Which of the following methods can successfully demagnetise a permanent steel magnet?
Cooling the magnet in dry ice for several hours
Leaving the magnet inside a coil connected to a direct current (d.c.) power supply
Placing the magnet in a coil connected to an alternating current (a.c.) supply and slowly removing it
Wrapping the magnet tightly in electrical insulating tape
169 exam-style questions on CIE IGCSE Physics Simple phenomena of magnetism, covering Simple phenomena of magnetism. Each one has a worked solution and a mark scheme showing where the marks go.