A student wants to test whether a steel rod retains magnetism after it has been placed in a strong magnetic field. Which method gives the clearest evidence?
Remove the field, then test whether the rod repels one pole of a compass.
Keep the field present, then test whether a magnet attracts both rod ends.
Keep the field present, then test whether the rod attracts an iron nail.
Remove the field, then test whether a magnet attracts one end of the rod.
70 exam-style questions on Edexcel GCSE Physics 12.1 Magnets and magnetic fields, covering 12.1.1 Magnetic poles, 12.1.2 Magnetic materials; permanent and induced magnets, 12.1.3 Magnetic fields, and 12.1.4 Plotting compasses and the Earth's magnetic field. Each one has a worked solution and a mark scheme showing where the marks go.