Mechanical Engineering

 Strength Of Materials MCQ

1.Strain is defined as the

ratio of

(a) change in volume to original volume
(b) change in length to original length
(c) change   in   cross-sectional
area to original cross-sectional area
(d) any one of the above
(e) none of the above.
Ans: d

2. Hooke’s law holds good up to
(a) yield point
(b) limit of proportionality
(c) breaking point
(d) elastic limit
(e) plastic limit.
Ans: b

3. Young’s modulus is defined as the ratio of
(a) volumetric stress and volumetric strain
(b) lateral stress and lateral strain
(c) longitudinal   stress   and
 longitudinal strain
(d) shear stress to shear strain
(e) longitudinal stress and lateral strain.
Ans: c

4. The unit of Young’s modulus is
(a)mm/mm
(b)kg/cm
(c)kg
(d)kg/cm2
(e)kg cm2.
Ans: d

5.Deformation per unit length in the direction of force is known
as
(a)strain
(b) lateral strain
(c) linear strain  
(d) linear stress
(e) unit strain.
Ans: c

It equal and opposite forces applied to a body tend to elongate it, the
stress so produced is called
(a) internal resistanpe
(b) tensile stress
(c) transverse stress
(d) compressive stress
(e) working stress.
Ans: b

7. The materials having same elastic
properties in all directions are called
(a) ideal materials
(b) uniform materials
(c) isotropic materials
(d) paractical materials
(e) elastic materials.
Ans: c

8. A thin mild steel wire is loaded by adding
loads in equal increments till it breaks. The extensions noted with increasing
loads will behave as under
(a) uniform throughout
(b) increase uniformly
(c) first increase and then decrease
(d) increase uniformly first and then
increase rapidly
(e) increase rapidly first and then
uniformly.
Ans: d

9. Modulus of rigidity is defined as the
ratio of
(a) longitudinal stress and longitudinal
strain
(b) volumetric stress and volumetric strain
(c) lateral stress and lateral strain
(d) shear stress and shear strain
(e) linear stress and lateral strain.
Ans: d

10. If the radius of wire stretched by a load
is doubled, then its Young’s modulus will be
(a) doubled
(b) halved
(c) become four times
(d) become one-fourth
(e) remain unaffected.
Ans: e

11. The ultimate tensile stress of mild steel
compared to ultimate compressive stress is
(a) same
(b) more
(c) less
(d) more or less depending on other factors
(e) unpredictable.
Ans: b

12. Tensile strength of a material is
obtained by dividing the maximum load during the test by the
(a) area at the time of fracture
(b) original cross-sectional area
(c) average of (a) and (b)
(d) minimum area after fracture
(e) none of the above.
Ans: b

13. The impact strength of a material is an
index of its
(a) toughness      
(b) tensile strength
(c) capability of being cold worked
(d) hardness
(e) fatigue strength.
Ans: a

14. The Young’s modulus of a wire is defined
as the stress which will increase the length of wire compared to its original
length
(a) half
(b) same amount
(c) double
(d) one-fourth
(e) four times.
Ans: b

15. Percentage reduction of area in
performing tensile test on cast iron may be of the order of
(a) 50%
(b) 25%
(c) 0%
(d) 15%
(e) 60%.
Ans: c

16. The intensity of stress which causes unit
strain is called
(a) unit stress    
(b) bulk modulus
(c) modulus of rigidity
(d) modulus of elasticity
(e) principal stress.
Ans: d

17. True stress-strain curve for materials is
plotted between
(a) load/original cross-sectional area and
change in length/original length
(b) load/instantaneous cross-sectional area
original area and log.
(c) load/instantaneous cross-sectional area
and change in length/original length
(d) load/instantaneous area and instantaneous
area/original area
(e) none of the above.
Ans: b

18. During a tensile test on a specimen of 1 cm cross-section, maximum load
observed was 8 tonnes and area of cross-section at neck was 0.5 cm2. Ultimate
tensile strength of specimen is
(a) 4 tonnes/cm2
(b) 8 tonnes/cm2
(c) 16 tonnes/cm2
(d) 22 tonnes/cm2
(e) none of the above.
Ans: b

19. For steel, the ultimate strength in shear
as compared to in tension is nearly
(a) same
(b) half
(c) one-third
(d) two-third
(e) one-fourth.
Ans: b

20. Which of the following has no unit
(a) kinematic viscosity
(b) surface tension
(c) bulk modulus
(d) strain
(e) elasticity.
Ans: d

21. Which is the false statement about true
stress-strain method
(a) It does not exist
(b) It is more sensitive to changes in both
metallurgical and mechanical conditions
(c) It gives, a more accurate picture of the
ductility
(d) It can be correlated with stress-strain
values in other tests like torsion, impact, combined stress tests etc.
(e) It can be used for compression tests as
well.
Ans: a

