Which of the following procedures would successfully demagnetise a permanent steel magnet?
Heating the bar strongly to a red heat and allowing it to cool while lying in an east-west direction
Submerging the bar in a beaker of ice-cold distilled water for several hours
Connecting the ends of the bar directly to a low-voltage direct current (d.c.) power supply
Stroking the bar repeatedly in one direction with the north pole of a strong permanent magnet
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.