A furlong is a unit of length that is used primarily in horse racing and some other sports, as well as in some older systems of measurement. In modern terms, one furlong is equal to 1/8th of a mile. This is equivalent to 660 feet or 220 yards.
The term "furlong" has historical roots and was originally used in medieval England as a way to measure distances for plowing fields. Over time, it became associated with horse racing and is still used today to describe the length of a horse racing track. In horse racing, races are often measured in furlongs, and the distance of a race may be referred to as "6 furlongs" or "10 furlongs," for example.
While the furlong is not commonly used in everyday measurements, it is still relevant in certain specialized contexts, particularly in horse racing and related sports.
The Bohr radius, often denoted as "a₀," is a fundamental physical constant in quantum mechanics and atomic physics. It is named after the Danish physicist Niels Bohr, who made significant contributions to our understanding of atomic structure.
The Bohr radius represents the average distance between the nucleus and the electron in the lowest energy state (ground state) of a hydrogen atom, or a hydrogen-like ion with a single electron (e.g., helium ion with only one electron remaining). It is a key parameter in the Bohr model of the hydrogen atom.
The Bohr radius is defined as:
a₀ = (4πε₀ħ²) / (me²),
where:
When you calculate the Bohr radius using these constants, you get a value of approximately 5.29177210903 x 10⁻¹¹ meters, or about 0.5292 angstroms (Å).
The Bohr radius is a critical parameter in understanding the structure of atoms, particularly hydrogen-like atoms. It provides a basic scale for the size of atomic orbitals and helps in describing the energy levels of electrons in these atoms.