Q$\mathrm{.}6.$ NaCl structure is shown in the unit cell given. The ionic radius of $N{a}^{+}$is $0\mathrm{.}97$ and the ionic radius of $C{l}^{-}$is $1\mathrm{.}81.$

a$)$ Calculate the linear density along $[100]$ direction by showing the direction on the unit cell shown.

b$)$ Calculate the planar density of $(011)$ plane by showing the plane on the unit cell shown.

$($Hint: Assume that $N{a}^{+}$ions are in contact with $C{l}^{-}$ions$).$