Year 11 - Science
The generator effect
Electromagnetism
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit explores magnetism, including permanent and induced magnets, magnetic fields, and Earth's magnetism. It covers current-induced magnetic effects, electric motors, and devices like microphones and loudspeakers, with an emphasis on models, calculations, and practical applications.
Lesson Summary
You will learn to describe how different factors affect the size and direction of an induced current or potential.
Key Notes
- A magnet moving relative to a wire connected in a complete circuit can cause a current to flow in the wire.
- A magnet moving in the opposite direction relative to a wire induces a current in the opposite direction.
- A magnet moving relative to a wire can cause a potential difference across the wire called the induced potential.
- Induced potential is proportional to mag. field strength and the relative speed of movement between a wire and a magnet.
- For a magnet moving relative to a coil, the induced potential is proportional to the number of turns of wire in a coil.
Vocabulary To Learn
- induced current: The current generated in a circuit moving relative to a magnetic field.
- generator effect: The effect of inducing a current by the relative movement of a circuit and a magnetic field.
- milliammeter: A sensitive ammeter able to measure thousandths of an amp.
- induced potential: The potential difference generated in a conductor moving relative to a magnetic field.
Common Mistakes To Avoid
- Magnets can attract or repel electric charges in a wire.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
A magnet moving relative to a wire connected in a complete circuit can cause a current to flow in the wire. A magnet moving in the opposite direction relative to a wire induces a current in the opposite direction.
2. Define this scientific word and use it in context. 'induced current'
The current generated in a circuit moving relative to a magnetic field. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: Magnets can attract or repel electric charges in a wire. Correction: Explain that the cause of induced current is complex and is usually taught to pupils studying physics at university. At this point it is sufficient to be able to describe and predict what happens when a conductor is moving in a magnetic field.
More Lessons In This Unit
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