Field lines and field strength, uniform fields between plates, Coulomb's law for point charges, and the potential that ties it all together. Play the five simulations below. The gamified lessons and the topic Paper 4 practice are live below too.
Simulations · live
Interactive · liveElectric fields and field linesStep through the field-line patterns for single charges, dipoles, like charges and parallel plates, with the force F = qE on a test charge.Loads only when you launch, so the page stays fast.
Interactive · liveUniform electric fieldsParallel plates with E = V / d, and a charged particle deflected into a parabola as it crosses the field.Loads only when you launch, so the page stays fast.
Interactive · liveCoulomb's lawTwo point charges with equal and opposite force arrows; vary the charges and separation to see the inverse-square law.Loads only when you launch, so the page stays fast.
Interactive · liveElectric field of a point chargeA radial field with E = Q / (4πε₀r²), read off an inverse-square curve as you move the test point.Loads only when you launch, so the page stays fast.
Interactive · liveElectric potentialThe 1/r potential beside the 1/r² field, showing how the field is the negative gradient of the potential.Loads only when you launch, so the page stays fast.
Paper 4 practice · live
Structured questions · with worked solutionsTen original Paper 4 style questionsA full topic set across field lines, uniform fields, Coulomb’s law, the field of a point charge, and potential, with questions linking the lessons and full worked solutions.Open practice →