ESIC - Machine Design 1000+ MCQ [Solved] PDF Download

1. A special case of ductility which permits materials to be rolled or hammered into thin sheets, is called
A. Plasticity
B. Elasticity
C. Ductility
D. Malleability
Answer : D

2. The coefficient of friction in belt drive depends upon
A. Material of belt
B. Material of pulley
C. Materials of belt and pulley
D. Belt velocity
Answer : C

3. In radial bearings, the load acts __________ to the axis of rotation.
A. Parallel
B. Perpendicular
C. Both A and B
D. None of these
Answer : B

4. Basic shaft is one
A. Whose upper deviation is zero
B. Whose lower deviation is zero
C. Whose lower as well as upper deviations are zero
D. Does not exist
Answer : A

5. The edges of the plates for cylindrical vessels are usually bevelled to an angle of 80° for
A. Reducing stress concentration
B. Ease of manufacture
C. Safety
D. Fullering and caulking
Answer : D

6. If two springs are in parallel then their overall stiffness will be
A. Half
B. Same
C. Double
D. None of the above
Answer : C

7. According to Indian standard specifications, 100 H6/g5 means that
A. Tolerance grade for the hole is 6 and for the shaft is 5
B. Tolerance grade for the shaft is 6 and for the hole is 5
C. Tolerance grade for the shaft is 4 to 8 and for the hole is 3 to 7
D. Tolerance grade for the hole is 4 to 8 and for the shaft is 3 to 7
Answer : A

8. A triple riveted butt joint with double straps of unequal width is to be designed for a boiler shell. The pitch of the rivets in the outer row is double the pitch in the inner row and zigzag riveting is proposed. Which of the following statement is correct?
A. There are four rivets per pitch length, all in double shear
B. There are four rivets per pitch length, out of which two are in single shear and two are in double shear
C. There are five rivets per pitch length, all in double shear
D. There are five rivets per pitch length, out of which four are in double shear and one is in single shear
Answer : D

9. In order to remove internal stresses produced by hardening the steel, the process usually adopted is
A. Tempering
B. Normalising
C. Annealing
D. Spheroidising
Answer : A

10. Multiple threads are used to secure
A. Low efficiency
B. High efficiency
C. High load lifting capacity
D. High mechanical advantage
Answer : B

11. The draw of cotter should not be more than
A. 3 mm
B. 6 mm
C. 8 mm
D. 12 mm
Answer : A

12. 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

13. 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

14. Coaxing is the procedure of increasing
A. Metal strength by cycling
B. Metal hardness by surface treatment
C. Metal resistance to corrosion by coating
D. Fatigue limit by overstressing the metal by successively increasing loadings
Answer : D

15. According to I.B.R., the efficiency of a triple riveted butt joint with double straps of unequal width (5 rivets per pitch length) should be
A. 45 to 60 %
B. 63 to 70 %
C. 70 to 83 %
D. 80 to 90 %
Answer : D

16. When the screw in a mechanical screw jack rotates, the load kept on the top of it moves
A. Axially upwards
B. Axially downwards
C. Axially upwards or downwards
D. None of these
Answer : C

17. The helix angle for single helical gears ranges from
A. 10° to 15°
B. 15° to 20°
C. 20° to 35°
D. 35° to 50°
Answer : C

18. According to maximum shear stress theory, the maximum shear stress in the shaft is
A. (1/2) × ?(?² + 4?²)
B. ?(?² + 4?²)
C. (1/2) × [? + ?(?² + 4?²)]
D. ? + ?(?² + 4?²)
Answer : A

19. Which of the following statement is wrong for a connecting rod?
A. The connecting rod will be equally strong in buckling about X-axis and Y-axis, if I_xx = 4 I_yy
B. If I_xx > 4 I_yy, the buckling will occur about Y-axis
C. If I_xx < 4 I_yy, the buckling will occur about X-axis
D. The most suitable section for the connecting rod is T-section
Answer : D

20. The endurance limit in shear of carbon steel can be obtained by multiplying the endurance limit in flexure by a factor of
A. 0.45
B. 0.55
C. 0.65
D. 0.75
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. In cross or regular lay ropes
A. Direction of twist of wires in strands is opposite to the direction of twist of strands
B. Direction of twist of wires and strands are same
C. Wires in two adjacent strands are twisted in opposite direction
D. Wires are not twisted
Answer : A

23. A double strap butt joint (with equal straps) is
A. Always in single shear
B. Always in double shear
C. Either in single shear or double shear
D. Any one of these
Answer : B

24. The value of Lewis form factor used in design of gears is
A. Dependent on number of teeth of a gear
B. Dependent on system of teeth
C. Independent of size of teeth
D. All of these
Answer : D

25. An Involute pinion and gear are in mesh. If both have the same size of addendum, then there will be interference between the
A. Tip of the pinion and flank of gear
B. Tip of the gear and flank of pinion
C. Flanks of both gear and pinion
D. Tip of both gear and pinion
Answer : B

