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How do you calculate/measure irradiance without a solar meter?
Using light of a 65 W fluorescent light (equivalent to 300 W), how do you measure the irradiance of the the light at a certain distance away from the light source?
- ?Lv 51 decade agoFavorite Answer
The most accurate was is with a pyranometer. You can get one at he AltE Store for a reasonable price, http://www.altestore.com/store/Meters-Communicatio...
However, if you must calculate it, you must find out its rated brightness in Lumens (L). Brightness (B) = L / 4Pi x Distance (d) squared.
Or, the inverse square law says when the distance from a light doubles, its brightness should decrease by a factor of four. I = C/d squaredSource(s): AltE Store - http://www.altestore.com/store/ http://cosmology.berkeley.edu/Education/Projects/D...