In the Bragg's equation for diffraction of $X$-rays, $n$ represents:

If the edge length of a $Cu$ unit cell with $fcc$ structure is $361 \, pm$, then the radius of the $Cu$ atom will be ......... $pm$.

An element with atomic mass $100$ has a $bcc$ structure and edge length $400 \, pm$. The density of the element is .............. $g \, cm^{-3}$.

Lithium crystallises into a body-centered cubic $(BCC)$ structure. What is the radius of lithium if the edge length of its unit cell is $351 \ pm$ (in $pm$)?

$KBr$ has a rock salt type structure and has a density of $3.70 \ g/cm^3$. The edge length of the unit cell is approximately [molecular weight of $KBr = 120 \ g/mol$]:

The inter-planar spacing between the $(2, 2, 1)$ planes of a cubic lattice of length $450 \, pm$ is $.... \, pm$