1000+ Machine Design Multiple Choice Question Answer [Solved]

1. The number of slots in a 25 mm castle nut is
A. 8
B. 6
C. 4
D. 2
Answer : A

2. The centre to centre distance between two consecutive rivets in a row, is called
A. Margin
B. Pitch
C. Back pitch
D. Diagonal pitch
Answer : B

3. In case of pressure vessels having open ends, the fluid pressure induces
A. Longitudinal stress
B. Circumferential stress
C. Shear stress
D. None of these
Answer : B

4. When spring index increases, the value of Wahl's stress factor
A. Increases linearly
B. Decreases linearly
C. Remains same
D. Increases exponentially
Answer : D

5. A double fillet welded joint with parallel fillet weld of length l and leg s is subjected to a tensile force P. Assuming uniform stress distribution, the shear stress in the weld is given by
A. ?2P/s.l
B. P/2.s.l
C. P/?2.s.l
D. 2P/s.l
Answer : C

6. In levers, leverage is the ratio of
A. Load lifted to the effort applied
B. Mechanical advantage to the velocity ratio
C. Load arm to the effort arm
D. Effort arm to the load arm
Answer : D

7. Belt slip may occur due to
A. Heavy load
B. Loose belt
C. Driving pulley too small
D. All of the above
Answer : D

8. When carbon in the cast iron is principally in the form of graphite, the cast iron will be of
A. Brown colour
B. Yellow colour
C. White colour
D. Grey colour
Answer : D

9. A taper key which fits half in the key way of the hub and half in the key way of shaft, is known as
A. Angular bevel gears
B. Mitre gears
C. Crown Bevel gears
D. Internal bevel gears
Answer : B

10. The shock absorbing capacity of a bolt may be increased by
A. Increasing its shank diameter
B. Decreasing its shank diameter
C. Tightening the bolt properly
D. Making the shank diameter equal to core diameter of thread
Answer : B

11. In Vickers hardness testing, the pyramid indentor apex is
A. 40°
B. 122°
C. 136°
D. 152°
Answer : C

12. The strength of a riveted joint is equal to
A. Tearing strength of plate (P_t)
B. Shearing strength of rivet (P_s)
C. Crushing strength of rivet (P_c)
D. Least value of P_t P_s and P_c
Answer : D

13. 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

14. Stress concentration is caused due to
A. Variations in load acting on a member
B. Variations in properties of materials in a member
C. Abrupt change of cross-section
D. All of these
Answer : C

15. The gears are termed as medium velocity gears, if their peripheral velocity is
A. 1-3 m/s
B. 3-15 m/s
C. 15-30 m/s
D. 30-50 m/s
Answer : B

16. 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

17. 18/8 steel contains
A. 18% nickel and 8% chromium
B. 18% chromium and 8% nickel
C. 18% nickel and 8% vanadium
D. 18% vanadium and 8% nickel
Answer : B

18. In V-belt drive, belt touches
A. At bottom
B. At sides only
C. Both at bottom and sides
D. Could touch anywhere
Answer : B

19. Which of the following statement is correct?
A. The stress concentration in static loading is more serious in ductile materials and less serious in brittle materials
B. The stress concentration in static loading is more serious in brittle materials and less serious in ductile materials
C. The toughness of a material increases when it is heated
D. The shear stress in a beam varies from zero at the neutral surface and maximum at the outer fibres
Answer : B

20. Shear stress theory is applicable for
A. Ductile materials
B. Brittle materials
C. Elastic materials
D. All of the above
Answer : A

21. According to Indian standards, total numbers of tolerance grades are
A. 8
B. 12
C. 18
D. 20
Answer : C

22. When the fulcrum is in between the load and effort, the lever is said to be of
A. First type
B. Second type
C. Third type
D. Any one of these
Answer : A

24. Fabric belts are used in industrial applications because
A. They are cheap
B. They can work at high temperature
C. They are unaffected by moisture and humidity
D. None of the above
Answer : A

25. Transverse fillet welded joints are designed for
A. Tensile strength
B. Compressive strength
C. Shear strength
D. Bending strength
Answer : A

