- Only electrons transfer when objects are charged by friction — protons stay in the nucleus
- Only insulators build up static charge — conductors allow electrons to flow away
- Like charges repel; unlike charges attract (the fundamental rule)
- Electric field lines show direction of force on a positive charge
- Field lines are denser where the field is stronger
- Field lines never cross
- Around a positive charge: field lines point outward
- Around a negative charge: field lines point inward
- Earthing prevents dangerous charge build-up by providing a conducting path to ground
- A lightning conductor is a pointed metal rod connected to earth — it focuses the electric field at its tip, enabling gradual discharge rather than a violent strike
- The unit of charge is the Coulomb (C)
Quick Check: A glass rod is rubbed with silk. The glass rod becomes positively charged. What happened at the atomic level?
Electrons were transferred from the glass rod to the silk. The glass rod lost electrons so it now has fewer electrons than protons — giving it a net positive charge. The silk gained electrons so it becomes negatively charged. Protons did not move.
This key facts covers Key Facts About Static Electricity within Static Electricity for GCSE Physics. Revise Static Electricity in Electricity for GCSE Physics with 15 exam-style questions and 12 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 9 of 15 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Static Electricity
When a plastic rod is rubbed with a cloth, the rod becomes negatively charged. Which statement best explains why?
Explain why a fuel tanker must be earthed before fuel is pumped, and describe how earthing prevents a dangerous spark.