A student rubs a plastic ruler with a dry cloth, giving the ruler an overall positive charge.
Which of these sentences explains why the overall charge on the ruler is positive?
Positive charge has been added to the ruler.
Positive charge has been removed from the ruler.
Negative charge has been added to the ruler.
Negative charge has been removed from the ruler.
47 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.