The pressure inside an $X$-ray tube is approximately:

If the potential difference between the anode and cathode of the $X$-ray tube is increased,then which of the following statements is correct regarding the given $X$-ray spectrum graph?

When the atomic number of the first target is $Z_1 = 64$ and the atomic number of the second target is $Z_2 = 80$,the approximate ratio of the wavelengths of the $K_{\alpha,1}$ and $K_{\alpha,2}$ radiations is .......

The minimum wavelength of $X$-rays produced in a Coolidge tube operating at $40 \ kV$ is ..... $\mathring A$.

For the production of characteristic $K_{\beta}$ $X$-rays,the electron transition is:

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 $.5$)