Light intensity: Why to keep lights as close as possible

[smokybear]

oh! here the set up,check out my current threads heres one I have two going


http://boards.cannabis.com/showthread.php?t=86604

[stinkyattic]

damn that 'you must spread rep' box. DAMN IT!!!
After all, you and the Bear are always posting informative stuff.
DAMN DAMN DAMN.
nice one.

[4x5]

Just google 'Inverse Square Law'

The distances are not measured in linear feet, but total area of illumination. distance doubles, light is quartered (same total light, just spread over 4 times the area). A good set of reflective (white foam-core, or mylar covered) panels nearly negate this.

Light intenstiy = Total Light Emitted / ((4 x pi) x (radius^2))

And light intensity decreases by 1/x^2 where x is the distance.

So like if you have 135,000 lumens at 1 foot, you increase that to 2 ft, you it would be 135,000 x 1/2^2 which is 1/4 so basically one fourth of 135,000 = 33,750. Add one more foot, 135,000 x 1/3^2 = 135,000 x 1/9 = 15,000.

Crazy huh? Thats why the top bud always is so big and the bottom ones are smaller, cause they get a lot less light. LST'ing takes that problem away, preventing you from having like 5 feet from the top to the bottom of the plant.

So thats the science behind bigger buds.