Question

what is value of quanta of charge ?

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Answer 1

Answer:

Symbol: e or sometimes q e. Value in coulombs: 1.602176634×10−19 C. The elementary charge, usually denoted by e or sometimes q e, is the electric charge carried by a single proton or, equivalently, the magnitude of the negative electric charge carried by a single electron, which has charge −1 e

Answer 2

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• The elementary charge, usually denoted by e or sometimes qe, is the electric charge carried by a single proton or, equivalently, the magnitude of the negative electric charge carried by a single electron, which has charge −1 e. This elementary charge is a fundamental physical constant. To avoid confusion over its sign, e is sometimes called the elementary positive charge.
• From the 2019 redefinition of SI base units, which took effect on 20 May 2019, its value is exactly 1.602176634×10−19 C[1], by definition of the coulomb. In the centimetre–gram–second system of units (CGS), it is 4.80320425(10)×10−10 statcoulombs.
• Making the value of the elementary charge exact implies that the value of ε0 (electric constant), which was an exact value before, is now subject to experimental determination: ε0 had an exactly defined value until the 2019 SI redefinition, after which it has become a subject of experimental refinement over time. The SI committees (CGPM, CIPM, etc.) had long considered redefining the SI base units entirely in terms of physical constants so as to remove their dependence on physical artifacts (such as the International Prototype of the Kilogram): for this to work, it was necessary to define fixed values for the physical constants.

• Robert A. Millikan's oil drop experiment first measured the magnitude of the elementary charge in 1909.
• In some natural unit systems, such as the system of atomic units, e functions as the unit of electric charge, that is e is equal to 1 e in those unit systems. The use of elementary charge as a unit was promoted by George Johnstone Stoney in 1874 for the first system of natural units, called Stoney units.[7] Later, he proposed the name electron for this unit. At the time, the particle we now call the electron was not yet discovered and the difference between the particle electron and the unit of charge electron was still blurred. Later, the name electron was assigned to the particle and the unit of charge e lost its name. However, the unit of energy electronvolt reminds us that the elementary charge was once called electron.
• In high-energy physics (HEP), Lorentz–Heaviside units are used, and the charge unit is a dependent one, {\displaystyle {\sqrt {\hbar c}}}{\sqrt {\hbar c}}, so that e = √ 4 π α √ħc ≈ 0.30282212088 √ħc, where α is the fine-structure constant, c is the speed of light, {\displaystyle \hbar }\hbar is the reduced Planck's constant.