The energy of an $X$-ray photon of wavelength $1.65 \mathring{A}$ is ....... $keV$. $(h = 6.6 \times 10^{-34} \ J \cdot s, \ c = 3 \times 10^8 \ m/s, \ 1 \ eV = 1.6 \times 10^{-19} \ J)$ (in $.5$)

For the production of $X$-rays of wavelength $0.1 \mathring{A}$,the minimum potential difference required will be.....$kV$.

If the series limit of the Balmer series for hydrogen is $3646 \ \mathring{A}$,calculate the atomic number $(Z)$ of the element which gives an $X$-ray wavelength of the $K_{\alpha}$ line as $1.0 \ \mathring{A}$.

The wavelength of an $X$-ray beam is $10 \, \mathring{A}$. The mass of a fictitious particle having the same energy as that of the $X$-ray photons is $\frac{x}{3} h \, \text{kg}$. The value of $x$ is ....... . ($h =$ Planck's constant)

$X$-rays are produced in the laboratory by:

The energy of the $K_\alpha$ $X$-ray line of an element is $8578$ units,and the energy of the $L$ level is $-2859$ units. The energy of the $K$ level is . . . . . . units.