Electromagnetic Spectrum MW ovens (2.45 GHz): = 12.2 cm Remote controls = 980 nm KBCO (97.3 MHz): = 3.08 m KVOD (88.1 MHz): l = 3.33 m

Solar Spectrum wavelength in Å Joseph von Fraunhofer, 1814

Radiation from hot objects

Emission Spectra Emission spectrum of Hydrogen

Emission Spectra Emission spectrum of Hydrogen Emission spectrum of Iron

Kirchhoff’s Three Laws of Spectroscopy: Light from a hot solid object has a continuous spectrum with no dark lines The same light, passed through a cool gas has the same spectrum, but with certain wavelengths missing  dark lines (absorption spectrum) Light emitted by a hot gas  bright lines superimposed on an otherwise black background  emission spectrum UV IR