IGCSE›Cambridge IGCSE Physics›Mind mapsElectric ChargeCambridge IGCSE Physics: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsTwo chargesTwo types: positive and negativeLike charges repelUnlike charges attractMeasured in coulombs (C)Charging by frictionRub two insulators togetherOnly electrons transfer, never protonsGains electrons → negativeLoses electrons → positiveBalloon on jumper attracts small paperElectric chargestatic and fieldsC −Electric fieldsRegion where a charge feels a forceDirection is force on a positive chargePoint charge: lines radiate out (+) or in (−)Parallel plates: straight, even lines from + to −Conductors and insulatorsConductors have free electrons, e.g. metalsCharge in a conductor disperses quicklyInsulators hold charge where placedPlastic and rubber suit friction experimentsExam tipsPositive appears because electrons are lostPositive charge itself never movesField direction uses a positive test charge