Violet light and the color violet is at the lower end of the visible spectrum. Green and Blue are in the middle of visible spectrum of light. Red is at the upper end of the spectrum. This means that violet light has a shorter wave length and higher frequency and that red light has a longer wave length and short frequency.

Law of Refraction

All light may be defined as a pulse or a wave. This explanation is beyond the scope fo th article but has bearing on it never the less. A pulse (and a wave) carries energy through a medium from one location to another. When the pulse reaches the end of the medium, where does the energy go? Does the energy disappear? Does the energy pass into the new medium? The phenomenon which occurs when a wave reaches the end of the medium through which it travels is often termed boundary behavior. There are a variety of observations that can be made of the boundary behavior of a pulse. Such observations pertain to the changes (or lack of changes) in the frequency, wavelength, speed, amplitude, and phase of the pulse.

The animation below depicts the boundary behavior of a pulse which is moving along a less dense medium and incident towards (i.e. approaching) a more dense medium. Note that when the pulse reaches the end of the medium, a portion of its energy is transmitted into the denser medium (in the form of a transmitted pulse), and a portion of its energy remains in the less dense medium (in the form of a reflected pulse).