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Emissivity e varies with zenith angle according to e = E*cos(theta)

  1. Aug 19, 2005 #1
    If the emissivity e varies with zenith angle according to e = E*cos(theta) where E is the emissivity normal to the surface. Would this surface be an isotropic source of radiation?

    Well, since e varies with angle then the flux density must vary accordingly so the surface would radiate anistropically.

    Anybody disagree?
    Callisto
     
  2. jcsd
  3. Aug 20, 2005 #2

    selfAdjoint

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    This cosine law is like the one for intensity of incoming solar radiation, and that's a cylinder, so I agree, anisotropic.
     
  4. Aug 20, 2005 #3

    Bystander

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    "Anisotropic" for a point on a surface; integrate intensity at any point above an infinite plane surface, and it's isotropic.
     
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