Hard $X$-rays produced from a Coolidge tube are due to .........

The graph between the square root of the frequency of a characteristic line in the $X$-ray spectrum and the atomic number of the target is:

The order of voltage applied across the ends of an $X$-ray tube is ...... $V$.

The minimum wavelength of the $X$-rays produced by electrons accelerated through a potential difference of $V$ volts is directly proportional to

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:

If a voltage applied to an $X$-ray tube is increased to $1.5$ times, the minimum wavelength $(\lambda_{\min})$ of an $X$-ray continuous spectrum shifts by $\Delta \lambda = 26 \, pm$. The initial voltage applied to the tube is: