Quiznetik

Material Science | Set 2

1. the imperfection sin crystal structure influence the of materials

Correct : D. all of the above

2. the effect of imperfections in crystal struture can be

Correct : C. both a or b

3. due to change in mechanical properties of the material can be changed

Correct : C. imperfectio ns

4. imperfections are introduced during

Correct : D. all of the above

5. vacancy, self interstitial, substitutional are all types of

Correct : D. point defects

6. point defects include

Correct : D. vacancy, substitution al, interstitial defects

7. line defects include

Correct : A. edge and screw dislocation

8. surface defects includes

Correct : D. grain boundaries, twin boundaries, low angle boundary

9. whioch of the following is not line defect ?

Correct : D. both b and c

10. which of the following is line defect ?

Correct : A. dislocation

11. which of the following defect is not surface defect ?

Correct : D. both b and c

12. which of the following is a type of surface defect ?

Correct : B. low angle grain boundary

13. lattice vibration affects the                    properties of material

Correct : D. all of the above

14. atoms are bonded with each other through               bond

Correct : D. a or b

15. the bonding between atoms breaks due to the

Correct : B. increase in energy possesed by them

16. vacancy defect is assocoated with

Correct : D. both a and b

17. any atom when leaves its position and occupies the interstitial sites is called as

Correct : A. slf interstitial

18. when any atom occupies the interstitial position of material increases

Correct : A. strength

19. when any atom occupies the interstitial position of material increases

Correct : C. both of the above

20. substitutional impurity defect is associated with

Correct : B. foreign atom occupies the lattice posiiton of regular atomic structure

21. Frenkel defect is associated with

Correct : A. vacancy and self interstitial defect

22. if an anion and cation are absent in pair the defect is known as

Correct : A. schottky

23. point defect increase and decrease

Correct : A. hardness, electrical conductivity

24. the defect associated with addition / missing / misalighnment of a series of atoms from its designated posiiton is called as

Correct : B. linear defect

25. the linear defects are introduced in the material during _ of material

Correct : D. all of the above

26. burgers vector

Correct : B. is a measure of lattice distortion and is measured as distance along the close packed directions

27. a measure of lattice distortion which is measured as a distance along the close packed directions

Correct : A. burgers vector

28. the magnitude of lattice distortion in edge dislocation si near the dislocation as compared to region away from dislocation

Correct : C. higher

29. the magnitude of edge dislocation in a lattice structure can be measured by

Correct : B. burgers vector

30. linear defects increase and Decrease

Correct : C. hardness, electrical resistance

31. surface defects are

Correct : B. two dimensional defect

32. surafec defects are associated with

Correct : D. any of the above

33. the surface defects are introduced in the material during of material

Correct : D. all of the above

34. the is defect that causes sepeartion of grain

Correct : A. grain boundary

35. a garin boundary represents

Correct : C. two dimenstiona l defect

36. a garin boundary is a transition region which represents _

Correct : A. imperfectio ns in arrengement of atoms

37. the defect which has mirror image of atomic arrangement across the dislocation is called

Correct : D. twin boundary defect

38. the twin is the region

Correct : D. twin boundary defect

39. in a given material adjacent grains will have

Correct : D. a or b

40. the defect associated with slight mismatch of crystalline orientation from one grain to adjacent grain is called

Correct : C. low angle boundary defect

41. the low angle boundary defect is assocaited with

Correct : D. stacking faults

42. the stacking fault defect is assocaited with

Correct : A. erroe in sequence of close- packed atomic planes

43. surface defects increase and decrease

Correct : A. hardness & strength

44. vacancies are known as _

Correct : B. zero dimensional defect

45. dislocations are known as

Correct : A. one dimensional defect

46. in positive edge dislocation

Correct : A. extra row of atoms is present in the upper region

47. in positive edge dislocation

Correct : B. the region in dislocation is under

48. the dislocations are classified as

Correct : D. all of the above

49. in screw dislocation

Correct : C. the region in dislocation is under shear

50. when the metal is stresses below its elastic limit, the resulting deformation is

