This exam focus covers Exam Focus — I-V Characteristics within I-V Characteristics for GCSE Physics. Revise I-V Characteristics in Extra Topics for GCSE Physics with 13 exam-style questions and 11 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 10 of 12 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
🎯 Exam Focus — I-V Characteristics
Examined in Edexcel 1PH0/2 (Paper 2). CP10 (I-V characteristics) is an Edexcel Core Practical tested directly — expect method, variable identification, circuit diagram, and analysis questions. "Suggest" questions appear for novel component behaviour in unfamiliar circuit contexts.
Most Common Question Types
- Describe and explain the shape of an I-V graph for a filament lamp [3 marks] — must explain increasing resistance with temperature
- Sketch the I-V characteristic for a named component [2 marks]
- Calculate resistance from a given point on an I-V graph [2 marks]
- Describe how to carry out the required practical [4 marks] — circuit diagram with correct meter placement
- Explain why a diode is used for rectification [2 marks]
What Examiners Want to See
When explaining the filament lamp curve, examiners want: voltage increases → current increases → lamp gets hotter → ions vibrate more → more collisions with electrons → resistance increases → gradient of I-V graph decreases. Many students describe the shape without explaining the reason in terms of temperature and lattice vibrations.
Practice questions for I-V Characteristics
What does an I-V characteristic graph show for a component?
Explain why the I-V graph for a filament lamp is not a straight line.