PHYSICS CONNECTION
Geometry separates resistance from resistivity
A wire’s resistance depends on its length and area as well as the material. Resistivity describes the material at a specified temperature.
R = ρL/A
Follow the reasoning
- Measure or calculate the wire’s cross-sectional area.
- Find resistance from voltage and current.
- Use the dimensions to calculate resistivity.
OFFICIAL OCR QUESTIONS
Try it in a past paper 2
Open the question, then use its mark scheme to check your work.
Question 4
Interpret the gradient of a resistance–length graph.
Question 10
Distinguish resistance from resistivity when wire length changes.
A curated collection checked against the question papers and mark schemes; not a complete past-paper catalogue. Links open official OCR PDFs in a new tab.
ORIGINAL PHYSICSUK QUESTIONS
Put the ideas to work
More practice is on its way
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Specification outcomes (3)
- 4.2.4(a)(i) Define resistivity using R = ρL / A.
- 4.2.3(a) Define resistance using R = V / I and state the unit ohm.
- 4.2.3(b) State and apply Ohm’s law.