A tabletop exhibit uses a permanent magnet beneath a board to pull an unmagnetised steel counter towards it. The north pole of the magnet faces the counter. An unmagnetised nickel counter, an unmagnetised cobalt block and a second permanent magnet are also available. Objects placed on the board can slide freely but cannot rotate, so any attractive magnetic force makes an object move towards the magnet.
Which change would allow the exhibit to continue working by magnetic attraction?
Replace the steel counter with the unmagnetised nickel counter.
Replace the steel counter with the second permanent magnet, with north poles facing.
Replace the permanent magnet with the unmagnetised cobalt block.
Keep the steel counter but move it outside the permanent magnet's magnetic field.
80 exam-style questions on AQA GCSE Physics 7.1 Permanent and induced magnetism, magnetic forces and fields, covering 7.1.1 Poles of a magnet and 7.1.2 Magnetic fields. Each one has a worked solution and a mark scheme showing where the marks go.