MCQ-FOR Mechanical Operation

 

1. Arrange the following particle shapes in order of increasing sphericity of : cube, sphere, cylinder, and hemisphere

A) cylinder, cube, hemisphere, sphere
B) hemisphere, cube, cylinder, sphere
C) cube, cylinder, hemisphere, sphere
D) cube, hemisphere , cylinder, sphere

ANSWER= (D) cube, hemisphere, cylinder, sphere
Explain:-Because sphere has the highest sphericity then cylinder, then hemisphere and finally cube has the least sphericity.

 

2. Which of the following shapes has the highest shape factor ?

A) Cylinder
B) Cube
C) Hemisphere
D) Sphere

ANSWER= (B) Cube
Explain:- We know that Shape factor is inversally Proportional to Sphericity, Here the Cube has the least Sphericity so it have highest Shape factor.

 

3. When compared to Cohesive Solid, the value of internal friction for granular solid is.

A) higher
B) lower
C) Nearly equal
D) None of the above

ANSWER= (B) lower
Explain:- Cohesive Solid means the solid which is sticky it means it have high friction when it move. If we compare granular solid it is not sticky so it feel low friction during travel.

 

4. The value of internal friction for granular solids varies from.

A) 5°-10°
B) 10°-15°
C) 15°-30°
D) 40°-50°

ANSWER= (C) 15°-30°
Explain:-

 

5. Which of the following is a non-cohesive material?

A)Plastic chip
B) Dehydrated peas
C) Dry sand
D) All of the above

ANSWER= (D) All of the above
Explain:- Non-Cohesive means the material which is non-sticky(जो चिपचिपा न हो)। If we see our options so all materials which are given in the options are non-sticky.

 

6. For a cylindrical particle of height equal to twice the diameter, the Sphericity value is.

A)0.655
B) 0.728
C) 0.832
D) 0.915

ANSWER= (C) 0.832
Explain:-

 

7. The shape factor for a hemisphere is.

A) equal to 1
B) greater than 1
C) less than 1
D) none of the above

ANSWER= (B) greater than 1
Explain:-

 

8. A bin is a rectangular or cylindrical storage vessel with.

A) height equal to width (diameter)
B) height more than width
C) height less than width
D) Nothing in particular

ANSWER= (C) height less than width
Explain:-

 

9. Which of the following Particle has the lowest value of sphericity?

A) Rounded sand
B) Pulverized coal
C) Tungsten powder
D) Mica flakes

ANSWER= (D) Mica flakes
Explain:-

 

10. For Measurement of particles size in the range of 0.1 to 10 μm (micro-meter), the technique adopted is

A) Sedimentation
B) Screening
C) Elutriation
D) light scattering

ANSWER= (D) light scattering
Explain:-

 

11. Rittingers law is best applicable to feed material of

A) fine size
B) Coarse size
C) intermediate size
D) Coarse and intermediate size

ANSWER= (A) fine size
Explain:-

 

12. For feed size greater than 50 mm, the crushing law applicable is

A) Rittingers law
B) Kick's law
C) Bond's law
D) all of the above

ANSWER= (B) Kick's law
Explain:-

 

13. The value of work index (kWh/toone) for hard material is

A) 7-9
B) 9-14
C) 14-20
D) greater than 20

ANSWER= (C) 14-20
Explain:-

 

14. Jet mill comes under the category of

A) grinder
B) intermediate crusher
C) coarse crusher
D) ultra fine grinder

ANSWER= (D) ultra fine grinder
Explain:-

 

15. An example of an intermedia crusher is a

A) roll crusher
B) cage mill
C) rod mill
D) ball mill

ANSWER= (B) cage mill
Explain:-

 

16. Reduction ratio of a coarse crusher varies from

A) 1-2
B) 3-7
C) 8-12
D) >12

ANSWER= (B) 3-7
Explain:-

 

17. The hardness of the following materials expressed in Mohs scale in the increasing order will be

A) diamond,bauxite,marble,talc
B) bauxite, diamond,talc, marble
C) talc, bauxite, diamond, marble
D) talc, marble, bauxite, diamond

ANSWER= (D) talc, marble, bauxite, diamond
Explain:-

 

18. An example of an ultrafine grinder is

A) Semi-autogenous mill
B) ball mill
C) fluidised - bed opposed jet mill
D) Pebble mill

ANSWER= (C) fluidised - bed opposed jet mill
Explain:-

 

19. Size reduction equipment required to get a product of 0.2-mm size from a feed of 2-mm size is a

A) hammer mill
B) bradford breaker
C) semi-autogenous mill
D) fluidised - bed opposed jet mill

ANSWER= (A) hammer mill
Explain:-

 

20. Cone crusher is reduction equipmemt under the category of

A) intermediate crusher
B) coarse crusher
C) fine crusher
D) ultrafine grinder

ANSWER= (B) coarse crusher
Explain:-