Four small spheres P, Q, R and S are all charged. They are tested in pairs without touching. The table shows the results.
| Pair | Interaction |
|---|---|
| P and Q | Repulsion |
| Q and R | Attraction |
| R and S | Repulsion |
S is positively charged. Which statement gives the signs of P and R?
P is negative and R is positive.
P is positive and R is negative.
P is negative and R is negative.
P is positive and R is positive.
91 exam-style questions on Edexcel GCSE Physics 11.1 Charging by friction, covering 11.1.1 Charging insulators by friction, 11.1.2 Forces between charges, 11.1.3 Electrostatic phenomena, and 11.1.4 Earthing and removing charge. Each one has a worked solution and a mark scheme showing where the marks go.