Physics: Elementary charge

Electromagnetism Nuclear & Particle

Elementary charge e = 1.602×10⁻¹⁹ C The elementary charge, usually denoted by e, is a fundamental physical constant, defined as the electric charge carried by a single proton (+1 e) or, equivalently, the negative of the electric charge carried by a single electron, which has charge −1 e.

Commentary

Elementary charge Symbol: e = 1.602×10⁻¹⁹ C The elementary charge, usually denoted by e, is a fundamental physical constant, defined as the electric charge carried by a single proton (+1 e) or, equivalently, the negative of the electric charge carried by a single electron, which has charge −1 e. Why e ma tters This constant appears everywhere in physics equations. It defines a fundamental limit or relationship in nature that holds true everywhere in the universe. Understanding e e = 1.602×10⁻¹⁹ C The elementary charge, usually denoted by e, is a fundamental physical constant, defined as the electric charge carried by a single proton (+1 e) or, equivalently, the negative of the electric charge carried by a single electron, which has charge −1 e. In SI units, the coulomb is defined such that the value of the elementary charge is exactly e = 1.602176634×10−19 C. Since the 2019 revision of the SI, the seven SI base units are defined in terms of seven fundamental physical constants, of which the elementary charge is one. Robert A. Millikan and Harvey Fletcher's oil drop experiment first directly measured the magnitude of the elementary charge in 1909, differing from the modern accepted value by just 0.6%. Under assumptions of the then-disputed atomic theory, the elementary charge had also been indirectly inferred to ~3% accuracy from blackbody spectra by Max Planck in 1901 and (through the Faraday constant) at order-of-magnitude accuracy by Johann Loschmidt's measurement of the Avogadro constant in 1865.

Sources: Wikipedia