| Rayleigh criterion | <microscopy> A criterion chosen by Lord Rayleigh to define the limit of resolution of a diffraction-limited optical instrument. It is the condition that arises when the centre of one diffraction pattern is superimposed with the first minimum of another diffraction pattern, produced by a point (or line) source equally bright as the first. For a microscope under this condition, a 26.5% dip in brightness appears between the two maxima, giving rise to the sensation (or probability) of twoness. See: Abbe limit, Sparrow limit (of resolution). (05 Aug 1998) |
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| criterion | A standard by which something may be judged. Origin: Gr. Kriterion = a means for judging (18 Nov 1997) |
| criterion-related validity | The degree of effectiveness with which performance on a test or procedure predicts performance in a real-life situation; e.g., a good correlation between a score on an intelligence test such as the Scholastic Aptitude Test and one's 4-year college grade point average. (05 Mar 2000) |
| suydam stability criterion | <physics> A criterion for the stability of modes localised arbitrarily close to a mode-rational surface in a circular cylindrical geometry. See: rational surface. (19 Jan 1998) |
| Lawson criterion | <physics> Scientific breakeven criterion based on the product of energy confinement time and particle density. Together with plasma temperature, the Lawson value of a plasma indicates how close it is to self-sustained (ignited) fusion. See: ignition. (09 Oct 1997) |