Ma. Catalina B. Mallillin Professor Shila Sia IV–31 BSE General Science January 17, 204 Written Report in Astronomy Understanding Spectra Three Important Properties Spectra: 1. There are three kinds of spectra: (i.) continuous spectra (ii.) absorption or dark line spectra (iii.) emission or bright line spectra 2. Photons are emitted or absorbed wh en an electron in an atom makes a transition from one energy level to another. 3. Most modern astronomy books display spectra as graphs of intensity versus wavelength. Lyman series - is the series of transitions and resultingultravioletemission lines of thehydrogenatomas anelectron goes from n≥ 2 ton= 1 (where nis theprincipal quantum number)the lowest energy level of the electron. Balmer series - is the designation of one of a set of six different named series descri bing the spectral line emissions of thehydrogen atom.Paschen series - are the series of lines in the spectrum of the hydrogen atom which corresponds to transitions between the state with principal quantum number n = 3 and successive higher states. In 1859, long before scientists understood atoms and energy levels, the German scientist Gustav Kirchhoff formulated three rules, now known as Kirchhoff’s laws, that describes the three t ypes of spectra. Kirrchhoff’s LawsLaw I: The Continuous Spectrum A solid, liquid, or dense gas ex cited to emit light will radiate at all wavelengths and thus produce a continuous spectrum Law II: The Emission Spectrum A low-density gas excited to emit light will do so at specific wavelengths and thus produce an emission spectrum. Law III: The Absorption Spectrum If light comprising a continuous spectrum passes through a cool, low-density gas, the result will be an absorption spectrum.
