A student places a plotting compass on the bench. The needle points north.
She holds a long straight wire just above the compass, so that the wire lies along the direction of the needle. The wire is connected to a power supply and a switch.
The student closes the switch.
Describe what happens to the compass needle.
Explain why this happens.
The student reverses the connections to the power supply and closes the switch again.
Describe what happens to the compass needle.
State two changes the student could make to increase the movement of the compass needle.
The student opens the switch.
State the direction in which the compass needle now points.
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.