A negatively charged rod attracts an initially neutral conducting ball. The ball touches the rod and gains electrons. It is then repelled. Which explanation describes the attraction before contact and the repulsion afterwards?
Electron transfer makes the whole ball negative; charge separation then makes the ball positive.
Charge separation makes the near side negative; electron transfer then makes the ball positive.
Electron transfer makes the whole ball positive; charge separation then makes the ball negative.
Charge separation makes the near side positive; electron transfer then makes the ball negative.
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.