Talk:Wien approximation

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I'm not familiar enough with the subject matter to say -- on RC patrol, I ran into this user, who added this to the article. Several of their edits today have appeared questionable -- anyone care to comment? Luna Santin 19:45, 9 October 2006 (UTC)

[edit] Article name

This function is not consistently referred to by the same name in physics textbooks, although "Wien's law" seems to be used more frequently than other names (despite the ambiguity of the name with Wien's displacement law). Several users in a Jan 2007 discussion at Wikipedia Talk:WikiProject Physics decided to use "Wien approximation" as the title for this article. Note, however, that a move in the future may be appropriate. Dr. Submillimeter 13:20, 15 January 2007 (UTC)

Dr. S, good work on fixing up this article. Thanks: --Sadi Carnot 12:19, 25 January 2007 (UTC)
I was under the impression that Wien Approximation more commonly refers to Wien's Displacement Law. Dr. S, think this page would be better named as "Wien Distribution"? That's what it was linked as when I first reached it. --Keflavich 20:12, 8 May 2007 (UTC)
I think Wien Distribution Law might be OK, but it should probably be discussed more first. I suggest starting a new discussion at Wikipedia Talk:WikiProject Physics or placing a post there to direct people to a discussion here. Dr. Submillimeter 07:01, 9 May 2007 (UTC)

[edit] There's something wrong!

The article tells right in the beginning, that "The law may be written as":

I(\nu, T) = \frac{2 h \nu^3}{c^2} e^{-\frac{h \nu}{kT}}

and just beneath that "This equation may also be written as":

I(\lambda, T) = \frac{2 h c^2} {\lambda^5} e^{-\frac{hc}{\lambda kT}}

Obviously noone encountered so far, that you don't get the 2nd from the 1st. Replacing the ν by c / λ would lead to:

I(\lambda, T) = \frac{2 h c} {\lambda^3} e^{-\frac{hc}{\lambda kT}}

As references are cited for both equations, one has to be wrong!

This is not a case where it is as simple as replacing ν by c / λ. I(ν,T) is a derivative of ν, whereas I(λ,T) is a derivative of λ. Note that dν = − (c / λ2)dλ. When this is taken into account, the two equations should be equal. Dr. Submillimeter 08:05, 19 July 2007 (UTC)