Edexcel A-Level Physics Core Practical 3 Young Modulus

Use a micrometer (screw gauge) Or (vernier)digital calipers

- At different orientations and/or positions along the wire

- Calculate/determine/take/find a mean/average value

(1)

(1)

(1)

*16(c)

- This question assesses a student's ability to show a coherent and logically structured answer with linkages and fully-sustained reasoning.

- Marks are awarded for indicative content and for how the answer is structured and shows lines of reasoning.

- The following table shows how the marks should be awarded for indicative content.

- The following table shows how the marks should be awarded for structure and lines of reasoning.

Total marks awarded is the sum of marks for indicative content and the marks for structure and lines of reasoning

Indicative content

- For long(er) wire, the extension will be large(r)

- (For the same load) extension is proportional to the original length

Or $\frac{\text { extension }}{\text { original length }}=$ constant

- For a thin(ner) wire, the extension will be large(r)

- (For the same load) extension is inversely proportional to cross-sectional area (may be explained in terms of $E, \sigma$ and $\varepsilon$ )

- The percentage uncertainty in the extension/length will be lower (although this will be greater for the cross-sectional area)

- A small(er) load can be used with a long/thin wire