Quiznetik

Material Science | Set 4

1. In FCC, the lattice parameter (a) is

Correct : C. (4/√2) r

2. In geometrical hardening, at the beginning λ is

Correct : A. less than 45°

3. In geometrical softening, at the beginning λ is

Correct : B. more than 35°

4. In hot working force required is than cold working

Correct : B. less

5. In hot working microstructure is

Correct : D. both b & c

6. In vacancy point defects, stress field produced in the vicinity.

Correct : A. tension

7. Indexing or designation in a unit cell can be done for a particular

Correct : D. all of the above

8. Inter atomic distance is more                    the dislocation line in negative edge dislocation

Correct : A. above

9. Inter atomic distance is more                    the dislocation line in positive edge dislocation

Correct : B. below

10. It is a type of Twin

Correct : A. annealing

11. Lattice constant represents

Correct : A. distance between adjacent atoms of unit cell

12. Lattice structure represents arrangement of unit cells in

Correct : B. 3- dimensional axes system

13. Ligancy number for HCP is

Correct : B. 12

14. Material having cohesive strength shows large plastic deformation

Correct : A. high

15. Material having CRSS shows large plastic deformation

Correct : B. low

16. Miller indices of the line of intersection of (⎯ 1⎯ 11) and (110) are

Correct : D. [-110]

17. Minimum number of slip systems that must be operative during plastic deformation

Correct : C. 5

18. Most polymers are type of materials

Correct : A. non- crystalline

19. Negative screw dislocation is represented by

Correct : D. ┬

20. No. of atoms in Body-Centered Cubic structure are …..

Correct : B. 2

21. No. of atoms in hexagon close packed structure are …..

Correct : D. 6

22. No.of atoms in FCCstructure are …..

Correct : C. 4

23. Oxidation of metals occurs during cold working.

Correct : B. false

24. Plastic deformation results from the following.

Correct : D. all of the above

25. Poor surface finish in………process

Correct : B. hot working

26. Positive screw dislocation is represented by

Correct : A. ┴

27. Recrystallisation temperature of Iron is ………..

Correct : A. 727 °c

28. Recrystallization rate varies in the following manner with temperature

Correct : C. exponential

29. Repeatable entity of a crystal structure is known as

Correct : C. unit cell

30. Requirement for cross-slip movement of dislocation

Correct : C. no preferred slip plane

31. Round brackets are used to represent crystallographic

Correct : C. plane

32. Schottky defect found in

Correct : C. ionic

33. Schottky defect have missing of

Correct : D. both a&b

34. Schottky-defect in ceramic material is

Correct : C. pair of nearby cation and anion vacancies

35. Schottky-defect is of this type.

Correct : A. point

36. screw dislocations have burger vector for dislocation line

Correct : A. perpendicul ar

37. screw dislocations includes

Correct : C. shear lattice strain

38. Sharp break in dislocation line that is in slip plane .

Correct : B. kink

39. slip plane orientation after grain boundary

Correct : C. change

40. Slip systems having two types one is glide & another one is

Correct : A. climb

41. Square brackets are used to represent crystallographic

Correct : B. direction

42. Stacking fault energies are in the range of

Correct : A. 0.01-0.1 j/m2

43. Stacking fault is type of defect

Correct : D. surface

44. Surface decarburisation in steels in cold working .

Correct : A. does not occurs

45. Surface decarburisation in steels in hot working .

Correct : B. occurs

46. Surface finish is good in

Correct : B. cold working

47. Surface finish is poor in

Correct : A. hot working

48. Temp. required for cold working is

Correct : C. below recrystalliza tion

49. Temp. required for hot working is

Correct : D. above recrystalliza tion

50. The arrangement of multiple unit cells together is called

Correct : A. crystal structure

51. The atomic diameter of an BCC crystal (if a is lattice parameter) is

Correct : C. a/(4/√3)

52. The atomic diameter of an FCC crystal (if a is lattice parameter) is

Correct : D. a/(4/√2)

53. The basis of determining index values for a simple structure is unit cell consisting of

Correct : B. 3- dimensional spatial axes

54. The constant distance between adjacent atoms of unit cell is called as

Correct : D. lattice constant

55. The following mechanism contributes very little the diffusivity

Correct : D. self- interstitial

56. The geometry of unit cell can be completely defined by _ -

Correct : D. both b & c

57. The lattice above the dislocation line is in in negative edge dislocations

Correct : A. tension

58. The lattice above the dislocation line is in in positive edge dislocations

Correct : C. compression

59. The plane (1⎯ 11) is parallel to

Correct : A. (-11-1)

60. The smallest representation of geometry of crystal structure of a material is called

Correct : C. unit cell

61. The study of different pattern formation of atoms is called as

Correct : B. crystallogra phy

62. This is a one type of stacking fault

Correct : B. extrinsic

63. This is a one type of twin

Correct : D. mechanical

64. Time dependent permanent deformation is called _.

Correct : C. creep

65. Typical density of dislocations in a solid

Correct : D. 108-1010 m-2

66. Value of critical shear stress is independent of

Correct : B. slip direction

67. What is the atomic packing factor of BCC

Correct : A. 0.68

68. Which of the following is false?

Correct : C. abc abc abc…is stacking sequence for hcp crystal

69. Which one of following should be preferred for brittle materials

Correct : A. hot working

70. Which one of the following is not basic component of Materials Science?

Correct : A. cost

71. Which structure having higher density?

Correct : B. fcc

72. There are basic crystal systems

Correct : C. 7

73. Total no of bravais lattice is

Correct : B. 14

74. Co-ordianation no. of Simple cubic structure is

Correct : B. 6

75. Simple cube have atomic packing factor =

Correct : C. 0.52

76. In metals the plastic deformation generally takes place by the mechanism of

Correct : A. slipping

77. The shear stress required to produce slip on a single crystal plane is called the                    shear stress

Correct : D. critical resolved

78. CRSS is calculated by using                      law

Correct : B. schimd\s

79. slip occurs in discrete multiples of

Correct : C. atomic spacing

80. imperfections involve missing of cation from it's respective position

Correct : B. schottky

81. imperfections involve missing of cation & anion from it's respective position

Correct : A. frankel

82. The displacement distance for atoms around the dislocation is the

Correct : C. burger vector

83. dislocations can glide & climb

Correct : B. edge

84. dislocations can glide only

Correct : A. screw

85. Surface defects are the                      dimensional regions in a crystal.

Correct : B. 2

86. Edge dislocations are the                    dimensional regions in a crystal

Correct : D. 1

87. plays an important role in crystal growth.

Correct : B. screw dislocations

88. work hardening reduces :

Correct : C. ductility

89. Chances of cracks propagation is more in :

Correct : B. cold working

90. In working refinement of crystal occurs.

Correct : A. hot

91. working is always accompanied by strain hardening

Correct : B. cold

92. working increases ultimate tensile strength.

Correct : B. cold

93. (a√3)/4 is the radius of

Correct : B. bcc

94. (a√2)/4 is the radius of

Correct : C. fcc

95. Miller indices are the same for :

Correct : A. parallel planes

96. 0.68 is atomic factor of

Correct : B. bcc

97. 4 is avg. atoms per unit cell for

Correct : C. fcc

98. (001) is a plane of the cube & is

Correct : A. horizontal

99. (100) is a plane of the cube & is

Correct : B. vertical

100. (010) is a plane of the cube & is

Correct : B. vertical