A student places an identical small positive test charge at different distances from a fixed, isolated charged particle. The measured force is recorded in the table.
| Distance from particle (cm) | Force on positive test charge (N) | Direction of force |
|---|---|---|
| 2.0 | 0.032 | Away from the particle |
| 4.0 | 0.0080 | Away from the particle |
| 8.0 | 0.0020 | Away from the particle |
Explain what the results show about the sign of the fixed particle, then predict the direction and relative strength of the force on an equal-magnitude negative test charge placed 8.0 cm from it, compared with the force on a positive test charge 2.0 cm from it.
80 exam-style questions on Edexcel GCSE Physics 11.2 Uses, dangers and electric fields, covering 11.2.1 Uses of electrostatic charge, 11.2.2 Dangers of sparking, 11.2.3 Electric fields, and 11.2.4 Electric fields and static electricity. Each one has a worked solution and a mark scheme showing where the marks go.