Minimum wavelength of continuous X-ray spectrum is given by –

Here, energy of incident electrons (in eV)

Also, the energy of the incident electrons is more than the ionization energy of the K shell electrons (i.e. 72.5 keV). Therefore, characteristic X-ray spectrum will also be obtained because energy of incident electron is high enough to knock out the electron from or shells.

→ Question based on continuous and characteristic spectrum was also asked in screening 2001. Remember that source of continuous spectrums acceleration of electron, while source of characteristic spectrum is de-excitation of electron.