The number of tetrahedral voids per unit $HCP$ cell is

$Ga$ (atomic mass $70 \, u$) crystallizes in a hexagonal close packed structure. The total number of voids in $0.581 \, g$ of $Ga$ is $\dots \dots \dots \dots \dots \times 10^{21}$. (Round off to the Nearest Integer).

Calculate the total volume occupied by all particles in a $fcc$ unit cell if the volume of unit cell is $5.2 \times 10^{-23} \ cm^3$.

If the number of atoms in a unit cell is $2$,then the number of tetrahedral and octahedral voids will be ....... and ....... respectively.

The volume occupied by the atoms in a unit cell of hexagonal close packing $(HCP)$ or cubic close packing $(CCP)$ is equal to:

In the closest packing of atoms,