Convert Bohr Radius (a₀) to Cubit (UK) (cubit (uk)) instantly.
About these units
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.
Cubit (UK) (cubit (uk))
The UK cubit is a traditional English unit derived from the length of the forearm, roughly 0.4572 meters (18 inches). It was historically used in construction, land measurement, and woodworking, providing a human-scale reference for practical tasks before standardized units were widely adopted. In England, the cubit also played a role in surveying and architectural planning, often subdivided into smaller units such as hands or fingers for precision. Builders and craftsmen relied on the cubit because it allowed approximate measurement without instruments, a feature especially valuable in early medieval and pre-industrial periods. Although replaced by the foot and yard over time, the cubit remains an important historical reference for studying British architecture, surveying records, and early measurement systems.