Year 11 - Science
Electric generators
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 a dynamo works to generate DC and how an alternator works to generate AC.
Key Notes
- Rotating a conducting loop in a uniform magnetic field induces a potential across the ends of the loop.
- An electrical generator can be made in the same way as an electric motor.
- A DC generator (dynamo) generates a varying DC current.
- The connections in an AC generator (an alternator) are different to those of a dynamo.
- An alternator makes an alternating current that repeatedly reverses direction as the coil spins round.
Vocabulary To Learn
- induced potential: The potential difference generated in a conductor moving relative to a magnetic field.
- direct current (DC): An electric current that consistently flows in one direction.
- dynamo: A generator of direct current.
- alternating current (AC): An electric current that repeatedly reverses direction.
- alternator: A generator of alternating current.
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.
Rotating a conducting loop in a uniform magnetic field induces a potential across the ends of the loop. An electrical generator can be made in the same way as an electric motor.
2. Define this scientific word and use it in context. 'induced potential'
The potential difference generated in a conductor 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 correct explanation for what is happening 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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