Executive Difficulty Verdict

This series of CIE 9702 Physics represents a well-structured assessment that strictly rewards candidates who possess a deep conceptual understanding over simple rote memorisation. While foundational topics like Kinematics and Particle Physics offered highly accessible points, the structured questions on Wave Superposition and DC Practical Circuits challenged students with complex graphical sketching and qualitative reasoning. Overall, the papers are of moderate to high difficulty, demanding rigorous execution under tight time constraints.

Where the Marks Are Won or Lost

In Paper 23, critical marks were concentrated in the drawing of force vectors (such as distinguishing upthrust and viscous drag) and the subsequent derivation of terminal speed. Many students struggled with Question 4(b)(iii), where they had to sketch the intensity profile against diffraction angle \(\theta\) between \(-15^{\circ}\) and \(+15^{\circ}\). Students lost marks here by failing to locate the peaks precisely at \(\pm 6.2^{\circ}\) and \(\pm 12^{\circ}\), or by failing to show zero-intensity values between the maxima.

For the practical component (Paper 33), marks were heavily focused on experimental precision—specifically, presenting raw measurements to correct significant figures and maintaining absolute consistency (e.g., raw \(h\) values to the nearest 0.1 cm).

Examiner Pitfalls & Mistakes to Avoid

  • Vague Definitions: Defining pressure simply as \(\text{force} / \text{area}\) without stating that the force must be normal or perpendicular to the cross-sectional area.
  • Atomic Diagrams: In tritium model drawings, failing to clearly separate the single orbital electron from the tightly bound proton-neutron nucleus.
  • Awkward Graph Scales: Choosing scale ratios like 3:10 or 3:5 in Paper 3, which inevitably leads to plot-reading mistakes and zero marks for graph plotting.
  • Significant Figure Justifications: Expressing the constant \(k\) with too many decimal places without showing that its precision is restricted by the least precise raw measurement (usually the diameter or voltage).

Preparation Strategy & Next Steps

To secure a top grade in upcoming series, candidates must prioritise active plotting and derivation practice. Focus heavily on resistivity scaling relations (e.g., \(R \propto L/r^2\)) and practice sketching non-linear component characteristics under varying temperature profiles. For Paper 3, master the calculation of absolute and percentage uncertainties of linear instruments, ensuring you always present uncertainties to 1 significant figure.