Biology 1202B Lecture Notes - Lecture 6: Electromagnetic Spectrum, Visible Spectrum, Conjugated System
20 Jan 2016
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Electromagnetic energy is given off by the sun due to the fusion of hydrogen: is responsible for all life on earth. Gamma rays have smallest wavelengths (also most energy) Visible spectrum is 400-700 nm in length. The portion of electromagnetic spectrum that humans can see: very small portion. Photons energy particles of light: act like particles in motion they have fixed quantity of energy, wavelength of light is inverse to amount of energy. Violet light has more energy than red. Light has no mass, but still interacts with matter. When light hits an object it can: be reflected, be transmitted through, be absorbed. Excites an electron raising the energy level. Further electron is from nucleus = greater amount of energy. To be used as a source of energy it must be absorbed. Molecules which are efficient at absorbing photons: due to bonding arrangement of carbon atoms. Electrons are delocalized and available to interact with a photon of light.
