A piece of glass or other transparent material cut at an accurate angle and plane in an optical device, which can be used to analyze and reflect light. Ordinary triangular prism can separate white light into its constituent color, which is called spectrum. Each color or wavelength that makes up white light is bent or refracted, but in different amounts. The shorter wavelength (towards the purple end of the spectrum) bends the most, while the longer wavelength (towards the red end of the spectrum) bends the least. These prisms are used in some spectrometers, in instruments for analyzing light, and in determining the identification and structure of materials that emit or absorb light.