Quiznetik

Material Science | Set 5

1. (111) is a plane of the cube & is

Correct : C. inclined to z axis

2. The crystal structure of most common metals is

Correct : B. cubic

3. A crystal structure in a regular array of atoms is arranged in one of the              space lattices

Correct : C. 14

4. The linear disturbance of atomic arrangement is known as

Correct : C. dislocations

5. is a system of notations of planes within a crystal of space lattice

Correct : C. miller indices

6. Atom movements in twinnning are much than atomic spacing

Correct : B. less

7. diffusion implies atomic movement along the surface of a plane

Correct : B. surface

8. In a simple cubic structure, [100] and (100) parallel?

Correct : A. no

9. The miller indices of a plane are proportional to :

Correct : A. the reciprocal of numerical parameters of the intercepts

10. A material having different properties in different directions is known as

Correct : B. anisotropic

11. Presence of carbon atom in iron is an example of impurity

Correct : B. interstitial

12. Directions of edge dislocation & burger vector are to each other

Correct : A. perpendicul ar

13. On thermal excitation this                    defect may cause

Correct : A. vacancy

14. The grain boundary area decreases when a polycrystalline material is heated

Correct : B. above recrystalliza tion temp.

15. Ideal crystals have

Correct : A. no imperfectio ns

16. The imperfections may be minimised by

Correct : D. all of the above

17. Volume imperfections can be

Correct : D. noncrystalli ne regions

18. The cross slip occurs in :

Correct : B. screw dislocation

19. .......... defects are inperfect point like region in a crystal.

Correct : B. point

20. A ............is the simplest point defect and envolves a missing atom within a metal.

Correct : B. vacancy

21. -------- imperfections involve vacancies of a pair ions of opposite charges.

Correct : B. schottky

22. The displacement distance for atoms around the dislocation is the---- --.

Correct : A. burger vector

23. -------- dislocation can glide and climb.

Correct : B. edge

24. -------- are difined as the irregularities in the structure of metals.

Correct : B. dislocation

25. Surface defects are the -------- dimensional regions in a crystal.

Correct : B. two

26. -------- dislocation plays an important role in crystal growth.

Correct : B. screw

27. Work hardening reduces:

Correct : D. ductility

28. -------- is the low temperature phenomenon which results in the rstoration of the physical properties without any observable change in microstructure.

Correct : B. recovery

29. Grain growth is an increase in ----- --.

Correct : A. grain size

30. A metal is said to be--------- worked, if it is mechanically processed below the crystallization temperature of the metal.

Correct : B. cold

31. Chances of cracks propogation is more in:

Correct : B. cold working

32. In ------working refinement of crystal occures.

Correct : B. hot

33. -------- working is always accompanied by strain hardening.

Correct : B. cold

34. -------- working increases ultimate tensile strength.

Correct : A. cold

35. Annealing is done:

Correct : C. relievin g stresse s

36. Among the crystal structure, which has the highest packing fraction.

Correct : B. fcc

37. The miller indices are the same for:

Correct : A. parall el plane s

38. The crystal structure of silver is:

Correct : A. fcc

39. 0.68 is the atomic packing factore of:

Correct : A. bcc

40. (001) is a plane of the cube and is:

