The minimum wavelength of $X$-rays produced in a Coolidge tube operated at a potential difference of $40 \ kV$ is ....... $\mathring{A}$.

The wavelength of the series limit of the Lyman series in the hydrogen spectrum is $911 \ \mathring{A}$. Calculate the atomic number of the element that emits characteristic $X$-rays with a minimum wavelength of $0.7 \ \mathring{A}$.

The minimum wavelength of the $X$-rays produced at an accelerating potential $V$ is $\lambda$. If the accelerating potential is changed to $2V$, then the minimum wavelength would become:

Let ${\lambda _\alpha }$,${\lambda _\beta }$ and ${\lambda '_\alpha }$ denote the wavelengths of the $X-$ rays of the ${K_\alpha }, {K_\beta }$ and ${L_\alpha }$ lines in the characteristic $X-$ rays for a metal.

The energy of an electromagnetic radiation is $14.4 \, KeV$. To which part of the electromagnetic spectrum does it belong?

Consider a photon of continuous $X$-ray and a photon of characteristic $X$-ray of the same wavelength. Which of the following is different for the two photons?