26. For applications involving high stresses in one direction only the following type of thread would be best suited
A. ISO metric thread
B. Acme thread
C. Square thread
D. Buttress thread
Answer : D

27. The relation between the pitch of the chain (p) and pitch circle diameter of the sprocket (D) is given by (where T = Number of teeth on the sprocket)
A. p = D sin (90°/T)
B. p = D sin (120°/T)
C. p = D sin (180°/T)
D. p = D sin (360°/T)
Answer : C

28. Two shafts A and B under pure torsion are of identical length and identical weight and are made of the same material. The shaft A is solid and the shaft B is hollow. We can say that
A. Shaft B is better than shaft A
B. Shaft A is better than shaft B
C. Both the shafts are equally good
D. None of these
Answer : A

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

30. In a journal bearing, the load on the bearing is __________ to the axis of the journal.
A. Parallel
B. Perpendicular
C. Both A and B
D. None of these
Answer : B

31. Which of the following property is essential for spring materials?
A. Stiffness
B. Ductility
C. Resilience
D. Plasticity
Answer : C

32. 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

33. Auto frettage is the method of
A. Joining thick cylinders
B. Calculating stresses in thick cylinders
C. Pre-stressing thick cylinders
D. Increasing the life of thick cylinders
Answer : C

34. In designing a key, it is assumed that the distribution of forces along the length of key
A. Varies linearly
B. Is uniform throughout
C. Varies exponentially, being more at the torque-input end
D. Varies exponentially, being less at the torque-input end
Answer : B

35. A hot short metal is
A. Brittle when cold
B. Brittle when hot
C. Brittle under all conditions
D. Ductile at high temperature
Answer : B

36. The ultimate strength of steel in tension in comparison to shear is in the ratio of
A. 1 : 1
B. 2 : 1
C. 3 : 2
D. 2 : 3
Answer : C

37. The backlash for spur gears depends upon
A. Module
B. Tooth profile
C. Both module and pitch line velocity
D. Pitch line velocity
Answer : C

38. The allowable static stress for steel gears is approximately __________ of the ultimate tensile stress.
A. One-fourth
B. One-third
C. One-half
D. Double
Answer : B

39. The yield point in static loading is __________ as compared to fatigue loading.
A. Higher
B. Lower
C. Same
D. None of these
Answer : A

40. The taper on a rectangular sunk key is
A. 1 in 16
B. 1 in 32
C. 1 in 48
D. 1 in 100
Answer : D

41. The largest diameter of an external or internal screw thread is known as
A. Minor diameter
B. Major diameter
C. Pitch diameter
D. None of these
Answer : B

42. 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

43. A connecting rod is designed as a
A. Long column
B. Short column
C. Strut
D. All of these
Answer : C

44. According to Indian standards, a bolt thread of 6 mm size of coarse pitch and with allowance on the threads and normal tolerance grade is designated as
A. M6
B. M8
C. M6 - 8d
D. M8 - 6d
Answer : C

45. When the connected members are very yielding (soft gasket) as compared to the bolt, 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 applid
D. Initial tension or external load, whichever is greater
Answer : C

46. In cylindrical cams, the follower moves
A. In a direction perpendicular to the cam axis
B. In a direction parallel to the cam axis
C. In any direction irrespective of cam axis
D. Along the cam axis
Answer : B

47. A bolt
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. Is provided with pointed threads
Answer : A

48. In a belt drive, if the pulley diameter is doubled keeping the tension and belt width constant, then it will be necessary to
A. Increase the key length
B. Increase the key depth
C. Increase the key width
D. Decrease the key length
Answer : A

49. The ratio of driving tensions for flat belts, neglecting centrifugal tension, is (where T?, and T? = Tensions on the tight and slack sides of belt respectively, ? = Coefficient of friction, between the belt and pulley, and ? = Angle of contact)
A. T?/T? = ??
B. log (T?/T?) = ??
C. T?/T? =e??
D. T?/T? = log ??
Answer : C

50. The helix angle for double helical gears may be made up to
A. 45°
B. 60°
C. 75°
D. 90°
Answer : A