(આપેલ : $h =6.63 \times 10^{-34} \,Js , N _{ A }=6.02 \times 10^{23} \,mol ^{-1}$, $c =3 \times 10^{8}\, ms ^{-1}$ )
\(\frac{6.63 \times 10^{-34} \times 3 \times 10^{8}}{300 \times 10^{-9}} \times 6.02 \times 10^{23}\)
\(=399.13 \times 10^{3} \,Joule / mole\)
\(=399\, kJ / mole\)
$O ^{2-}, F ^{-}, Al , Mg ^{2+}, Na ^{+}, O ^{+}, Mg , Al ^{3+}, F$