angle of incidence

Let L1 and L2 be a pair of lines, both in a projective plane and expressed in homogeneous coordinates: L1:[m1:b1:1]L L2:[m2:b2:1]L where m1 and m2 are slopes and b1 and b2 are y-interce ...

See also:

Incidence geometry, Incidence geometry - Intersection of a pair of lines, Incidence geometry - Determining the line passing through a pair of points, Incidence geometry - Checking for incidence of a line on a point, Incidence geometry - Concurrence, Incidence geometry - Collinearity

Read more here: » Incidence geometry: Encyclopedia II - Incidence geometry - Intersection of a pair of lines

An X-ray microscope uses electromagnetic radiation in the soft X-ray band to produce images of very small objects. Unlike visible light microscopes, X-rays do not reflect or refract easily, and they are invisible to the human eye. Therefore the basic process of an X-ray microscope is to expose film or use a charge-coupled device (CCD) detector to detect X-rays that pass through the specimen, rather than light which bounces off the specimen. Early X-ray microscopes by Kirkpatrick and Baez used grazing-incidence reflective optics ...

Read more here: » X-ray microscope: Encyclopedia - X-ray microscope

Dictionary definitions from Wiktionary Textbooks from Wikibooks Quotations from Wikiquote Source texts from Wikisource Images and media from Commons News stories from Wikinews Weather is an all-encompassing term used to describe all of the many and varied phenomena that can occur in the atmosphere of a planet. The term is normally taken to mean the activity of these phenomena over short periods of time, usually no more than a few days in length. Avera ...

Including:

• Weather - Basic mechanism
• Weather - Terrestrial weather
• Weather - Shaping the Planet
• Weather - Human History
• Weather - In the Future
• Weather - Extra-terrestrial weather
• Weather - Extra-planetary weather

Read more here: » Weather: Encyclopedia - Weather

A wing is a surface used to produce an aerodynamic force normal to the direction of motion by travelling in air or another gaseous medium, facilitating flight. It is a specific form of airfoil. The first use of the word was for the foremost limbs of birds, but has been extended to include the wings of Insects, bats and pterosaurs; also man-made devices. A wing is an extremely efficient device for generating lift. Its aerodynamic quality, expressed as a Lift-to-drag ratio, can be up to 60 on some gliders and even more. Th ...

Including:

• Wing - Use
• Wing - Artificial wings
• Wing - Terms used to describe aeroplane wings
• Wing - Design features
• Wing - Wing types
• Wing - Science of wings
• Wing - Evolution of wings in animals

Read more here: » Wing: Encyclopedia - Wing

Fixed-wing aircraft is a term used to refer to what are more commonly known as airplanes in North American English and aeroplanes in Commonwealth English. An airplane is a heavier-than-air aircraft where movement of the wings in relation to the aircraft is not used to generate lift. All aircraft wings flex, and some aircraft have wings that can tilt, sweep back or fold, but if none of these movements are used to g ...

Including:

• Fixed-wing aircraft - Conventional airplanes
• Fixed-wing aircraft - Fixed parts
• Fixed-wing aircraft - Mobile parts
• Fixed-wing aircraft - Flight lift
• Fixed-wing aircraft - Types of fixed-wing aircraft
• Fixed-wing aircraft - Propeller aircraft
• Fixed-wing aircraft - Jet aircraft
• Fixed-wing aircraft - Super sonic aircraft
• Fixed-wing aircraft - Rocket-powered aircraft
• Fixed-wing aircraft - Ramjet aircraft
• Fixed-wing aircraft - History
• Fixed-wing aircraft - Designing and constructing an airplane
• Fixed-wing aircraft - Industrialized production
• Fixed-wing aircraft - Safety

Read more here: » Fixed-wing aircraft: Encyclopedia - Fixed-wing aircraft

Alhazen Abu Ali al-Hasan Ibn Al-Haitham (also: Ibn al Haythen), (965-1040), was a mathematician; he is sometimes called al-Basri, after his birthplace Basrah, Iraq. Alhazen - Life. Alhazen was born at Basra, then part of Buwayhid Persia, now part of Iraq (See [1] and [2]), and probably died in Cairo, Egypt. One account of his career has him summoned to Egypt by the mercurial caliph Hakim to regulate the flooding of the Nile. After his field work made him aware of the impracticality of t ...

Including:

• Alhazen - Life
• Alhazen - Works
• Alhazen - Optics
• Alhazen - Other Alhazens
• Alhazen - Bibliography

Read more here: » Alhazen: Encyclopedia - Alhazen

The albedo is a measure of reflectivity of a surface or body. It is the ratio of electromagnetic radiation (EM radiation) reflected to the amount incident upon it. The fraction, usually expressed as a percentage from 0% to 100%, is an important concept in climatology and astronomy. This ratio depends on the frequency of the radiation considered: unqualified, it refers to an average across the spectrum of visible light. It also depends on the angle of incidence of the radiation: unqualified, normal incidence. Fresh snow albedos are hig ...

