# Photons In A Lumen



## thinkFlashlights01 (Jan 19, 2015)

How many Photons are in a Lumen? It's a question that i have always wondered. :sweat:


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## TEEJ (Jan 19, 2015)

thinkFlashlights01 said:


> How many Photons are in a Lumen? It's a question that i have always wondered. :sweat:



Photons per second might be a better way to phrase the question.

It will depend upon the wavelength of the light, as, the lumen scale is a weighted scale that places more weight on the parts of the spectrum we are most senstive to, and less on our less sensitive reception, etc.

So: (Pasted) 
Photon flux of 540 nm light from the mechanical equivalent of light and the integrated spectral sensitivity of the human eye:


= 3.8 x 10 ^15 photons/second


6.3×10−9_m__o__l_/_s_ (moles of photons per second)

This is for 540 nm wavelength light.
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## thinkFlashlights01 (Jan 19, 2015)

TEEJ said:


> Photons per second might be a better way to phrase the question.
> 
> It will depend upon the wavelength of the light, as, the lumen scale is a weighted scale that places more weight on the parts of the spectrum we are most senstive to, and less on our less sensitive reception, etc.
> 
> ...


So...Something-Octillion is how many photons are in a lumen.  That's a disappointingly low amount of photons. :sigh:


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