Final answer:
A prism's main refractive characteristic is its ability to disperse white light into its spectrum of colors, a phenomenon known as dispersion.
Step-by-step explanation:
The principal refractive characteristic of a prism is its ability to disperse white light into its constituent colors. This process is called dispersion, and it occurs because different frequencies of light have different refractive indices when passing through the prism material.
As white light enters the prism, each color is refracted by a different amount, with shorter wavelengths (like violet) bending more than longer wavelengths (like red).
Figure 5.9 illustrates this concept by showing how a beam of white light is separated into a spectrum of colors when it passes through a triangular glass prism.
Moreover, binoculars and other optical instruments like lenses employ similar principles of refraction and total internal reflection, suggesting the widespread applicability of the prism's refractive properties.