Correct : A. horizontal

41. The crystal structure of all the following material is HCP except:

Correct : D. aluminium

42. The crystal structure of graphite is:

Correct : A. hcp

43. The crystal structure of Germanium is:

Correct : D. diamon d cube

44. How many atoms are there per unit cell in a body centered cubic lattice system?

Correct : A. 2

45. How many molecules per unit cell are there in a face centered cubic lattice?

Correct : B. 4

46. The crystal structure of most common metal is:

Correct : B. cubic

47. The metal which has got BCC structure is:

Correct : B. tungsten

48. The structure of SiO2 quartz is:

Correct : A. hcp

49. The metal which has HCP structure is:

Correct : C. magnesium

50. The crystal structure of the following materials is FCC except:

Correct : B. magnesium

51. A crystal structure in a regular array of atoms is arranged in one of the:

Correct : C. 14 space lattices

52. There are 2 atoms in a unit cell of:

Correct : A. body centered cubic space lattice

53. Which of the following elements has hexagonal close packed structure?

Correct : C. cadmium

54. Atomic packing factore is maximum for:

Correct : C. fcc

55. The crystal structure of brass is:

Correct : B. fcc

56. The crystal structure of gamma iron is:

Correct : C. fcc

57. Cold work is done on metals:

Correct : A. below thermal critical range

58. In crystal imperfections, the lattice sites from which atoms are missing are called:

Correct : B. vacancies

59. Which of the following metals does not have face centered cubic structure?

Correct : C. tin

60. The process which occures with heating in excess of that used recovery is called:

Correct : B. recrystalliz at ion

61. Recrystallization temperature of aluminium is 150˚ C and that of copper is:

Correct : B. 200˚

62. The linear disturbance of atomic arrangment is known as:

Correct : C. dislocations

63. Every point of a space lattice has ------ surrounding:

Correct : D. identical

64. ------- parameter means the dimensions of the unit cell in any of the crystallographic arrangements.

Correct : D. lattice

65. ------- is defined as the number of nearest atoms which are directly surrounding a given atom.

Correct : D. co- ordinatio n number

66. The ratio of the volume of atoms per unit cell to the total volume occupied by the unit cell called------ --.

Correct : B. atomi c packin g factor

67. -------- is a system of notation of planes within a crystal of space lattice.

Correct : C. miller indices

68. The change in dimension of foems of matter under the action of applied forces is called---.

Correct : C. deformation

69. ------- deformation is the deformation which disappears when the load is removed.

Correct : B. elastic

70. In metals the plastic deformation generally takes place by the process of ---- ----.

Correct : B. slipping

71. In ----- the orientation of the crstal above and below the slip plane is same after deformation as before.

Correct : B. slip

72. ------- defects are imperfect point like regions in a crystal.

Correct : B. point

73. A ------is the simplest point defect and involves a missing atom within a metal.

Correct : B. vacancy

74. ------- imperfection involves vacancies of pair of ions of opposite charges.

Correct : B. schottky

75. A linear disturbance of atomic arrangement which can move very easily on the slip plane through the crstal is known as -----.

Correct : C. dislocation

76. The Burger's vectore is at------- to the edge dislocation line.

Correct : C. right angle

77. In ------dislocation only shear stress field exists.

Correct : C. screw

78. ------ slip is process where by a screw dislocation glides into another slip plane having a slip direction in common with the original slip plane.

Correct : C. cross

79. -------- dislocation plays an important role in crystal growth.

Correct : C. screw

80. Non-random alignment of crystals or molecules is known as ----- orientation.

Correct : C. perferred

81. Chances of crack propagation is more in -- -----.

Correct : A. cold working

82. The tiny block formed by the arrangement of small group of atom is called ----- --.

Correct : A. unit cell

83. According to Bravais there are ------ possible types of space lattice in the seven basic crystal system.

Correct : B. 14

84. In metals the plastic deformation generally takes place by the process of ---- -----.

Correct : B. slipping

85. The shear stress required to produce slip on a crystal plane is called the ------ shear stress.

Correct : A. critical resolve d

86. --------- occure over wide planes.

Correct : A. slip

87. In -------- every atomic plane is involved.

Correct : C. twinning

88. A linear disturbance of atomic arrangement, which can move very easily on the slip plane through the crystal is known as ------ --.

Correct : C. dislocation

89. The Burger's vectore is at------- to the edge dislocation line.

Correct : C. right angles

90. In a screw dislocation Burger's vectore is - ------- to the linear defect but there is distoration of the plane.

Correct : A. parallel

91. In -------- dislocation only shear stress field exists.

Correct : C. screw

92. Cold working increasings:

Correct : C. ultimat e tensile

93. Alloying elements of impurities greatly increase the lattice imperfections which decrease/increase the conductivity.

Correct : A. decrease

94. Any mechanical process that increases the number of dislocations will result in decrease/increase in the electrical resistance of the metal.

Correct : B. increases

95. The capacit of material to undergo deformation under tension without rupture is known as:

Correct : D. ductility

96. The structure of common glass is:

Correct : A. amorphous

97. Which of the following materials has body centered cubic structure?

Correct : A. molybdenum

98. Which of the following materials does not have body centered cubic structure?

Correct : D. calcium

99. Which of the following factores govern the grain size?

Correct : D. all of the above

100. In -------- fracture the surface obtained in shining and accompanied with the formation of slip planes.

Correct : B. ductile