After passing through a gold film of thickness $5 \times 10^{-3} \ m$,the intensity of an $X$-ray beam decreases to $36.8\%$ of its initial intensity. The absorption coefficient is ....... $m^{-1}$.

Hydrogen atom does not emit $X$-rays because

An $X$-ray tube with a copper target emits a $Cu$ $K_{\alpha}$ line of wavelength $1.50 \ \mathring{A}$. What should be the minimum voltage through which electrons are to be accelerated to produce this wavelength of $X$-rays? $(h = 6.63 \times 10^{-34} \ \text{J}\cdot\text{s}, c = 3 \times 10^8 \ \text{m/s})$

The energy of a photon of characteristic $X-$ rays from a Coolidge tube comes from

Find the wavelength of $K_\alpha$ $X$-rays.

Stopping potentials of $24, 100, 110$ and $115 \ kV$ are measured for photoelectrons emitted from a certain element (with $24 \ kV$ minimum) when it is irradiated with monochromatic $X-rays$. If this element is used as a target in an $X-ray$ tube,what will be the wavelength of the $K_{\alpha}$ line?