ClipArt ETC
"The radiation of light, or the intensity of light is inversely proportional to the square of the distance from the light source." —Croft 1917

Light Intensity

"The radiation of light, or the intensity of light is inversely proportional to the square of the distance…

"A card placed at point A receives normal light. At point B the card receives four times as much light, but only at 1/4 intensity. At point C nine times the area covered, but only 1/9 the intensity." —Quackenbos 1859

Light Intensity at Different Distances

"A card placed at point A receives normal light. At point B the card receives four times as much light,…

"The intensity of light from a candle decreases proportionally with an increase in distance from the candle." -Comstock 1850

Dispersion of Light

"The intensity of light from a candle decreases proportionally with an increase in distance from the…