Difficulty Verdict

This examination set represents a very standard difficulty level (3 out of 5 stars) for the CAIE 9702 syllabus. It successfully tests fundamental conceptual definitions alongside multi-step calculations. While Paper 1 contains several classic distractor options, Paper 2 is highly accessible, rewarding structured and neat mathematical layout.

Where the Marks Are

The bulk of the marks are concentrated in three key thematic areas: Mechanics (upthrust, moments, and conservation of momentum), Electricity (potential divider circuits involving LDRs and Kirchhoff's laws), and Particle Physics (meson compositions and nuclear decays). The structured questions particularly reward candidates who explicitly state their formulas before substituting values—such as using \( E_k = \frac{1}{2}mv^2 \) with proper conversion of atomic mass units (\( u \)), and applying \( n\lambda = d\sin\theta \) with correct conversion of slit units.

Examiner Pitfalls & Traps

Several areas in this series proved highly challenging for candidates:

  • Uncertainty propagation: In Paper 2 Question 1(c), many students forgot to double the percentage uncertainty of velocity \( v \) due to the term being squared (\( v^2 \)) in the formula.
  • Parallel Springs: In the pulley system (Question 3), candidates often incorrectly doubled the extension rather than halving it when a second spring was added in parallel under a constant cable tension.
  • Complete definitions: Neglecting to mention "no external forces" or "isolated system" when stating the principle of conservation of momentum.

Success Strategy

To maximize performance, candidates must practice structural drawing (forces on pulleys), familiarize themselves with reading values from LDR/thermistor resistance-temperature/intensity graphs, and build absolute confidence in metric prefix conversions (e.g., converting \(\text{mA}\) to \(\text{A}\) and \(\text{k}\Omega\) to \(\Omega\)).

Upcoming Series Predictions

Future examinations are highly likely to place greater emphasis on decelerating systems with non-constant mass (such as rocket or thruster mechanics) and complex potential dividers where the voltmeter is placed across the active variable sensor rather than the fixed resistor. Additionally, double-slit questions focusing on changes in medium indices remain highly overdue.