$A$ metal crystallises in $bcc$ structure with edge length $4 \times 10^{-8} \ cm$. If density of unit cell is $10 \ g \ cm^{-3}$,what is its molar mass?

Iron crystallizes in different structures. At $911 \, ^oC$,it undergoes a transition from $bcc$ to $fcc$ structure. If the distance between the nearest neighbors is the same in both structures at the transition temperature,the ratio of the densities of $bcc$ and $fcc$ structures will be ..........

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

How can you determine the atomic mass of an unknown metal if you know its density and the dimension of its unit cell? Explain.

Gold has a face-centered cubic $(fcc)$ lattice with an edge length of the unit cube of $407 \, pm$. The diameter of the gold atom is .............. $pm$.

For a crystal, the angle of diffraction $(2 \theta)$ is $90^{\circ}$ and the second order line has a $d$ value of $2.28 \ \text{Å}$. The wavelength (in $\text{Å}$) of $X$-rays used for Bragg's diffraction is