Question

The shortest wavelength of $X$-rays coming from an $X$-ray tube depends on the

• A. voltage applied to the tube
• B. current in the tube
• C. atomic number of target element
• D. nature of gas in the tube

Answer 1

Answer: (A)

When the electron loses whole of its energy in a single collision with the atoms, an $X$-ray photon of maximum energy
$h_{\max }$ is emitted ie, $\frac{1}{2}m{v}^2=eV$
$=h{v}_{\max }=\frac{hc}{{\lambda }_{\min }}$
Minimum wavelength = cut-off wavelength of $X$-ray
${\lambda }_{\min }=\frac{hc}{eV}=\frac{12375}{V_{(\text{in out })}}\mathring{A}$