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The Electromagnetic Spectrum. Blackbody Radiation. Atmospheric absorption and scattering changes spectrum at earth’s surface. VISIBLE Light. Glow Bar spectra. Light Emitting Diode. Laser. Photo-electric Effect. Is RED or BLUE easier to see at Night? During day?. Radiometric Terms.
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Blackbody Radiation Atmospheric absorption and scattering changes spectrum at earth’s surface VISIBLE Light
Radiometric Terms ‘Intensity’ If you are interested in only VISIBLE light and detection BY THE EYE, then replace ‘radiant’ with ‘luminous’. Also units change.. Eg. ‘watt’ becomes ‘lumen’. ‘Watt/steradian’ becomes ‘candela’.
Terms generally refer to either source, propagation and then detection Note: concept of Radiant Exitance needed if source is extended
Radiant Intensity NOTE: For this isotropically radiating source, Radiant Intensity DOES NOT DEPEND on how far you are away…. The area ΔA shrinks or expands to keep SOLID ANGLE fixed.