electricity electricity set physical phenomena associated presence flow electric charge electricity gives wide variety known effects lightning static electricity electromagnetic induction electric current addition electricity permits creation reception electromagnetic radiation radio waves electricity charges produce electromagnetic fields act charges electricity occurs types physics electric charge property particles determines electromagnetic interactions electrically charged matter influenced produces electromagnetic fields electric charges positive negative electric field charges surrounded electric field electric field produces force charges changes electric field travel speed light electric potential capacity electric field work electric charge typically measured volts electric current movement flow electrically charged particles typically measured moving charges produce magnetic field electric currents generate magnetic fields changing magnetic fields generate electric currents electrical engineering electricity electric power electric current equipment electronics deals electrical circuits involve active electrical components vacuum tubes integrated circuits associated passive technologies electrical phenomena studied antiquity progress theoretical understanding remained slow seventeenth eighteenth centuries practical applications electricity late nineteenth century engineers able industrial residential use rapid expansion electrical technology time transformed industry society electricity extraordinary versatility means set applications include transport heating lighting communications electrical power backbone modern industrial society history long knowledge electricity existed people aware electric fish ancient egyptian texts dating bce referred fish described fish electric fish reported later ancient greek roman arabic physicians ancient writers elder attested effect electric delivered electric rays knew travel conducting objects patients suffering directed touch electric fish hope powerful cure possibly earliest nearest approach discovery identity lightning electricity source attributed arabs 15th century arabic word lightning applied electric ray ancient cultures mediterranean knew certain objects rods amber cat fur attract light objects like feathers series observations static electricity bce believed friction rendered amber magnetic contrast minerals needed incorrect believing attraction magnetic effect later science prove link electricity according controversial theory knowledge based discovery baghdad battery resembles cell uncertain artifact electrical nature electricity remain little intellectual curiosity english scientist careful study electricity distinguishing effect static electricity produced amber coined new latin word amber like amber greek word amber refer property attracting small objects association gave rise english words electric electricity appearance print work conducted 18th century conducted extensive research electricity selling possessions fund work june reputed attached metal key string flown storm threatened sky succession sparks jumping key hand showed lightning electrical nature explained apparently behavior device storing large amounts electrical charge terms electricity consisting positive negative charges published discovery demonstrating electricity medium passed signals muscles battery pile alternating layers copper provided scientists reliable source electrical energy machines previously recognition unity electric magnetic phenomena invented electric motor analysed electrical circuit electricity light definitively linked particular physical lines force early 19th century seen rapid progress electrical science late 19th century greatest progress electrical engineering people 1st baron electricity turned scientific curiosity essential tool modern life driving force second industrial revolution discovered illuminated light create electric sparks easily published paper explained experimental data effect result light energy carried discovery led quantum revolution awarded nobel prize physics discovery law effect effect employed found solar panels frequently electricity commercially solid state device cat 1900s radio receivers like wire placed lightly contact solid crystal crystal order detect radio signal contact junction effect solid state component current confined solid elements compounds engineered specifically switch current flow understood forms negatively charged positively charged electron deficiencies called holes charges holes understood terms quantum physics building material solid state device came invention common solid state devices include chips ram specialized type ram called flash ram flash drives recently solid state drives replace rotating magnetic disc hard disk drives solid state devices prevalent 1950s 1960s transition vacuum tubes integrated circuit light led concepts electric charge presence charge gives rise force charges exert force effect known understood antiquity lightweight ball suspended string charged touching glass rod charged cloth similar ball charged glass rod found repel charge acts force balls apart balls charged amber rod repel ball charged glass rod amber rod balls found attract phenomena investigated late eighteenth century charge opposing forms discovery led known like charged objects repel opposite charged objects attract force acts charged particles charge tendency spread evenly possible conducting surface magnitude electromagnetic force attractive given law relates force product charges square relation distance electromagnetic force strong second strength strong interaction unlike force operates distances comparison weaker force electromagnetic force pushing apart times attraction pulling study shown origin charge certain types particles property electric charge electric charge gives rise electromagnetic force fundamental forces nature familiar carriers electrical charge electron experiment shown charge quantity net charge isolated system remain constant regardless changes taking place system system charge transferred bodies direct contact