Correct : B. temporary

51. when the metal is stresses above its elastic limit, the resulting deformation is

Correct : D. a or c

52. stress required during plastic deformation is than that required during elastic deformation

Correct : B. high

53. different shapes can be permentaly given to metals by virtue of property

Correct : B. plastic

54. mechannnial properties of the metal after plastic deformation

Correct : B. either increase or decrease

55. the plastic deformation can takes place through

Correct : D. all of the above

56. slip is defined as displacement of one part of crystal relative to other

Correct : C. shear

57. slip takes place due to

Correct : A. stress applied on material

58. slip occurs along             plane and in direction

Correct : D. specific, specific

59. the plane on which slip takes place is called plane

Correct : C. slip

60. in slip, the crystal structure above and below the plane remains

Correct : B. undistorted

61. slip occurs on plae which has

Correct : C. maximum number of atoms

62. slip direction is direction in the slip plane which has

Correct : C. maximum number of atoms

63. twin takes place due to

Correct : A. stress applied on material

64. in twinning, the structure in the distorted region forms of the crystal structure in the distorted region

Correct : B. mirror image

65. the planes along which mirror image is formed is called planes

Correct : D. twin

66. the plastic deformation takes place due to and

Correct : C. both of the above

67. twining is the phenomenon observed due to

Correct : D. a or b

68. metals are more ductile than metals

Correct : B. fcc,bcc

69. generally metals with crystal structure are more ductile

Correct : B. fcc

70. generally metals with crystal structure shows plastic deformation mainly by slip mechanism

Correct : D. a and c

71. generally metals with crystal structure shows plastic deformation mainly by twinning mechanism

Correct : C. hcp

72. twinning occurs along plane and direction

Correct : D. specific, specific

73. requires more stress to be initiated with respect to

Correct : B. twinning, slip

74. as compared to slip the stress required to propogate twin is

Correct : B. lesser

75. the appears as a pair of thick lines in the microscopic structure even after polishing

Correct : B. twinning

76. The appears as a single thin line in the microscopic structure

Correct : A. slip

77. the disappears after polishing

Correct : A. slip

78. the can be seen in metal even after polishing

Correct : B. twinning

79. the mechanism can be takes place due to thermal treatment

Correct : B. twinning

80. metals with FCC crystal structure are often subjected to

Correct : D. all of the above

81. metals with FCC and BCC crystal structure are often subjected to

Correct : D. all of the above

82. number of slip systems in metals decides about

Correct : C. ductility of metal

83. number of slip systems in FCC are

Correct : A. 12

84. the law is used to determine the value of critical shear stress

Correct : C. schmids

85. the schmids law is used to calculate critical shear stress for _                     structure

Correct : B. single crystal

86. the maximum resolved shear stress is given by

Correct : C. Ƭresolve = σt/2

87. slip starts to occur when the value of resolved shear stress

Correct : C. increases abive critical shear stress

88. FCC metals have value of critical shear stress as compared to BCC metals

Correct : B. lower

89. FCC metals have higher ductility than BCC metals since _

Correct : B. fcc metals have lower

90. the phenomenon by virtue of which metals become harder and stronger without any heat treatment is called

Correct : C. all of the above

91. after intial cold working, the stress required to further deform the material is

Correct : C. higher

92. work hardening is the phenomenon observed if metal is worked the recrystallization temperature

Correct : C. independent of

93. working of metal below crystallization temperature is known as

Correct : A. cold working

94. working of metal above crystallization temperature is known as

Correct : B. hot working

95. for a given metal its recrystallization temperature depends on

Correct : D. all of the above

96. finer is the grain size -

Correct : B. lesser is the recrystalliza tion temperature

97. Frank-Reed source is associated with -

Correct : C. multiplicati on of dislocations

98. finer is the grain size -

Correct : A. more is dislocation density in cold working

99. the mechanism of plastic deformation in polycrystalline material is than the mechanism in single crystal structure

Correct : B. complex

100. the stress required to produce same deformation is higher in case of                         polycrystalline material as compared to polycrystalline materials

Correct : C. a or b