Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interactions. Electrically charged matter is influenced by, and produces, electromagnetic fields. The interaction between charge and field is the source of the electromagnetic force, which is one of the four fundamental forces. CPT-symmetry is a fundamental symmetry of physical laws under transformations that involve the inversions of charge, parity and time simultaneously. ... In the standard model of particle physics the Cabibbo Kobayashi Maskawa matrix (CKM matrix, sometimes earlier called KM matrix) is a unitary matrix which contains information on the strength of flavour changing weak decays. ... CP is the product of two symmetries: C for charge conjugation, which transforms a particle into its antiparticle, and P for parity, which creates the mirror image of a physical system. ... A phenomenon is said to be chiral if it is not identical to its mirror image (see Chirality (mathematics)). The spin of a particle may be used to define a handedness for that particle. ... A subatomic particle is a particle smaller than an atom: it may be elementary or composite. ... Electromagnetic interaction is a fundamental force of nature and is felt by charged leptons and quarks. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Electromagnetism is the physics of the electromagnetic field: a field, encompassing all of space, composed of the electric field and the magnetic field. ... A fundamental interaction is a mechanism by which particles interact with each other, and which cannot be explained by another more fundamental interaction. ...

Overview

Electric charge is a characteristic of subatomic particles, and is quantized. When expressed as a multiple of the so-called elementary charge e, electrons have a charge of −1. Protons have the opposite charge of +1. Quarks have a fractional charge of −1/3 or +2/3. The antiparticle equivalents of these have the opposite charge. There are other charged particles. The elementary charge (symbol e or sometimes q) is the electric charge carried by a single proton, or equivalently, the negative of the electric charge carried by a single electron. ... Properties The electron is a lightweight fundamental subatomic particle that carries a negative electric charge. ... Properties In physics, the proton (Greek proton = first) is a subatomic particle with an electric charge of one positive fundamental unit (1. ... Quarks are one of the two basic constituents of matter in the Standard Model of particle physics. ... Corresponding to each kind of particle, there is an associated antiparticle with the same mass and spin. ... In physics, a charged particle is a particle with an electric charge. ...

The electric charge of a macroscopic object is the sum of the electric charges of its constituent particles. Often, the net electric charge is zero, since naturally the number of electrons in every atom is equal to the number of the protons, so their charges cancel out. Situations in which the net charge is non-zero are often referred to as static electricity. Furthermore, even when the net charge is zero, it can be distributed non-uniformly (e.g., due to an external electric field), and then the material is said to be polarized, and the charge related to the polarization is known as bound charge (while the excess charge brought from outside is called free charge). An ordered motion of charged particles in a particular direction (typically these are the electrons) is known as electric current. Macroscopic is commonly used to describe physical objects that are measurable and observable by the naked eye. ... Properties In chemistry and physics, an atom (Greek άτομον meaning indivisible) is the smallest possible particle of a chemical element that retains its chemical properties. ... For alternative meanings see proton (disambiguation). ... Static electricity is a class of phenomena involving the net charge present on an object; typically referring to charged object with voltages of sufficient magnitude to produce visible attraction, repulsion, and sparks. ... In physics, an electric field or E-field is an effect produced by an electric charge (or a time-varying magnetic field) that exerts a force on charged objects in the field. ... In electrostatics, the polarization is the vector field that results from permanent or induced electric dipole moments in a dielectric material. ... In classical electromagnetism, the polarization density (or electric polarization, or simply polarization) is the vector field that expresses the density of permanent or induced electric dipole moments in a dielectric material. ... Electric current is the flow of electric charge. ...

The SI unit of electric charge is the coulomb, which represents approximately 6.24 × 10¹⁸ elementary charges (the charge on a single electron or proton). The coulomb is defined as the quantity of charge that has passed through the cross-section of a conductor carrying one ampere within one second. The symbol Q is used to denote a quantity of electric charge. Cover of brochure The International System of Units. ... The coulomb (symbol: C) is the SI unit of electric charge. ... The elementary charge (symbol e or sometimes q) is the electric charge carried by a single proton, or equivalently, the negative of the electric charge carried by a single electron. ... In science and engineering, conductors are materials that contain movable charges of electricity. ... The ampere (symbol: A) is the SI base unit of electric current. ...

