Convert Rood (rood) to Electron Cross Section (σₑ) instantly.
About these units
Rood (rood)
A rood equals 1/4 of an acre, or 10,890 square feet, and was used in medieval and early modern England for land measurement. The rood often appeared in agricultural records, taxation documents, and estate descriptions. Farmers used the rood to describe smaller plots of arable land, orchards, and grazing fields. Although obsolete today, the rood reflects the practical needs of historical agrarian societies, where manageable sub-acres allowed fine-grained recordkeeping and land division within larger estates.
Electron Cross Section (σₑ)
The electron cross section, often denoted σₑ, is not a fixed unit but rather a physical area representing the effective interaction size of an electron in scattering experiments. It is typically expressed in barns or submultiples such as square femtometers (fm²). Electron cross sections are vital in quantum electrodynamics (QED), X-ray scattering, atomic physics, and materials science. These values describe how electrons interact with photons, atoms, or other electrons, determining phenomena such as absorption, conductivity, and radiation shielding. Because electron interactions are probabilistic, σₑ provides a statistical measure of likelihood rather than a physical surface, illustrating how area units are used conceptually at quantum scales.