Question

Electrons with energy $80KeV$ are incident on the tungsten target of an X-ray tube. $K$ shell electrons of tungsten have $-72.5keV$ energy. X-rays emitted by the tube contain only :

• A. A continuous X-ray spectrum (Bremsstrahlung) with a minimum wavelength of $-0.155\mathring{A}$
• B. A continuous X-ray spectrum (Bremsstrahlung) with all wavelengths
• C. A continuous X-ray spectrum of tungsten
• D. A continuous X-ray spectrum (Bremsstrahlung) with a minimum wavelength of $-0.155\mathring{A}$ and the characteristic X-ray spectrum of tungsten

Answer 1

The correct option is D A continuous X-ray spectrum (Bremsstrahlung) with a minimum wavelength of $-0.155\mathring{A}$ and the characteristic X-ray spectrum of tungsten

The minimum wavelength of continuous spectrum $\lambda =hc/E$

$\lambda =\frac{6.6\times {10}^{-34}\times 3\times {10}^8}{80\times {10}^3\times 1.6\times {10}^{-19}}$

Since the energy of the incident radiation is more than that of K shell electrons. The characteristic wave will appear as a peak on the continuous spectrum .