Rezistivitet

Resistivity is a fundamental electrical property of a material that quantifies how strongly it resists the flow of electric current. It is an intrinsic property of the material itself, independent of its shape or size, unlike electrical resistance. Resistivity is typically denoted by the Greek letter rho (ρ) and is measured in ohm-meters (Ω·m) in the International System of Units.

A material with low resistivity, such as copper or silver, is a good conductor of electricity, meaning that electric charge can flow through it with relatively little opposition. Conversely, a material with high resistivity, such as rubber or glass, is a good electrical insulator, impeding the flow of electric current. The resistivity of a material is influenced by temperature, with most conductors exhibiting an increase in resistivity as temperature rises, while semiconductors and insulators may show a decrease.

The mathematical relationship between resistivity, resistance (R), length (L), and cross-sectional area (A) of a conductor is given by the formula R = ρ(L/A). This equation highlights how the physical dimensions of an object made from a material affect its overall resistance, while resistivity remains a constant characteristic of the material itself. Understanding resistivity is crucial in various applications, from designing electrical circuits and wires to selecting appropriate materials for insulation and semiconductor devices.