A small sphere repels a positively charged rod. The sphere is then fully discharged by earthing. The same rod is brought close to the sphere without touching it. Which statement describes the sphere before earthing and the force after earthing?
Initially positive; it is then attracted to the rod.
Initially negative; it is then repelled by the rod.
Initially positive; it is then repelled by the rod.
Initially negative; it is then attracted to the rod.
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.