A charged balloon is held a few centimetres from a charged plastic rod. The balloon and the rod push each other apart without touching. The force between them is
a contact force, because the air between them touches both
a contact force, because the balloon touches the plastic rod
a non-contact force, because the two objects are not touching
a non-contact force, because moving air pushes them apart
40 exam-style questions on AQA GCSE Physics 2.5 Static electricity, covering 2.5.1 Static charge and 2.5.2 Electric fields. Each one has a worked solution and a mark scheme showing where the marks go.