| OHI | <abbreviation> Oral Hygiene Index. (05 Mar 2000) |
|---|---|
| OHI-S | <abbreviation> Simplified Oral Hygiene Index. (05 Mar 2000) |
| ohm | <physics> The standard unit in the measure of electrical resistance, being the resistance of a circuit in which a potential difference of one volt produces a current of one ampere. As defined by the International Electrical Congress in 1893, and by United States Statute, it is a resistance substantially equal to 10^9 units of resistance of the C.G.S. System of electromagnetic units, and is represented by the resistance offered to an unvarying electric current by a column of mercury at the temperature of melting ice 14.4521 grams in mass, of a constant cross-sectional area, and of the length of 106.3 centimeters. As thus defined it is called the international ohm. <physics> Ohm's law, the statement of the fact that the strength or intensity of an electrical current is directly proportional to the electromotive force, and inversely proportional to the resistance of the circuit. Origin: So called from the German electrician, G.S. Ohm. Source: Websters Dictionary (01 Mar 1998) |
| 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) |
| Ohm, Georg | <person> German physicist, 1787-1854. See: ohm, Ohm's law. (05 Mar 2000) |
| ohmammeter | A combined ohmmeter and ammeter. (05 Mar 2000) |
| ohmmeter | An instrument for determining the resistance, in ohms, of a conductor. (05 Mar 2000) |
| ohne Hauch | Term used to designate the nonspreading growth of nonflagellated bacteria on agar media; also applied to somatic agglutination. See: O antigen. Origin: Ger. Without breath (05 Mar 2000) |
| Ohngren's line | A theoretical plane passing between the medial canthus of the eye and the angle of the mandible; used as an arbitrary dividing line in classifying localised tumours of the maxillary sinus; tumours above the line invade vital structures early and have a poorer prognosis, whereas those below the line have a more favourable prognosis. (05 Mar 2000) |