In $AgBr$ crystal,the ion size lies in the order $Ag^{+} << Br^{-}$. The $AgBr$ crystal should have the following characteristics:

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.

Non-stoichiometric defects do not include which of the following?

Frenkel and Schottky defects are

Which one of the following compounds shows both,Frenkel as well as Schottky defects?

Which defect causes a decrease in the density of a crystal?