4. Astronomers classify stars as being in the Am class by spectral signatures with strong emissions at a wavelength of 424.6 nm for excited Sr2+ ions and significantly weaker emissions for Sc2+ ions at 421.5 nm. Sr has a lower second ionization energy (11.03 eV) than Sc (12.89 eV), resulting in its greater abundances; hotter stars have both these elements present in the doubly ionized states. a. Calculate the energy, in eV, of a single photon from an Am class star's scandium on emission line at 421.5 nm. b. Describe the specific energy source of the 421.5nm photons