# Ohm

- Defined as the resistance of a conductor through which a current of one ampere is flowing when the potential difference across it is one volt.
- Ohm's law:
- where
*V*= potential difference across*R**I*= current through*R*[A]*R*= resistance [ohm]
- Field form of Ohm's law:
- where
*J*= current density- σ = conductivity
*E*= electric field
- The power disipated by a resistor is given by Joule′s law:
- where
*W*= power disipated [Watt]*I*= current [Ampere]*R*= resistance [Ohm]*V*= potential difference across resistor [Volt]
| Enter two values and the other values will be calculated. |

1 mean international ohm | = | 1.00049 absolute ohm |

**See also: **Abohm, Ohm, Georg Simon, Ohm Metre, Ohmmeter, Ohms per Square, Resistance, Statohm.

**Subjects: ** Physics