opacity


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opacity

1. the state or quality of being opaque
2. an opaque object or substance
3. Physics Photog the ratio of the intensity of light incident on a medium, such as a photographic film, to that transmitted through the medium
4. Logic Philosophy the property of being an opaque context

opacity

(oh-pass -ă-tee) A measure of the ability of a gaseous, solid, or liquid body to absorb radiation. It is the ratio of the total radiant energy received by the body to the total energy transmitted through it. For gaseous material of a particular chemical composition, opacity depends on both temperature and density. Various processes contribute to the opacity: energy absorption by electrons bound to an atom or ion, allowing them to jump to a higher level or to escape from the atom as free electrons (bound-bound or bound-free absorption); absorption by free electrons (free-free absorption); scattering of photone of radiation by free electrons or atoms (Compton scattering); absorption of γ-ray photons by ambient ‘gas' photons (photon-photon absorption). The negative hydrogen ion, H, is a particularly important source of opacity in a star like the Sun, and the solar opacity is seen to drop rapidly to zero at the Sun's limb.

Opacity

Quality of being impenetrable by light; not reflecting light, or transmitting light, neither transparent nor translucent.

opacity

[ō′pas·əd·ē]
(optics)
The light flux incident upon a medium divided by the light flux transmitted by it.

opacity

The quality of being opaque, as the capacity of a paint to cover or obliterate a background over which it is applied.

opacity

Being "opaque," which prevents light from shining through. For example, in an image editing program, the opacity level for some function might range from completely transparent (0) to completely opaque (100).
References in periodicals archive ?
There is little empirical work that compares the effectiveness of these opacity proxies and their relation to one another.
Whereas two cases, showed dense white (leucoma) opacity as a result of scar formation sequele to corneal ulceration on 7 (th) day and further the opacities did not show any regression in size or density upto 15 (th) day, which was attributed to the deeper initial injuries which produced more dense and permanent scars with no tendency for clearing.
In 2006, the Mars Climate Sounder (MCS) onboard the Mars Reconnaissance Orbiter allowed additional retrievals of dust opacity.
0]--a measured value of opacity in a set mode at a maximum crank shaft speed,%; t--time (duration) of free acceleration mode, s; a and b--equation coefficients; a x [e.
MVPs were synthesized with different amounts of amines added to the organic phase, and the product characterized in terms of dry film opacity and average particle size.
Initially, increasing the amount of TiO(2) in a paint formu - lation improves opacity by increasing the light scattering power of the coating.
Several approaches to the novel discovery of increased opacity were studied utilizing calcium carbonate.
To calculate opacity within the solar interior, solar physicists first accept that the Sun can radiate internally.
Whole-body radiographs revealed obliteration of the right-sided air sacs, a soft-tissue plaque and/ or density in the left caudal thoracic air sac, soft-tissue opacity over the coelomic organs, and increased medullary opacity in the distal right humerus.
Indeed, the differentiation between age-related lens opacity and agerelated cataract is typically based on the latter causing measurable loss of visual function rather than a difference in grade or density of opacity.