Rongzhou at 06:33, 2 October 2026

2026-10-02T06:33:07Z

← Older revision		Revision as of 06:33, 2 October 2026
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	{{#content:Q1937}}		{{#content:Q1937}}

			== Charge density ==

			For a thin, long conductor (e.g., electric cable):

			$$\text{charge density } \lambda = \frac{dQ}{dL}$$

			For a thin surface (e.g., aluminium foil):

			$$\text{charge density } \sigma = \frac{dQ}{dA}$$

Rongzhou at 14:38, 1 October 2026

2026-10-01T14:38:35Z

← Older revision		Revision as of 14:38, 1 October 2026
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	~~== Overview ==~~		'''Electrical charge''' is a fundamental property of matter.

	~~fundamental physical property~~		== SI Unit ==

			The SI unit of electrical charge is '''Coulomb (C)''', named after French physicist [[Person:Charles Augustine de Coulomb\|Charles Augustine de Coulomb]].<ref>{{#cite:Q1934}}</ref>

			== Charge of subatomic particles ==

			{\| class="wikitable"
			! Particle !! Symbol !! Absolute charge (Coulombs) !! Relative charge (to proton)
			\|-
			\| [[proton]] \|\| $p^+$ \|\| $+1.602 \times 10^{-19}$ \|\| +1
			\|-
			\| [[neutron]] \|\| $n^0$ \|\| 0 \|\| 0
			\|-
			\| [[electron]] \|\| $e^-$ \|\| $-1.602 \times 10^{-19}$ \|\| −1
			\|}

			<ref>{{#cite:Q1791}}</ref><ref>{{#cite:Q1793}}</ref>

			== Properties ==

			=== Quantisation ===

			Any electrical charge is a whole multiple of $e \equiv 1.602 \cdot 10^{-19} C$.<ref>{{#cite:Q1934}}</ref>

			i.e.,

			$$
			\forall Q, Q=ae, a \in Z
			$$

			=== Restricted type ===

			A charge must be either positive or negative.<ref>{{#cite:Q1934}}</ref>

			Positive and negative charges can cancel each out, therefore the total charge of a system is the algebraic sum of charges of all its elements.<ref>{{#cite:Q1934}}</ref>

			i.e.,
			$$
			Q_{system}=\sum Q_{element}
			$$

			<blockquote>
			'''Warning''': This does not mean the entire system can be always approximated as a point charge of $\sum Q_{elements}$, as the distribution of charges heavily influence the electrostatic behaviour of a system.
			</blockquote>

			=== Conservation ===

			Charge can neither be created or destroyed but only transfered. The amount of charge in any closed system is constant.<ref>{{#cite:Q1934}}</ref>

			i.e.,

			{{#content:Q1938}}

			=== Electrostatic force ===

			Any charge exert an electrostatic force on any other charge.<ref>{{#cite:Q1934}}</ref>

			This phenomenon is described by Coulomb's law:

			{{#content:Q1937}}

Rongzhou: Created the wiki page for electric charge

2026-10-01T14:36:56Z

Created the wiki page for electric charge

New page

== Overview ==

fundamental physical property

Electric charge - Revision history

Rongzhou at 06:33, 2 October 2026

Rongzhou at 14:38, 1 October 2026

Rongzhou: Created the wiki page for electric charge