This set of Materials Science Multiple Choice Questions & Answers (MCQs) focuses on “Point Defects – 2″.
1. Which type of diffusion occurs due to the exchange of an atom with vacancies?
a) Substitution diffusion
b) Elimination diffusion
c) Passive diffusion
d) Facilated diffusion
2. Which of the following technique is not used to measure the concentration of vacancy to determine the activation energy for its formation?
a) Positron annihilation technique
b) Thermal expansion measurements
c) Measuring resistivity after quenching
d) Thermal imaging
3. Which thermodynamic property increases in a crystalline solid due to the presence of vacancies?
c) Internal energy
d) Work done
4. Calculate temperature of copper at which equilibrium number of vacancies per cubic meter is 2.2*1020 vacancies/m3. The energy of vacancy formation is 0.7ev/atom and total number of atom is 2*1030atom/m3.
5. How is the concentration of defect related with free energy?
a) The concentration of defect increases free energy
b) The concentration of defect decrease free energy
c) The concentration of defect is equal to free energy
d) The concentration of defect is not related to free energy
6. Which of the following phenomenon creates point defect in ceramics?
a) Thermal excitation
d) Electrical conductivity
7. Which of the following is not the feature of solute and solvent atoms that determine the degree to which former dissolve in latter?
a) Corrosion factor
b) Atomic size factor
c) Crystal structure
8. In which type of defect smaller cation can get displaced into an interstitial void?
a) Schottky defect
b) Intrinsic defect
c) Extrinsic defect
d) Frankel defect
9. Which of the following oxides are highly defective?
10. In case of point defect in polymers probability of which part of the polymer is likely to be defected more compared to other?
a) Center of polymer chain
b) Chain ends
c) Main chain units
d) Starting part of chain