If molten $NaCl$ contains $SrCl_2$ as impurity,crystallization can generate

$A$ silicon specimen is made into a $p-$type semiconductor by doping,on an average,one indium atom per $5 \times 10^7$ silicon atoms. If the number density of atoms in the silicon specimen is $5 \times 10^{28} \ \text{atoms} \ m^{-3}$,then the number of acceptor atoms in silicon per cubic centimeter will be

Match List-$I$ with List-$II$.

List-$I$ (Defect)	List-$II$ (Examples)
$A$. Frenkel defects	$1$. $FeO$
$B$. Schottky defects	$2$. $NaCl$
$C$. Vacancy defects	$3$. $AgCl$
$D$. Metal deficiency defects	$4$. Crystals with vacant lattice sites

When electrons are trapped into the crystal in anion vacancy,the defect is known as

Identify the type of defect from the following in stainless steel.

The color of $LiCl$ due to $F$-centers is .......