Copper crystallises in $fcc$ with a unit cell length of $361 \ pm$. What is the radius of copper atom? ............... $pm$

Calculate the number of particles present per unit cell if the mass of a particle is $8.0 \times 10^{-23} \ g$ and the product of density and volume of the unit cell $(\varrho \times a^3)$ is $3.2 \times 10^{-22} \ g$.

Niobium crystallizes in a $bcc$ structure. If its density is $8.55 \, g/cm^3$, calculate the atomic radius of niobium. [Atomic mass of $Nb = 93 \, u$] (in $pm$)

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 ................ $\mathring{A}$.

Calculate the edge length of $bcc$ unit cell if the radius of a particle present in it is $186 \ pm$.

$A$ compound forms a $bcc$ unit cell with an edge length of $400 \text{ pm}$. Determine the molar mass of the compound if the density of the compound is $3.5 \text{ g cm}^{-3}$. (Given: $N_A = 6.022 \times 10^{23} \text{ mol}^{-1}$)