26. 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

27. A stud
A. Has a head on one end and a nut fitted to the other
B. Has head at one end and other end fits into a tapped hole in the other part to be joined
C. Has both the ends threaded
D. Has pointed threads
Answer : C

28. Three different weights fall from a certain height under vacuum. They will take
A. Same time to reach earth
B. Times proportional to weight to reach earth
C. Times inversely proportional to weight to reach earth
D. None of the above
Answer : A

29. The permissible stress for carbon steel under static loading is generally taken as
A. 2000-3000 kg/m²
B. 3000-4000 kg/cm²
C. 4000-4500 kg/cm²
D. 7500-10,000 kg/cm²
Answer : C

30. The initial tension (in newtons) in a bolt used for making a fluid tight joint like steam engine cover joints, is calculated by the relation (where d = Nominal diameter of bolt in mm)
A. 1420 d
B. 1680 d
C. 2080 d
D. 2840 d
Answer : D

31. If a bearing is designated by the number 305, it means that the bearing is of
A. Medium series whose bore is 5 mm
B. Medium series whose bore is 25 mm
C. Light series whose bore is 25 mm
D. Light series whose bore is 5 mm
Answer : B

32. 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

33. When bevel gears connect two shafts whose axes intersect at an angle greater than a right angle and one of the bevel gears has a pitch angle of 90°, then they are known as
A. Angular bevel gears
B. Mitre gears
C. Internal bevel gears
D. Crown bevel gears
Answer : D

34. The fatigue stress concentration factor is defined as
A. The ratio of endurance limit with stress concentration to the endurance limit without stress concentration
B. The ratio of endurance limit without stress concentration to the endurance limit with stress concentration
C. The product of the endurance limits with and without stress concentration
D. All of the above
Answer : B

35. The value of stress concentration factor depends upon
A. Material and geometry of the part
B. Geometry of the part
C. Material of the part
D. None of these
Answer : A

36. The speed of the sprocket reduces as the chain pitch __________ for a given number of teeth.
A. Increases
B. Decreases
C. Remain same
D. None of these
Answer : A

37. The minimum number of teeth on the pinion which will mesh with any gear without interference for 20° full depth involute teeth will be
A. 12
B. 14
C. 18
D. 24
Answer : C

38. The angle of twist of shaft is
A. Directly proportional to (shaft diameter)²
B. Inversely proportional to (shaft diameter)²
C. Directly proportional to (shaft diameter)?
D. Inversely proportional to (shaft diameter)?
Answer : D

39. The expression 0.175 - 0.841/T is the Lewis form factor for
A. 14 ½° composite and full depth involute system
B. 20° full depth involute system
C. 20° stub system
D. None of the above
Answer : C

40. According to I.B.R., when the thickness of boiler shell (t) is greater than 8 mm, then the diameter of rivet hole (d) is obtained by
A. Equating tearing resistance of the plate to the shearing resistance of the rivets
B. Equating tearing resistance of the plate to the crushing resistance of the rivets
C. Equating shearing resistance to the crushing resistance of the rivets
D. None of the above
Answer : B

41. Stress concentration in static loading is more serious in
A. Ductile materials
B. Brittle materials
C. Equally serious in both cases
D. Depends on other factors
Answer : B

42. The shear stress at a point in a shaft subjected to a torque is
A. Directly proportional to the polar moment of inertia and to the distance of the point from the axis
B. Directly proportional to the applied torque and inversely proportional to the polar moment of inertia
C. Directly proportional to the applied torque and the polar moment of inertia
D. Inversely proportional to the applied torque and the polar moment of inertia
Answer : B

43. A bolt of uniform strength can be developed by
A. Keeping the core diameter of threads equal to the diameter of unthreaded portion of the bolt
B. Keeping the core diameter smaller than the diameter of the unthreaded portion
C. Keeping the nominal diameter of threads equal to the diameter of unthreaded portion of the bolt
D. None of the above
Answer : A

44. The included angle for the V-belt is usually
A. 10°-20°
B. 30°-40°
C. 40°-60°
D. 60°-80°
Answer : B

45. In the levers of first type, the mechanical advantage is __________ one.
A. Less than
B. Equal to
C. More than
D. None of these
Answer : C

46. The most important dimension in the design of a nut is
A. Pitch diameter
B. Inside diameter
C. Outside diameter
D. Height
Answer : D

47. When a beam of rectangular cross-section of width b and depth d, is subjected to a shear force F, the maximum shear stress induced will be
A. F/bh
B. 3F/2bh
C. 2F/bh
D. 4F/bh
Answer : B

48. When a nut is tightened by placing a washer below it, the bolt will be subjected to following type of loads
A. Compression
B. Tension
C. Shear
D. Combined loads
Answer : B

49. A sliding bearing which operates without any lubricant present, is called
A. Zero film bearing
B. Boundary lubricated bearing
C. Hydrodynamic lubricated bearing
D. Hydrostatic lubricated bearing
Answer : A

50. Cold working
A. Increases the fatigue strength
B. Decreases the fatigue strength
C. Has no influence on fatigue strength
D. Alone has no influence on fatigue strength
Answer : A