$X-$rays are produced due to

The $K_{\alpha}$ $X$-ray emission from tungsten occurs at $\lambda = 0.021 \ nm$. The energy difference between the $K$ and $L$ levels in the atom is:

The wavelengths of $K_\alpha$ lines of two elements are $250 \, pm$ and $179 \, pm$, respectively. The number of elements between these two elements in the periodic table will be:

The wavelength of the ${K_\alpha}$ line for an element of atomic number $29$ is $\lambda$. Then the wavelength of the ${K_\alpha}$ line for an element of atomic number $15$ is (Take Moseley's constant $b = 1$ for both elements).

The distance between interatomic lattice planes is $10\ \mathring A$. The maximum wavelength of $X$-rays that can be diffracted by this crystal is ......$\mathring A$.

When $X$-rays of wavelength $0.5 \, Å$ pass through an $Al$ sheet of thickness $10 \, mm$, their intensity is reduced to one-sixth of its initial value. The absorption coefficient for aluminum is ............. $mm^{-1}$.