22. In a tensile test on mild steel specimen,
the breaking stress as compared to ultimate tensile stress is
(a) more
(b) less
(c) same
(d) more/less depending on composition
(e) may have any value.
Ans: b

23. If a part is constrained to move and
heated, it will develop
(a) principal stress
(b) tensile stress
(c) compressive stress
(d) shear stress  
(e) no stress.
Ans: c

24. Which of the following materials is most
elastic
(a) rubber
(b) plastic
(c) brass
(d) steel
(e) glass.
Ans: d

25. The value of modulus of elasticity for
mild steel is of the order of
(a) 2.1xl05 kg/cm2
(b) 2.1 X 106 kg/cm2
(c) 2.1 x 107 kg/cm2
(d) 0.1 xlO6 kg/cm2 (<?) 3.8 x 106 kg/cm2.
Ans: b

26. The value of Poisson’s ratio for steel is
between
(a) 0.01 to 0.1    
(b) 0.23 to 0.27
(c) 0.25 to 0.33  
(d) 0.4 to 0.6
(e) 3 to 4.
Ans: c

27. The buckling load for a given material
depends on
(a) slenderness ratio and area of
cross-section
(b) Poisson’s ratio and modulus of elasticity
(c) slenderness ratio and modulus of
elasticity
(d) slenderness ratio, area of cross-section
and modulus of elasticity
(e) Poisson’s ratio and slenderness ratio.
Ans: d

28. The total elongation produced in a bar of
uniform section hanging vertically downwards due to its own weight is equal to
that produced by a weight
(a) of same magnitude as that of bar and
applied at the lower end
(b) half the weight of bar applied at lower
end
(c) half of the square of weight of bar applied at lower end
(d) one-fourth of weight of bar applied at
lower end
(e) none of the above.
Ans: b

29. The property of a material by virtue of
which a body returns to its original, shape after removal of the load is called
(a) plasticity
(b) elasticity
(c) ductility
(d) malleability
(e) resilience.
Ans: b

30. The materials which exhibit the same
elastic properties in all directions are called
(a)  homogeneous
(b)  inelastic
(c)  isotropic
(d)  isentropic
(e)  visco-elastic.
Ans: c

31. The value of Poisson’s ratio for cast
iron is
(a) 0.1 to 0.2      
(b) 0.23 to 0.27
(c) 0.25 to 0.33  
(d) 0.4 to 0.6
(e) 3 to 4.
Ans: b

32. The property of a material which allows
it to be drawn into a smaller section is called
(a) plasticity
(b) ductility
(c) elasticity
(d) malleability
(e) drawabihty.
Ans: b

33. Poisson’s ratio is defined as the ratio
of
(a) longitudinal stress and longitudinal
strain
(b) longitudinal stress and lateral stress
(c) lateral stress and longitudinal stress
(d) lateral stress and lateral strain
(e) none of the above.
Ans: c

34. For which material the Poisson’s ratio is
more than unity
(a) steel
(b) copper
(c) aluminium    
(d) cast iron
(e) none of the above.
Ans: e

35. The property of a material by virtue of
which it can be beaten or rolled into plates is called
(a) malleability  
(b) ductility
(c) plasticity
(d) elasticity
(e) reliability.
Ans: a

36. The change in the unit volume of a
material under tension with increase in its Poisson’s ratio will ,
(a) increase
(b) decrease
(c) remain same
(d) increase initially and then decrease
(e) unpredictable.
Ans: b

37. The percentage reduction in area of a
cast iron specimen during tensile test would be of the order of
(a) more than 50%
(b) 25—50%      
(c) 10—25%
(d) 5—10%
(e) negligible.
Ans: e

38. If a material expands freely due to heating it will develop
(a) thermal stresses
(b) tensile stress
(c) bending
(d) compressive stress
(e) no stress.
Ans: e

39. In a tensile test, near the elastic limit
zone, the
(a) tensile strain increases more quickly
(b) tensile strain decreases more quickly
(c) tensile strain increases in proportion to
the stress
(d) tensile strain decreases in proportion to
the stress
(e) tensile strain remains constant.
Ans: a

40. The stress necessary to initiate yielding
is
(a) considerably greater than that necessary
to continue it
(b) considerably lesser than that necessary
to continue it
(c) greater than that necessary to stop it
(d) lesser than that necessary to stop it
(e) equal to that necessary to stop it.
Ans: a

41. In the tensile test, the phenomenon of
slow extension of the material, i. e. stress increasing with the time at a
constant load is called
(a) creeping
(b) yielding
(c) breaking
(d) plasticity
(e) none of the above.
Ans: a

42. The stress developed in a material at
breaking point in extension is called
(a) breaking stress
(b) fracture stress
(c) yield point stress
(d) ultimate tensile stress
(e) proof stress.
Ans: a

