A negatively charged balloon is held near a neutral wall. A student says that the wall must repel the balloon because the wall contains electrons. Which explanation accounts for the observed attraction?
Protons leave for the balloon, so the entire wall becomes negative by transfer across the air gap.
Electrons shift towards it, so the nearer like charge gives a stronger force than the farther opposite charge.
Electrons shift away, so the nearer opposite charge gives a stronger force than the farther like charge.
Electrons leave for the balloon, so the entire wall becomes positive by transfer across the air gap.
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.