A small negative test bead is held at the same distance from each of two isolated positively charged metal spheres. The bead has the same charge in both tests.
| Sphere | Charge on sphere | Distance from bead | Force on bead |
|---|---|---|---|
| A | +2.0 nC | 1.0 cm | 0.18 mN |
| B | +4.0 nC | 1.0 cm | 0.36 mN |
Compare the forces on the bead in the two tests and explain the difference. Explain the direction of the force on the bead.
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.