Electric charge can be directly measured with an electrometer. The discrete nature of electric charge was demonstrated by Robert Millikan in his oil-drop experiment. An electrometer is an electrical instrument for measuring electric charge or electrical potential difference. ... Robert Millikan. ... The purpose of Robert Millikans oil-drop experiment (1909) was to measure the electric charge of the electron. ...

Formally, a measure of charge should be a multiple of the elementary charge e (charge is quantized), but since it is an average, macroscopic quantity, many orders of magnitude larger than a single elementary charge, it can effectively take on any real value. Generally, quantization is the state of being constrained to a set of discrete values, rather than varying continuously. ... Macroscopic is commonly used to describe physical objects that are measurable and observable by the naked eye. ... In mathematics, the real numbers are intuitively defined as numbers that are in one-to-one correspondence with the points on an infinite line—the number line. ...

History

As reported by the Ancient Greek philosopher Thales of Miletus around 600 BC, charge (or electricity) could be accumulated by rubbing fur on various substances, such as amber. The Greeks noted that the charged amber buttons could attract light objects such as hair. They also noted that if they rubbed the amber for long enough, they could even get a spark to jump. This property derives from the triboelectric effect. For the French electronics and defence contractor, see Thales Group Thales (in Greek: Θαλης) of Miletus (circa 635 BC - 543 BC), also known as Thales the Milesian, was a pre-Socratic Greek philosopher and one of the Seven Sages of Greece. ... Centuries: 8th century BC - 7th century BC - 6th century BC Decades: 650s BC 640s BC 630s BC 620s BC 610s BC - 600s BC - 590s BC 580s BC 570s BC 560s BC 550s BC The 600s BC are the years 609 to 600 BC. Events and trends Fall of the Assyrian... A dogs fur usually consists of longer, stiffer, guard hairs—which can be straight, wiry, or wavy, and of various lengths, hiding a soft, short-haired undercoat. ... Amber pendants. ... Young Girl Fixing her Hair, by Sophie Gengembre Anderson Hair, is a filamentous outgrowth from the skin, found only in mammals. ... Amber pendants. ... The triboelectric effect is a type of contact electrification in which certain materials become electrically charged after coming into contact with another, different, material, and are then separated. ...

