PHY 121 Lecture Notes - Lecture 21: Smog, Photon, Thermal Radiation
11 Dec 2016
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Document Summary
Involved in production and use of energy, as well as environmental consequence. Thermal radiation released in atmosphere and bodies of water by electric power plants. Radioactivity: emitted in production of energy in nuclear power plants. Visible light is the most commonly acknowledged form of electromagnetic radiation. A wave id s disturbance (vibration) which propagates through space. Mechanical waves require a medium but light does not need a medium. Frequency: number of oscillations per second (measured in hertz, hz,). Period t: time for 1 oscillation to pass. V = (wave length represented as lambda) multiplied by (frequency, f) Maxwell"s model predicts light which propagates at c = 3. 00x10 to 8th power meters per second. Radio, microwave, infrared, visible, ultra violet, x-rays, gamma rays. As alluded to, wave-like model fails at times. Example: photoelectric effect: circuit is broken, get current with light on plate and ejects electrons. Albert einstein provided an explanation: each e- will absorb one incident photon.
