The wavelength of $X-$rays is

Fraunhofer lines of the solar system are an example of

$X$-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:

$20 \ kV$ electrons can produce $X$-rays with a minimum wavelength of

The electron transition required for the emission of characteristic $K_\beta$ $X$-rays is:

For the production of characteristic $K_{\beta}$ $X$-rays,the electron transition is: