Lab1 Blackbody Radiation(1).doc

What color do you get when you combine red and green

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What color do you get when you combine red and green light? 3
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Blackbody Radiation W HAT   IS   A  B LACKBODY  O BJECT ? blackbody object  is an object that absorbs all of the energy that hits it, causing it to heat up, and then radiates energy based solely on its temperature.  Most dense objects (solids,  liquids and dense gases) behave like blackbody objects in an ideal sense.  Our bodies  radiate heat in the infrared portion of the electromagnetic spectrum based on the  temperatures of our bodies (night vision goggles are able to detect this radiation, which  allow you to see warm objects even at night).  Stars also behave like blackbody objects.   The energy they emit is based on their surface temperatures, and their overall spectra can  be approximated by blackbody radiation. The energy radiated by a blackbody object obeys two laws: Stefan-Boltzmann law The total intensity of light emitted by a blackbody object is directly proportional to the  temperature of the object, raised to the fourth power. I =  T 4 The  intensity  of an object is the amount of energy it emits per second through a small  square of unit size (one meter squared, for example).  This is equal to the total energy  emitted by the object per second divided by its total surface area. The Stefan-Boltzmann constant,  , is equal to 5.67 x 10 -8  watts meter -2  K -4 , and is simply  a constant of proportionality between the intensity and the temperature to the fourth  power. Wien’s law The light emitted by a blackbody object is not emitted at only one wavelength, but is  emitted over a range of wavelengths, although it is not emitted uniformly at every  wavelength.  The peak wavelength, or the wavelength at which the object emits mostly, is inversely proportional to the temperature of the object.
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Christopher Reinemann
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