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Physics 3 exam Friday 27th May 2011
In the exam they could ask you what a transformer does and how it works. There is
a lot to say about a question like that; therefore it is vital that you know exactly
what happens as an extra four/five marks could boost you up a grade!
What happens in a transformer?
(this answer has been taken directly from a mark scheme)
1. Insulation prevents electricity or current from flowing through the iron core
2. There is an alternating current (a.c) through the primary coil
3. This produces a changing magnetic field in the iron core
4. And hence a magnetic field in the secondary coil
5. This induces an alternating potential difference (voltage) across the secondary coil
6. This therefore means there is an alternating current in the secondary coil
Step up transformer Step down transformer
INCREASES the voltage DECREASES the voltage
More turns on the SECONDARY coil More turns on the PRIMARY coil