The figure represents the observed intensity of $X-$ rays emitted by an $X-$ ray tube as a function of wavelength. The sharp peaks $A$ and $B$ denote

What determines the hardness of the $X-$rays obtained from the Coolidge tube?

Find the wavelength of $K_\alpha$ $X$-rays.

The continuous $X-$ray spectrum produced by an $X-$ray machine at constant voltage has

$X$-rays of wavelength $\lambda$ are reflected from parallel planes of atoms in a crystal with spacing $d$ between two planes, as shown in the figure. If the two reflected beams interfere constructively, then the condition for maxima will be (where $n$ is the order of the interference fringe):

If $10000\, V$ is applied across an $X$-ray tube,what will be the ratio of the de-Broglie wavelength of the incident electrons to the shortest wavelength of $X$-rays produced? (Given: $\frac{e}{m}$ for an electron is $1.8 \times 10^{11}\, C\, kg^{-1}$)