Definitions Continued

[Brian Essi]

From: http://study.com/academy/lesson/white-l ... ctrum.html

Definition of White Light
The electromagnetic spectrum is comprised of a variety of types of electromagnetic waves, each with different wavelengths or frequencies. For example, x-rays, gamma rays, infrared radiation and ultraviolet radiation are examples of electromagnetic waves. Only a small portion of the spectrum of wavelengths can be seen by the human eye. This visible portion of the electromagnetic spectrum is called the visible spectrum. This shows the full spectrum of electromagnetic radiation and highlights the small part of the spectrum that can be called the visible spectrum.

White light is defined as the complete mixture of all of the wavelengths of the visible spectrum. This means that if I have beams of light of all of the colors of the rainbow and focus all of the colors onto a single spot, the combination of all of the colors will result in a beam of white light.

Sources of White Light
White light can be generated by a variety of sources both in space and by artificial sources on earth. For example, the sun and other stars are sources of white light. The sun is the most obvious source of white light in our solar system. As for artificial sources, fluorescent light bulbs and white LEDs produce white light. Other light bulbs, like the incandescent lamp, do not produce white light. They produce light of much longer wavelengths along the yellow to red range.

Spectrum
This illustrates the full electromagnetic spectrum. It highlights just how small the visible spectrum is as compared to the rest of the electromagnetic spectrum. White light is a mixture of all of the visible wavelengths.

[cameron karslake]

Brian,

You used one of my favorite words earlier!

Check out what I saw while out for a walk last winter...talk about subliminal!