October/November 2025 Series Analysis

The October/November 2025 sitting of the Cambridge IGCSE Physics (0625) examination provided a balanced yet rigorous assessment across all assessment objectives. With an overall difficulty index of 3.2 out of 5, the papers successfully tested fundamental understanding while introducing several discriminating questions to challenge top-tier candidates. In particular, Paper 43 featured nuanced questions on space physics and electromagnetic induction that required precise technical vocabulary and strong mathematical application.

Where the Marks Were Won and Lost

As always, the lion's share of the marks resides in Electric Circuits and Energy, Work and Power. In Paper 43, the combination of potential divider analysis with an LDR and the application of parallel LED characteristics required careful graphical interpretation. Candidates who could accurately read current values from the curves and apply Ohm's Law secured easy marks, while many struggled with the concept of reverse bias (where current drops to zero). Additionally, the a.c. generator question proved to be a major discriminator. Many students failed to relate the horizontal coil position with the peak e.m.f. or incorrectly explained the role of slip rings and brushes.

Common Examiner Pitfalls and Candidate Traps

Examiners highlighted several persistent areas of weakness:

  • Elliptical Orbits and Gravity: A classic pitfall appeared in the space physics section, where candidates were asked to sketch a comet's orbit and indicate its velocity changes. Many drew perfect circles instead of highly eccentric ellipses, or placed the Sun at the direct center rather than at one of the focal points. Furthermore, explaining speed changes using energy conservation required stating that gravitational potential energy is converted to kinetic energy as the comet approaches the Sun.
  • Graph Plotting and Triangles: In Paper 63, the light and electricity questions required plotting. Students frequently lost marks for using small, inadequate plotting scales (less than half the grid), drawing excessively thick lines, or failing to show the large triangle construction on the graph for gradient calculation.
  • Prefixes and Unit Conversions: Simple mathematical slips, such as failing to convert milliseconds (\(\text{ms}\)) to seconds (\(\text{s}\)) or milliamperes (\(\text{mA}\)) to amperes (\(\text{A}\)), severely impacted scores in momentum and power calculations.

Strategic Revision Blueprint

To secure an A* in upcoming sittings, candidates should prioritize the following strategies:

  1. Master Circuit Analysis: Ensure you are comfortable with non-ohmic components like LDRs, thermistors, and diodes. Practice sketching and interpreting their current-voltage (\(I\)-\(V\)) characteristic graphs.
  2. Refine Experimental Descriptions: In the planning question (Paper 63), focus on structured responses containing clear lists of apparatus, a list of controlled variables, a mock table with correct units, and a logical path to a conclusion.
  3. Focus on Space Physics: Since its expansion in the syllabus, Space Physics has become a major source of high-yield marks. Be ready to explain cosmic microwave background radiation (CMBR) and perform planetary orbital speed calculations using \(v = \frac{2\pi r}{T}\) with appropriate time conversions.