Ionization Limit (Solution)

The energy of ionization is 13.6 eV. Using the conversion factor between eV and ergs, this corresponds to 2.18 x 10^-11 ergs. The corresponding wavelength is obtained by taking the product of the speed of light and Planck's constant and dividing that by the energy and is 9.1 x 10^-6 cm, which lies in the UV part of the spectrum. Thus, hydrogen is easily ionized in the presence of UV radiation.