The graph that correctly represents the relation of frequency $\nu$ of a particular characteristic $X$-ray with the atomic number $Z$ of the material is

In an $X$-ray tube,when the accelerating voltage is increased from $10 \ kV$ to $20 \ kV$,the difference between the wavelength of the $K_\alpha$ line and the short-wavelength limit of the continuous spectrum increases by a factor of $3$. The atomic number of the target element 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:

$X$-rays will travel the minimum distance in which of the following materials?

The wavelength $\lambda$ of the ${K_{\alpha}}$ line of characteristic $X$-ray spectra varies with atomic number $Z$ approximately as:

Which of the following is accompanied by the characteristic $X-$ray emission?