. . . "I" . . "Radiant Intensity is a measure of the intensity of electromagnetic radiation. It is defined as power per unit solid angle." . "Radiant Intensity"@en . "http://en.wikipedia.org/wiki/Radiant_intensity"^^ . "\\(I = \\frac{d\\Phi}{d\\Omega}\\), where \\(d\\Phi\\) is the radiant flux leaving the source in an elementary cone containing the given direction with the solid angle \\(d\\Omega\\)."^^ .