Including:

• Albedo - Some examples of albedo effects
• Albedo - Fairbanks Alaska
• Albedo - The tropics
• Albedo - Small scale effects
• Albedo - Pine forests
• Albedo - Urban areas
• Albedo - Trees
• Albedo - Snow
• Albedo - Clouds
• Albedo - Aerosol effects
• Albedo - Black carbon

Read more here: » Albedo: Encyclopedia - Albedo

Let P1 and P2 be a pair of points, both in a projective plane and expressed in homogeneous coordinates: P1:[x1:y1:z1], P2:[x2:y2:z2]. Let g−1 be the inverse duality mapping: which maps points onto their dual lines. Then the unique line passing through points P ...

See also:

Incidence geometry, Incidence geometry - Intersection of a pair of lines, Incidence geometry - Determining the line passing through a pair of points, Incidence geometry - Checking for incidence of a line on a point, Incidence geometry - Concurrence, Incidence geometry - Collinearity

Read more here: » Incidence geometry: Encyclopedia II - Incidence geometry - Determining the line passing through a pair of points

Three lines in a projective plane are concurrent if all three of them intersect at one point. That is, given lines L1, L2, and L3; these are concurrent iff If the lines are represented using homogeneous coordinates in the form [m:b:1]L with m being slope and b being the y-intercept, then c ...

See also:

Incidence geometry, Incidence geometry - Intersection of a pair of lines, Incidence geometry - Determining the line passing through a pair of points, Incidence geometry - Checking for incidence of a line on a point, Incidence geometry - Concurrence, Incidence geometry - Collinearity

Read more here: » Incidence geometry: Encyclopedia II - Incidence geometry - Concurrence

Given line L and point P in a projective plane, and both expressed in homogeneous coordinates, then P⊂L iff the dual of the line is perpendicular to the point (so that their dot product is zero); that is, if where g is the duality mapping. An equivalent way of checking for this same incidence is to see whether is true. ...

See also:

Incidence geometry, Incidence geometry - Intersection of a pair of lines, Incidence geometry - Determining the line passing through a pair of points, Incidence geometry - Checking for incidence of a line on a point, Incidence geometry - Concurrence, Incidence geometry - Collinearity

Read more here: » Incidence geometry: Encyclopedia II - Incidence geometry - Checking for incidence of a line on a point

The dual of concurrency is collinearity. Three points P1, P2, and P3 in the projective plane are collinear if they all lie on the same line. This is true iff but if the points are expressed in homogeneous coordinates then these three different equations can be collapsed into one equation: which is more sy ...

See also:

Incidence geometry, Incidence geometry - Intersection of a pair of lines, Incidence geometry - Determining the line passing through a pair of points, Incidence geometry - Checking for incidence of a line on a point, Incidence geometry - Concurrence, Incidence geometry - Collinearity

Read more here: » Incidence geometry: Encyclopedia II - Incidence geometry - Collinearity

Alhazen was born at Basra, then part of Buwayhid Persia, now part of Iraq (See [1] and [2]), and probably died in Cairo, Egypt. One account of his career has him summoned to Egypt by the mercurial caliph Hakim to regulate the flooding of the Nile. After his field work made him aware of the impracticality of this scheme, and fearing the caliph's anger, he feigned madness. He was kept under house arrest until Hakim's death in 1021. During this time he wrote scores of i ...

See also:

Alhazen, Alhazen - Life, Alhazen - Works, Alhazen - Optics, Alhazen - Other Alhazens, Alhazen - Bibliography

Read more here: » Alhazen: Encyclopedia II - Alhazen - Life

While it is true that the creation of an evanescent wave does not affect the conservation of energy under ordinary conditions, i.e. the evanescent wave transmits zero net energy, if a medium with a higher refractive index is placed less than several wavelengths distance from the boundary of the first medium, the strength of the evanescent wave will be large enough to effect a change in the field of the second material. Electrons driven by the field allow ...

See also:

Total internal reflection, Total internal reflection - Frustrated Total Internal Reflection

Read more here: » Total internal reflection: Encyclopedia II - Total internal reflection - Frustrated Total Internal Reflection

Retroreflection (sometimes called retroflection) is used on road surfaces, road signs, vehicles and clothing (large parts of the surface of special safety clothing, less on regular coats). When the headlights of a car illuminate a retroflective surface, the reflected light is directed towards the car and its driver, and not wasted by going in all directions as with diffuse reflection. However, a pedestrian can see a retroreflective surface in the dark only if there is a light source directly between them and the reflector, e.g. a torch they ...

