The difference between soft and hard $X-$rays is due to their:

The wavelength of an $X$-ray photon is $0.01 \ \mathring A$. Its momentum in $kg \ m/s$ is .........

The wavelength of ${K_{\alpha }}$ $X$-rays produced by an $X$-ray tube is $0.76 \, \mathring{A}$. The atomic number of the anticathode material is:

When $X$-rays from a Coolidge tube pass through an aluminum foil of thickness $0.3 \, mm$,$50\%$ of the $X$-rays are transmitted. If the potential difference between the target and the cathode is increased,the fraction of $X$-rays transmitted through the same foil will be .......

Fraunhofer lines of the solar system are an example of

If the minimum wavelength of an $X$-ray is $2 \mathring{A}$,then the potential difference between the anode and the cathode is ...... $kV$.