In 1600 the English scientist William Gilbert returned to the subject in De Magnete, and coined the modern Latin word electricus from ηλεκτρον (elektron), the Greek word for "amber", which soon gave rise to the English words electric and electricity. He was followed in 1660 by Otto von Guericke, who invented what was probably the first electrostatic generator. Other European pioneers were Robert Boyle, who in 1675 stated that electric attraction and repulsion can act across a vacuum; Stephen Gray, who in 1729 classified materials as conductors and insulators; and C. F. Du Fay, who proposed in 1733 [1] that electricity came in two varieties which cancelled each other, and expressed this in terms of a two-fluid theory. When glass was rubbed with silk, DuFay said that the glass was charged with vitreous electricity, and when amber was rubbed with fur, the amber was said to be charged with resinous electricity. 1597 1598 1599 - 1600 - 1601 1602 1603 |- | align=center colspan=2 | Decades: 1570s 1580s 1590s - 1600s - 1610s 1620s 1630s |- | align=center | Centuries: 15th century - 16th century - 17th century |} // Events January January 1 - Scotland adopts January 1st as being New Years Day February February 17 - Giordano Bruno burned at the... William Gilbert William Gilbert was born May 24, 1544, Colchester, England and died November 30, 1603, probably in London. ... Modern Latin is the form of the Latin language that was developed in the Western world after the Middle Ages. ... Events Expulsion of the Carib indigenous people from Martinique by French occupying forces. ... Otto von Guericke Otto von Guericke (originally spelled Gericke) (November 20, 1602 May 11, 1686 (Julian calendar); November 30, 1602 - May 21, 1686 (Gregorian calendar)) was a German scientist, inventor, and politician (mayor of Magdeburg from 1646 to 1676). ... Electrostatics is the branch of physics that deals with the force exerted by a static (i. ... Robert Boyle The Honourable Robert Boyle (January 25, 1627 - December 30, 1691) was an Irish natural philosopher, noted for his work in physics and chemistry. ... Events January 5 - The Battle of Turckeim June 18 - Battle of Fehrbellin August 10 - King Charles II of England places the foundation stone of the Royal Greenwich Observatory in London - construction begins November 11 - Guru Gobind Singh becomes the Tenth Guru of the Sikhs. ... Stephen Gray (December, 1666 - February 7, 1736) was an English dyer and amateur astronomer, who was the first to systematically experiment with electrical conduction, rather than simple generation of static charges and investigations of the static phenomena. ... Events July 30 - Baltimore, Maryland is founded. ... In science and engineering, conductors are materials that contain movable charges of electricity. ... // Definition An Insulator is a material or object which resists the flow of electric charge. ... Charles François de Cisternay du Fay (Paris, 1698 - 1739) was a French scientist and superintendent of the Jardin du Roi. ... Events February 12 - British colonist James Oglethorpe founds Savannah, Georgia. ...

One of the foremost experts on electricity in the 18th century was Benjamin Franklin, who argued in favor of a one-fluid theory of electricity. Franklin imagined electricity as being a type of invisible fluid present in all matter; for example he believed that it was the glass in a Leyden jar that held the accumulated charge. He posited that rubbing insulating surfaces together caused this fluid to change location, and that a flow of this fluid constitutes an electric current. He also posited that when matter contained too little of the fluid it was "negatively" charged, and when it had an excess it was "positively" charged. Arbitrarily (or for a reason that was not recorded) he identified the term "positive" with vitreous electricity and "negative" with resinous electricity. William Watson arrived at the same explanation at about the same time. (17th century - 18th century - 19th century - more centuries) As a means of recording the passage of time, the 18th century refers to the century that lasted from 1701 through 1800. ... Benjamin Franklin by Jean-Baptiste Greuze 1777 Benjamin Franklin (January 17 [O.S. January 6] 1706 – April 17, 1790) was one of the most prominent of the Founders and early political figures and statesmen of the United States. ... Glass can be made transparent and flat, or into other shapes and colours as shown in this ball from the Verrerie of Brehat in Brittany. ... Original capacitor The Leyden jar was the original capacitor, developed in the 18th century and used to conduct many early experiments in electricity. ... William Watson (3 April 1715 – 10 May 1787) was an English physician and scientist who was born and died in London. ...

We now know that the Franklin/Watson model was close, but too simple. Matter is actually composed of several kinds of electrically charged particles, the most common being the positively charged proton and the negatively charged electron. Rather than one possible electric current there are many: a flow of electrons, a flow of electron "holes" which act like positive particles, or in electrolytic solutions, a flow of both negative and positive particles called ions moving in opposite directions. To reduce this complexity, electrical workers still use Franklin's convention and they imagine that electric current (known as conventional current) is a flow of exclusively positive particles. The conventional current simplifies electrical concepts and calculations, but it ignores the fact that within some conductors (electrolytes, semiconductors, and plasma), two or more species of electric charges flow in opposite directions. The flow direction for conventional current is also backwards compared to the actual electron drift taking place during electric currents in metals, the typical conductor of electricity, which is a source of confusion for beginners in electronics. Properties In physics, the proton (Greek proton = first) is a subatomic particle with an electric charge of one positive fundamental unit (1. ... Properties The electron is a lightweight fundamental subatomic particle that carries a negative electric charge. ... Electric current is the flow of electric charge. ... An electrolyte is a substance that dissociates into free ions when dissolved (or molten), to produce an electrically conductive medium. ... Dissolving table salt in water In chemistry, a solution is a homogeneous mixture composed of one or more substances, known as solutes, dissolved in another substance, known as a solvent. ... // An ion is an atom, group of atoms, or subatomic particle with a net electric charge. ... In electricity, current is the rate of flow of charges, usually through a metal wire or some other electrical conductor. ... A Plasma lamp, illustrating some of the more complex phenomena of a plasma, including filamentation A solar coronal mass ejection blasts plasma throughout the solar system. ...

