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Abbe number. In optics and lens design, the Abbe number, also known as the V-number or constringence of a transparent material, is an approximate measure of the material's dispersion (change of refractive index versus wavelength), with high values of V indicating low dispersion. It is named after Ernst Abbe (1840–1905), the German physicist ...
Corrective lens. A corrective lens is a transmissive optical device that is worn on the eye to improve visual perception. The most common use is to treat refractive errors: myopia, hypermetropia, astigmatism, and presbyopia. Glasses or "spectacles" are worn on the face a short distance in front of the eye.
t. e. Advanced Placement ( AP) Human Geography (also known as AP Human Geo, AP Geography, APHG, AP HuGe, AP HuG, AP Human, or HGAP) is an Advanced Placement social studies course in human geography for high school, usually freshmen students in the US, culminating in an exam administered by the College Board. [1]
Abbe condensers are difficult to use for magnifications of above 400X, as the aplanatic cone is only representative of a numerical aperture (NA) of 0.6. This condenser is composed of two lenses, a plano-convex lens somewhat larger than a hemisphere and a large bi-convex lens serving as a collecting lens to the first.
Advanced Placement ( AP) examinations are exams offered in United States by the College Board and are taken each May by students. The tests are the culmination of year-long Advanced Placement (AP) courses, which are typically offered at the high school level. AP exams (with few exceptions [1]) have a multiple-choice section and a free-response ...
The multifocal lenses can correct defective vision in multiple focus, for example: near-vision as well as far-vision. This are particularly beneficial for presbyobia. Contact lenses. Alternatively, many people choose to wear contact lenses. One style is hard contact lenses, which can distort the shape of the cornea to a desired shape.
Prism dioptres. Prism correction is commonly specified in prism dioptres, a unit of angular measurement that is loosely related to the dioptre. Prism dioptres are represented by the Greek symbol delta (Δ) in superscript. A prism of power 1 Δ would produce 1 unit of displacement for an object held 100 units from the prism. [2]
The Supreme Court on Friday upended a 40-year-old decision that made it easier for the federal government to regulate the environment, public health, workplace safety and consumer protections ...