Minimum X-ray wavelength

Bremsstrahlung is the radiation generated as high energy incident electrons, are accelerated, by interaction with the atoms of a target material. The maximum photon energy is the total kinetic energy of the incident electron. Incident electron energy is just eV in electron Volts..

At once....

hf = eV

... and maximum photon frequency....

fmax = eV/h

lmin is given by the wave equation c.=.fl as....

lmin = ch/eV

In a typical case; anode voltage 2x104 Volts....

lmin = 3.0x108 x 6.63x10-34 / (1.6x10-19 x 2x104)

= 6.2x10(8 - 34 +19 - 4)

= 0.62x10-10 meters