Electromagnetism

Electricity · Magnetism Electrostatics  · Electric charge · Coulomb’s law · Electric field · Electric flux · Gauss’ law · Electric potential · Electrostatic induction · Electric dipole moment ·

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Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. Electromagnetism is the Physics of the Electromagnetic field: a field which exerts a Force on particles that possess the property of In Physics, magnetism is one of the Phenomena by which Materials exert attractive or repulsive Forces on other Materials. Electrostatics is the branch of Science that deals with the Phenomena arising from what seems to be stationary Electric charges Since Classical ---- Bold text Coulomb's law', developed in the 1780s by French physicist Charles Augustin de Coulomb, may be stated in scalar form In Physics, the space surrounding an Electric charge or in the presence of a time-varying Magnetic field has a property called an electric field (that can In Electromagnetism, electric flux is Flux of the Electric field. At a point in space the electric potential is the Potential energy per unit of charge that is associated with a static (time-invariant Electric field Electrostatic induction is a redistribution of Electrical charge in an object caused by the influence of nearby charges In Physics, the electric dipole moment (or electric dipole for short is a measure of the polarity of a system of Electric charges. A subatomic particle is an elementary or composite Particle smaller than an Atom. In Physics, the electromagnetic force is the force that the Electromagnetic field exerts on electrically charged particles Electrically charged matter is influenced by, and produces, electromagnetic fields. The electromagnetic field is a physical field produced by electrically charged objects. The interaction between a moving charge and an electromagnetic field is the source of the electromagnetic force, which is one of the four fundamental forces. In Physics, the electromagnetic force is the force that the Electromagnetic field exerts on electrically charged particles In Physics, a fundamental interaction or fundamental force is a mechanism by which particles interact with each other and which cannot be explained in terms

Contents 1 Overview 2 Units 3 History 4 Properties 5 Conservation of charge 6 See also 7 References 8 External links

Overview

Electric charge is a characteristic of some subatomic particles. It is quantized in that, when expressed in units of the so-called elementary charge e, it takes integer or fractional values. The elementary charge, usually denoted e, is the Electric charge carried by a single Proton, or equivalently the negative of the electric charge carried Electrons by convention have a charge of −1, while protons have the opposite charge of +1. The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive Quarks have a fractional charge of −1/3 or +2/3. In Physics, a quark (kwɔrk kwɑːk or kwɑːrk is a type of Subatomic particle. The antiparticle equivalents of these (positrons, antiprotons, and antiquarks, respectively) have the opposite charge. to most kinds of particles, there is an associated antiparticle with the same Mass and opposite Electric charge. The positrons or antielectron is the Antiparticle or the Antimatter counterpart of the Electron. The antiproton ( pronounced p-bar) is the Antiparticle of the Proton. In Physics, a quark (kwɔrk kwɑːk or kwɑːrk is a type of Subatomic particle. There are other charged particles. In Physics, a charged particle is a particle with an Electric charge. The discrete nature of electric charge was proposed by Michael Faraday in his electrolysis experiments, and then directly demonstrated by Robert Millikan in his oil-drop experiment. Michael Faraday, FRS ( September 22 1791 – August 25 1867) was an English Robert Andrews Millikan (March 22 1868 – December 19 1953 was an American experimental physicist, and Nobel laureate in physics for his measurement The Purpose of Robert Millikan and Harvey Fletcher 's oil-drop experiment (1909 was to measure the Electric charge of the Electron

In general, same-sign charged particles repel one another, while different-sign charged particles attract. This is expressed quantitatively in Coulomb's law, which states that the magnitude of the electrostatic repelling force between two particles is proportional to the product of their charges and the inverse square of the distance between them. ---- Bold text Coulomb's law', developed in the 1780s by French physicist Charles Augustin de Coulomb, may be stated in scalar form

