What is a wave?
A wave is a disturbance that travels from one location to another, transporting energy from one place to another as individual matter are temporarily displaced then returned to its original resting position.
Nature of light
Light acts like a wave. The wave speed of a light wave is the speed of light, and the various wavelengths of light waves are seen as different colors. The energy of a light wave is inversely proportional to its wavelength. Low energy waves have long wavelengths and thus, lower frequency; high energy light waves have short wavelengths and thus, higher frequency.
White light is made up of the 7 colors of the rainbow: red, orange, yellow, green, blue, indigo and violet. The light waves of these colors travel at different speeds and have their own wavelengths.