Bohr Radius
The Bohr radius is a fundamental physical constant that represents the average distance between the nucleus and the electron in a hydrogen atom in its ground state, according to the Bohr model of the atom.
Its value is approximately 5.29177 × 10⁻¹¹ meters (about 0.529 angstroms).
Named after physicist Niels Bohr, who introduced the model in 1913.
It sets a natural length scale in atomic physics and quantum mechanics.
Used to describe atomic sizes and electron orbitals.
Key facts:
Bohr radius ≈ 5.29 × 10⁻¹¹ m
Represents the typical size of a hydrogen atom’s electron orbit
Fundamental to quantum physics and atomic structure
The Bohr radius is essential for understanding atomic dimensions and quantum behavior of electrons.
Megameter
A megameter (Mm) is a unit of length in the metric system, equal to 1 million meters (1 Mm = 10⁶ meters or 1,000 kilometers). Megameters are used to measure very large distances, typically on a global or planetary scale. For example, the Earth’s diameter is about 12.7 megameters. Although it’s a valid metric unit, the megameter is rarely used in everyday life or science, as kilometers or other astronomical units are more common for such distances.