Material science

Provide the justification Please

i). Which type of stress is involved in the motion of screw dislocation? a) Tensile stress b) Shear stress c) Compressive stress d) Does not involve stress ii). Which technique is used to observe dislocation? a) Positron annihilation technique b) Thermal imaging c) Thermal expansion measurements d) Transmission Electron-microscope technique e) Scanning electron microscope technique iii). The magnitude and direction of lattice distortion are expressed in terms of which vector? a) Dislocation vector b) Screw vector c) Edge vector d) Burger vector iv). Which of the following phenomenon creates point defect in ceramics? a) Thermal excitation b) Precipitation c) Densification d) Electrical conductivity e) All of the above f) None of the Above v). Stiffness is a. area under stress-strain curve till yield point b. area under stress-strain curve till fracture point c. area under stress-strain curve till ultimate stress point d. None of the above vi) Toughness is a. Area under elastic deformation b. Area under plastic deformation c. Area under both elastic and plastic deformation d. None of the above vii) Co-ordination number of a simple cubic structure is a. 1 b. 2 c. 4 d. None of the above viii) Ductility can be measured as the a. Area under plastic deformation b. Area under both elastic and plastic deformation c. Percentage elongation upto the ultimate tensile stress d. None of the above