See also:

Retroreflector, Retroreflector - Retroreflectors on roads, Retroreflector - Retroreflectors on the Moon, Retroreflector - Retroreflectors and invisibility

Read more here: » Retroreflector: Encyclopedia II - Retroreflector - Retroreflectors on roads

The original Cherokees were the Cherokee 150 and Cherokee 160 (PA-28-150 and PA-28-160), which started production in 1961 (unless otherwise mentioned, the model number always refers to horsepower). In 1962, Piper added the Cherokee 180 (PA-28-180): the extra power made it practical to fly with all four seats filled, and the Cherokee 180 remains popular on the used-airplane market. Piper continued to expand the line rapidly: in 1963, the company introduced the even more powerful Cherokee 235 (PA-28-235), which competed favourably with the Ces ...

See also:

Piper Cherokee, Piper Cherokee - History, Piper Cherokee - Wing design, Piper Cherokee - Flight Controls and Flaps, Piper Cherokee - Specifications PA-28-161 Warrior II 1982-, Piper Cherokee - General characteristics, Piper Cherokee - Performance, Piper Cherokee - Related content, Piper Cherokee - Designation sequence, Piper Cherokee - Related development, Piper Cherokee - Similar aircraft, Piper Cherokee - Related lists, Piper Cherokee - External links

Read more here: » Piper Cherokee: Encyclopedia II - Piper Cherokee - History

On Earth, regularly occuring weather phenomena include such things as wind, cloud, rain, snow, fog and dust storms. Less common events include natural disasters such as tornadoes, hurricanes and ice storms. Almost all recognised weather phenomena on Earth occur in the troposphere (the lower part of the atmosphere). Weather does occur in the stratosphere and does affect weather lower down in the troposphere, but ...

See also:

Weather, Weather - Basic mechanism, Weather - Terrestrial weather, Weather - Shaping the Planet, Weather - Human History, Weather - In the Future, Weather - Extra-terrestrial weather, Weather - Extra-planetary weather

Read more here: » Weather: Encyclopedia II - Weather - Terrestrial weather

In aviation, washout refers to the practice of building a wing with a slight twist, reducing the angle of incidence from root to tip. This is to ensure that, at the stall, the wing root stalls before the tips. Wingtip stall is unlikely to occur symmetrically. When one wingtip stalls it leads to wing drop, a rapid rolling motion. Also, roll control may be reduced if the airflow over the ailerons is disrupted by the stall reducing their effectiveness. Thus,the pilot may not be able to maintain control perhaps leading to an unrecoverable spin. ...

See also:

Washout, Washout - Aviation, Washout - External links, Washout - Road and rail transport, Washout - Jamaican culture

Read more here: » Washout: Encyclopedia II - Washout - Aviation

The historical sequence of events now brings us to the discovery of the achromatic telescope. The first person who succeeded in making achromatic refracting telescopes seems to have been Chester Moor Hall, a gentleman of Essex. He argued that the different humours of the human eye so refract rays of light as to produce an image on the retina which is free from colour, and he reasonably argued that it might be possible to produce a like result by combining lenses composed of different refracting media. After devoting some time to the i ...

See also:

History of telescopes, History of telescopes - Refracting telescopes, History of telescopes - Reflecting telescopes, History of telescopes - Achromatic Telescope, History of telescopes - Related links

Read more here: » History of telescopes: Encyclopedia II - History of telescopes - Achromatic Telescope

Wing - Terms used to describe aeroplane wings. Flaps partially deployed Full flaps Full flaps, with airbrakes and spoilers deployed for ground braking Leading edge: the front edge of the wing Trailing edge: the back edge of the wing Span: distance from wing tip to wing tip Chord: distance from wing leading edge to wing trailing edge, usually measured parallel to the long axis of the fuselage Aspect ratio: ratio of span to standard mean chord ...

See also:

Wing, Wing - Use, Wing - Artificial wings, Wing - Terms used to describe aeroplane wings, Wing - Design features, Wing - Wing types, Wing - Science of wings, Wing - Evolution of wings in animals

Read more here: » Wing: Encyclopedia II - Wing - Artificial wings

Even with modern techniques, the cutting and polishing of a diamond crystal always results in a dramatic loss of weight; rarely is it less than 50 percent. The round brilliant cut is preferred when the crystal is an octahedron, as often two stones may be cut from one such crystal. Oddly shaped crystals such as macles are more likely to be cut in a fancy cut—that is, a cut other than the round brilliant—which the particular crystal shape lends itself to. The prevalence and choice of a particular fancy cut is also influenced by fash ...

See also:

Diamond cut, Diamond cut - Theory, Diamond cut - Choice of cut, Diamond cut - Round brilliant, Diamond cut - Facet count and names, Diamond cut - Proportions, Diamond cut - Fancy cuts, Diamond cut - Modified brilliants, Diamond cut - Step cuts, Diamond cut - Mixed cuts, Diamond cut - Rose cuts, Diamond cut - Cut grading, Diamond cut - History

Read more here: » Diamond cut: Encyclopedia II - Diamond cut - Fancy cuts