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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 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.
[g] The maximum magnitude of this wavelength shift is h/m e c, which is known as the Compton wavelength. [116] For an electron, it has a value of 2.43 × 10 −12 m. [80] When the wavelength of the light is long (for instance, the wavelength of the visible light is 0.4–0.7 μm) the wavelength shift becomes negligible.
Thus, an object's charge can be exactly 0 e, or exactly 1 e, −1 e, 2 e, etc., but not 1 / 2 e, or −3.8 e, etc. (There may be exceptions to this statement, depending on how "object" is defined; see below.) This is the reason for the terminology "elementary charge": it is meant to imply that it is an indivisible unit of charge.
The value of the fine-structure constant α is linked to the observed value of this coupling associated with the energy scale of the electron mass: the electron's mass gives a lower bound for this energy scale, because it (and the positron) is the lightest charged object whose quantum loops can contribute to the running.
The CODATA value is = = 10 973 731.568 157 (12) m −1, [2] where is the rest mass of the electron (i.e. the electron mass),; is the elementary charge,; is the permittivity of free space,
Lorentz force on a charged particle (of charge q) in motion (velocity v), used as the definition of the E field and B field. Here subscripts e and m are used to differ between electric and magnetic charges .
Einstein Triangle. The energy–momentum relation is consistent with the familiar mass–energy relation in both its interpretations: E = mc 2 relates total energy E to the (total) relativistic mass m (alternatively denoted m rel or m tot), while E 0 = m 0 c 2 relates rest energy E 0 to (invariant) rest mass m 0.