Talk:Rayleigh–Jeans law

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Common notation should be used between this page and that on Wien's Approximation (Law) so that the results shown in the figure can be easily reconciled with the equations.

[edit] Energy densities

There is a potential confusion: Energy per unit volume, which is what one usually means by energy density, has different units from energy density per unit wavelength which, in turn, has different units from energy density per unit frequency. It is stated that the function given is the energy density which cannot be the energy per unit volume by dimensional analysis. Furthermore, the Plank law originally written had wavelength-cubed dependence in the denominator which I changed to wavelength-to-the-fifth. This is necessary to get the first equation as the short-wavelength limit. Which form of the energy `density' one uses is a matter of convention but because of non-trivial Jacobian factors which appear in going from one to the other, the functional dependence of these forms is quite different. —The preceding unsigned comment was added by Wdlinch3 (talk • contribs) 18:11, 22 March 2007 (UTC).

[edit] energy density formula

on my school book the energy density formula is $f(\lambda) = \frac{8\pi c k T}{\lambda^4}$ instead of $f(\lambda) = \frac{8\pi k}{c}~\frac{T}{\lambda^4}$ . light constant is in the upper side of the expression. right now i can't check on other sources.