A small, light plastic tray hangs from an insulating thread and is negatively charged. It hangs next to a metal filing cabinet that stands on insulating supports and has no conducting connection to Earth. The cabinet is neutral overall.
The tray swings towards the cabinet but does not touch it. The tray is then lifted away from the cabinet, still without touching it.
Explain why the tray swings towards the filing cabinet and state the overall charge on the cabinet after the tray has been lifted away.
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.