Move a conductor through a magnetic field or change the field through a coil, then compare how speed, field strength and direction alter the induced voltage.
The diagrams show some equipment that the physicist Ørsted used in an investigation in 1820.
Diagram 1 shows the position of eight compass needles around a wire with no current in the wire.
The compass needles line up with and show the direction of the Earth's magnetic field lines.
Diagram 2 shows the position of the same compass needles when a current is in the wire.
The power supply in diagram 3 is replaced by an ammeter.
When the wire is moved, a current is detected.
Explain which direction the wire is moved in the magnetic field to produce a current in the wire.
Explain why a current is produced in the wire when the wire is moved in the magnetic field.