Which action will demagnetise a magnetised steel bar?
Cooling it in a freezer for several days.
Placing it inside a solenoid connected to a direct current (d.c.) supply.
Placing it inside a solenoid connected to an alternating current (a.c.) supply and slowly withdrawing it.
Storing it near a block of unmagnetised soft iron.
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.