The ohm (seembol: Ω) is the SI derived unit o electrical resistance, named efter German pheesicist Georg Simon Ohm. Altho several empirically derived staundart units for expressin electrical resistance wur developed in connection wi early telegrafie practice, the Breetish Association for the Advancement o Science proponed a unit derived frae existin units o mass, lenth an time an o a convenient size for practical wirk as early as 1861. The defineetion o the "ohm" unit wis revised several times. The day the value o the ohm is expressed in terms o the quantum Hall effect.

Aeldre kulmassemodstande.jpg
Several resistors. Thair resistance, in ohms, is indicatit bi a color code.
Unit information
Unit seestemSI derived unit
Unit oElectrical resistance
Named efterGeorg Ohm
In SI base units:1 Ω = 1 kg·m2·s-3·A-2