A light metal sphere is attracted to a positively charged rod. A student concludes that the sphere must be negatively charged. Which further observation would establish that the sphere is negatively charged?
The sphere is attracted by a neutral metal object.
The sphere is attracted by a negatively charged rod.
The sphere is attracted by a second positive rod.
The sphere is repelled by a negatively charged 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.