Ohm's law
Definition and meaning of Ohm's law in chemistry.
Ohm's law states that the electrical current flowing through a conductor between two points is directly proportional to the voltage across those two points.
In more detail
This fundamental principle relates current, voltage, and resistance in electrical circuits, forming the basis for understanding electrochemical systems and instrumental analysis equipment. It is mathematically expressed as V = IR, where V is the voltage, I is the current, and R is the resistance. The law applies strictly to ohmic conductors at a constant temperature, meaning that their resistance remains constant regardless of the applied voltage. However, non-ohmic conductors, such as semiconductors and many electrolyte solutions, exhibit variable resistance and deviate from this linear relationship.
Key facts
| Field | Physical Chemistry |
|---|---|
| Equation | V = IR |
| Constant parameter | Temperature must remain constant |
| Application | Electrochemical cells |
In a basic electrochemical cell, knowing the cell potential and the internal resistance allows a chemist to precisely calculate the expected current using Ohm's law, which in turn helps determine the rate of the redox reaction.