Difficulty Verdict

The October/November 2024 Combined Science Paper 43 is evaluated as a solid Level 4 difficulty (Extended Level), presenting a balanced split across Biology, Chemistry, and Physics. The paper combines straightforward knowledge retrieval with multi-step analytical and mathematical problem-solving tasks.

Where the Marks are Found

The highest concentration of marks is found in three primary domains:

  • Physics Mechanics & Electricity: Specifically, speed-time graph analysis, work/power calculations, and complex parallel circuit analysis (worth 19 marks combined).
  • Organic Chemistry: Dot-and-cross diagrams, general formulae, and unsaturated hydrocarbon tests (worth 10 marks).
  • Animal Transport: Double circulatory systems and data-graph interpretation of CHD trends (worth 10 marks).

Examiner Pitfalls & Misconceptions

Candidates frequently lose marks on highly specific areas. In the dot-and-cross diagram of methanol, many candidates failed to draw the four non-bonding outer-shell electrons on the oxygen atom, focusing solely on the shared pairs. In the parallel circuit question, a common error was neglecting to halve the branch current to find the resistance of a single, identical headlamp, or failing to identify the relationship of cross-sectional area and length on a wire's resistance (leading to an incorrect factor of 6 calculation).

Preparation & Exam Strategy

To maximize success in future papers, students must:

  1. Show complete working out for physics equations (e.g., \( v = f\lambda \) and \( P = \frac{W}{t} \)) and always write down the unit.
  2. Memorize the exact qualitative tests and color changes for biological molecules and organic chemicals (e.g., bromine water on alkanes vs. alkenes).
  3. Understand that during the electrolysis of dilute sulfuric acid, only water is decomposed, meaning the concentration of the acid changes while the total mass of the acid remains constant.

Predictions

Given the absence of Stoichiometry and Space Physics in this variant, these topics are highly predicted to be tested with high weightage in the next exam series.