Physics 9702/34 May/June 2025: question paper and mark scheme

Mark scheme

1(a)(i) Values of L1 and L2 with consistent unit 1 and L2 in the range 15.0–18.0 cm. 1(a)(ii) Value of T on answer line in the range 0.70–1.50 s with unit. 1 Repeats: At least two measurements of nT where n ⩾ 5. 1 1(b) Six sets of readings of L1 (different values), L2 and T with correct trend (as L1 decreases, L2 and average T decreases) and 3 without help from Supervisor scores 3 marks, five sets scores 2 marks etc. Range: At least one value of L2 ⩽ 6.0 cm. 1 Column headings: 1 Each column heading must contain a quantity and a unit where appropriate. The presentation of quantity and unit must conform to accepted scientific convention e.g. (√L1 + √L2) / cm½. Consistency: All values of L1 and L2 must be given to the nearest mm. 1 Significant figures: All values of (√L1 + √L2) given to 3 significant figures. 1 Calculation: (√L1 + √L2) calculated correctly. 1 1(c)(i) Axes: 1 Axes must be labelled with the required quantities. Scales must be chosen so that the plotted points occupy at least half the graph grid in both the x and y directions. Scale markings are no more than 2 cm (one large square) apart. Sensible scales must be used, no awkward scales (e.g. 3:10 or fractions). Plotting of points: 1 All observations in the table must be plotted on the grid. Diameter of plotted points must be ⩽ half a small square. Points must be plotted to an accuracy of half a small square in both x and y directions. Quality: 1 Trend of points must be positive. All points in the table must be plotted (at least 5 points) for this mark to be awarded. It must be possible to draw a straight line that is within ± 0.5 cm½ on the (√L1 + √L2)-axis of all plotted points. 1(c)(ii) Line of best fit: 1 ‘Best fit’ is judged by the balance of all points on the grid (at least 5 points) about the candidate’s line. There must be an even distribution of points either side of the line along the full length. Lines must not be kinked or thicker than half a square. Some candidates may choose to identify an anomalous point. If 6 or more points are plotted and they identify one point as anomalous (e.g. by circling or labelling) then this point is to be disregarded when judging the line of best fit. 1(c)(iii) Gradient: 1 The hypotenuse of the triangle used must be greater than half the length of the drawn line. Both read-offs must be accurate to half a small square in both the x and y directions. Method of calculation must be correct, not Δx / Δy. Gradient sign on answer line must be consistent with graph drawn. y-intercept: 1 Intercept read directly from the graph, with read-off at x = 0, accurate to half a small square in y direction. or Correct read-off from a point on the line is substituted into y = mx + c or an equivalent expression. Read-off accurate to half a small square in both x and y directions. 1(d) a = candidate’s gradient value and b = candidate’s intercept value. 1 Values must not be written as fractions or given to only one significant figure. Units for a and b correct (e.g. s cm–½ for a and s for b). 1 1(e) Correct calculation for g with consistent unit. 1

Mark scheme

2(a)(i) Value for D in range 5.00–7.00 mm, with unit 1 Evidence of repeated measurements of D. 1 2(a)(ii) Value for d in range 4.50–5.50 mm with unit and to at least the nearest 0.1 mm. 1 2(b)(i) Value of time in the range 0.8–20.0 s with unit and to the nearest 0.1 s or better. 1 Evidence of repeated measurements of t. 1 2(b)(ii) Percentage based on absolute uncertainty in t of 0.2–0.5 s. 1 Correct method of calculation to obtain percentage uncertainty e.g. (absolute uncertainty / value from (b)(i)) × 100. If repeated readings have been taken, then the uncertainty can be half the range (but not zero) if the working is clearly shown. 2(c) Second value of d. 1 Second value of t. 1 Value for second t < first t. 1 2(d)(i) Two values of k calculated correctly. 1 The final k values must not be written as fractions. 2(d)(ii) Justification based on the significant figures in t and (D2 – d2). 1 2(e) Calculation of percentage difference between candidate’s two k values. 1 Comparison of percentage difference with 10%, leading to a consistent conclusion. 2(f)(i) A Two (sets of) readings are not enough to draw a (valid) conclusion (not “not enough for accurate results”, “few 4 readings”). B Large percentage uncertainty in t / time. C Difficult to measure t / fall time / time between markers since it is difficult to judge when ball reaches the tape / marker. D Difficult to measure D with reason e.g. tube cross section not circular / tube changes shape when measuring / internal jaws of calipers too big. E Difficult to measure d with reason e.g. difficult to hold ball in jaws of calipers. F Difficulty with balls e.g. difficult to remove balls with magnet / balls hit side of tube when falling. 1 mark for each point up to a maximum of 4. 2(f)(ii) A Take more readings and plot a graph or take more readings and compare k values (not “repeat readings” on its own). 4 B Increase the fall distance / use a long(er) tube. C Record / film / video with timer in view. D Use glass / rigid tube / use travelling microscope. E Use micrometer screw gauge. F Use strong(er) magnet / have more balls (of each size). 1 mark for each point up to a maximum of 4.