Three lightweight insulating discs, X, Y and T, are suspended separately by insulating threads. The charge on disc T is known to be positive. The charge on each of the other discs is unknown.
The tests are carried out without allowing the discs to touch.
| Test | Discs brought close together | Observation |
|---|---|---|
| 1 | X and Y | X and Y move apart |
| 2 | Y and T | Y and T move towards each other |
Explain what can be concluded about the charges on discs X and Y.
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.