Identify the instrument used to determine the crystal structure from the following:

Calculate the number of unit cells in $1 \ cm^3$ volume of metal if the unit cell edge length is $1.25 \times 10^{-8} \ cm$.

Calculate the edge length of a unit cell for a metal with an atomic radius of $128 \ pm$ that forms an $fcc$ unit cell structure.

$A$ metal crystallises in a body-centred cubic $(BCC)$ lattice with the metallic radius $\sqrt{3} \ \mathring{A}$. The volume of the unit cell in $m^3$ is:

An element occurs in the body-centred cubic $(BCC)$ structure with an edge length of $288 \ pm$. The density of the element is $7.2 \ g \ cm^{-3}$. The number of atoms present in $208 \ g$ of the element is nearly:

$Fe$ crystallizes in a $bcc$ lattice. If the edge length is $286.65 \,pm$ and the density is $7.874 \,g/cm^3$, calculate the Avogadro number. $(Fe = 55.845 \,u)$