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 $.52$)

If the voltage of an $X$-ray tube is doubled,the intensity of the $X$-rays will be ...... .

The wavelength of the $K_{\alpha}$ line for an element with atomic number $57$ is $\lambda$. What will be the wavelength of the $K_{\alpha}$ line for an element with atomic number $29$?

Two elements $A$ and $B$ with atomic numbers $Z_{A}$ and $Z_{B}$ are used to produce characteristic $X$-rays with frequencies $v_{A}$ and $v_{B}$ respectively. If $Z_{A}: Z_{B} = 1: 2$, then $v_{A}: v_{B}$ will be

An $X$-ray tube produces a continuous spectrum of radiation with its shortest wavelength of $45 \times 10^{-2} \text{ Å}$. The maximum energy of a photon in the radiation in $eV$ is (in $27,500$). $(h = 6.62 \times 10^{-34} \text{ J-s}, c = 3 \times 10^8 \text{ m/s})$.

The wavelengths of $K_{\alpha}$ $X$-rays of two metals $A$ and $B$ are $\frac{4}{1875R}$ and $\frac{1}{675R}$ respectively,where $R$ is Rydberg's constant. The number of elements lying between $A$ and $B$ according to their atomic numbers is