Here's why:
* Electromagnetic Spectrum: Visible light is just a small portion of the electromagnetic spectrum, which includes everything from low-energy radio waves to high-energy gamma rays.
* Wavelength and Color: The color we perceive from visible light is determined by its wavelength.
* Red light has the longest wavelength (around 700 nm).
* Violet light has the shortest wavelength (around 400 nm).
* The other colors of the rainbow fall between these extremes.
Therefore, the range of 400 to 700 nm encompasses the entire spectrum of colors that humans can see.
