Definition:Electric Charge/Quantum

Definition

Electric charge has been demonstrated to be quantized.

The quantum of electric charge is the elementary charge $\E$:

$\E = 1.60217 \, 6634 \times 10^{−19}$ coulombs exactly.

This sequence is A081823 in the On-Line Encyclopedia of Integer Sequences (N. J. A. Sloane (Ed.), 2008).

This is so small that to all practical purposes in everyday measurement of electricity, it can be treated as though it were continuous.

Symbol

The symbol used to denote the elementary charge is usually $\E$ or $e$.

The preferred symbol on $\mathsf{Pr} \infty \mathsf{fWiki}$ is $\E$.

Examples

$60 \ \mathrm W$ Bulb at $200 \ \mathrm V$

Consider a $60 \ \mathrm W$ light bulb running at $200 \ \mathrm V$.

Approximately $2 \times 10^{18}$ units of elementary charge flow along the filament of the light bulb every second.

Technical Note

The $\LaTeX$ code for \(\E\) is \E .

Sources

• 1958: C.A. Coulson: Electricity (5th ed.) ... (previous) ... (next): Chapter $\text {I}$: Preliminary Survey: $\S 1$. Electrostatics
• 1978: A.P. French and Edwin F. Taylor: An Introduction to Quantum Physics ... (previous) ... (next): $1$: Simple models of the atom: $\text {1-3}$: The Electrical Structure of Matter
• 1990: I.S. Grant and W.R. Phillips: Electromagnetism (2nd ed.) ... (previous) ... (next): Chapter $1$: Force and energy in electrostatics: $1.1$ Electric Charge