As you can see, the light bulb flashes the moment you connect the switch to the battery.
The explanation is, that the magnetic field coming from the upper electromagnet flows through the lower iron core.
The change in that magnetic field, in turn induces an electric current in the lower coil.
You should note that the current in the lower coil ceases once the magnetic field has stabilised.
If you switch off the current , you get another flash, because the magnetic field disappears. The change in the field induces another current in the lower core, and makes the light bulb flash again.
In order to apply your knowledge of electromagnetism and induction, you may now return to the page on wind turbine generators.
© Copyright 1997-2003 Danish Wind Industry Association
Updated 12 August 2003