The wavelength of $X-$rays is of the order of

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:

$X-$rays are in nature similar to

The energy of the $L$ shell is $7200$ units and the energy of the $K$ shell is $1800$ units. Therefore,the energy of the $K_\alpha$ line is equal to ...... units.

The ratio of the energy of an $X$-ray photon of wavelength $1 \mathring{A}$ to that of visible light of wavelength $5000 \mathring{A}$ is:

For harder $X$-rays: