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)

Frequency of the $K_{\alpha}$ $X$-ray for the element calcium $(Ca, Z = 20)$ is $8.95 \times 10^{17} \ Hz$. The frequency of the $K_{\alpha}$ $X$-ray for the element cadmium $(Cd, Z = 48)$ will be:

What does the $K\alpha$ characteristic $X$-ray represent?

The wavelength of the most energetic $X$-rays emitted when a metal target is bombarded by $40 \ keV$ electrons is approximately ....... $\mathring{A}$. $(h = 6.62 \times 10^{-34} \ J \cdot s; 1 \ eV = 1.6 \times 10^{-19} \ J; c = 3 \times 10^8 \ m/s)$

In an $X-$ray experiment,what do $K_{\alpha}$ and $K_{\beta}$ denote?

An $X$-ray tube with a copper target emits a $Cu$ $K_{\alpha}$ line of wavelength $1.50 \ \mathring{A}$. What should be the minimum voltage through which electrons are to be accelerated to produce this wavelength of $X$-rays? $(h = 6.63 \times 10^{-34} \ \text{J}\cdot\text{s}, c = 3 \times 10^8 \ \text{m/s})$