Ohm's Law

What is ohm's law?

Ohm's Law states that the current through a conductor between two points is directly proportional to the voltage across the two points, provided temperature is constant: V = IR. Where V is potential difference in volts, I is current in amps, and R is resistance in ohms. The law holds for ohmic conductors (most metallic conductors at constant temperature); non-ohmic components like filament bulbs or diodes do not obey it. A-Level Physics extends to internal resistance: V = ε − Ir.