Talk:Black-body radiation

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Application to people[edit]

The math in this section is wrong and the result 1000 W is way off. This needs to be fixed by an expert. — Preceding unsigned comment added by 161.130.189.238 (talk) 17:10, 24 January 2022 (UTC)[reply]

Yes it is nonsense. The heat loss is 100 W. 1000 W is radiation, but needs absorbtion too. — Preceding unsigned comment added by 78.30.183.44 (talk) 19:54, 8 February 2022 (UTC)[reply]

Mistake at the end of Further … subsection, just before Equations[edit]

The formula E = σT^4 is incorrect, if E is “radiant heat”. First, it is an equation, not a formula.

The correct equation is j* = σT^4 where j* is the energy flux, i.e., the power per unit area. Indeed T is absolute temperature and the Stefan-Boltzmann constant has the correct dimensions.

David B. Benson (talk) 21:02, 30 May 2022 (UTC)[reply]

What does "its" refer to under first graph?[edit]

Danred99 (talk) 03:36, 19 March 2023 (UTC)[reply]

Is it or is it not true[edit]

Is it or is it not true that all macroscopic objects emit BB radiation? I think this article is confused, and I think it's likely because the editors are confused. The lead defines it in a way that means it doesn't exist. There are no perfect thermal equilibria, nor do any perfect black bodies exist. The concept that seems to be missing here is "idealization". Not approximation, not estimate; idealization. All macroscopic bodies emit EMR. Full stop. Of course, we can jump into the weeds (into the can of worms) and ask what is meant by "body" (or object)? (general answer would be something like an arbitrary closed surface), but let's not do that. My understanding of BB radiation is that it is the emission which would be emitted by a black body at the same temperature as the object in question. The REAL object will have additional features in its emission spectrum (both additive and subtractive). This means it is an "as if". It probably would be useful to state that there are no objects that are able to absorb all possibly incident EMR radiation. (Black holes aside). Finally, I want to stress that the editors aren't wrong, but they don't handle the entire universe of contexts in which BB radiation is a useful concept. In fact, their formal definition is a disconnect with the real-world (and the real utility of the concept).71.30.95.172 (talk) 06:00, 7 April 2023 (UTC)[reply]

Calling Sun and almost every other object in Universe (beside reflecting objects) a "Black Body", is a typical confusion of modern Science... It should be called Body Thermal Radiation ... 79.98.159.114 (talk) 15:31, 6 May 2023 (UTC)[reply]

Discrepancy in Wien's displacement law ?[edit]

There are two examples for 293K in section Wien's displacement law, which do not match each other... When interpolating Planck's law Bν(T) maximum for T=293K, I get maximum at ν=17.225THz, which has wavelength of 17.404μm, which is the second case in that article section... What is then the 9.9μm maximum in first case in that article section? For Λ=c/f the two values 17THz and 9.9μm do not match each other... 79.98.159.114 (talk) 15:08, 6 May 2023 (UTC)[reply]

This is not a mistake, see Wien's displacement law#Maxima differ according to parameterization for details. Jähmefyysikko (talk) 17:10, 6 May 2023 (UTC)[reply]

Ok, when the Planck's formula result is divided by μm per 1 Hz, and then integrated per unit wavelength, then the peak is near 9.9μm ... Maybe it is not sufficiently explained in the article... 79.98.159.114 (talk) 09:59, 7 May 2023 (UTC)[reply]