Review Exam 1 - Review Exam 1: Ch. 1-3 Ch. 3 Global Energy...

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Ch. 3 Global Energy Balance Greenhouse Effect Electromagnetic Radiation Earth is heated by 50% of sun’s radiation (visible light) Properties o Self-propagating electric and magnetic wave that is similar to a wave that moves on surface of a pond o Wave of ER –light, UV, infrared radiation—moves at fixed speed c “speed of light” 3.00x10 8 m/s o Series of crests and troughs; wavelength : distance between two adjacent crests o Frequency of wave: number of crests, passing by an observer standing at a fixed point in path of a wave, in one second o Speed of wave must equal product of number of wave crests that pass a given point each second (frequency) and the distance between the crests (wavelength) o Longer the wavelength of an electromagnetic wave, the lower its frequency, vice versa. Photons, Photon Energy o Photon: a single particle or pulse of ER; smallest independent amount of energy transported by electromagnetic wave of a given frequency. Energy E of a photon= its frequency; h Planck’s constant 6.63x10 -34 J -s o High-frequency (short wavelength) photons have high energy; low- frequency… o Difference in photon energy— important when ER interacts with matter, high and low- frequency photons have different effects High-energy photons can break molecules apart and cause chemical reactions Low-energy photons cause molecules to rotate faster/ vibrate more strongly Electromagnetic Spectrum o Full range of forms of ER which differ by their wavelengths (or frequencies) o Wavelengths in visible range measured in nanometers (nm) o Visible radiation: visible light; consists of a narrow range of wavelengths, 400-700nm. Color of light depends on wavelength. o Visible spectrum : range of component wavelengths of visible light o 40% of Sun’s energy is emitted at wavelengths longer than visible limit, 700nm in a region, infrared region o Infrared radiation : IR wavelengths longer than visible light wavelengths
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This note was uploaded on 10/14/2011 for the course HIST 389 taught by Professor Lauralovett during the Spring '08 term at UMass (Amherst).

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Review Exam 1 - Review Exam 1: Ch. 1-3 Ch. 3 Global Energy...

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