The electric charge of a macroscopic object is the sum of the electric charges of its constituent particles. Macroscopic is commonly used to describe physical objects that are measurable and observable by the Naked eye. Often, the net electric charge is zero, because it is favorable for the number of electrons in every atom to equal the number of protons (or, more generally, for the number of anions, or negatively charged atoms, in every molecule to equal the number of cations, or positively charged atoms). History See also Atomic theory, Atomism The concept that matter is composed of discrete units and cannot be divided into arbitrarily tiny The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by When the net electric charge is non-zero and motionless, one has the phenomenon known as static electricity. For the science of static charges see Electrostatics Static electricity refers to the accumulation of excess Electric charge in a Even when the net charge is zero, it can be distributed non-uniformly (e. g. , due to an external electric field, or due to molecular motion), in which case the material is said to be polarized. In Physics, the space surrounding an Electric charge or in the presence of a time-varying Magnetic field has a property called an electric field (that can In Classical electromagnetism, the polarization density (or electric polarization, or simply polarization) is the Vector field that expresses The charge due to the polarization is known as bound charge, while the excess charge brought from outside is called free charge. In Classical electromagnetism, the polarization density (or electric polarization, or simply polarization) is the Vector field that expresses The motion of charged particles (e. g. , of electrons in metals) in a particular direction is known as electric current. Electric current is the flow (movement of Electric charge. The SI unit of electric current is the Ampere.

Units

The SI unit of quantity of electricity or electric charge is the coulomb, which is equivalent to about 6. In Physics the term quantity of Electricity refers to the quantity of Electric charge. The coulomb (symbol C) is the SI unit of Electric charge. It is named after Charles-Augustin de Coulomb. 25 × 10¹⁸ elementary charges (the charge on a single electron or proton). The elementary charge, usually denoted e, is the Electric charge carried by a single Proton, or equivalently the negative of the electric charge carried Hence, the charge of an electron is approximately −1. 602 x 10⁻¹⁹ C. The coulomb (symbol C) is the SI unit of Electric charge. It is named after Charles-Augustin de Coulomb. The coulomb is defined as the quantity of charge that has passed through the cross-section of an electrical conductor carrying one ampere within one second. In Science and engineering, a conductor is a material which contains movable Electric charges. The ampere, in practice often shortened to amp, (symbol A is a unit of Electric current, or amount of Electric charge per second The symbol Q is often used to denote a quantity of electricity or charge. The quantity of electric charge can be directly measured with an electrometer, or indirectly measured with a ballistic galvanometer. An electrometer is an electrical instrument for measuring Electric charge or electrical Potential difference. A galvanometer is a type of Ammeter; an instrument for detecting and measuring Electric current.

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. Macroscopic is commonly used to describe physical objects that are measurable and observable by the Naked eye. In Mathematics, the real numbers may be described informally in several different ways Furthermore, in some contexts it is meaningful to speak of fractions of a charge; e. g. in the charging of a capacitor. A capacitor is a passive electrical component that can store Energy in the Electric field between a pair of conductors

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. Thales of Miletus According to Bertrand Russell, "Philosophy begins with Thales Fur is a body hair of any non-human Mammal, also known as the Pelage. Amber is Fossil tree Resin, which is appreciated for its color and beauty The Greeks noted that the charged amber buttons could attract light objects such as hair. Hair is a keratinised protein filament that grows through the epidermis from follicles deep within the Dermis. They also noted that if they rubbed the amber for long enough, they could even get a spark to jump. Amber is Fossil tree Resin, which is appreciated for its color and beauty This property derives from the triboelectric effect. Triboelectric Series Materials are often listed in order of the polarity of charge separation when they are touched with another object