43. Rupture stress is
(a) breaking stress
(b) maximum load/original cross-sectional
area
(c) load at breaking point/A
(d) load at breaking point/neck area
(e) maximum stress.
Ans: d

44. The elasticity of various materials is
controlled by its
(a) ultimate tensile stress
(b) proof stress
(c) stress at yield point
(d) stress at elastic limit
(e) tensile stress.
Ans: d

45. The ratio of lateral strain to the linear
strain within elastic limit is known as
(a) Young’s modulus
(b) bulk modulus
(c) modulus of rigidity
(d) modulus of elasticity
(e) Poisson’s ratio.
Ans: e

46. The ratio of direct stress to volumetric
strain in case of a body subjected to three mutually perpendicular stresses of
equal intensity, is equal to
(a) Young’s modulus
(b) bulk modulus
(c) modulus of rigidity
(d) modulus of elasticity
(e) Poisson’s ratio.
Ans: b

47. The stress at which extension of the material takes place more quickly as
compared to the increase in load is called
(a) elastic point of the material
(b) plastic point of the material
(c) breaking point of the material
(d) yielding point of the material
(e) ultimate point of the material.
Ans: d

48. In question 56, the internal reaction in
bottom 80 cm length will be
(a) same in both cases
(b) zero in first case
(c) different in both cases
(d) data are not sufficient to determine same
(e) none of the above.
Ans: b

49. Flow stress corresponds to
(a) fluids in motion
(b) breaking point
(c) plastic deformation of solids
(d) rupture stress
(e) none of the above.
Ans: c

50. When it is indicated that a member is
elastic, it means that when force is applied, it will
(a) not deform    
(b) be safest
(c) stretch
(d) not stretch
(e) none of the above.
Ans: c

51. The energy absorbed in a body, when it is
strained within the elastic limits, is known as
(a) strain energy
(b) resilience
(c) proof resilience
(d) modulus of resilience
(e) toughness..
Ans: a

52. Resilience of a material is considered
when it is subjected to
(a) frequent heat treatment
(b) fatigue
(c) creep
(d) shock loading
(e) resonant condition.
Ans: d

53. The maximum strain energy that can be
stored in a body is known as
(a) impact energy
(b) resilience
(c) proof resilience
(d) modulus of resilience
(e) toughness.
Ans: c

54. The total strain energy stored in a body
is termed as
(a) resilience
(b) proof resilience
(c) modulus of resilience
(d) toughness      
(e) impact energy.
Ans: a

55. Proof  resilience   per
material is known as
(a) resilience      
(b) proof resilience
(c) modulus of resilience
(d) toughness      
(e) impact energy.
Ans: c

56. The stress induced in a body due to
suddenly applied load compared to when it is applied gradually is
(a) same
(b) half
(c) two times      
(d) four times
(e) none of the above.
Ans: c

57. The strain energy stored in a body due to
suddenly applied load compared to when it is applied gradually is
(a) same
(b) twice
(c) four times    
(d) eight times
(e) half.
Ans: c

58. A material capable of absorbing large
amount of energy before fracture is known as
(a) ductility
(b) toughness
(c) resilience      
(d) shock proof
(e) plasticity.
Ans: b

59. Coaxing is the method of increasing
(a) strength by reversible cycling
(b) corrosion resistance by spraying
(c) hardness by surface treatment
(d) fatigue resistance by over-stressing the
metal by successively increasing loadings
(e) creep by head treatment.
Ans:

60. A beam is loaded as cantilever. If the
load at the end is increased, the failure will occur
(a) in the middle
(b) at the tip below the load
(c) at the support
(d) anywhere
(e) none of the above.
Ans: d

61. A non-yielding support implies that the
(a) support is frictionless
(b) support can take any amount of reaction
(c) support holds member firmly
(d) slope of the beam at the support is zero
(e) none of the above.
Ans: d

62. The ratio of elongation in a prismatic
bar due to its own weight (W) as compared to another similar bar carrying an
additional weight (W) will be
(a) 1:2
(b) 1 : 3
(c) 1 : 4
(d) 1 : 2.5
(e) 1 : 2.25.
Ans: b

63. In a prismatic member made of two materials so joined that they deform
equally under axial stress, the unit stresses in two materials are
(a) equal
(b) proportional to their respective moduli
of elasticity
(c) inversely proportional to their moduli of
elasticity
(d) average of the sum of moduli of
elas-ticity
(e) none of the above.
Ans: b

64. In riveted boiler joints, all stresses, shearing, bearing and tensile are
based on the
(a) size of rivet
(b) size of the drilled or reamed hole
(c) average of size of rivet and hole
(d) smaller of the two
(e) any one of the above.
Ans: b