passing conducting material wire informal term static electricity refers net presence charge body usually caused materials transferring charge charge opposite sign charge expressed negative positive convention charge carried deemed negative positive custom originated work charge usually given symbol expressed electron carries charge approximately charge equal opposite charge possessed matter bearing equal opposite charge corresponding particle charge measured number means early instrument gold leaf use classroom demonstrations superseded electronic electric current movement electric charge known electric current intensity usually measured current consist moving charged particles commonly charge motion constitutes current historical convention positive current defined having direction flow positive charge contains flow positive circuit negative current defined manner called conventional current motion negatively charged electric circuit familiar forms current deemed positive opposite direction depending conditions electric current consist flow charged particles direction directions positive negative convention widely situation process electric current passes material termed electrical nature varies charged particles material travelling examples electric currents include metallic flow conductor metal charged flow electrical sparks particles slowly average drift velocity millimetre second electric field drives close speed light enabling electrical signals pass rapidly wires current causes effects historically means recognising presence water current pile discovered process known work greatly expanded current resistance causes heating effect studied important discoveries relating current accidentally preparing lecture witnessed current wire disturbing needle magnetic compass discovered fundamental interaction electricity level electromagnetic emissions generated electric high produce electromagnetic interference detrimental workings adjacent equipment engineering household applications current described direct current alternating current terms refer current varies time direct current produced example battery required electronic devices flow positive circuit negative common flow carried travelling opposite direction alternating current current direction repeatedly takes form wave alternating current forth conductor charge moving net distance time time averaged value alternating current zero delivers energy direction reverse alternating current affected electrical properties observed steady state direct current properties important subjected electric field concept electric field introduced electric field created charged body space surrounds results force exerted charges placed field electric field acts charges similar manner way field acts masses like extends infinity shows square relationship distance important difference gravity acts attraction drawing masses electric field result attraction large bodies planets generally carry net charge electric field distance usually zero gravity dominant force distance universe despite weaker electric field generally varies space strength point defined force unit charge felt stationary charge placed point conceptual charge termed test charge small prevent electric field disturbing main field stationary prevent effect magnetic fields electric field defined terms force force follows electric field having magnitude direction specifically field study electric fields created stationary charges called field set imaginary lines direction point field concept introduced term lines force sees use field lines paths point positive charge seek forced field imaginary concept physical existence field intervening space lines field lines stationary charges key properties originate positive charges terminate negative charges second enter good conductor right angles cross close hollow conducting body carries charge outer surface field zero places inside body operating principal cage conducting metal shell interior outside electrical effects principles important designing items high voltage equipment finite limit electric field strength medium point electrical breakdown occurs electric arc causes charged parts air example tends arc small gaps electric field strengths exceed larger gaps breakdown strength weaker visible natural occurrence lightning caused charge separated clouds rising columns air raises electric field air greater withstand voltage large lightning cloud high discharge energies great field strength greatly affected nearby conducting objects particularly intense forced curve sharply pointed objects principle exploited lightning conductor sharp spike acts encourage lightning stroke develop building serves protect electric potential concept electric potential closely linked electric field small charge placed electric field experiences force brought charge point force requires work electric potential point defined energy required bring unit test charge infinite distance slowly point usually measured volts potential work expended bring charge infinity definition potential formal little practical application useful concept electric potential difference energy required unit charge specified points electric field special property conservative means path taken test charge irrelevant paths specified points energy unique value potential difference stated strongly identified unit choice measurement description electric potential difference term voltage sees greater everyday usage practical purposes useful define common reference point expressed compared infinity useful reference earth assumed potential reference point naturally takes earth ground earth assumed infinite source equal amounts positive negative charge electrically electric potential quantity magnitude direction viewed analogous height released object fall difference heights caused field charge fall voltage caused electric field relief maps lines marking points equal height set lines marking points equal potential known drawn charged object cross lines force right angles lie parallel conductor surface produce force charge carriers potential