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

$A$ 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 tungsten,the energy of a $K$-shell electron is $20 \, keV$ and that of an $L$-shell electron is $2 \, keV$. When an electron jumps from the $L$ shell to the $K$ shell,the wavelength of the emitted $X$-ray photon will be:

Electrons of mass $m$ with de-Broglie wavelength $\lambda$ fall on the target in an $X$-ray tube. The cutoff wavelength $(\lambda_0)$ of the emitted $X$-ray is

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

What is the difference between soft and hard $X-$rays?