How are $X-$rays produced?

The wavelength of ${K_{\alpha }}$ $X$-rays produced by an $X$-ray tube is $0.76 \, \mathring{A}$. The atomic number of the anticathode material is:

$X$-rays of wavelength $0.1 \ \mathring A$ are allowed to fall on a metal and get scattered. The wavelength of the scattered radiation is $0.111 \ \mathring A$. If $h = 6.624 \times 10^{-34} \ J \cdot s$ and $m_0 = 9 \times 10^{-31} \ kg$,then the direction of the scattered photons will be:

$A$ metal target with atomic number $Z=46$ is bombarded with a high-energy electron beam. The emission of $X$-rays from the target is analyzed. The ratio $r$ of the wavelengths of the $K_\alpha$-line and the cut-off wavelength is found to be $r=2$. If the same electron beam bombards another metal target with $Z=41$,the value of $r$ will be

In vacuum,an electron of energy $10 \ keV$ hits a tungsten target. The emitted radiation will be:

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