Convert Russian Archin (archin) to Bohr Radius (a₀) instantly.
About these units
Russian Archin (archin)
The archin was a Russian unit of length equal to approximately 71.1 cm. Like many traditional European units, it was based on body proportions and was widely used in textile trade, tailoring, land measurement, and carpentry. Before Russia adopted the metric system in the early 20th century, the archin formed part of a larger system of customary units such as the sazhen and vershok. Merchants relied heavily on the archin when measuring cloth and other traded goods, making it central to the economic life of Imperial Russia. Today, the archin appears in historical documents, literature, and museum records. Understanding the archin is essential for historians studying Russian industrialization, daily commerce, and rural life before modernization efforts transformed the measurement landscape.
Bohr Radius (a₀)
The Bohr radius, equal to approximately 5.29177 × 10⁻¹¹ meters, is the most probable distance between the electron and nucleus in the ground state of hydrogen according to the Bohr model. While modern quantum mechanics has evolved far beyond the Bohr model, the radius remains a remarkably accurate approximation for average atomic dimensions. The Bohr radius acts as a natural "yardstick" for the size of atoms and is frequently used in atomic physics and quantum chemistry. Many atomic properties — orbital sizes, electron probability distributions, and energy levels — are conveniently expressed in multiples of the Bohr radius. Because it reflects fundamental constants, including Planck's constant and the electron charge, the Bohr radius also appears in theoretical analyses of physical systems and helps unify atomic physics concepts across different contexts.