GCSE›Edexcel GCSE Physics›Mind mapsCurrent, Potential Difference & ResistanceEdexcel GCSE Physics: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsCurrentRate of flow of chargeIn metals: flow of electronsQ=ItQ = ItQ=It2 A for 10 s → 20 CTotal current in = total out at a junctionPotential differenceEnergy per unit charge between two points1 volt = 1 joule per coulombE=QVE = QVE=QVMetersAmmeter connects in seriesVoltmeter connects in parallelVoltmeter measures p.d. across a componentCurrent, p.d., RV = IRAVΩCResistanceOpposes the flow of currentV=IRV = IRV=IRUnit: ohm (Ω)Variable resistor controls the currentMore resistance → less currentSeries vs parallelSeries: same current everywhereSeries: p.d. shared between componentsParallel: current splits between branchesParallel: same p.d. across each branchSeries resistors: total resistance increasesParallel resistors: total resistance decreasesExam tipsAdding a resistor does not always raise resistanceOnly true in seriesRearrange the equation before substituting