The variation of wavelength $\lambda$ of the $K_{\alpha}$ line with atomic number $Z$ of the target is shown by the following curve of

When cathode rays strike a metal target with a high melting point and high atomic number,what is produced?

The Compton effect is associated with

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

If $\lambda_{Cu}$ is the wavelength of the $K_{\alpha}$ $X$-ray line of copper (atomic number $Z = 29$) and $\lambda_{Mo}$ is the wavelength of the $K_{\alpha}$ $X$-ray line of molybdenum (atomic number $Z = 42$),then the ratio $\frac{\lambda_{Cu}}{\lambda_{Mo}}$ is close to:

$A$ 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