Where Can I Find the Dimensional Analysis of Emissivity?

AI Thread Summary
Emissivity is a dimensionless ratio representing a material's ability to emit energy by radiation, defined as the energy radiated by a material compared to that of a black body at the same temperature. To prove that emissivity is dimensionless through dimensional analysis, one must analyze the formula and show that both the numerator and denominator share the same dimensions. The discussion references Wikipedia for foundational knowledge on emissivity and dimensional analysis. Participants emphasize the need for a deeper understanding of the derivation of the emissivity formula. The conversation highlights the importance of proving the dimensionless nature of emissivity through equations involving mass, length, and time.
mikekyrou
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Homework Statement



Does anyone know where can i find (book?) the dimensional analysis of emissivity?

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The Attempt at a Solution

 
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hi mikekyrou! :smile:

emissivity is a dimensionless ratio (i supppose it might be better called relative emissivity)

see http://en.wikipedia.org/wiki/Emissivity" …
The emissivity of a material (usually written ε or e) is the relative ability of it's [spelling!] surface to emit energy by radiation. It is the ratio of energy radiated by a particular material to energy radiated by a black body at the same temperature. A true black body would have an ε = 1 while any real object would have ε < 1. Emissivity is a dimensionless quantity.​
 
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Thanks for the reply tiny-tim. I know what is emissivity and i want to prove that emissivity is dimensionless. I know that is because is a ratio but i want to prove it through equations(dimensional analysis-using mass,length,time).
 
but if it's a ratio of two things that are the same dimensionally, then it has to be dimensionless
 
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