Light, Vision, and Photometry

Аннотация

When a beam of light traveling in air falls upon a glass surface at an angle, it is refracted or bent. The amount of refraction depends upon the wavelength, its variation with wavelength being known as dispersion. Similarly, when the beam, traveling in glass, emerges into air, it is refracted (with dispersion). A glass prism provides a refracting system of this type. Because different wavelengths are refracted by different amounts, an incident white beam is split up into several beams corresponding to the many wavelengths contained in the composite white beam. This is how the spectrum is obtained.