65. The distance between the centres of the
rivets in adjacent rows of zig-zag riveted joint is known as
(a) pitch
(b) back pitch
(c) diagonal pitch
(d) diametral pitch
(e) lap.
Ans: c

66. Efficiency of a riveted joint is the
ratio of its strength (max. load it can resist without failure) to the strength
of the unpunched plate in
(a) tension
(b) compression
(c) bearing
(d) any one of the above
(e) none of the above.
Ans: a

67. When two plates are butt together and
riveted with cover plates with two rows of rivets, the joi;it is known as
(a) lap point
(b) butt joint
(c) single riveted single cover butt joint
(d) double riveted double cover butt joint
(e) single riveted double cover butt joint.
Ans: d

68. A riveted joint in which every rivet of a
row is opposite to other rivet of the outer row, is known as
(a) chain riveted joint
(b) diamond riveted joint
(c) criss-cross riveted joint
(d) zig-zag riveted joint
(e) none of the above.
Ans: a

69. A riveted joint in which the number
otrivets decrease from innermost to outer most row is called
(a) chain riveted joint
(b) diamond riveted joint
(c) criss-cross riveted joint
(d) zig-zag riveted joint
(e) none of the above.
 Ans: b

70. If the rivets in adjacent rows are
staggered and the outermost row has only one rivet, the arrangement of the
rivets is called
(a) chain riveting
(b) zig zag riveting
(c) diamond riveting
(d) criss-cross riveting
(e) none of the above.
Ans: c

71. Diamond riveted joint can be adopted in
the case of following type of joint
(a) butt joint
(b) lap joint
(c) double riveted lap joints
(d) all types of joints
(e) none of the above.
Ans: a

72. Rivets are made of following type of
material
(a) tough
(b) hard
(c) resilient
(d) ductile
(e) malleable.
Ans: d

73. The weakest section of a diamond riveting
is the section which passes through
(a) the first row
(b) the second row
(c) the central row
(d) one rivet hole of the end row
(e) none of the above.
Ans: d

74. The deformation of a bar under its own
weight compared to the deformation of same body subjected to a direct load equal
to weight of the body is
(a) same
(b) double
(c) half
(d) four times
(e) one-fourth.
Ans: c

75. The force acting along the circumference
will cause stress in the walls in a direction normal to the longitudinal axis
of cylinder; this stress is called
(a) longitudinal stress
(b) hoop stress
(c) yeiled stress
(d) ultimate stress
(e) none of the above.
Ans: b

76. A boiler shell 200 cm diameter and plate
thickness 1.5 cm is subjected to internal pressure of 1.5 MN/m , then the hoop
stress will be
(a) 30 MN/m2    
(b) 50 MN/m2
(c) 100 MN/m2  
(d) 200 MN/m2
(e) 300 MN/m2.
Ans: c

77. A cylindrical section having no joint is
known as
(a) jointless section
(b) homogeneous section
(c) perfect section
(d) manufactured section
(e) seamless section.
Ans: e

78. Longitudinal stress in a thin cylinder is
(a) equal to the hoop stress
(b) twice the hoop stress
(c) half of the hoop stress
(d) one-fourth of hoop stress
(e) four times the hoop stress.
Ans: c

79. The safe twisting moment for a compound
shaft is equal to the
(a) maximum calculated value
(b) minimum calculated value
(c) mean value
(d) extreme value
(e) none of the above.
Ans: b

80. The torsional rigidity of a shaft is
expressed by the
(a) maximum torque it can transmit
(b) number of cycles it undergoes before
failure
(c) elastic limit up to which it resists
torsion, shear and bending stresses
(d) torque required to produce a twist of one
radian per unit length of shaft
(e) maximum power it can transmit at highest
possible-speed.
Ans: d

81. The value of shear stress which is
induced in the shaft due to the applied couple varies
(a) from maximum at the center to zero at the
circumference
(b) from zero at the center to maximum at the
circumference
(c) from maximum at the center to mini-mum at
the cricumference
(d) from minimum at the centro to maxi-mum at
the circumference
(e) none of the above.
Ans: b

82. A key is subjected to side pressure as
well at shearing forces. These pressures are called
(a) bearing stresses
(b) fatigue stresses
(c) crushing stresses
(d) resultant stresses
(e) none of the above.
Ans: a

83. In a belt drive, the pulley diameter is
doubled, the belt tension and pulley width remaining same. The changes required
in key will be
(a) increase key length
(b) increase key depth
(c) increase key width
(d) double all the dimensions
(e) none of the above.
Ans: c

84. Shear stress induced in a shaft subjected
to tension will be
(a) maximum at periphery and zero at center
(b) maximum at center
(c) uniform throughout
(d) average value in center
(e) none of the above.
Ans: e