example+course+work

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EXAMINER'S MARKING:



EXAMINER'S COMMENTS:

**A: Summary of case study or physics-based visit**

A mark should not be awarded for S1: Carries out a visit OR uses library, consulting a minimum of three different sources of information (e.g. books/websites/journals/ magazines) as the candidate has not used three different sources of information — all sources use the internet. The candidate states that ‘the resistivity is related to it by some constant k x R’. This relationship is too vague — the full equation expressing the relationship including resistivity is expected and therefore it is not possible to give a mark for S4: Makes correct statement on relevant physics principles. The candidate refers to ‘area’ when ‘cross-sectional area’ is more appropriate. Therefore a mark has not been awarded for S5: Uses relevant specialist terminology correctly. Although there is a relationship between the case study of a practical application of physics and the experiment, the candidate has not made this clear in the report and therefore cannot be awarded a mark for S9: Explains how the practical relates to the visit or case study. **B: Planning**

The candidate suggested using a micrometer so he achieved the mark for P2: States how to measure one relevant quantity using the most appropriate instrument. The candidate needs to state that a ruler will be used to measure the length of the wire in order to get the mark for P4: States how to measure a second relevant quantity using the most appropriate instrument. Other variables have not been mentioned, eg the need to ensure that the temperatures of the wires are the same when each measurement is taken and therefore a mark for P8: Identifies and states how to control all other relevant variables to make it a fair test has not been awarded. Although the candidate states that he will repeat each resistance reading twice he has not commented on why he thinks this is appropriate. Neither has the candidate suggested checking the diameter in more than one place. There is no evidence in the results section that he has repeated any measurements or calculated an average value for the diameter of the wire. He has therefore lost a mark for P9: Comments on whether repeat readings are appropriate in this case. As there are no comments on safety, or possible sources of uncertainty and/or systematic error, the student cannot score a mark for P10: Comments on safety or P12: Identifies the main sources of uncertainty and/or systematic error. For example, the candidate could have mentioned that current was allowed to flow through the wire for the shortest possible period of time as the heating effect of the current can affect the resistance of the wire and hence the magnitude of the current that flows. **C: Implementation and measurements**

There are several reasons for not awarding a mark for M1: Records all measurements using the correct number of significant figures, tabulating measurements where appropriate. The candidate has used too many significant figures in the table of results and the diameter of the wire has been stated to the nearest 0.1mm even though a micrometer will measure to the nearest 0.01mm. Not only has the candidate failed to insert a unit in the last column of the results table, he has used a mixture of units when dividing the length (metres) by the area (millimetres squared). He has, therefore, not scored a mark for M2: Uses correct units throughout. The candidate should have included evidence to show that he had repeated the measurements of the diameter of the wire at different places along the wire to obtain the mark for M4: Obtains measurements over an appropriate range. **D: Analysis**

The graph is not scaled appropriately (it only occupies a third of the grid) and therefore the candidate failed to achieve the mark for A2: Produces a graph with sensible scales. It does not have the correct units on the x-axis and the best line of fit should go through the origin; therefore marks were not awarded for A1: Produces a graph with appropriately labelled axes and with correct units and A4: Draws line of best fit (either a straight line or a smooth curve). The candidate has not recognised that the first couple of points are anomalies. A mark was not given for A6: Derives relationship between two variables or determines constant as the constant is not correctly determined even though the candidate commented on the trend. The candidate has some idea of the physics principles to apply but has not applied any meaningful error analysis to this experiment and therefore fails to get any marks for A8 to A10. **E: Report**

The case study report lacked structure. The use of appropriate subheadings would be advisable to achieve a mark for R2: Summary is structured using appropriate subheadings.