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Principle of the periscope. The periscope on the left uses mirrors whereas the right uses prisms. a Mirrors b Prisms c Observer's eye Principle of the lens periscope. The two periscopes differ in the way they erect the image. The left one uses an erecting prism whereas the right uses an erecting lens and a second image plane. a Objective lens b ...
Halo (optical phenomenon) A halo (from Ancient Greek ἅλως (hálōs) 'threshing floor, disk') [1] is an optical phenomenon produced by light (typically from the Sun or Moon) interacting with ice crystals suspended in the atmosphere. Halos can have many forms, ranging from colored or white rings to arcs and spots in the sky.
The extraocular muscles, or extrinsic ocular muscles, are the seven extrinsic muscles of the eye in humans and other animals. [1] Six of the extraocular muscles, the four recti muscles, and the superior and inferior oblique muscles, control movement of the eye. The other muscle, the levator palpebrae superioris, controls eyelid elevation.
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Prism (optics) An optical prism is a transparent optical element with flat, polished surfaces that are designed to refract light. At least one surface must be angled — elements with two parallel surfaces are not prisms. The most familiar type of optical prism is the triangular prism, which has a triangular base and rectangular sides.
Optical phenomena are any observable events that result from the interaction of light and matter . All optical phenomena coincide with quantum phenomena. [1] Common optical phenomena are often due to the interaction of light from the Sun or Moon with the atmosphere, clouds, water, dust, and other particulates.
Take a polygon with n vertices, n edges. Its prism has 2n vertices, 3n edges, and 2 + n faces. Take a polyhedron with V vertices, E edges, and F faces. Its prism has 2V vertices, 2E + V edges, 2F + E faces, and 2 + F cells. Take a polychoron with V vertices, E edges, F faces, and C cells. Its prism has 2V vertices, 2E + V edges, 2F + E faces ...
Visual perception is the ability to interpret the surrounding environment through photopic vision (daytime vision), color vision, scotopic vision (night vision), and mesopic vision (twilight vision), using light in the visible spectrum reflected by objects in the environment. This is different from visual acuity, which refers to how clearly a ...
Four-sided dice, abbreviated d4, [1] are often used in tabletop role-playing games to obtain random integers in the range 1–4. Three forms exist of this die: a tetrahedron (pyramid shape) with four equilateral triangle -shaped faces, a rectangular prism with rounded or pointed ends, and an elongated long die with four triangular faces.
a score of zero by a batsman in cricket, supposedly derived from the zero-like shape of a duck's egg. Hence to "break one's duck": to score one's first run. c.f. US: "get the monkey off one's back" Hence to "break one's duck": to score one's first run. c.f. US: "get the monkey off one's back"
