Calculate the wavelength of the $K_{\alpha}$ line for $Z=31$, given $a=5 \times 10^7 \text{ Hz}^{1/2}$ for a characteristic $X$-ray spectrum.

If $\lambda_{Cu}$ is the wavelength of the $K_{\alpha}$ $X$-ray line of copper (atomic number $Z = 29$) and $\lambda_{Mo}$ is the wavelength of the $K_{\alpha}$ $X$-ray line of molybdenum (atomic number $Z = 42$),then the ratio $\frac{\lambda_{Cu}}{\lambda_{Mo}}$ is close to:

If the potential difference $V$ applied to the Coolidge tube is doubled, then the cut-off wavelength

The wavelength of the most energetic $X$-ray emitted when a metal target is bombarded by $100 \text{ keV}$ electrons is approximately.......$ \mathring{A} $

The wavelength of the $K\alpha$ line in copper is $1.54 \ \mathring{A}$. The ionization energy of the $K$ electron in copper in Joules is:

Which of the following wavelengths in $\mathring{A}$ represents 'hard' $X$-rays?