White light is a combination of a spectrum of wavelengths. Each wavelength
is a different colour. See below.
|There are six main colours: red, orange, yellow, green, blue and violet.
You may have heard that there are seven colours of the rainbow but there
are really only six.
When all of the wavelengths between 780 nm and 390 nm enter our eyes
in roughly equal intensity, we perceive white light. White light is the
sum of all of the colours of a rainbow.