The voltage applied across an $X$-ray tube is nearly......$V$.

Penetrating power of $X$-rays increases with an increase in

For the production of $X$-rays, the target should be made of

The characteristic $X-$ray radiation is emitted,when

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:

If the $K_\alpha$ radiation of $Mo (Z=42)$ has a wavelength of $0.71 \;\mathring A$,calculate the wavelength of the corresponding $K_\alpha$ radiation of $Cu (Z=29)$ (in $\mathring A$). (in $.52$)