A student sets up an experiment to investigate the magnetic field around a straight, vertical wire carrying a current. The wire passes vertically through the centre of a horizontal sheet of card.
Describe how the student could use iron filings and a small plotting compass to find both the pattern (shape) and the direction of the magnetic field lines on the card.
The current in the wire flows vertically upwards. Describe the shape and direction of the magnetic field lines.
If a magnetic compass is kept away from any local magnets or current-carrying wires, it always points in a North-South direction. Explain how this observation provides evidence about the Earth's core.
17 exam-style questions on OCR GCSE Physics Magnets and magnetic fields. Each one has a worked solution and a mark scheme showing where the marks go.