Practice question

**Excitation** energy required to go from n=1 to n=3 is 12.09 eV, from ground to n=∞ ionization 13.6 eV, state n=∞ means ionized, electron free with zero energy, highest level reached by electron beam energy determines which levels can be excited, e.g., 11 eV beam from ground can reach n=2 (10.2 eV) but not n=3 (12.09 eV), so max n=2. E₁ = -13.6 eV . E_n = -13.6 + 12.5 = -1.1 eV . -1.1 = -(13.6/n²) ⇒ n² ≈ 12.36 ⇒ n = 3 (since E₃ = -1.51 eV < -1.1 eV , n = 3 ). Using E_n = -13.6/n² eV, r_n =