# Shared Flashcard Set

## Details

AQA P3 Module Transformers
AQA Physics Module 3 revision cards for transformers
10
Physics
Not Applicable
05/02/2008

## Cards Return to Set Details

Term
 Why is mains electricty AC?
Definition
 Generators produce AC and transformers need AC to work.
Term
 Describe a transformer
Definition
 A transformer is two coils of wire both wrapped around a circular core made of a magnetic material like iron.  One coil is connected to an AC power source.
Term
 Describe a step up transformer
Definition
 A step up transformer has less turns on the primary coil than the secondary coil.It makes potential differences bigger and currents smaller.
Term
 Describe a step down transformer
Definition
 A step down transformer has more turns on the primary coil than the secondary coil.It makes potential differences smaller and currents bigger.
Term
 What does the primary coil behave like?
Definition
 The primary coil has an alternating current flowing through it so it is an electromagnet but because the current changes so does the strength of the electromagnet.  So it produces a changing magnetic field (behaves like a moving magnet)
Term
 Why is a potential difference created in the secondary coil?
Definition
 THe secondary coil cuts through the cahnging magnetic field line produced by the primary coil hence a potential difference is generated
Term
 Describe an electromagnet
Definition
 An electromagnet is a coil (solenoid) of wire carrying an electric current. It has the same shape magnetic field as a bar magnet.
Term
 How can you make an electromagnet stronger?
Definition
 You can make the electric current larger.You can increase the number of turns on the coil.You can put a magnetic material like iron or steel inside the coil.
Term
 How would an electromagnet behave if an alternating current (AC) flows through it?
Definition
 The strength of the electromagent would get stronger (as the current got bigger) and weaker (as the current got smaller). The magnet would switch poles (when the current changed direction). The electromagnet would behave like a moving magnet.
Term
 What happens to a current carrying wire when placed in a magnetic field?
Definition
 The moving electrons in the wire will feel a force and this makes the wire move.
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