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  2. Snellen chart - Wikipedia

    en.wikipedia.org/wiki/Snellen_chart

    In the most familiar acuity test, a Snellen chart is placed at a standard distance: 6 metres. At this distance, the symbols on the line representing "normal" acuity subtend an angle of five minutes of arc, and the thickness of the lines and of the spaces between the lines subtends one minute of arc. This line, designated 6/6 (or 20/20), is the ...

  3. Stereopsis - Wikipedia

    en.wikipedia.org/wiki/Stereopsis

    Stereopsis (from Ancient Greek στερεός (stereós) 'solid' and ὄψις (ópsis) 'appearance, sight') is the component of depth perception retrieved through binocular vision. [ 1 ] Stereopsis is not the only contributor to depth perception, but it is a major one. Binocular vision happens because each eye receives a different image ...

  4. Paschen's law - Wikipedia

    en.wikipedia.org/wiki/Paschen's_law

    Paschen's law is an equation that gives the breakdown voltage, that is, the voltage necessary to start a discharge or electric arc, between two electrodes in a gas as a function of pressure and gap length. [2][3] It is named after Friedrich Paschen who discovered it empirically in 1889. [4]

  5. Brachistochrone curve - Wikipedia

    en.wikipedia.org/wiki/Brachistochrone_curve

    The curve of fastest descent is not a straight or polygonal line (blue) but a cycloid (red).. In physics and mathematics, a brachistochrone curve (from Ancient Greek βράχιστος χρόνος (brákhistos khrónos) 'shortest time'), [1] or curve of fastest descent, is the one lying on the plane between a point A and a lower point B, where B is not directly below A, on which a bead slides ...

  6. Nyquist stability criterion - Wikipedia

    en.wikipedia.org/wiki/Nyquist_stability_criterion

    The Nyquist plot for () = + + with s = jω.. In control theory and stability theory, the Nyquist stability criterion or Strecker–Nyquist stability criterion, independently discovered by the German electrical engineer Felix Strecker [] at Siemens in 1930 [1] [2] [3] and the Swedish-American electrical engineer Harry Nyquist at Bell Telephone Laboratories in 1932, [4] is a graphical technique ...

  7. External ballistics - Wikipedia

    en.wikipedia.org/wiki/External_ballistics

    External ballistics or exterior ballistics is the part of ballistics that deals with the behavior of a projectile in flight. The projectile may be powered or un-powered, guided or unguided, spin or fin stabilized, flying through an atmosphere or in the vacuum of space, but most certainly flying under the influence of a gravitational field.

  8. Stereoscopic acuity - Wikipedia

    en.wikipedia.org/wiki/Stereoscopic_acuity

    A second peg, below it, can be moved back and forth until it is just detectably nearer than the fixed one. Stereoacuity is defined as the minimum angle detectable, calculated as the difference between the angles subtended by both positions, A and B. Stereoacuity is possible due to binocular disparity, i.e., the difference in their binocular ...

  9. Tortuosity - Wikipedia

    en.wikipedia.org/wiki/Tortuosity

    Tortuosity. Tortuosity is widely used as a critical parameter to predict transport properties of porous media, such as rocks and soils. But unlike other standard microstructural properties, the concept of tortuosity is vague with multiple definitions and various evaluation methods introduced in different contexts.