surface electric field formally defined force exerted unit charge concept potential allows useful equivalent definition electric field local gradient electric potential usually expressed volts metre direction field line greatest slope potential lie closest discovery magnetic field existed sides wire carrying electric current indicated direct relationship electricity interaction different forces forces nature known force compass needle direct away current carrying wire acted right angles slightly obscure words electric conflict acts revolving manner force depended direction current flow reversed force fully understand discovery observed effect current force magnetic field force current phenomenon investigated discovered parallel current carrying wires exerted force wires conducting currents direction attracted wires containing currents opposite directions forced apart interaction magnetic field current produces forms basis international definition relationship magnetic fields currents extremely important led invention electric motor motor consisted permanent sitting pool mercury current allowed wire suspended pivot mercury exerted force wire making circle long current maintained experimentation revealed wire moving perpendicular magnetic field developed potential difference ends analysis process known electromagnetic induction enabled state principle known law induction potential difference induced closed circuit proportional rate change magnetic loop exploitation discovery enabled electrical generator converted mechanical energy rotating copper disc electrical energy disc inefficient use practical generator showed possibility generating electric power possibility taken followed work ability chemical reactions produce electricity conversely ability electricity drive chemical reactions wide array uses important electricity initial invention pile cells evolved different types batteries cells aluminium produced vast quantities way portable devices electrically powered cells electric circuits electric circuit electric components electric charge flow closed path circuit usually perform useful task components electric circuit forms include elements switches electronics electronic circuits contain active components usually typically exhibit non linear behaviour requiring complex analysis simplest electric components termed passive linear temporarily store energy contain sources exhibit linear responses simplest passive circuit elements suggests current dissipating energy heat resistance consequence motion charge conductor metals example resistance primarily collisions law basic law circuit theory stating current passing resistance directly proportional potential difference resistance materials relatively constant range temperatures currents materials conditions known unit resistance named honour greek letter resistance produce potential difference response current development device store charge storing electrical energy resulting field consists conducting plates separated thin layer practice thin metal increasing surface area unit volume unit named given symbol develops potential difference stores charge connected voltage supply initially causes current charge current decay time fills eventually falling zero permit steady state current instead blocks conductor usually wire stores energy magnetic field response current current changes magnetic field inducing voltage ends conductor induced voltage proportional time rate change current constant termed unit henry named contemporary henry induce potential difference current changes rate second behaviour regards freely allow current opposes rapidly changing electric power electric power rate electric energy transferred electric circuit unit power second electric power like mechanical power rate work measured represented letter term colloquially mean electric power electric power produced electric current consisting charge seconds passing electric potential voltage difference formula electric charge time seconds electric current electric potential voltage volts electricity generation electric generators supplied chemical sources electric batteries means wide variety sources energy electric power generally supplied businesses homes electric power industry electricity usually sold hour product power kilowatts multiplied running time hours electric utilities measure power electricity meters running total electric energy delivered customer unlike fossil electricity low form energy converted motion forms energy high efficiency electronics electronics deals electrical circuits involve active electrical components vacuum tubes integrated circuits associated passive technologies behaviour active components ability control electron flows makes weak signals possible electronics widely information processing telecommunications signal processing ability electronic devices act switches makes digital information processing possible technologies circuit boards electronics packaging technology varied forms communication infrastructure complete circuit functionality transform mixed components regular working system today electronic devices use components perform electron control study devices related technology considered branch solid state physics design construction electronic circuits solve practical problems come electronics engineering electromagnetic wave work showed time varying magnetic field acted source electric field time varying electric field source magnetic field field changing time field necessarily induced phenomenon properties wave naturally referred electromagnetic wave electromagnetic waves analysed theoretically developed set describe electric field magnetic field electric charge electric current prove wave necessarily travel speed light light form electromagnetic radiation laws unify light fields charge great theoretical physics work researchers enabled use electronics convert signals high frequency currents suitably shaped electricity permits transmission reception signals radio waves long distances production uses generation transmission 6th century greek philosopher experimented amber