When atoms are placed at the corners of all $12$ edges of a unit cell,what is the number of atoms present per unit cell?

Which of the following represents the correct axial distances and axial angles for the rhombohedral crystal system?

Bravais lattices are of (in $types$)

If the distance between $Na^{+}$ and $Cl^{-}$ ions in sodium chloride crystal is '$Y$' $pm$,the length of the edge of the unit cell will be:

The triclinic unit cell has the following parameters:

Calculate the number of unit cells in $1 \ cm^3$ volume of metal if the volume of one unit cell is $3.448 \times 10^{-23} \ cm^3$.