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

1. Two shafts of the same length and material are joined in series. If the ratio of their diameters is 2, then the ratio of their angles of twist will be
A. 2
B. 4
C. 8
D. 16
Answer : D

2. 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

3. 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

4. When a material is subjected to fatigue loading, the ratio of the endurance limit to the ultimate tensile strength is
A. 0.20
B. 0.35
C. 0.50
D. 0.65
Answer : C

5. Which process will increase the fatigue duration of parts?
A. Finishing and polishing
B. Shotpeening
C. De-carburisation
D. Electroplating
Answer : B

6. 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

7. 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

8. A transmission shaft includes
A. Over head shaft
B. Counter shaft
C. Line shaft
D. All of these
Answer : D

9. Which of the following formula is used in designing a connecting rod?
A. Euler's formula
B. Rankine's formula
C. Johnson's straight line formula
D. Johnson's parabolic formula
Answer : B

10. A steel containing 0.8% carbon is known as
A. Eutectoid steel
B. Hypereutectoid steel
C. Hypo-eutectoid steel
D. None of these
Answer : A

11. When the length of the journal is equal to the diameter of the journal, then the bearing is said to be a
A. Short bearing
B. Long bearing
C. Medium bearing
D. Square bearing
Answer : D

12. In a flange coupling, the bolts are subjected to
A. Tensile stress
B. Compressive stress
C. Shear stress
D. None of these
Answer : C

13. 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 of a tooth to the bottom of a tooth
D. Addendum circle to the clearance circle
Answer : B

14. Two rigid plates are clamped by means of bolt and nut with an initial force F. After tightening, a separating force P (P < F) is applied to the lower plate, which in turn acts on the nut. The tension in the both after this is
A. F + P
B. F P
C. P
D. F
Answer : A

15. Which is positive drive?
A. Flat belt drive
B. V-belt drive
C. Crossed belt drive
D. Timing belt
Answer : D

16. 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

17. In designing a sleeve coupling, length of the sleeve is taken as (where d = Diameter of the shaft)
A. d + 17 mm
B. 2d + 13 mm
C. 2d + 20 mm
D. 3.5d
Answer : D

18. An elastic bar is fixed at the upper end and loaded at the lower end by a falling weight. The shock load produced can be reduced by
A. Increasing the length of bar
B. Decreasing the cross-sectional area of the bar
C. Decreasing the modulus of elasticity of the bar
D. All of the above
Answer : D

19. Tapered roller bearings can take
A. Axial load only
B. Both radial and axial loads and the ratio of these being greater than unity
C. Radial load only
D. Both radial and axial loads and the ratio of these being less than unity
Answer : B

20. 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

21. A plate with an elliptical hole in the centre, with semi-major axis (A) perpendicular to the direction of loading and semi-minor axis (b) along the direction of loading, is subjected to a pull P. The maximum stress induced at the edge of the hole is equal to (where ? = Stress for a plate with no hole i.e. nominal stress)
A. ? [1 + (b/2a)]
B. ? [1 + (2a/b)]
C. ? [1 + (b/3a)]
D. ? [1 + (3a/b)]
Answer : B

22. According to Unwin's formula, the relation between the diameter of rivet hole (d) and the thickness of plate (t) is given by (where d and t are in mm)
A. d = t
B. d = 1.6 t
C. d = 2t
D. d = 6t
Answer : D

23. 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

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

25. The stress in the threaded part of the bolt will be __________ as compared to the shank.
A. Same
B. Higher
C. Lower
D. None of these
Answer : B

26. 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

27. Eye bolts are used for
A. Foundation purposes
B. Absorbing shock and vibrations
C. Transmission of power
D. Lifting and transportation of machines and cubicles
Answer : D

28. 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

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

30. The coefficient of friction between the belt and pulley depends upon the
A. Material of belt and pulley
B. Slip of belt
C. Speed of belt
D. All of these
Answer : D

31. 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

32. The acme threads are usually found on
A. Spindles of bench vices
B. Railway carriage couplings
C. Feed mechanism of machine tools
D. Screw cutting lathes
Answer : D

33. 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

34. 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

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

36. When the belt speed increases
A. Power transmitted increases
B. Power transmitted decreases
C. Power transmitted increases to a maximum value and then decreases
D. Power transmitted remains the same
Answer : C

37. When an open coiled helical compression spring is subjected to an axial load (W), the compression produced in the spring will be (where n = No. of active turns of the spring, and G = Modulus of rigidity for the spring material)
A. 2WD³n/Gd?
B. 4WD³n/Gd?
C. 8WD³n/Gd?
D. 16WD³n/Gd?
Answer : C

38. The shear plane in case of bolts should
A. Be across threaded portion of shank
B. Be parallel to axis of bolt
C. Be normal to threaded portion of shank
D. Never be across the threaded portion
Answer : D

39. 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

40. 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

41. The load cup of a screw jack is made separate from the head of the spindle to
A. Prevent the rotation of load being lifted
B. Enhance the load carrying capacity of the jack
C. Reduce the effort needed for lifting the working load
D. Reduce the value of frictional torque
Answer : A

42. 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 applied
D. Initial tension or external load, whichever is greater
Answer : C

43. Which of the following cotter joint will be used to connect strap end of a connecting rod?
A. Spigot and socket cotter joint
B. Sleeve and cotter joint
C. Gib and coter joint
D. Any one of these
Answer : C

44. The objective of idler pulley in belt drive is to
A. Decrease the tendency of belt to slip
B. Increase the power transmission capacity
C. Increase the wrap angle and belt tension
D. All the above objectives
Answer : D

45. 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

46. The strap end of a connecting rod of steam engine is joined by
A. Gib of cotter joint
B. Sleeve and cotter joint
C. Spigot socket cotter joint
D. Knuckle joint
Answer : A

47. 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

48. The spring mostly used in gramophones is
A. Helical spring
B. Conical spring
C. Flat spiral spring
D. Volute spring
Answer : C

49. In designing a connecting rod, it is considered like __________ for buckling about X-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 : A

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