rods experiments studies production electrical energy method known effect lift light objects generate sparks extremely inefficient invention pile eighteenth century viable source electricity available pile modern descendant electrical battery store energy available demand form electrical energy battery versatile common power source suited applications energy storage finite discharged disposed large electrical demands electrical energy generated transmitted continuously transmission lines electrical power usually generated electro mechanical generators driven steam produced fossil fuel heat released nuclear reactions sources energy extracted wind flowing water modern steam turbine invented sir today generates percent electric power world variety heat sources generators bear resemblance disc generator rely electromagnetic principle conductor linking changing magnetic field potential difference ends invention late nineteenth century meant electrical power transmitted efficiently higher voltage lower current efficient electrical transmission meant turn electricity generated power stations benefited economies scale relatively long distances needed electrical energy easily stored quantities large meet demands national scale times exactly produced required requires electricity utilities careful predictions electrical loads maintain constant power stations certain generation held reserve electrical grid inevitable disturbances losses demand electricity grows great nation economy develops united_states showed increase demand year decades twentieth century rate growth experienced emerging economies india china historically growth rate electricity demand forms energy environmental concerns electricity generation led increased focus generation sources particular wind debate expected continue environmental impact different means electricity production final form relatively clean applications electricity convenient way transfer energy adapted huge growing number uses invention practical light 1870s led lighting publicly available applications electrical power electrification brought dangers replacing naked flames gas lighting greatly reduced fire hazards homes factories public utilities set cities targeting burgeoning market electrical lighting heating effect employed light sees direct use electric heating versatile seen electrical generation required production heat power station number countries denmark issued legislation restricting banning use electric heating new buildings electricity highly practical energy source heating air conditioning heat pumps representing growing sector electricity demand heating cooling effects electricity utilities increasingly obliged accommodate electricity telecommunications electrical telegraph demonstrated commercially earliest applications construction intercontinental telegraph systems 1860s electricity enabled communications minutes globe optical satellite communication taken share market communications systems electricity expected remain essential process effects visibly employed electric motor provides clean efficient means motive power stationary motor easily provided supply power motor moves application electric vehicle obliged carry power source battery collect current sliding contact electronic devices use important twentieth century fundamental building block modern modern integrated circuit contain billion region centimetres square electricity fuel public transportation including electric buses trains electricity natural world effects voltage applied human body causes electric current tissues relationship non linear greater voltage greater current threshold perception varies supply frequency path current frequency electricity current low detected effect certain conditions current sufficiently high cause muscle heart tissue burns lack visible sign conductor electrified makes electricity particular hazard pain caused electric shock intense leading electricity times employed method torture death caused electric shock referred means judicial execution jurisdictions use recent times electrical phenomena nature electricity human invention observed forms nature prominent manifestation lightning interactions familiar level touch friction chemical bonding interactions electric fields atomic scale earth magnetic field thought arise natural circulating currents planet core certain crystals sugar generate potential difference faces subjected external pressure phenomenon known greek meaning press discovered effect material subjected electric field small change physical dimensions takes place organisms sharks able detect respond changes electric fields ability known termed able generate serve predatory defensive weapon order best known example electric detect prey high generated modified muscle cells called animals transmit information cell membranes voltage called action functions include communication nervous system muscles electric shock system causes muscles contract action responsible coordinating activities certain plants cultural perception asked scientist electricity valuable answered day sir tax 19th early 20th century electricity everyday life people western world popular culture time accordingly depicts mysterious quasi magical force living revive dead bend laws nature attitude began experiments legs dead frogs shown application animal electricity apparently dead drowned persons reported medical literature shortly work results known authored method monster monsters electricity later stock theme horror films public familiarity electricity second industrial revolution grew cast positive light workers finger death gloves end piece living wires poem sons martha electrically powered vehicles sort featured large adventure stories books masters electricity fictional real including scientists popularly conceived having wizard like powers electricity novelty necessity everyday life later half 20th century required particular attention popular culture stops flowing event usually signals disaster people flowing hero song cast heroic wizard like figures
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