$X$-rays were discovered by

$A$ hydrogen atom does not emit $X$-rays because

The structure of solid crystals is investigated by using

The $K, L$ and $M$ energy levels of platinum lie roughly at $78, 12$ and $3 \ keV$ respectively. The ratio of the wavelength of the $K_{\alpha}$ line to that of the $K_{\beta}$ line in the $X$-ray spectrum is:

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

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