Machine Design 1000+ MCQ with answer for RRB Group D

1. The pitch of threads on a Jock nut in comparison to pitch of nut is
A. Same
B. Coarser
C. Finer
D. Very fine
Answer : A

2. When a belt drive is transmitting maximum power,
A. Effective tension is equal to centrifugal tension
B. Effective tension is half of centrifugal tension
C. Driving tension on slack side is equal to centrifugal tension
D. Driving tension on tight side is twice the centrifugal tension
Answer : D

3. In order to avoid tearing of the plate at edge, the distance from the center line of the rivet hole to the nearest edge of the plate in terms of dia. of rivet d should be equal to
A. d
B. 1.25 d
C. 1.5 d
D. 1.75 d
Answer : C

4. In helical gears, the distance parallel to the axis, between similar faces of adjacent teeth, is called
A. Normal pitch
B. Axial pitch
C. Diametral pitch
D. Module
Answer : B

5. The wire ropes make contact at
A. Bottom of groove of the pulley
B. Sides and bottom of groove of the pulley
C. Anywhere in the groove of the pulley
D. Sides of groove of the pulley
Answer : A

6. The ball bearings are provided with a cage
A. To reduce friction
B. To facilitate slipping of balls
C. To prevent the lubricant from flowing out
D. To maintain the balls at a fixed distance apart
Answer : D

7. In a flange coupling, the flanges are coupled together by means of
A. Bolts and nuts
B. Studs
C. Headless taper bolts
D. None of these
Answer : A

8. The ratio of the ultimate stress to the design stress is known as
A. Elastic limit
B. Strain
C. Factor of safety
D. Bulk modulus
Answer : C

9. A leaf spring in automobiles is used
A. To apply forces
B. To measure forces
C. To absorb shocks
D. To store strain energy
Answer : C

10. A shaft is subjected to fluctuating loads for which the normal torque (T) and bending moment (M) are 1000 N-m and 500 N-m respectively. If the combined shock and fatigue factor for bending is 1.5 and combined shock and fatigue factor for torsion is 2, then the equivalent twisting moment for the shaft is
A. 2000 N-m
B. 2050 N-m
C. 2100 N-m
D. 2136 N-m
Answer : D

11. The function of a washer is to
A. Provide cushioning effect
B. Provide bearing area
C. Absorb shocks and vibrations
D. Provide smooth surface in place of rough surface
Answer : B

12. The following type of nut is used with alien bolt
A. Hexagonal nut
B. Slotted nut
C. Castle nut
D. Any one of the above
Answer : D

13. Which one of the following is a positive drive?
A. V-belt drive
B. Rope drive
C. Crossed flat belt drive
D. Chain drive
Answer : D

14. When screw threads are to be used in a situation where power is being transmitted in one direction only, then the screw threads suitable for this will be
A. Knuckle threads
B. Square threads
C. Acme threads
D. Buttress threads
Answer : D

15. In worm, gears, pitch lead angle is
A. Half the angle between two inclined faces in axial plane
B. The angle between the tangent to the pitch helix and the plane of rotation
C. The angle between the tangent to the pitch helix and an element of the cylinder
D. None of the above
Answer : B

16. In a hydrodynamic lubricated bearing
A. There is a thick film of lubricant between the journal and the bearing
B. There is a thin film of lubricant between the journal and the bearing
C. The lubricant is forced between the journal and the bearing, by external pressure
D. There is no lubricant between the journal and the bearing
Answer : A

17. According to I.B.R., the distance between the rows of rivets, for equal number of rivets in more than one row for lap joint or butt joint (chain riveting) shall not be less than
A. d
B. 1.5 d
C. 2d
D. 2.5 d
Answer : C

18. In designing a connecting rod, it is considered like __________ for buckling about Y-axis.
A. Both ends hinged
B. Both ends fixed
C. One end fixed and the other end hinged
D. One end fixed and the other end free
Answer : B

19. For hardening alloy steels and high speed steels, they are heated to
A. 1100 to 1300°C
B. 1300 to 1500°C
C. 500 to 600°C
D. 700 to 900°C
Answer : A

20. The notch angle of the Izod impact test specimen is
A. 10°
B. 20°
C. 30°
D. 45°
Answer : D

21. A screw is said to be a self locking screw, if its efficiency is
A. Less than 50 %
B. More than 50 %
C. Equal to 50 %
D. None of these
Answer : A

22. If the centre distance of the mating gears having involute teeth is increased, then the pressure angle
A. Increases
B. Decreases
C. Remains unchanged
D. None of these
Answer : A

23. The toughness of a material _________ when it is heated
A. Does not change
B. Increases
C. Decreases
D. None of the Above
Answer : C

24. The size of a cam depends upon
A. Base circle
B. Pitch circle
C. Prime circle
D. Pitch curve
Answer : A

25. The application of third type levers is found in
A. Handle of a hand pump
B. Hand wheel of a punching press
C. Lever of a loaded safety valve
D. A pair of tongs
Answer : D

