. . "\\(\\varepsilon\\)"^^ . . "\\(\\varepsilon = \\frac{M}{M_b}\\), where \\(M\\) is the radiant exitance of a thermal radiator and \\(M_b\\) is the radiant exitance of a blackbody at the same temperature."^^ . . . "http://en.wikipedia.org/wiki/Emissivity"^^ . "Emissivity of a material (usually written \\(\\varepsilon\\) or e) is the relative ability of its surface to emit energy by radiation."^^ . "Emissivity"@en .