Question

Electrons with energy `80 keV` are incdent on the tungsten target of an X - rays tube , k- shell electrons of tangsten have `72.5 keV` energy X- rays emitted by the tube constain only
A. a contimuous X - rays spectrum (Bremasstrablung) with a miximum wavelength of `0.155Å`
B. a contimuous X - rays spectrum (Bremasstrablung) with all wavelength
C. the characteristic X - rays spectrum of tungsten`
D. a contimuous X - rays spectrum (Bremasstrablung) with a miximum wavelength of `0.155Å` and the characteristic X - rays spectrum of tungsten.

Answer 1

Correct Answer - D
KEY CONCEPT :
`lambda_(min) = (he)/(E )`
`:.lambda_(min) = (12400)/(80 xx 10^(3)) Å = 0.155 Å`
Energy of incident electrons is greater than the ionization energy of electron in `K- shell`, the `K- shell` electrons will be knocked off . Hence, characteristic X - ray spectrum will be obtained