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

In an $X-ray$ tube,when the accelerating voltage $V$ is halved,the difference between the wavelength of the $K_{\alpha}$ line and the minimum wavelength of the continuous $X-ray$ spectrum:

The patient is asked to drink $BaSO_4$ for examining the stomach by $X$-rays because $X$-rays are

When the potential difference applied to an $X$-ray tube is increased, the resulting emitted radiation shows:

The ratio of the energy of the photon emitted by the $K_{\alpha}$ line to that of the $K_{\beta}$ line is

The distance between interatomic lattice planes is $10\ \mathring A$. The maximum wavelength of $X$-rays that can be diffracted by this crystal is ......$\mathring A$.