$W$. $K$. Roentgen discovered

Which of the following wavelengths falls in the $X-$ray region in $\mathring{A}$?

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:

The potential difference applied to an $X$-ray tube is increased. As a result,in the emitted radiation

If the minimum wavelength obtained in an $X-ray$ tube is $2.5 \times 10^{-10} \ m$,the operating potential of the tube will be.....$kV$.

Stopping potentials of $24, 100, 110$ and $115 \ kV$ are measured for photoelectrons emitted from a certain element (with $24 \ kV$ minimum) when it is irradiated with monochromatic $X-rays$. If this element is used as a target in an $X-ray$ tube,what will be the wavelength of the $K_{\alpha}$ line?