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The area of → optics which treats of the laws and properties of light reflected from reflective surfaces.
Fr.: équation de Cauchy
A relationship between the → refractive index (n) and the wavelength of light (λ) passing through a medium. It is commonly stated in the following form: n = A + B/λ2 + C/λ4, where A, B, and C are constants characterizing the medium. The two-component Cauchy equation is n = A + B/λ2, from which the dispersion becomes dn/dλ = -2B/λ3 showing that dispersion varies approximately as the inverse cube of the wavelength. The dispersion at 4000 A will be about 8 times as large as at 8000 Å.
Named after Augustin Louis Cauchy (1789-1857), French mathematician and physicist who found the first equation of dispersion in 1836; → equation.
Fr.: théorème de Cauchy
If f(x) and φ(x) are two → continuous functions on the → interval [a,b] and → differentiable within it, and φ'(x) does not vanish anywhere inside the interval, there will be found, in [a,b], some point x = c, such that [f(b) - f(a)] / [φ(b) - φ(a)] = f'(c) / φ'(c).
Of, involving, or constituting a cause; indicative of or expressing a cause.
Adj. from → cause.
Fr.: structure causale
The relationship between causes and effects
Causality, from → causal + -ity.
Bonârmandi, from bonâr→ cause + -mand suffix denoting relation, affinity + -i noun forming suffix.
Fr.: principe de causalité
The principle that cause must always precede effect.
Fr.: relation de cause à effet
Verbal noun from → cause.
Fr.: causatif, causal, responsable
1) Effective or operating as a cause or agent.
1) bonâr; 2) bonâridan
Fr.: 1) cause; 2) causer
From L. causa "reason, purpose," of unknown origin.
Bonâr, from bon "basis, root, origin, ground", from Mid.Pers. bun "base, root, origin;" Av. buna- "ground" (cf. Skt. budhna- "ground, bottom, depth", L. fundus "bottom", PIE base *bhud-/*bhund-) + âr short form of âvar present stem of âvardan "to cause or produce; to bring," → production; compare with Ger. die Ursache "cause," from ur- "primal" + die Sache "thing, matter."
1) Capable of burning, corroding, or destroying living tissue. A caustic substance.
M.E., from O.Fr. caustique, from L. causticus "burning," from Gk. kaustikos "capable of burning," from kaust(os) "combustible," from kaiein "to burn" + -ikos, → -ic.
Sucân, from suc- "to burn," variant of suz-, suzidan, suxtan "to burn;" cf. Baluci suc-, soc-; Mid.Pers. sôxtan, sôzidan "to burn;" Av. base saoc- "to burn, inflame" sūcā "brilliance," upa.suxta- "inflamed;" cf. Skt. śoc- "to light, glow, burn," śocati "burns," (caus.) socayati, śuc- "flame, glow," śoka- "light, flame;" PIE base *(s)keuk- "to shine."
Fr.: courbe caustique
The intersection of a → caustic surface with a plane passing through the beam of rays.
Fr.: surface cuastique
In an → optical system, the → envelope of all the → reflected or → refracted rays (by a → mirror or a → lens respectively) which do not come to a common focal point because of geometrical → aberration. This occurs when parallel rays of light fall on a → concave mirror or when a → convex lens receives parallel light. In the case of → spherical aberration, the caustic surface has an axis of symmetry.
The quality of being physically caustic.
1) An apparently hollow formation in the structure of an astronomical
object, for example a sizable hole on the surface of a
→ molecular cloud created by
→ ultraviolet photons of a
→ massive star.
From M.Fr. cavité, from L.L. cavitas "hollowness," from L. cavus "hollow."
Kâvâk, related to verb kâvidan (kâftan) "to dig; to examine, investigate," cf. L. cavus "hollow" (E. derivatives: cavity, concave, cave, excavate), Gk. koilos "hollow," Armenian sor, PIE *kowos "hollow."
Fr.: détecteur CCD bidimensionnel
A CCD detector having two dimensions.
âškârgar-e sisidi (#)
Fr.: détecteur CCD
Fr.: image CCD
One of a series of astronomical images obtained using a CCD detector in particular for calibration purposes.
Fr.: gain de CCD
In a → CCD detector, the ratio of the initial number of electrons in a → pixel to the final number of → analog-to-digital units (or counts) reported by camera software. For example, a gain of 1.8 e-/count means that the camera produces 1 count for every 1.8 recorded electrons.