An industrial robotic arm slowly lowers a powerful permanent magnet vertically towards a small iron bolt resting on a horizontal conveyor belt.
Explain why the bolt remains stationary on the belt at first, but then suddenly jumps upwards to meet the magnet only when the magnet is lowered to a certain critical height.
Practise Edexcel GCSE Physics Magnets and magnetic fields with exam-style questions for Foundation and Higher tier. 100 questions, matched to the Edexcel GCSE Physics (1PH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.