A student wants to investigate how the number of turns on a coil affects the strength of an electromagnet.
She has insulated wire, an iron nail, a power supply, an ammeter, a variable resistor and a box of identical paper clips.
Describe how the student could carry out this investigation.
In your answer, explain how the coil and the iron nail produce a strong magnetic field.
44 exam-style questions on OCR GCSE Physics 4.1 Magnets and magnetic fields, covering 4.1.1 Magnetic poles, attraction and repulsion, 4.1.2 Permanent and induced magnets, 4.1.3 The magnetic field of a magnet, 4.1.4 Compasses and the Earth's magnetic field, 4.1.5 The magnetic field around a current-carrying wire, 4.1.6 Field strength, current and distance, and 4.1.7 Solenoids and electromagnets. Each one has a worked solution and a mark scheme showing where the marks go.