UPSC IES - Machine Design 1000+ MCQ [Solved] PDF Download

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

2. A flange coupling is used to connect two shafts
A. Which are perfectly aligned
B. Which are not in exact alignment
C. Have lateral misalignment
D. Whose axes intersect at a small angle
Answer : A

3. Resilience of a material is important, when it is subjected to
A. Combined loading
B. Fatigue
C. Thermal stresses
D. Shock loading
Answer : D

4. 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

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

6. 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

7. 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

8. The toughness of a material _________ when it is heated
A. Does not change
B. Increases
C. Decreases
D. None of the Above
Answer : C

9. 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

10. The bending stress in a curved beam is
A. Zero at the centroidal axis
B. Zero at the point other than centroidal axis
C. Maximum at the neutral axis
D. None of these
Answer : B

11. The expansion joint is mostly used for pipes which carry steam at __________ pressures.
A. Low
B. High
C. Medium
D. None of these
Answer : B

12. A steel containing __________ 0.8% carbon is known as hypoeutectoid steel.
A. Equal to
B. Less than
C. Greater than
D. None of these
Answer : B

13. When compared to the rod of the same diameter and material, a wire rope
A. Is less flexible
B. Has a much smaller load carrying capacity
C. Does not provide much warning before failure
D. Provides much greater time for remedial action before failure
Answer : B

14. A leaf spring in automobiles is used
A. To apply forces
B. To measure forces
C. To absorb shocks
D. To store strain energy
Answer : C

15. Which of the following spring is used in mechanical wrist watch?
A. Helical compression spring
B. Spiral spring
C. Torsion spring
D. Belleville spring
Answer : C

16. The product of the diametral pitch and circular pitch is equal to
A. 1
B. 1/?
C. ?
D. ? × number of teeth
Answer : C

17. The circumferential and longitudinal strains in a cylindrical boiler under internal steam pressure are ?c and ?l respectively. The change in volume of the boiler cylinder per unit volume will be
A. ?_c + 2?_l
B. 2?_c + ?_l
C. ?_c + ?_l²
D. ?_c² + ?_l
Answer : B

18. 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

19. 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

20. 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

21. In standard taper roller bearings, the angle of taper of outer raceway is
A. 5°
B. 8°
C. 15°
D. 25°
Answer : D

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

23. 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

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

25. According to I.B.R., when the thickness of the boiler shell (t) is less than 8 mm, then the diameter of the 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 : C

26. 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

27. 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

28. Which of the following statement is wrong?
A. The V-belt may be operated in either direction with tight side of the belt at the top or bottom
B. The V-belt drive is used with large centre distance
C. The power transmitted by V-belts is less than flat belts for the same coefficient of friction, arc of contact and allowable tension in the belts
D. The ratio of driving tensions in V-belt drive is more than flat belt drives
Answer : B

29. Fibrous fracture occurs in
A. Ductile material
B. Brittle material
C. Elastic material
D. Hard material
Answer : A

30. 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

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

32. 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

33. 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

34. In a horizontal flat belt drive, it is customary to use
A. Bottom side of belt as slack side
B. Top side of belt as slack side
C. Idler pulley
D. None of the above
Answer : B

35. In a steam engine, the piston rod is usually connected to the crosshead by means of a
A. Knuckle joint
B. Cotter joint
C. Oldham coupling
D. Universal joint
Answer : B

36. The stiffness of a closely coiled helical spring subjected to an axial load W is equal to (where G = Modulus of rigidity, and n = Number of active coils)
A. Gd?/ 8D³n
B. Gd³/ 8D³n
C. Gd?/ 4D³n
D. Gd?/ 8D²n
Answer : A

37. 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

38. A bolt is designed on the basis of __________ with a large factor of safety.
A. Direct tensile stress
B. Direct compressive stress
C. Direct bending stress
D. Direct shear stress
Answer : A

39. The valve rod in a steam engine is connected to an eccentric rod by
A. Cotter joint
B. Bolted joint
C. Knuckle joint
D. Universal coupling
Answer : C

40. 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

41. 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

42. The bending moment M and a torque T is applied on a solid circular shaft. If the maximum bending stress equals to maximum shear stress developed, then M is equal to
A. T/2
B. T
C. 2T
D. 4T
Answer : A

43. When two non-parallel or intersecting but coplanar shafts are connected by gears, the arrangement is known as,
A. Bevel gearing
B. Helical gearing
C. Worm gearing
D. None of these
Answer : A

44. 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

45. The ball bearings are, usually, made from
A. Low carbon steel
B. High carbon steel
C. Medium carbon steel
D. High speed steel
Answer : C

46. Ball bearing type screws are found in following application
A. Screw jack
B. Aeroplane engines
C. Crane
D. Steering mechanism
Answer : D

47. The design of pin of a rocker arm of an I.C. engine is based on
A. Bearing failure
B. Shearing failure
C. Bending failure
D. All of these
Answer : D

48. Which of the following is not correct procedure to increase the fatigue limit?
A. Cold working
B. Shot peening
C. Surface decarburisation
D. Under stressing
Answer : C

49. 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

50. For a shoe brake, the equivalent coefficient of friction is equal to (where ? = Actual coefficient of friction, and ? = Semi-block angle)
A. 2? sin?/(? + sin?)
B. ? sin?/(2? + sin 2?)
C. 4? sin?/(? + sin?)
D. 4? sin?/(2? + sin 2?)
Answer : D