| Dalton's law | Each gas in a mixture of gases exerts a pressure proportionate to the percentage of the gas and independent of the presence of the other gases present. Synonym: law of partial pressures. (05 Mar 2000) |
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| Nysten's law | Rigor mortis affects first the muscles of the head and spreads toward the feet. (05 Mar 2000) |
| Descartes' law | For two given media, the sine of the angle of incidence bears a constant relation to the sine of the angle of refraction. Synonym: Descartes' law, Snell's law. (05 Mar 2000) |
| Donders' law | The rotation of the eyeball is determined by the distance of the object from the median plane and the line of the horizon. (05 Mar 2000) |
| Draper's law | A chemical change is produced in a photochemical substance only by those light rays that are absorbed by that substance. (05 Mar 2000) |
| Du Bois-Reymond's law | A motor nerve responds, not to the absolute value, but to the alteration of value from moment to moment, of the electric current; i.e., rate of change of intensity of the current is a factor in determining its effectiveness. Synonym: Du Bois-Reymond's law. (05 Mar 2000) |
| Dulong-Petit law | The specific heats of many solid elements are inversely proportional to their atomic weights. (05 Mar 2000) |
| inverse square law | As applied to point sources, the intensity of radiation diminishes in proportion to the square of the distance from the source. (05 Mar 2000) |
| isodynamic law | For energy purposes, the different foodstuffs may replace one another in accordance with their caloric values when burned in a calorimeter. (05 Mar 2000) |
| Ochoa's law | The content of the X-chromosome tends to be phylogenetically conserved. (05 Mar 2000) |
| ohm's law | <physics> The relationship between the net current and the electric field in a conducting medium. For simple resistors, the voltage equals current times resistance, V = IR. In plasmas the generalised Ohm's Law is a more complex tensor relationship involving the vector current density, the vector for the electric field, and a generalised resistance tensor that relates the two. (09 Oct 1997) |
| Tait's law | An obsolete dictum that an exploratory laparotomy should be performed in every case of obscure pelvic or abdominal disease that threatens health or life. (05 Mar 2000) |
| third law of thermodynamics | <chemistry> The entropy of a perfect crystal at 0 K is zero. (09 Jan 1998) |
| Einthoven's law | In the electrocardiogram the potential of any wave or complex in lead II is equal to the sum of the potentials of leads I and III. Synonym: Einthoven's equation. (05 Mar 2000) |
| Elliott's law | Adrenaline acts upon those structures innervated by sympathetic nerve fibres. (05 Mar 2000) |