A metal has face-centred cubic unit cell. The radius of an atom of the metal is 1.28Å. What is the edge length of the unit cell?

In face centred cubic unit cell edge length is

In a face- centred cubic unit cell, the edge length is

In face centred cubic unit cell edge length is

In a face centred cubic unit cell of close packed atoms, the radius of atom ( r ) is related to the edge length (a) of the unit cell by the expression

In the body-centred cubic unit cell and face centred cubic unit cell, the radius of atom in terms of edge length(a) of the unit cell is respectively: