# Wavelength of radiation given off by stuff heated by the sun? **URL:** \ **Category:** Factual Questions\ **Created:** [August 26, 2015, 10:22pm UTC](https://boards.straightdope.com/t/wavelength-of-radiation-given-off-by-stuff-heated-by-the-sun/728992 "2015-08-26T22:22:27Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![sweeteviljesus](https://avatars.discourse-cdn.com/v4/letter/s/898d66/32.png) [@sweeteviljesus](https://boards.straightdope.com/u/sweeteviljesus)\ **Post date:** [August 26, 2015, 10:22pm UTC](https://boards.straightdope.com/t/wavelength-of-radiation-given-off-by-stuff-heated-by-the-sun/728992/1 "2015-08-26T22:22:27Z")
Say I leave a black plastic bucket or something out in the sun on a clear day. What is the range of wavelengths of the photons radiated by it as it heats up? Thanks, Rob ---
**Author:** ![Itself](https://avatars.discourse-cdn.com/v4/letter/i/d07c76/32.png) [@Itself](https://boards.straightdope.com/u/Itself)\ **Post date:** [August 26, 2015, 10:38pm UTC](https://boards.straightdope.com/t/wavelength-of-radiation-given-off-by-stuff-heated-by-the-sun/728992/2 "2015-08-26T22:38:48Z")
A blackbody radiates at all frequencies, though not with the same intensity. (That is, the average number of photons emitted per time varies with frequency.) By Wien’s displacement law, the wavelength at which it’s maximized is proportional to 1/T. Taking room temperature T = 300 K, the peak wavelength occurs close to 10 um, squarely in the infrared region (as one would expect). ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [August 26, 2015, 10:45pm UTC](https://boards.straightdope.com/t/wavelength-of-radiation-given-off-by-stuff-heated-by-the-sun/728992/3 "2015-08-26T22:45:05Z")
Yep, 10, maybe 9 if it got nice and warm. If it’s a blackbody or graybody. But if it has a peaky spectrum you might get most of the radiation at a longer wavelength.