In 1600 the English scientist William Gilbert returned to the subject in De Magnete, and coined the New Latin word electricus from ηλεκτρον (elektron), the Greek word for "amber", which soon gave rise to the English words "electric" and "electricity. William Gilbert, also known as Gilbard ( Colchester, England, May 24, 1544 &ndash London, England, November 30 The term New Latin or Neo-Latin is used to describe a form the Latin language used between the end of the Medieval Latin period (c " He was followed in 1660 by Otto von Guericke, who invented what was probably the first electrostatic generator. Otto von Guericke (originally spelled Gericke ˈgeːʁɪkə ( November 20, 1602 &ndash May 11, 1686 ( Julian calendar) Electrostatics is the branch of Science that deals with the Phenomena arising from what seems to be stationary Electric charges Since Classical 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. Robert Boyle was a Natural philosopher, chemist physicist inventor and early Gentleman scientist, noted for his work in Physics and Chemistry Year 1729 ( MDCCXXIX) was a Common year starting on Saturday (link will display the full calendar of the Gregorian calendar (or a Common In Science and engineering, a conductor is a material which contains movable Electric charges. An insulator, also called a Dielectric, is a material that resists the flow of Electric current. Charles François de Cisternay du Fay (Paris 14 September[[ 698]] &ndash 1739 was a French Chemist and superintendent of the Jardin du Roi. Year 1733 ( MDCCXXXIII) was a Common year starting on Thursday (link will display the full calendar of the Gregorian calendar (or a When glass was rubbed with silk, du Fay 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. In 1839 Michael Faraday showed that the apparent division between static electricity, current electricity and bioelectricity was incorrect, and all were a consequence of the behavior of a single kind of electricity appearing in opposite polarities. Year 1839 ( MDCCCXXXIX) was a Common year starting on Tuesday (link will display the full calendar of the Gregorian Calendar (or a Common It is arbitrary which polarity you call positive and which you call negative. Positive charge can be defined as the charge left on a glass rod after being rubbed with silk. ^[1]

One of the foremost experts on electricity in the 18th century was Benjamin Franklin, who argued in favour of a one-fluid theory of electricity. The 18th century lasted from 1701 to 1800 in the Gregorian calendar, in accordance with the Anno Domini / Common Era numbering system Benjamin Franklin ( April 17 1790 was one of the Founding Fathers of the United States of America. 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. Glass in the common sense refers to a Hard, Brittle, transparent Solid, such as that used for Windows many The Leyden jar is a simple device that "stores" static electricity in large amounts 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. William Watson ( 3 April 1715 &ndash 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 fundamentally correct. There is only one kind of electrical charge, and only one variable is required to keep track of the amount of charge. ^[2] On the other hand, just knowing the charge is not a complete description of the situation. Matter is composed of several kinds of electrically charged particles, and these particles have many properties, not just charge.

The most common charge carriers are the positively charged proton and the negatively charged electron. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J The movement of any of these charged particles constitutes an electric current. In many situations, it suffices to speak of the conventional current without regard to whether it is carried by positive charges moving in the direction of the conventional current and/or by negative charges moving in the opposite direction. Electric current is the flow (movement of Electric charge. The SI unit of electric current is the Ampere. This macroscopic viewpoint is an approximation that simplifies electromagnetic concepts and calculations.

At the opposite extreme, if one looks at the microscopic situation, one sees there are many ways of carrying an electric current, including: a flow of electrons; a flow of electron "holes" which act like positive particles; and both negative and positive particles (ions or other charged particles) flowing in opposite directions in an electrolytic solution or a plasma). Electric current is the flow (movement of Electric charge. The SI unit of electric current is the Ampere. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge An electrolyte is any substance containing free Ions that behaves as an electrically conductive medium In Chemistry, a solution is a Homogeneous Mixture composed of two or more substances In Physics and Chemistry, plasma is an Ionized Gas, in which a certain proportion of Electrons are free rather than being bound

Beware that in the common and important case of metallic wires, the direction of the conventional current is opposite to the drift velocity of the actual charge carriers, i. e. the electrons. This is a source of confusion for beginners.

Properties

Flavour in particle physics v • d • e

Flavour quantum numbers: Lepton number: L Baryon number: B Strangeness: S Charm: C Bottomness: B' Topness: T Isospin: Iz or I Weak isospin: Tz Electric charge: Q Combinations: Hypercharge: Y Y=2(Q-Iz) Weak hypercharge: YW YW=2(Q-Tz) YW=B−L Related topics: CPT symmetry CKM matrix CP symmetry Chirality

