1 |
| C. | < 1 |
| D. | > 1 |
| Answer» D. > 1 | |
| 32. |
Feed size of 25 cms can be accepted by |
| A. | ball mill |
| B. | rod mill |
| C. | fluid energy mill |
| D. | jaw crusher |
| Answer» E. | |
| 33. |
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 | |
| 34. |
The most suitable equipment for removing the fine dust particle (< 1 micron dia.) from air below its dew point will be a/an |
| A. | bag filter |
| B. | electrostatic precipitator |
| C. | cyclone separator |
| D. | wet scrubber |
| Answer» C. cyclone separator | |
| 35. |
Laminar flow region is said to exist during agitation of a liquid in an agitator, when the value of Reynolds number is |
| A. | >10 |
| B. | <10 |
| C. | >100 |
| D. | <100 |
| Answer» C. >100 | |
| 36. |
__________ mixer is used for devulcanisation of rubber scrap & making water dispersion & rubber solution. |
| A. | Tumbler |
| B. | Banbery |
| C. | Muller |
| D. | Rubbon blender |
| Answer» C. Muller | |
| 37. |
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. | |
| 38. |
Screen capacity is not a function of |
| A. | its openings size. |
| B. | screening mechanism. |
| C. | screening surface. |
| D. | atmospheric humidity. |
| Answer» E. | |
| 39. |
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 | |
| 40. |
Pine oil used in froth floatation technique acts as a/an |
| A. | collector |
| B. | modifier |
| C. | frother |
| D. | activator |
| Answer» D. activator | |
| 41. |
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 |
| Answer» C. roll crusher | |
| 42. |
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. |
| Answer» B. energy absorbed by the solid to that fed to the machine. | |
| 43. |
The crushed material received for separation is called feed or |
| A. | tailing |
| B. | heading |
| C. | concentrate |
| D. | middling |
| Answer» C. concentrate | |
| 44. |
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 |
| Answer» C. Flat blade turbine | |
| 45. |
__________ is defined as the geometric mean of the relative rejections and the relative recoveries of two minerals. |
| A. | Separation efficiency |
| B. | Selectivity index |
| C. | Concentration ratio |
| D. | none of these |
| Answer» C. Concentration ratio | |
| 46. |
Rittinger's number designates the new surface created per unit mechanical energy absorbed by the material being crushed. Larger value of Rittinger's number of a material indicates its |
| A. | easier grindability |
| B. | poor grindability |
| C. | high power consumption in grinding |
| D. | none of these |
| Answer» B. poor grindability | |
| 47. |
Addition of filter aid to the slurry before filtration is done to ...... of the cake. |
| A. | increase the porosity |
| B. | increase the compressibility co-efficient |
| C. | decrease the porosity |
| D. | decrease the compressibility co-efficient |
| Answer» B. increase the compressibility co-efficient | |
| 48. |
Size reduction of asbestos and mica is done by |
| A. | hammer mills |
| B. | rod mills |
| C. | gyratory crushers |
| D. | crushing rolls |
| Answer» B. rod mills | |
| 49. |
Size reduction does not occur due to compression in case of |
| A. | rod mills |
| B. | gyratory crushers |
| C. | jaw crushers |
| D. | smooth roll crushers |
| Answer» B. gyratory crushers | |
| 50. |
Which of the following gives the work required for size reduction of coal to -200 mesh in a ball mill most accurately ? |
| A. | Rittinger's law |
| B. | Kick's law |
| C. | Bond's law |
| D. | none of these |
| Answer» B. Kick's law | |