Light is both a wave and a particle. This is known as the duality of light. Max Planck explained that light can be a particle and a wave. Light exhibits various characteristics. The behavior of light depends on the source and the distance between the source. This is expressed in units of measurement. Lights are transverse and electromagnetic waves. These waves are arranged according to frequency, called the electromagnetic spectrum. Among the waves in the spectrum, the perceptible wave is visible light, which is composed of different colors abbreviated as ROYGBIV, also known as the colors of the rainbow. This has been proved by Sir Isaac Newton, who used a prism to separate white light into its component colors. This phenomenon is called dispersion.