Term
| Why is mains electricty AC? |
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Definition
| Generators produce AC and transformers need AC to work. |
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Term
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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. |
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Term
| Describe a step up transformer |
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Definition
A step up transformer has less turns on the primary coil than the secondary coil. It makes potential differences bigger and currents smaller. |
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Term
| Describe a step down transformer |
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Definition
A step down transformer has more turns on the primary coil than the secondary coil. It makes potential differences smaller and currents bigger. |
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Term
| What does the primary coil behave like? |
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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) |
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Term
| Why is a potential difference created in the secondary coil? |
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Definition
| THe secondary coil cuts through the cahnging magnetic field line produced by the primary coil hence a potential difference is generated |
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Term
| Describe an electromagnet |
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Definition
| An electromagnet is a coil (solenoid) of wire carrying an electric current. It has the same shape magnetic field as a bar magnet. |
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Term
| How can you make an electromagnet stronger? |
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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. |
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Term
| How would an electromagnet behave if an alternating current (AC) flows through it? |
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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. |
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Term
| What happens to a current carrying wire when placed in a magnetic field? |
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Definition
| The moving electrons in the wire will feel a force and this makes the wire move. |
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