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Stefan-Boltzmann Law: Relating Total Intensity with Temperature


    In a MATHEMATICAL sense, the Stefan-Boltzmann Law looks like this:


    By using this equation, we can determine just how BRIGHT (in an absolute sense) the thermal object is, that is, how many Watts / m2 of light (power) is coming from this object. As the temperature INCREASES, the power INCREASES. But it does so very rapidly: by the FOURTH power of the temperature. As you turn UP the temperature even just a little bit on the stove, it also gets much much brighter (see below).

    A few example calculations:

    • If the stove is currently 300 K, how bright in W/m2 is the center of the oven?
    • If a star has a surface brightness of 9 x 105 W/m2, what must be the surface temperature of the star?
    • If I increase the stove to twice the temperature, how much brighter is infrared light coming from the oven?