Physics 9702/31 October/November 2025: question paper and mark scheme

Mark scheme

1(a)(i) Value of m = 270 g with unit. 1 1(a)(ii) Final value of T 1 in the range 0.5 s to 1.5 s with unit. 1 Repeats: at least two measurements of nT where n ⩾ 5. 1 1(b) T2 < T1 1 1(c) Five sets of readings of m (different values), T 1 and T 2 with correct trend (as m increases T 1 (average) increases and 4 T2 (average) increases ) and without help from Supervisor scores 4 marks, four sets scores 3 marks etc. Range of m : mmin ⩽ 220 g and mmax ⩾ 350 g. 1 Column headings: Each column heading must contain a quantity and a unit where appropriate. 1 The presentation of quantity and unit must conform to accepted scientific convention , e.g. m / g, nT 1 / s, T 1 / s, T1 / s , T10.5 / s0.5. Consistency: All raw values of time must be given to 0.1 s or all given to 0.01 s. 1 Calculation: Correct calculation of T1 . 1 1(d)(i) Axes: 1 Axes must be labelled with the correct 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). 1(d)(i) 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: Trend of points must be positive. 1 All points in the table must be plotted on the grid for this mark to be awarded. It must be possible to draw a straight line that is within 0.01 s½ (to scale) on the T1 axis (normally x-axis) of all plotted points. 1(d)(ii) Line of best fit: 1 ‘Best fit’ is judged by the balance of all points on the grid (at least 4 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 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. There must be at least four points left after the anomalous point is disregarded. 1(d)(iii) Gradient: gradient sign on answer line consistent with graph drawn. 1 The hypotenuse of the triangle used should 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. y-intercept: 1 Either 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(e) P = candidate’s gradient value and 1 Q = candidate’s intercept value. Values must not be written as fractions or given to one significant figure. No units for P. Unit for Q s or s0.5. 1

Mark scheme

2(a) Values of raw d to the nearest mm and final d in range 6.5 cm to 7.5 cm. 1 Repeats: Evidence of repeat readings of d. 1 2(b)(i) Values of raw y to the nearest mm and final value of y in the range 15..0 cm to 30.0 cm. 1 2(b)(ii) Absolute uncertainty in y in range 2 mm to 6 mm. 1 Correct method of calculation to find 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 if the working is clearly shown, but NOT zero if values are equal. 2(c)(i) Value of p < y 1 2(c)(ii) Correct calculation of (y − p). 1 2(d) Second values of w and d. 1 Second values of y and p. 1 Quality : Second value of p < First value of p. 1 2(e)(i) Two values of k calculated correctly. 1 The final k values must not be written as fractions or given to one significant figure. 2(e)(ii) Justification for significant figures in k linked to significant figures in w and (y − p). 1 2(f) Calculation of percentage difference between candidate’s two k values. 1 Comparison of percentage difference with 10% leading to a consistent conclusion. 2(g)(i) 1 mark for each point up to a maximum of 4. 4 A Two readings are not enough to draw a conclusion wtte, e.g. reference to relationship B Difficulty with setting or measuring d, e.g. shape is not a circle or a perfect cylinder / diameter varies around the cylinder / paper clips flatten one side / damage paper with ruler or clips C Difficult to measure y or p with a reason, e.g. parallax error / springs moves when touched by rule / rule not steady / deciding position of end of the coiled section D Difficulty with squashing the cylinder, e.g. squashes in the middle and not at the edge / uneven deformation / difficult to locate mass on middle of cylinder E Difficult to set or measure h with a reason, e.g. metre rule is unwieldy / 30 cm ruler has snout / parallax error / to move boss and observe mass (at the same time) / boss does not move (mass smoothly) in small increments / when boss is tightened (mass rises) / mass base not parallel to bench. 2(g)(ii) 1 mark for each point up to a maximum of 4. 4 A Take more readings and plot a graph OR take more readings and compare k values. B Improved method to improve setting or measuring d, e.g. wrap around a proforma / use glue / tape (for cylinder) / mark a line where the two ends should meet (at 7π) / place two blocks either side of the cylinder and measure between the blocks or photograph from above with a mm grid in view. C Improved method to measure y or p, e.g. rule with pointers / clamp ruler D Improved method to ensure whole of longer cylinder is squashed, e.g. Glue a plastic oblong to the mass hanger (to cover the whole cylinder). E Improved method to set or measure h, e.g. Video with rule in view during adjustment / depth gauge / vernier caliper / compare to a block of height 2.5 cm / rule with pointers / hang springs from jaw of a clamp to allow small adjustment in height of masses.