Year 10 - Science
Interpreting I–V graphs
Circuit components
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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 current, resistance, and potential difference. It covers circuit design for lamps, diodes, and thermistors, and emphasises planning experiments, data interpretation, and presenting scientific conclusions.
Lesson Summary
You will learn to take readings from you–V graphs and use these to describe the changing resistance of a component.
Key Notes
- In forward–bias, a diode has a very small resistance when the p.d. is larger than the threshold voltage.
- In reverse–bias, a diode has a very large resistance and very little current can flow.
- The greater the p.d. across a component, the larger the push on electric charges in the component.
- The resistance of a component is calculated from an I–V graph using pairs of readings and the equation R = V ÷ I.
- The greater the current through a component, the larger the heating effect on it.
Vocabulary To Learn
- reverse–bias: When a diode is reverse–biased, it prevents current from flowing.
- forward–bias: When a diode is forward–biased, it allows current to flow.
- threshold p.d.: The threshold p.d. is the potential difference at which a diode allows current to flow.
- fuse: A fuse is a component that has a wire that melts if the current is too high.
- ion lattice: In a solid metal, the regular and repeating pattern that metal ions are arranged in is known as an ion lattice.
Common Mistakes To Avoid
- Pupils often cannot apply the main I–V graphs to similar components.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
In forward–bias, a diode has a very small resistance when the p.d. is larger than the threshold voltage. In reverse–bias, a diode has a very large resistance and very little current can flow.
2. Define this scientific word and use it in context. 'reverse–bias'
When a diode is reverse–biased, it prevents current from flowing. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: Pupils often cannot apply the main I–V graphs to similar components. Correction: Describe how the p.d. and current in components behaves to draw out similarities that can be used to describe unfamiliar components.
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