$ZnO$ shows yellow colour on heating due to:

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.

The incorrect statement about crystals with $Schottky$ defect is:

In the $AgBr$ crystal,the size of ions follows the order $Ag^{+} << Br^{-}$. Which of the following characteristics is shown by $AgBr$?

Which of the following compounds is likely to show both Frenkel and Schottky defects in its crystalline form?

When $CaCl_2$ is added to $AgCl$ crystal,the defect introduced is