Reflection of color in opaque and transparent materials

[AbsoluteZer0]

Hi,

The textbook I am using does not clearly explain why certain objects reflect certain frequencies of color.

If the frequency of light matches the frequency of the opaque object it is shined upon, will it be absorbed or reflected? I'm thinking that it may be absorbed for the same reason that ultraviolet light is not able to be transmitted through glass, because the vibrating frequency of ultraviolet light matches the natural frequency of glass. Does this mean that if the frequency of light is less than or greater than that of some object, it will be reflected?

What about transparent objects? What causes some colored light to be absorbed while the others are transmitted? With blue glass for example, is it because the natural frequency of the glass matches that of blue light? or is it something else?

Thanks,

 

[jbsteele]

The answer to this depends on the type of object being shined upon. For opaque objects, if the frequency of light matches that of the object, it is likely to be absorbed. This means that if the frequency of light is less than or greater than that of the object, it will be reflected. For transparent objects, the color of light that is absorbed or transmitted depends on the refractive index of the material. This is a measure of how much the material bends light when it passes through it. Different colors of light have different refractive indices and so some colors will be bent more than others, resulting in them being transmitted while others are absorbed. For example, with blue glass, blue light has a higher refractive index than other colors, so it will be bent more and thus be able to pass through the glass while other colors are absorbed.