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January 19th, 2018, 03:02 PM
Super Moderator
Join Date: Mar 2012
Re: Hindustan Aeronautics Limited Online Test

I am providing you the sample question paper of Hindustan Aeronautics Limited HAL Exam

HAL Exam question paper

1. Shape factor for a cylinder whose length equals its diameter is

(a) 1.5 (Ans)

(b) 0.5

(c) 1.0

(d) 2.0

2. The ratio of the actual mesh dimension of Taylor series to that of the next smaller screen is

(a) 2

(b) √2 (Ans)

(c) 1.5

(d) √3

3. The opening of a 200 mesh screen (Taylor series) is

(a) 0.0074 cm (Ans)

(b) 0.0074 mm

(c) 0.0047 cm

(d) 74 mili-microns

4. The ratio of the area of openings in one screen (Taylor series) to that of the openings in the next smaller screen is

(a) 1.5

(b) 1

(c) √2

(d) none of these (Ans)

5. Cumulative analysis for determining surface is more precise than differential analysis, because of the

(a) assumption that all particles in a single fraction are equal in size.

(b) fact that screening is more effective.

(c) assumption that all particles in a single fraction are equal in size, is not needed. (Ans)

(d) none of these.

6. Equivalent diameter of a particle is the diameter of the sphere having the same

(a) ratio of surface to volume as the actual volume. (Ans)

(b) ratio of volume to surface as the particle.

(c) volume as the particle.

(d) none of these

7. For coarse reduction of hard solids, use

(a) impact

(b) attrition

(c) compression (Ans)

(d) cutting

8. Soft & non-abrasive materials can be made into fines by

(a) attrition (Ans)

(b) compression

(c) cutting

(d) none of these

9. Crushing efficiency is the ratio of the

(a) surface energy created by crushing to the energy absorbed by the solid. (Ans)

(b) energy absorbed by the solid to that fed to the machine.

(c) energy created by crushing.

(d) energy absorbed by the solid to the surface energy created by crushing.

10. 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. (Ans)

(d) for a given machine and feed, crushing efficiency is dependent on the size of the feed & product.

11. Bond crushing law

(a) calls for relatively less energy for the smaller product particles, than does the Rittinger law. (Ans)

(b) is less realistic in estimating the power requirements of commercial crushers.

(c) state 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.

12. Work index is defined as the

(a) gross energy (k Wh/ton of feed) needed to reduce very large feed to such a size that 80% of the product passes through a 100 micron screen. (Ans)

(b) energy needed to crush one tonne of feed to 200 microns.

(c) energy (k Wh/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.

13. The operating speed of a ball mill should be ......... the critical speed.

(a) less than (Ans)

(b) much more than

(c) at least equal to

(d) slightly more than

14. A fluid energy mill is used for

(a) cutting

(b) grinding

(c) ultragrinding (Ans)

(d) crushing

15. Wet grinding in a revolving mill .... as compared to dry grinding.

(a) gives less wear on chamber walls

(b) requires more energy

(c) increases capacity (Ans)

(d) complicates handling of the product

16. Cement clinker is reduced to fine size by a

(a) roll crusher

(b) ball mill

(c) tube mill (Ans)

(d) hammer mill

17. Mixer used for rubber compounding is

(a) mixer-extruder

(b) banbury internal mixer (Ans)

(c) muller mixer

(d) pug mill

18. Molten ammonium nitrate is mixed with ground limestone in fertilizer plant in a

(a) pug mill (Ans)

(b) mixer-extruder

(c) banbury mixer

(d) muller mixer

19. For the preliminary breaking of hard rock, we use a

(a) gyratory crusher (Ans)

(b) ball mill

(c) tube mill

(d) squirrel-cage disintegrator

20. Fibrous material is broken by a

(a) roll crusher

(b) squirrel-cage disintegrator (Ans)

(c) ball mill

(d) tube mill

21. Ribbon blenders are exclusively meant for

(a) blending miscible liquids.

(b) non-flowing powder and thin pastes. (Ans)

(c) bath mixing.

(d) continuous mixing.

22. As the product becomes finer, the energy required for grinding

(a) decreases

(b) increases (Ans)

(c) is same as for coarser grinding

(d) is 1.5 times that for coarser grinding

23. Increasing the capacity of a screen ....... the screen effectiveness.

(a) decreases (Ans)

(b) increases

(c) does not effect

(d) none of these

24. Screen efficiency is

(a) recovery/rejection

(b) recovery

(c) rejection

(d) none of these (Ans)

25. Traces of solids are removed from liquid in a

(a) classifier

(b) clarifier (Ans)

(c) sparkler filter

(d) rotary vacuum filter

26. For classification of potable (drinking) water, we use a ...... filter.

(a) gravity sand (Ans)

(b) plate and frame

(c) vacuum leaf

(d) rotary vacuum

27. Vacuum filter is most suitable for the

(a) removal of fines form liquid.

(b) liquids having high vapour pressure.

(c) liquids of very high viscosity.

(d) none of these (Ans)

28. Filter aid is used to

(a) increase the rate of filtration.

(b) decrease the pressure drop.

(c) increase the porosity of the cake. (Ans)

(d) act as a support base for the septum.

29. Filter medium resistance is that offered by the

(a) filter cloth.

(b) embedded particles in the septum.

(c) filter cloth and the embedded particle collectively. (Ans)

(d) none of theses.

30. Filter medium resistance is important during the ......... of filtration.

(a) early stages. (Ans)

(b) final stages.

(c) entire process.

(d) none of these

31. Cake resistance is

(a) important in the beginning of filtration.

(b) decreased with the time of filtration.

(c) independent of pressure drop.

(d) none of these. (Ans)

32. During the washing of cake

(a) all the resistance are constant. (Ans)

(b) filter medium resistance increases.

(c) filter medium resistance decreases.

(d) cake resistance decreases.

33. The porosity of a compressible cake is

(a) minimum at the filter medium. (Ans)

(b) minimum at the upstream face.

(c) maximum at the filter medium.

(d) same throughout the thickness of cake.

34. The unit of specific cake resistance is

(a) gm/cm2 (Ans)

(b) cm/gm

(c) cm/gm2

(d) gm/cm

35. The filter medium resistance is controlled by

(a) pressure drop alone

(b) flow rate alone

(c) both pressure drop and flow rate (Ans)

(d) cake thickness

36. Compressibility co-efficient for an absolutely compressible cake is

(a) 0

(b) 1 (Ans)

(c) 0 to 1

(d) ∞

37. In continuous filtration (at a constant pressure drop), filtrate

(a) square root of the velocity. (Ans)

(b) square of the viscosity.

(c) filtration time only.

(d) washing time only.

38. For separation of sugar solution from settled out mud, we use a ......... filter.

(a) sparkler

(b) plate and frame

(c) centrifugal (Ans)

(d) rotary drum vacuum

39. Moisture can be removed from lubricating oil using

(a) tubular centrifuge (Ans)

(b) clarifier

(c) sparkler filter

(d) vacuum leaf filter

40. Dust laden air can be purified using a

(a) cyclone separator (Ans)

(b) bag filter

(c) gravity settler

(d) tubular centrifuge

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