Aqa As Level Physics 7407/2

Question 1 01.1 Many students incorrectly assumed the air-track glider’s velocity was zero at the first light gate. Other common mistakes seen included using the total travel time of 2.09 s rather than 1.19 s and assuming that the distance travelled was 10.0 cm. Nevertheless, nearly a quarter of students scored all three marks. 01.2 There were lots of undeveloped statements; students implied that a longer time equalled a greater distance. In many cases, the supporting arguments presented were flawed with many students stating that with the same acceleration a greater time would result in a larger distance. There was some good analysis of the data but such an approach was01.3 The lines of best fit seen were generally of good quality. Many students demonstrated best practice for determining the gradient. Large gradient triangles were drawn with the read-off co-ordinates and corresponding differences clearly seen. Mistakes that occurred most frequently included not taking the false origin into account and drawing a gradient triangle that was too small. Very nearly 90% of students scored at least one mark here. 01.4 Appropriate use of significant figures is particularly important in Section A. Calculated quantities should be shown to the number of significant figures of the data with the least number of significant figures. 53.4% of students gained this mark. 01.5 A significant number of students disregarded the instruction “without drawing another graph” and chose to describe how to test the relationship by drawing a graph. They did not appreciate the significance of the term “directly proportional” and could only apply it to descriptions of the graph one would expect for such a relationship. Students were unable to describe how such a relationship could be tested by non-graphical means. A common error presented was that a linear relationship was the same as a directly proportional one. This was evidenced by statements such as “constant gradient”, “straight line”, “as a increases, n increases”. Disappointingly, only 6.9% of students scored the mark. Question 2 02.1 Many students were able to demonstrate how to reduce the effect of the systematic error but only 12% were able to gain both marks. The main reason for this was the lack of detail in the description of how to reduce the effect of random error. Students need to ensure they give sufficient detail that is relevant to context and not limit answers to superficial “repeat and average” statements. 02.2 Many students were unfamiliar with how to use vernier callipers to measure internal diameters and lined up the magnet with the lower jaws instead. 31% of students were successful here. 02.3 High ability students dealt confidently and competently with this calculation. Their working was well-laid out containing few errors and no mid-calculation rounding. Other students gained some credit for partial workings where their method demonstrated some stages in the process. Students would be advised to ensure their workings are well-laid out with appropriate subjects to their calculations as this makes their partially correct work more convincing and more likely to receive compensatory marks. Some students attempted to find the difference in the diameters and use this in the formula for area rather than determining the areas separately and then determining the difference in areas. 02.4 The students often made little headway in this question. The plans seen lacked details on how to vary the mass and how to record the value of h. Many students did not know how to process the data to obtain a straight-line graph for F = k h -3. Just over 40% of students managed to score at least two marks here.