Light, visible light, or visible radiation is electromagnetic radiation that can be perceived by the human eye. [1][2] Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 terahertz.
In most everyday circumstances, the properties of light can be derived from the theory of classical electromagnetism, in which light is described as coupled electric and magnetic fields propagating through space as a traveling wave.
And what are some of the common properties of light, such as absorption, reflection, refraction and diffraction? You might think scientists know all the answers, but light continues to surprise them.
Light is just one form of electromagnetic radiation, or electromagnetic waves. These waves are all around us and come in many sizes. The largest electromagnetic waves, with wavelengths from a few centimeters to over 100 meters are called radio waves.
In common usage, the term light (or visible light) refers to electromagnetic radiation in a wavelength range that is visible to the human eye (about 400–700 nanometers (nm) (15.7-27.6 millionths of an inch)).
In order to see, there must be light. Light shines on an object, then bounces off, or reflects, back to our eyes. Our eyes are sensitive to a certain kind of light called visible light. Visible light is all the colors (red, yellow, blue, etc.) that we can see. But there are many other kinds…
Simply stated, light is nature's way of transferring energy through space. We can complicate it by talking about interacting electric and magnetic fields, quantum mechanics, and all of that, but just remember-- light is energy. Light travels very rapidly, but it does have a finite velocity.