The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye.
Electromagnetic radiation in this range is called VISIBLE LIGHT, or simply LIGHT.
A typical human eye will respond to wavelengths between 380 to 750 nm (Nanometers)
An eye that has adapted to daytime conditions generally has a maximum sensitivity around 555nm. Compared to the color red which optical spectrum is around 630 – 650nm our eye is closer to the Green region of the optical spectrum at 510 - 530nm.