Electrons of mass, $\mathit{m}$ with de-Broglie wavelength, $\mathrm{\lambda }$ fall on the target in an X-ray tube. The cutoff wavelength, $\left({\mathrm{\lambda }}_0\right)$ of the emitted X-ray is

• Correct answer
  A

  ${\mathrm{\lambda }}_0=\frac{2mc{\mathrm{\lambda }}^2}{h}$
• B

  ${\mathrm{\lambda }}_0=\frac{2h}{mc}$
• C

  ${\mathrm{\lambda }}_0=\frac{2m^2{c}^2{\mathrm{\lambda }}^3}{h^2}$
• D

  ${\mathrm{\lambda }}_0=\mathrm{\lambda }$

Hence, the correct answer is option: 'A'.