Aside from the properties described in articles about electromagnetism, charge is a relativistic invariant. In Particle physics, flavour or flavor (see spelling differences) is a Quantum number of Elementary particles related to their Particle physics is a branch of Physics that studies the elementary constituents of Matter and Radiation, and the interactions between them Quantum numbers describe values of conserved numbers in the dynamics of the Quantum system. In High energy physics, the lepton number is the number of Leptons minus the number of antileptons In Particle physics, the baryon number is an approximate conserved Quantum number of a system The charm Quark is a second-generation quark with an electric charge of +(2/3 e. The bottom quark is a third-generation Quark with a charge of − e. The top quark is the third- generation up-type Quark with a charge of +(2/3 e. In Physics, and specifically Particle physics, isospin ( isotopic spin, isobaric spin) is a Quantum number related to the The weak isospin in Particle physics is a quantum number relating to the Weak interaction, and parallels the idea of Isospin under the Strong In Particle physics, the hypercharge (represented by Y) of a particle is related to the Strong interaction, and it should not be confused with similarly The weak hypercharge in Particle physics is a quantum number relating the Electrical charge and the third component of Weak isospin, and is similar In High energy physics, B−L (pronounced "bee minus ell" is the Baryon number minus the Lepton number. CPT symmetry is a fundamental symmetry of Physical laws under transformations that involve the inversions of charge, parity and In the Standard Model of Particle physics, the Cabibbo-Kobayashi-Maskawa matrix ( CKM matrix, quark mixing matrix, sometimes also called In Particle physics, CP violation is a violation of the postulated CP symmetry of the laws of physics A phenomenon is said to be chiral if it is not identical to its Mirror image (see Chirality) Electromagnetism is the Physics of the Electromagnetic field: a field which exerts a Force on particles that possess the property of This page is about the scientific concept of relativity for philosophical or sociological theories about relativity see Relativism. In Mathematics and Theoretical physics, an invariant is a property of a system which remains unchanged under some transformation. 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 high 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). Helium ( He) is a colorless odorless tasteless non-toxic Inert Monatomic Chemical The nucleus of an Atom is the very dense region consisting of Nucleons ( Protons and Neutrons, at the center of an atom The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth

Conservation of charge

The total electric charge of an isolated system remains constant regardless of changes within the system itself. In the Natural sciences an isolated system, as contrasted with a open system, is a Physical system that does not interact with its Surroundings This law is inherent to all processes known to physics and can be derived in a local form from gauge invariance of the wave function. Gauge theory is a peculiar Quantum field theory where the Lagrangian is invariant under certain transformations A wave function or wavefunction is a mathematical tool used in Quantum mechanics to describe any physical system The conservation of charge results in the charge-current continuity equation. A continuity equation is a Differential equation that describes the conservative transport of some kind of quantity 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 area S, which is in turn equal to the net current I:

Thus, the conservation of electric charge, as expressed by the continuity equation, gives the result:

The charge transferred between time t_o and t is obtained by integrating both sides:

where I is the net outward current through a closed surface and Q is the electric charge contained within the volume defined by the surface. The linear surface or volume charge density is the amount of Electric charge in a line, Surface, or Volume. Current density is a measure of the Density of flow of a conserved charge. Electric current is the flow (movement of Electric charge. The SI unit of electric current is the Ampere.

See also

• Elementary charge
• Charge (physics)
• Static electricity
• Electricity
• Current density
• Electrostatic discharge
• SI electromagnetism units
• Quantity of electricity

References

1. ^ Electromagnetic Fields (2nd Edition), Roald K. The elementary charge, usually denoted e, is the Electric charge carried by a single Proton, or equivalently the negative of the electric charge carried In Physics, a charge may refer to one of many different quantities such as the Electric charge in Electromagnetism or the Color charge in For the science of static charges see Electrostatics Static electricity refers to the accumulation of excess Electric charge in a Current density is a measure of the Density of flow of a conserved charge. Electrostatic discharge ( ESD) is the sudden and momentary Electric current that flows between two objects at different Electrical potentials The term is See also SI units Speed of light Meter Ampere Second In Physics the term quantity of Electricity refers to the quantity of Electric charge. Wangsness, Wiley, 1986. ISBN 0-471-81186-6 (intermediate level textbook)
2. ^ One Kind of Charge

External links

• How fast does a charge decay?
• Science Aid: Electrostatic charge Easy-to-understand page on electrostatic charge.

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