According to [1], the conversion factor is about 715 at 540 nm. This is very near the mercury reference line at 546 nm, which is on center of the firefly emission, see also [2]. The conversion factor 683 is also reasonable, and for both, 0.045 mW is an overestimate, by efficiency factors either 93.2% or 97.6%. The question is not really about power, rather about efficiency. LEDs are very comparable in terms of quantum mechanical process, but typical efficiency statistics are much lower, 75-100 lm / Watt. The target is to get a comparable statistic for fireflies. The chemical pathway probably should be traced back to inhibition of mitochondrial oxygen consumption, whether or not this is accomplished using nitric oxide [3]. I don't know, but could hope that the fireflies would be considerably better than 10% efficient. Of course, the inverse process of photosynthesis is more important. Something similar happens... photon capture is extremely efficient, but energy conversion and dispersal involves more losses. --Brad [1] https://www.wolframalpha.com/input/?i=1+lumen+in+photons+per+second [2] https://rupress.org/jgp/article/48/1/95/31452/The-Spectral-Distribution-of-F... [3] https://academic.oup.com/jinsectscience/article/14/1/56/2386239 On Thu, Apr 23, 2020 at 7:43 AM Tom Knight <tk@csail.mit.edu> wrote:
Well, that’s the power delivered by the light, since 1 lux delivers approximately 1/683 watts for light at the optimal human sensitivity peak. Fireflies are pretty close to that peak, I think. So he is probably calculating .03 lumens/683 as the power, which is roughly right. Now, I don’t know what you are really asking. The firefly will use a lot more power to create that light, which is probably what you want to know. How far up the chemical pathway do you want to go?
On Apr 23, 2020, at 12:01 AM, Brad Klee <bradklee@gmail.com> wrote:
Either I don’t know, or I don’t care. Since the thread title isn’t asking for standard formulae, I am erring toward the side of real-world examples. Here’s another one, FIREFLY POWER.
A firefly lights it’s lantern to 0.03 lumens, and a scientist (so he claims) estimates the generating power as 0.045mW.
Is the estimate believable? Why or why not?
—Brad
On Apr 20, 2020, at 9:55 PM, Brent Meeker via math-fun < math-fun@mailman.xmission.com> wrote:
Power = Force*Speed = Force*Distance/Time = Work/Time
It doesn't matter whether the force is producing acceleration or just overcoming friction or gravity.
Brent
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