Defining White Light
White light is electromagnetic radiation that contains all wavelengths of the visible spectrum in roughly equal proportions. Unlike a single color like red or blue, white light is not a monochromatic light but rather a combination or mixture of all the colors that the human eye can perceive.
Composition and the Visible Spectrum
When white light passes through a prism, it separates into its constituent colors—red, orange, yellow, green, blue, indigo, and violet (ROYGBIV)—demonstrating its composite nature. These colors represent different wavelengths of light, and when combined, they appear white to our eyes.
Everyday Examples of White Light
The most common and natural example of white light is sunlight. The sun emits a broad spectrum of electromagnetic radiation, and the portion that reaches Earth's surface and is visible to us is perceived as white light. Artificial sources like incandescent bulbs, fluorescent lamps, and certain LED lights are also designed to produce light that appears white.
Significance in Vision and Science
White light is fundamental to how we perceive colors. Objects appear to have a certain color because they selectively absorb some wavelengths of white light and reflect others. Without white light as an illuminator, our ability to distinguish colors would be severely limited. In science, studying the spectrum of white light is crucial for understanding light sources and optical phenomena.