A solenoid and a single straight wire carry the same current.
Why is the magnetic field inside the solenoid stronger than the field near the straight wire?
The coil has a larger resistance, so the current in it is larger
The coil turns the wire into a permanent magnet with two poles
The fields from each turn of the coil add together inside it
The coil stops the field from spreading out beyond its ends
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.