Current, potential difference and resistance
Current, potential difference and resistance
Electric current is the rate of flow of charge. It is defined by I=ΔQΔtI = \frac{\Delta Q}{\Delta t}I=ΔtΔQ, so 1 A1 \, \text{A}1A means 1 C1 \, \text{C}1C passes a point each second.
Step-by-step lessons on Edexcel A Level Physics I-V characteristics and resistivity. Each one builds up to exam-style questions. Physics is one of the most mathematically demanding A Levels -- at least 40% of the marks across the three papers require maths skills at Level 2 (GCSE) standard or above, so build calculation and graph-handling fluency alongside the conceptual content from the start.