Colour (physics)
 coloured beams of light. All the colours mixed together produce white.', copy:'(Image %C2%A9 Research Machines plc)'});)
 is used to split a ray of white light into its spectral colours.', copy:'(Image %C2%A9 Research Machines plc)'});)
Click images to enlarge
In physics, quality or wavelength of light emitted or reflected from an object. Visible white light consists of electromagnetic radiation of various wavelengths, and if a beam is refracted through a prism, it can be spread out into the visible spectrum (that can be detected by the human eye), in which the various colours correspond to different wavelengths. From long to short wavelengths (from about 700 to 400 nanometres) the colours are red, orange, yellow, green, blue, indigo, and violet.
The colour of grass is green because grass absorbs all the colours from the spectrum and only transmits or reflects the wavelength corresponding to green. A sheet of white paper reflects all the colours of the spectrum from its surface; black objects absorb all the colours of the spectrum.
All colours can be obtained from mixing proportions of red, green, and blue light. These are known as primary colours. Different colour filters can also produce light of different colours. For example, a red filter only transmits red light, the remaining colours of the spectrum being absorbed by the filter.
Mixing red, green, and blue light in the correct proportions produces white light. When these colours are mixed in different proportions, secondary colours are formed, such as cyan, magenta, and yellow. For example, blue + red = magenta, red + green = yellow, and green + blue = cyan. Yellow light is reflected from the surfaces of some flowers as the petals absorb blue light. Red and green light are reflected back, and these mix to give the sensation of yellow.
No comments:
Post a Comment