State the types of point defects.

The correct statement$(s)$ regarding defects in solids is(are):
$A$. Frenkel defect is usually favoured by a very small difference in the sizes of cation and anion.
$B$. Frenkel defect is a dislocation defect.
$C$. Trapping of an electron in the lattice leads to the formation of $F$-center.
$D$. Schottky defects have no effect on the physical properties of solids.

In the laboratory,sodium chloride is made by burning sodium in an atmosphere of chlorine. The resulting crystal is yellow in color. The cause of this yellow color is:

When $AgCl$ is doped with $10^{-4} \, \text{mole percent}$ $RuCl_3$,what will be the concentration of cationic vacancies per mole of $AgCl$?

Which of the following is not a function of an impurity present in a crystal?

Write a short note on impurity defects.