Light & Color

Invisible Light

Light from an incandescent bulb is directed through a prism to a detector, and a line is drawn on a screen showing the brightness for each color in light source. The pattern on the screen shows that much of light transmitted we are unable to see. The highest intensity light, in the area where the curve peaks, is in the infrared range which the eye can't detect. Only about 10% of the energy of an incandescent light bulb is transmitted as visible light-the rest is emitted as infrared light. Fluorescent lights and sodium streetlights are much more energy-efficient, because they don't waste energy producing infrared light.