rafleiða

Rafleiða, also known as electrical conductivity, is a measure of a material's ability to conduct an electric current. It is the reciprocal of electrical resistivity, which quantifies a material's resistance to the flow of electric charge. Rafleiða is typically denoted by the Greek letter sigma (σ) and is measured in siemens per meter (S/m) in the International System of Units (SI).

Materials with high rafleiða, such as metals, are known as conductors because they allow electric current to flow freely. Conversely, materials with low rafleiða, like glass or rubber, are called insulators as they impede the flow of electric charge. Semiconductors, such as silicon, have rafleiða values between those of conductors and insulators and are crucial in the manufacturing of electronic devices.

The rafleiða of a material depends on several factors, including its atomic structure, temperature, and the presence of impurities. For most metals, rafleiða decreases with increasing temperature due to increased atomic vibrations that hinder the movement of electrons. However, in semiconductors, rafleiða generally increases with temperature as more electrons are excited into the conduction band.

Rafleiða is a fundamental property used in various applications, from designing electrical circuits to understanding geological formations. It plays a vital role in fields such as electronics, materials science, geophysics, and even in biological systems, where the conductivity of bodily fluids and tissues is essential for medical diagnostics and treatments.