AST101H1 Lecture Notes - Lecture 12: Absorption Spectroscopy, Low Frequency, Photosphere
9 Nov 2017
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AST101H1 Full Course Notes
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Temperature of object affects its spectrum: anything warm" glows, hot things are brighter (per area) Spectrum of hot things peak at shorter wavelength. 1000 k: orange: blue= hotter, orange/red= cooler. Speed of a wave is its frequency times its wavelength: s = fl. At constant speed: longer wavelengths = lower frequency, shorter wavelengths = higher frequency. Each photon of light has energy that is proportional to the wave"s frequency: e = hf. H = tiny number called planck"s constant: low frequency (long wavelength) photons have low energy, high frequency (short wavelength) photons have high energy. It is as if light waves are also particles. An electron can change to a lower energy orbital, if it emits a photon of light corresponding to the energy change. An electron can change to a higher energy orbital, if it absorbs a photon" of light corresponding to the energy change. Thermal radiation comes from a hot dense source.
