Polonium (atomic mass = $209$) crystallises in a simple cubic structure with a density of $9.32 \ g \ cm^{-3}$. Its lattice parameter (in $pm$) is closest to:

$Fe$ 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. $(Fe = 55.845 \,u)$

What is the atomic mass of an element with $BCC$ structure and density $10 \ g \ cm^{-3}$ having an edge length of $300 \ pm$?

What are the variables in the graph of powder diffraction pattern of a crystalline solid?

The number of atoms in $100 \ g$ of an $fcc$ crystal with density $d = 10 \ g/cm^3$ and cell edge equal to $100 \ pm$ is equal to

The second order Bragg's diffraction of $X$-rays with $\lambda = 1 \ \mathring{A}$ from a set of parallel planes in a metal occurs at an angle of $60^\circ$. The distance between the scattering planes in the crystal is ................ $\mathring{A}$.