為何X光的最短波長與X光管的電壓有關?

An x-ray spectrum composes of a continuous background and spectral lines that are characteristics of the target element.

The shortest wavelength refers to the shortest wavelength produced in the continuous background. It is produced because of rapid decceleration of fast moving electrons when they collide with heavy atoms in the target, such that all kinetic energy of an electron is transformed into electromagentic radiation. . The radiation so produced is called bremsstrahlung (i.e. braking radiation).

Be aware that the wavelengths of the characteristic spectral lines do not depend on the high tension used on the X-ray tube (i.e. independent of bombarding electron energy). They only depend on the target material.

天同:
How do the bombarding electrons convert all their energy into X-ray in this process?