Astronomy 1021 Chapter Notes - Chapter 5: Electromagnetic Spectrum, Photon, Radiography
16 Aug 2016
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Smooth surface: mirror like reflection in a particular direction. Rough surface: scattering= reflection in a variety of directions. The sun appears distorted at sunset because of refection in earth"s atmosphere. An object that absorbs all light is opaque. An object that only partially absorbs is translucent. Light can act either like a wave or like a particle. Particles of light are called photons o o. It interfere like waves but have momentum like particles. Wave- a pattern of motion that can carry energy w/o carrying matter along with it o. Frequency- number of times per second that wave vibrates up and down o. It interacts w/ charged particles through these electric and magnetic fields. Does not need a medium to propagate through o o o. Em waves travel at c: wavelength x frequency = 3. 00 x 108 m/s. Photon"s energy is directly proportional to its frequency l x f = c o l = wavelength.