26. When the shaft rotates in anticlockwise direction at slow speed in a bearing, it will
A. Have contact at the bottom most of the bearing
B. Move towards right of the bearing making no metal to metal contact
C. Move towards right of the bearing making the metal to metal contact
D. Move towards left of the bearing making metal to metal contact
Answer : D

27. The cam follower extensively used in aircraft engines is
A. Knife edge follower
B. Flat faced follower
C. Spherical faced follower
D. Roller follower
Answer : D

28. When the bolt is very yielding as compared to the connected members, then the resultant load on the bolt will be equal to the
A. Initial tension
B. External load applied
C. Sum of the initial tension and external load applied
D. Initial tension or external load, whichever is greater
Answer : D

29. Which of the following screw thread is adopted for power transmission in either direction?
A. Acme threads
B. Square threads
C. Buttress threads
D. Multiple threads
Answer : B

30. According to I.B.R., the efficiency of a double riveted butt joint with double cover straps of equal width should be
A. 45 to 60 %
B. 63 to 70 %
C. 70 to 83 %
D. 80 to 90 %
Answer : C

31. The steel pulleys are __________ in weight than cast iron pulleys of the same capacity.
A. Heavier
B. Lighter
C. Moderate
D. None of these
Answer : B

32. Resistance to fatigue of a material is measured by
A. Young's modulus
B. Coefficient of elasticity
C. Elastic limit
D. Endurance limit
Answer : D

33. The arms of the pulleys for flat belt drive have
A. Elliptical cross-section
B. Major axis in plane of rotation
C. Major axis twice the minor axis
D. All the three characteristics
Answer : D

34. In a partial journal bearing, the angle of contact of the bearing with the journal is
A. 120°
B. 180°
C. 270°
D. 360°
Answer : A

35. The belt slip occurs due to
A. Heavy load
B. Loose belt
C. Driving pulley too small
D. Any one of the above
Answer : D

36. A sliding bearing which can support steady loads without any relative motion between the journal and the bearing, is called
A. Hydrostatic lubricated bearing
B. Hydrodynamic lubricated bearing
C. Boundary lubricated bearing
D. Zero film bearing
Answer : A

37. A localised compressive stress at the area of contact between two members is known as
A. Bending stress
B. Shear stress
C. Tensile stress
D. Bearing stress
Answer : D

38. Elastic nut is a locking device in which
A. One small nut is tightened over main nut and main nut tightened against smaller one by loosening, creating friction jamming
B. A slot is cut partly in middle of nut and then slot reduced by tightening a screw
C. Hard fibre or nylon cotter is recessed in the nut and becomes threaded as the nut is stewed on the bolt causing a tight grip
D. Through slots are made at top and a cotter pin is passed through these and a hole in the bolt, and cotter pin splitted and bent in reverse direction at other end
Answer : C

39. The shear stress in a beam varies from zero at the outer fibres to a maximum at the________.
A. Neutral surface
B. Upper surface
C. Lower surface
D. None of these
Answer : A

40. Plastic flow in ductile materials
A. Increases the seriousness of static loading stress concentration
B. Lessens the seriousness of static loading stress concentration
C. Has no effect on it
D. Depends on other considerations
Answer : B

41. In thrust bearings, the load acts
A. Along the axis of rotation
B. Parallel to the axis of rotation
C. Perpendicular to the axis of rotation
D. In any direction
Answer : A

42. In unilateral system of tolerance, the tolerance is allowed on
A. Both sides of the actual size
B. One side of the actual size
C. One side of the nominal size
D. Both sides of the nominal size
Answer : C

43. The groove angle of pulleys for V-belt is
A. 340 to 360
B. 420 to 450
C. More than 400
D. 300 to 320
Answer : A

44. Residual stress in materials
A. Acts when external load is applied
B. Becomes zero when external load is removed
C. Is independent of external loads
D. Is always harmful
Answer : C

45. Guest's theory of failure is applicable for following type of materials
A. Brittle
B. Ductile
C. Elastic
D. Plastic
Answer : B

46. The bearings of medium series have capacity __________ over the light series.
A. 10 to 20 %
B. 20 to 30 %
C. 30 to 40 %
D. 40 to 50 %
Answer : C

47. Which of the following is not correct procedure to increase the fatigue limit?
A. Cold working
B. Shot peening
C. Surface decarburisation
D. Under stressing
Answer : C

48. Crowning on pulley helps
A. In decreasing the slip of the belt
B. In increasing the slip of the belt
C. To keep the belt in centre on a pulley while it is in motion
D. To increase pulley life
Answer : C

49. When compared to the rod of the same diameter and material, a wire rope
A. Is less flexible
B. Has a much smaller load carrying capacity
C. Does not provide much warning before failure
D. Provides much greater time for remedial action before failure
Answer : B

50. If the tearing efficiency of a riveted joint is 75%, then the ratio of diameter of rivet to the pitch is equal to
A. 0.2
B. 0.25
C. 0.50
D. 0.6
Answer : B