Convert Meter (m) to Bohr Radius (a₀) instantly.
About these units
Meter (m)
The meter is the foundational unit of length in the International System of Units (SI) and forms the backbone of virtually all modern scientific and engineering measurements. Originally defined in the late 18th century as one ten-millionth of the distance from the equator to the North Pole along a meridian, the meter's definition has evolved alongside advances in physics and measurement technology. For much of the 19th and 20th centuries, it was tied to a physical bar stored in Paris—an artifact vulnerable to temperature fluctuations and damage. Today, the meter is defined using a universal constant rather than a physical object: the distance light travels in vacuum in 1/299,792,458 of a second. This definition is elegant because it anchors the meter to an invariant physical constant, ensuring precision across laboratories and nations. It allows modern metrology labs to realize the meter through laser interferometry, achieving extraordinary accuracy. The meter's universality and reliability make it the most important single unit of length ever devised.
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.