A student wants to demagnetise a strong permanent bar magnet using electrical methods. Which procedure should the student follow?
Place the magnet inside a solenoid connected to a high-voltage direct current (d.c.) supply and then switch it off.
Place the magnet inside a solenoid connected to an alternating current (a.c.) supply and slowly withdraw the magnet.
Connect both ends of the magnet directly to a 12 V12\text{ V}12 V battery for several minutes.
Place the magnet in a strong magnetic field pointing in the opposite direction.
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.