When waves are transmitted, the wave continues through the material. Air, glass and water are common materials that are very good at transmitting light. They are transparent because light is transmitted with very little absorption. Translucent materials transmit some light but are not completely clear. Lamp shades, shower curtains and window blinds are often translucent objects.
When white light passes through a coloured filter, all colours are absorbed except for the colour of the filter. And if an object absorbs all of the frequencies of visible light except for the frequency associated with blue light, then the object will appear blue in the presence of ROYGBIV.
Consider the two diagrams below. The papers are impregnated with a chemical capable of absorbing one or more of the colors of white light. Such chemicals that are capable of selectively absorbing one or more frequency of white light are known as pigments. In Example A, the pigment in the sheet of paper is capable of absorbing red, orange, yellow, blue, indigo and violet. In Example B, the pigment in the sheet of paper is capable of absorbing orange, yellow, green, blue, indigo and violet.
In each case, whatever color is not absorbed is reflected. Check your understanding of these principles by determining which color s of light are reflected by the paper and what color the paper will appear to an observer.
See Answer Example A: Green will be reflected and so the paper appears green to an observer. Express your understanding of this principle by filling in the blanks in the following diagrams. See Answer Example A: Green will be transmitted and so the object appears green to an observer. Example B: Both green and blue will be transmitted and so the object appears greenish-blue to an observer. The colors perceived of objects are the results of interactions between the various frequencies of visible light waves and the atoms of the materials that objects are made of.
Many objects contain atoms capable of either selectively absorbing, reflecting or transmitting one or more frequencies of light. The frequencies of light that become transmitted or reflected to our eyes will contribute to the color that we perceive. Natural philosophers have long pondered the underlying reasons for color in nature.
One common historical belief was that colored objects in nature produce small particles perhaps light particles that subsequently reach our eyes. Different objects produce different colored particles, thus contributing to their different appearance.
Is this belief accurate or not? This view presumes that the appearance of an object is independent of the colors of light which illuminate the object. We observe that the same object appears different colors when viewed under different light. So the secret to an object's appearance is not strictly due to its ability to produce a color. Any two colors whose light together produces white are called complementary colors, e.
When pigments are mixed, the resulting sensations differ from those of the transmitted primary colors. The process in this case is subtractive, since the pigments subtract or absorb some of the wavelengths of light. Magenta red-violet , yellow, and cyan blue-green are called subtractive primaries, or primary pigments. A mixture of blue and yellow pigments yields green, the only color not absorbed by one pigment or the other.
Most materials are opaque. When light strikes an opaque object none of it passes through. Most of the light is either reflected by the object or absorbed and converted to heat.
Materials such as wood , stone, and metals are opaque to visible light.
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