In an electron microscope, a beam of high energy electrons can knock out core electrons from atoms in the sample. The subsequent relaxation of electrons from higher energy shells to the empty orbital results in the emission of light, the energy of which is characteristic of the element from which it was emitted. This process, called X-ray dispersive spectroscopy, can be used to identify the chemical composition of a sample. For a Cu sample, use the Bohr model to calculate the lowest energy, in eV, of X-rays emitted by this process when an n = 1 electron is knocked out. Ignore charge screening effects.