Electrons with energy `80 keV` are incident on the tungsten target of an X - rays tube , k- shell electrons of tungsten have `72.5 keV` energy X- rays emitted by the tube contain only

Options

A. a continuous X-rays spectrum (Bremsstrahlung) with a minimum wavelength of `~0.155` Å)
B. a continuous X-ray spectrum (Bremsstrahlung) with all wavelengths
C. the characteristic X-ray spectrum of tungsten
D. a continuous X-ray spectrum (Bremsstrahlung) with a minimum wavelength of `~0.155`Å and the characteristics X-ray spectrum of tungsten

Answer

C

Explanation

Since the energy of incident electron, E=80 keV. The minimum wavelength of X-rays produced is
`lamda=(hc)/(E)=(6.6xx10^(-34)xx3xx10^(8))/(80xx1000xx1.6xx10^(-19))`
`=0.155xx10^(-10),m=0.155` Å
Since, the energy of K-shell electron is -72.5 keV, so the incident electron of energy of 80 keV will not only produce continuous spectrum of minimum wavelength 0.155 Å but shell also knowck electron of K-shell out of atom, resulting emision of characteristics X-rays.