Search results
Results from the WOW.Com Content Network
In particle physics, the electron mass (symbol: m e) is the mass of a stationary electron, also known as the invariant mass of the electron. It is one of the fundamental constants of physics. It has a value of about 9.109 × 10 −31 kilograms or about 5.486 × 10 −4 daltons, which has an energy-equivalent of about 8.187 × 10 −14 joules or ...
The electron's mass is approximately 1 / 1836 that of the proton. [15] Quantum mechanical properties of the electron include an intrinsic angular momentum of a half-integer value, expressed in units of the reduced Planck constant, ħ. Being fermions, no two electrons can occupy the same quantum state, per the Pauli exclusion principle. [14]
The CODATA recommended value is −e/m e = −1.758 820 008 38 (55) × 10 11 C⋅kg −1. [2] CODATA refers to this as the electron charge-to-mass quotient, but ratio is still commonly used. There are two other common ways of measuring the charge-to-mass ratio of an electron, apart from Thomson and Dunnington's methods.
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 magnitude of the negative electric charge carried by a single electron, which has charge −1 e.
In general, however, the value of effective mass depends on the purpose for which it is used, and can vary depending on a number of factors. For electrons or electron holes in a solid, the effective mass is usually stated as a factor multiplying the rest mass of an electron, m e (9.11 × 10 −31 kg).
A set of base units in the atomic system as in one proposal are the electron rest mass, the magnitude of the electronic charge, the Planck constant, and the permittivity. [6] [9] In the atomic units system, each of these takes the value 1; the corresponding values in the International System of Units [10]: 132 are given in the table.
The masses of those particles are small compared to nucleons—the mass of an electron (0.511 MeV/c 2) [18] and the mass of a muon (with a value of 105.7 MeV/c 2) [19] are fractions of the mass of the "heavy" proton (938.3 MeV/c 2), and the mass of a neutrino is nearly zero. [20]
An electronvolt is the amount of energy gained or lost by a single electron when it moves through an electric potential difference of one volt.Hence, it has a value of one volt, which is 1 J/C, multiplied by the elementary charge e = 1.602 176 634 × 10 −19 C. [2]