If the atomic radius of an element is $75 \, pm$ and it crystallizes in a body-centered cubic $(BCC)$ lattice,what is the edge length of the unit cell in $pm$?

In $CsCl$ type structure, if the radius of the cation and anion are $80 \ pm$ and $100 \ pm$ respectively, then the closest distance between two cations is:

What is the number of atoms present per unit cell of aluminium having edge length $4 \ \mathring{A}$? (Given: density of $Al = 2.7 \ g \ cm^{-3}$,atomic mass of $Al = 27 \ g \ mol^{-1}$)

How is the density of a unit cell calculated?

Calculate the number of unit cells in $38.6 \ g$ of noble metal having density $19.3 \ g \ cm^{-3}$ and volume of one unit cell is $6.18 \times 10^{-23} \ cm^{3}$?

If the angle of incidence of $X$-ray of wavelength $3 \mathring{A}$ which produces a second order diffracted beam from the $(100)$ planes in a simple cubic lattice with interlayer spacing $a = 6 \mathring{A}$ is $30^{\circ}$,the angle of incidence that produces a first order diffracted beam from the $(200)$ planes is $.... \, ^{\circ}$