1000+ Machine Design Multiple Choice Question Answer [Solved]

1. Applications in which stresses are encountered in one direction only uses following type of threads
A. Metric
B. Buttress
C. Acme
D. Square
Answer : B

2. The sleeve or muff coupling is designed as a
A. Dun cylinder
B. Hollow shaft
C. Solid shaft
D. Thick cylinder
Answer : B

3. The endurance or fatigue limit is defined as the maximum value of the stress which a polished standard specimen can withstand without failure, for infinite number of cycles, when subjected to
A. Static load
B. Dynamic load
C. Static as well as dynamic load
D. Completely reversed load
Answer : D

4. The creep in the belt is due to
A. Effect of temperature on belt
B. Material of belt
C. Unequal extensions in the belt due to tight and slack side tensions
D. Stresses beyond elastic limit of belt material
Answer : C

5. When two springs are in series (having stiffness K), the equivalent stiffness will be
A. K
B. K/2
C. 2K
D. K/4
Answer : B

6. 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

7. If T is the actual number of teeth on a helical gear and ? is the helix angle for the teeth, then formative number of teeth is written as
A. T sec³?
B. T sec²?
C. T/sec³?
D. T cosec?
Answer : A

8. 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

9. The elasticity is the property of a material which enables it to
A. Regains its original shape after deformation when the external forces are removed
B. Draw into wires by the application of a tensile force
C. Resists fracture due to high impact loads
D. Retain deformation produced under load permanently
Answer : A

10. If threads on a bolt are left hand, threads on nut will be
A. Right hand with same pitch
B. Left hand with same pitch
C. Could be left or right hand
D. Right hand with fine pitch
Answer : B

11. 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

12. 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

13. Which of the following key is preferred for the condition when a large amount of impact type torque is to be transmitted in both direction of rotation?
A. Woodruff key
B. Feather key
C. Gib-head key
D. Tangent key
Answer : D

14. The property of a material which enables it to be drawn into wires with the application of a tensile force, is called
A. Plasticity
B. Elasticity
C. Ductility
D. Malleability
Answer : C

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

16. When two helical springs of equal lengths are arranged to form a cluster spring, then
A. Shear stress in each spring will be equal
B. Load taken by each spring will be half the total load
C. Only A is correct
D. Both A and B is correct
Answer : D

17. The power transmitted by belt drive depends upon
A. Belt velocity
B. Initial belt tension
C. Arc of contact
D. All of the above
Answer : D

18. In composite or reverse laid 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 : C

19. 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

20. If an application calls for stresses on screw threads in one direction only, then the following type of thread would be best suited
A. Square
B. Acme
C. Buttress
D. BSW
Answer : C

21. The dedendum is the radial distance from the
A. Pitch circle to the top of a tooth
B. Pitch circle to the bottom of a tooth
C. Top f a tooth to the bottom of a tooth
D. Addendum circle to the clearance circle
Answer : B

22. 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

23. Jam nut is a locking device in which
A. One smaller 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. A hard fibre or nylon cotter is recessed in the nut and becomes threaded as the nut is screwed 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 spitted and bent in reverse direction at other end
Answer : A

24. A thin spherical shell of internal diameter d is subjected to an internal pressure p. If V is the storage capacity of shell, then its diameter will be
A. (6V/ ?)^1/2
B. (6V/ ?)^1/3
C. (6V/ ?)²
D. (6V/ ?)³
Answer : B

25. The fatigue life of a part can be improved by
A. Electroplating
B. Polishing
C. Coating
D. Shot peening
Answer : D

26. The temperature required for full annealing in hypereutectoid steel is
A. 50°C above upper critical temperature
B. 50°C below upper critical temperature
C. 50°C above lower critical temperature
D. 50°C below lower critical temperature
Answer : A

27. 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

28. Machine screws are
A. Similar to small size tap bolts except that a greater variety of shapes of heads are available
B. Slotted for a screw driver and generally used with a nut
C. Used to prevent relative motion between two parts
D. Similar to stud
Answer : B

29. The process extensively used for making bolts and nuts is
A. Hot piercing
B. Extrusion
C. Cold peening
D. Cold heading
Answer : D

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

31. Which of the following is a permanent fastening?
A. Bolts
B. Keys
C. Cotters
D. Rivets
Answer : D

32. A locking device extensively used in marine type connecting rod ends is a
A. Jam nut
B. Castle nut
C. Sawn nut
D. Ring nut
Answer : D

33. A type of brake commonly used in motor cars is a
A. Shoe brake
B. Band and block brake
C. Band brake
D. Internal expanding brake
Answer : D

34. In a multiple V-belt drive, when a single belt is damaged, it is preferable to change the complete set in order to
A. Reduce vibration
B. Reduce slip
C. Ensure uniform loading
D. Ensure proper alignment
Answer : C

35. The pipe joint mostly used for pipes carrying water at low pressures is
A. Socket joint
B. Nipple joint
C. Union joint
D. Spigot and socket joint
Answer : A

36. 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

37. 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

38. Two helical springs of the same material and of equal circular crosssection, length and number of turns, but having radii 80 mm and 40 mm, kept concentrically (smaller radius spring within the larger radius spring), are compressed between two parallel planes with a load W. The inner spring will carry a load equal to
A. W/2
B. 2W/3
C. W/9
D. 8W/9
Answer : B

39. The objective of crowning of the flat pulleys of belt drive is to
A. Prevent the belt from running off the pulley
B. Increase the power transmission capacity
C. Increase the belt velocity
D. Prevent the belt joint from damaging the belt surface
Answer : A

40. If shearing stress in nut is half the tensile stress in a bolt, then nut length should be equal to
A. Diameter of bolt
B. 0.75 × diameter of bolt
C. 1.25 × diameter of bolt
D. 1.5 × diameter of bolt
Answer : A

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

42. Surface endurance limit of gear material is dependent upon its
A. Elastic strength
B. Yield strength
C. Brinell hardness number
D. Toughness
Answer : C

43. The centre distance between two meshing involute gears is equal to
A. (Sum of base circle radii)/cos?
B. (Difference of base circle radii)/cos?
C. (Sum of pitch circle radii)/cos?
D. (Difference of pitch circle radii)/cos?
Answer : A

44. 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

45. When a helical compression spring is cut into halves, the stiffness of the resulting spring will be
A. Same
B. Double
C. One-half
D. One-fourth
Answer : B

46. The power transmitted by the belt drive can be increased by
A. Increasing the initial tension in the belt
B. Dressing the belt to increase the coefficient of friction
C. Increasing wrap angle by using idler pulley
D. All of the above methods
Answer : D

47. Buttress threads are usually found on
A. Screw cutting lathes
B. Feed mechanisms
C. Spindles of bench vices
D. Railway carriage couplings
Answer : D

48. The distribution of the forces along the length of key fitted in a shaft
A. Varies linearly
B. Is uniform throughout
C. Varies exponentially, being more near the torque-input end
D. Varies exponentially, being less near the torque-input end
Answer : C

49. Which one of the following loading is considered for the design of axles?
A. Bending moment only
B. Twisting moment only
C. Combined bending moment and twisting moments
D. Combined action of bending moment, twisting moment and axial thrust
Answer : A

50. Silver based solder is used for
A. Flaring
B. Brazing
C. Soft soldering
D. Fusion welding
Answer : B