Properties

Aside from the properties described in articles about electromagnetism, charge is a relativistic invariant. This means that any particle that has charge q, no matter how fast it goes, always has charge q. This property has been experimentally verified by showing that the charge of one helium nucleus (two protons and two neutrons bound together in a nucleus and moving around at incredible speeds) is the same as two deuterium nuclei (one proton and one neutron bound together, but moving much more slowly than they would if they were in a helium nucleus). Electromagnetism is the physics of the electromagnetic field: a field, encompassing all of space, which exerts a force on those particles that possess the property of electric charge, and is in turn affected by the presence and motion of such particles. ... Wikisource has original text related to this article: Relativity: The Special and General Theory Albert Einsteins theory of relativity, or simply relativity, refers specifically to two theories: special relativity and general relativity. ... In physics, invariants are usually quantities conserved (unchanged) by the symmetries of the physical system. ... General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Atomic mass 4. ... A semi-accurate depiction of the helium atom. ... Properties In physics, the proton (Greek proton = first) is a subatomic particle with an electric charge of one positive fundamental unit (1. ... Properties In physics, the neutron is a subatomic particle with no net electric charge and a mass of 939. ... Deuterium, also called heavy hydrogen, is a stable isotope of hydrogen with a natural abundance in the oceans of one atom in 6400 of hydrogen (see VSMOW; the abundance changes slightly from one kind of natural water to another). ...

Conservation of charge

The total electric charge of an isolated system remains constant regardless of changes within the system itself. This law is inherent to all processes known to physics and can be derived in a local form from the gauge invariance of the wave function. Because the time derivative of charge is called electric current, the conservation of charge results in the charge-current continuity equation. More generally, the net change in charge density ρ within a volume of integration V is equal to the area integral over the current density J on the surface of the volume S, which is in turn equal to the net current I: A physical system is said to be isolated if it does not interact with anything. ... Gauge theories are a class of physical theories based on the idea that symmetry transformations can be performed locally as well as globally. ... In the most restricted usage in quantum mechanics, the wavefunction associated with a particle such as an electron, is a complex-valued square integrable function ψ defined over a portion of space normalized in such a way that In Max Borns probabilistic interpretation of the wavefunction, the amplitude squared... Electric current is the flow of electric charge. ... All the examples of continuity equations below express the same idea; they are all really examples of the same concept. ... Charge density is the amount of electric charge per unit volume. ... In electricity, current is the rate of flow of charges, usually through a metal wire or some other electrical conductor. ... In electricity, current refers to electric current, which is the flow of electric charge. ...

See also

• Charge decay
• Current density
• Electrical discharge
• SI electromagnetism units
• Quantity of electricity

In electricity, current is the rate of flow of charges, usually through a metal wire or some other electrical conductor. ... An electrostatic discharge (ESD) is a sudden flow of electric current through a material that is normally an insulator. ... ... In physics the term Quantity of Electricity refers to the quantity of electric charge. ...

External links

• Online Charge Converter - convert between various units of charge, such as coulomb, EMU of charge, franklin, ampere-hour, faraday, and so on

• Interactive Charge Conversion Table - convert selected unit to all other units of charge

• How fast does a charge decay?

• Science Aid: Electrostatic charge Easy to understand page on electrostatic charge.