An element has a $BCC$ structure. The edge length of the unit cell is $288 \, pm$. If the density of the crystal is $7.2 \, g \, cm^{-3}$, what is the atomic mass of the element?

If the density of a gold $(Au)$ crystal crystallizing in a $ccp$ structure is $19.3 \, g/cm^3$,what will be the radius of the atom? (Given: $Au = 197 \, amu$)

In the $x$-ray reflection $(n=1)$, the distance between two parallel planes of $NaCl$ is $280 \ pm$ and the diffraction angle is $5.2^{\circ}$. What is the wavelength of its light radiation? (Given: $\sin 5.2^{\circ} = 0.09$)

Derive the formula to determine the density of a unit cell.

Which formula is used to calculate edge length $(a)$ in a $bcc$ structure,where $r$ is the radius of the atom?

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