Machine Design 1000+ MCQ with answer for SSC CPO

1. Taper on the cotter and slot is provided
A. On both the sides
B. On one side only
C. On none of the sides
D. May be provided anywhere
Answer : B

2. Taper usually provided on cotter is
A. 1 in 5
B. 1 in 10
C. 1 in 24
D. 1 in 40
Answer : C

3. The connecting rod bolts are tightened up so that tightening stress
A. Is just sufficient to hold parts together
B. Approaches yield point
C. Is 50% of yield point
D. Is about yield point divided by safety factor
Answer : B

4. A column of length l is fixed at both ends. The equivalent length of the column is
A. l/2
B. l/?2
C. l
D. 2 l
Answer : A

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

6. In worm gears, the angle between the tangent to the pitch helix and an element of the cylinder, is known as
A. Helix angle
B. Pressure angle
C. Pitch lead angle
D. None of these
Answer : A

7. If d is the normal diameter of a bolt in mm, then the initial tension in kg in a bolt used for making a fluid tight joint as for steam engine cover joint is calculated by the relation
A. 124 d
B. 138 d
C. 151 d
D. 168 d
Answer : D

8. A connecting rod subjected to an axial load may buckle with
A. X-axis as neutral axis
B. Y-axis as neutral axis
C. X-axis or Y-axis as neutral axis
D. Z-axis
Answer : C

9. The process which improves the machinability of steels, but lowers the hardness and tensile strength is
A. Normalising
B. Full annealing
C. Process annealing
D. Spheroidising
Answer : D

10. The building up of worn and undersized parts, subjected to repeated loads by electroplating is
A. Best method
B. Extremely hazardous
C. Has no effect as regards fatigue strength
D. Cheapest method
Answer : A

11. Allen bolts are
A. Self locking bolts
B. Designed for shock load
C. Used in aircraft application
D. Provided with hexagonal depression in head
Answer : D

12. The taper on key is given on
A. Bottom side only
B. Top side only
C. On both sides
D. Any side
Answer : B

13. 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

14. Soderberg relation is based on __________ of the material whereas all other failure relation for dynamic loading are based on ultimate strength of the material.
A. Elastic strength
B. Yield strength
C. Shear strength
D. None of these
Answer : B

15. 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

16. 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

17. Lewis equation in gears is used to find the
A. Tensile stress in bending
B. Shear stress
C. Compressive stress in bending
D. Fatigue stress
Answer : C

18. In order to permit the thermal expansion/contraction of tubing, it should be
A. Crimped
B. Honed
C. Flared
D. Bent
Answer : D

19. The washer is generally specified by its
A. Outer diameter
B. Hole diameter
C. Thickness
D. Mean diameter
Answer : B

20. The constant factor in case of R10 series of preferred numbers is
A. 1.06
B. 1.12
C. 1.26
D. 1.58
Answer : C

21. 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

22. When a closely coiled helical spring is subjected to a couple about its axis, the stress induced in the wire material of the spring is
A. Bending stress only
B. A combination of torsional shear stress and bending
C. Direct shear stress only
D. A combination of bending stress and direct shear stress
Answer : A

23. 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

24. A key way lowers
A. The strength of the shaft
B. The rigidity of the shaft
C. Both the strength and rigidity of the shaft
D. The ductility of the shaft
Answer : C

25. The material commonly used for crane hooks is
A. Cast iron
B. Wrought iron
C. Mild steel
D. Aluminium
Answer : B

26. 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

27. In worm gears, the pressure angle is ________ the angle between two inclined faces in axial plane.
A. Half
B. Twice
C. Thrice
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. In a marine flange coupling, the pitch circle diameter of bolts is taken as
A. 1.2 d
B. 1.6 d
C. 2d
D. 2.5 d
Answer : B

30. The shock resistance of steel is increased by adding
A. Nickel
B. Chromium
C. Nickel and chromium
D. Cobalt and molybdenum
Answer : C

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

32. 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

33. 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

34. For standard coarse threads of nut, the threads will be as strong in failure by shear as the bolt in tension, if the height of nut (h) is approximately
A. 0.4 times
B. 0.6 times
C. 0.7 times
D. 0.8 times
Answer : A

35. In designing thick cylinders, the equation used is
A. Lame's equation
B. Birnie's equation
C. Clavarinos' equation
D. All of these
Answer : D

36. Tensile strength of a mild steel specimen can be roughly predicted from following hardness test
A. Brinell
B. Rockwell
C. Vickers
D. None of the above
Answer : A

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

38. For longitudinal joint in boilers, the type of joint used is
A. Butt joint with single cover plate
B. Butt joint with double cover plate
C. Lap joint with one ring overlapping the other
D. Any one of the above
Answer : B

39. 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

40. 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

41. The velocity of sliding ________ the distance of the point of contact from the pitch point.
A. Is directly proportional to
B. Is inversely proportional to
C. Is equal to cos ? multiplied by
D. Does not depend upon
Answer : A

42. 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

43. The objective of caulking in a riveted joint is to make the joint
A. Free from corrosion
B. Stronger in tension
C. Free from stress
D. Leak-proof
Answer : D

44. 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

45. 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

46. Lewis form factor for 14 ½° composite and full depth involute system is (where T = Number of teeth)
A. 0.124 - (0.684/T)
B. 0.154 - (0.912/T)
C. 0.175 - (0.841/T)
D. None of these
Answer : A

47. A fast and loose pulley drive is used when
A. Shafts are arranged parallel and rotate in the opposite directions
B. Shafts are arranged parallel and rotate in the same directions
C. Shafts are arranged at right angles and rotate in one definite direction
D. Driven shaft is to be started or stopped whenever desired without interfering with the driving shaft
Answer : D

48. 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

49. The contact ratio is the ratio of
A. Length of arc of recess to the circular pitch
B. Length of path of contact to the circular pitch
C. Length of arc of contact to the circular pitch
D. Length of arc of approach to the circular pitch
Answer : C

50. 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