26. The notch angle of the Izod impact test specimen is
(a) 10°
(b) 20°
(c) 30°
(d) 45°
(e) 60°.
Ans: d
27. In Vicker’s hardness testing, the pyramid indentor apex is
(a) 40°
(b) 122°
(c) 136°
(d) 152°
(e) 161°
Ans: c
28. Which is correct statement ?
Stress concentration in cyclic loading is
(a) very serious in brittle materials and less serious in ductile materials
(b) very serious in ductile materials and less serious in brittle materials
(c) equally serious in both types of materials
(d) seriousness would depend on other factors
(e) none of the above.
Ans: c
29. In testing a material for endurance strength, it is subjected to
(a) static load
(b) dynamic load
(c) impact load
(d) static as well as dynamic load
(e) completely reversed load.
Ans: e
30. If a material fails below its yield point, failure would be due to
(a) straining
(b) fatigue
(c) creep
(d) sudden loading
(e) impact loading
Ans: b
31. The fatigue limit of a material
(a) is greatly decreased by poor surface conditions
(b) remains same irrespective of surface conditions
(c) depends mainly on core composition
(d) is dependent upon yield strength of material
(e) none of the above.
Ans: a
32. Cold working
(a) increases the fatigue strength
(b) decreases the fatigue strength
(c) has no influence on fatigue strength
(d) alone has no influence on fatigue strength
(e) none of the above.
Ans: a
33. Yield point in fatigue loading as compared to static loading is
(a) same
(b) higher
(c) lower
(d) depends on other factors
(e) none of the above.
Ans: c
34. Residual stress in materials
(a) acts when external load is applied
(b) becomes zero when external load is removed
(c) is independent of external loads
(d) is always harmful
(e) is always beneficial.
Ans: c
35. The building up of worn and uridersized 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
(e) all of the above
Ans: a
36. In nitrided parts, the origins of the fatigue cracks will occur at
(a) surface
(b) just below the surface
(c) within the core
(d) could occur anywhere
(e) none of the above
Ans: e
37. Which process will increase the fatigue duration of parts ?
(a) finishing and polishing
(b) shot-peening
(c) decarburisation
(d) electroplating
(e) all of the above
Ans: b
38. Which is correct statement ?
(a) a member made of steel will generally be more rigid than a member of equal load-carrying ability made of cast iron
(b) a member made of cast iron will generally be. more rigid than a member of equal load carrying ability made of steel
(c) both will be equally rigid
(d) which one is rigid will depend on several other factors
(e) none of the above.
Ans: b
39. Resistance to fatigue of a material is measured by
(a) Young’s modulus
(b) coefficient of elasticity
(c) elastic limit
(d) ultimate tensile strength
(e) endurance limit.
Ans: e
40. In most machine members, the damping capacity of the material should be
(a) low
(b) zero
(c) high
(d) could be anything
(e) none of the above
Ans: c
41. The ratio of endurance limit in shear to the endurance limit in flexure is
(a) 0.33
(b) 0.4
(c) 0.5
(d) 0.55
(e) 0.6
Ans: d
42. For steel, the ultimate strength in shear as compared to ultimate strength in tension is
(a) same
(b) 1/2
(c) 1/3
(d) 1/4
(e) 2/3
Ans: e
43. The endurance limit in shear of carbon steel can be obtained by multiplying the endurance limit in flexure by a factor of
(a) 0.25
(b) 0.45
(r) 0.55
(d) 0.65
(e)0.75
Ans: e
44. At low temperatures (say 75°C) the notched-bar impact value of steel
(a) increases markedly
(b) decreases markedly
(c) remains same
(d) depends on heat treatment carried out
(e) none of the above
Ans: b
45. 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
(e) requires no nut
Ans: a
46. The crest diameter of a screw thread is same as
(a) major diameter
(b) minor diameter
(c) pitch diameter
(d) core diameter
(e) none of the above
Ans: a
47. If d is the diameter of bolt hole then for a flanged pipe joint to be leak proof, the circumferential pitch of the bolts should be
(a) 10VZ
(b) 10VZtol5Vd
(c) 15Vdto20VZ
(d) 20Vdto30Vd
(e) 30V5″to40Vd
Ans: d
48. Maximum principal stress theory is applicable for
(a) ductile materials
(b) brittle materials
(c) elastic materials
(d) all of the above
(e) none of the above.
Ans: b
49. The following type of nut is used with alien bolt
(a) alien nut
(b) hexagonal nut
(c) slotted nut
(d) castle nut
(e) any one of the above.
Ans: e
50. 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
(e) requires locking nuts.
Ans: c