May 2025 IB Physics HL Exam Analysis

The May 2025 Higher Level Physics examination presented a balanced but demanding test of both fundamental principles and experimental dexterity. With the restructuring of Paper 1 into Paper 1A (Multiple Choice) and Paper 1B (Practical Data Analysis), students had to pivot quickly from rapid problem-solving to meticulous error analysis.

Where the Marks Were Won and Lost

A significant portion of the marks lay in Simple Harmonic Motion (SHM) and Astrophysics/Fusion. In Paper 2, Question 9 combined SHM energy graphs with electromagnetic induction, proving to be one of the most integration-heavy questions in recent sessions. Students who excelled could decode the elastic potential energy graphs to calculate equilibrium stretch and amplitude. Conversely, many lost marks by failing to use the correct parallel spring constant relationship, \( k_{eff} = 2k \), or by ignoring Lenz's law during the qualitative explanation of electromagnetic damping.

Pitfalls and Examiner Report Insights

According to the marking guidelines, key performance slip-ups included:

  • Mass Defect Calculation: Omitting the mass of the two electrons in the proton-proton chain nuclear reaction, which led to incorrect calculations of energy released.
  • Relativistic Graphs: Sketching skewed spacetime axes incorrectly in special relativity, where the \( ct' \) and \( x' \) axes must be symmetric about the \( ct = x \) line.
  • Critical Angle Transitions: Failing to recognize that because sound travels faster in water than in air, the critical angle occurs for sound transitioning from air to water, leading to total internal reflection.

Strategy for Success and Future Predictions

Paper 1B remains an excellent repository of highly accessible marks if students practice drawing lines of maximum/minimum gradient and translating uncertainties correctly through multi-step equations (such as converting density from \( \text{g cm}^{-3} \) to \( \text{kg m}^{-3} \) with correct precision). For upcoming cohorts, we predict a re-emergence of Rigid Body Mechanics and Wave Phenomena (Diffraction Gratings) in Paper 2, as these topics were predominantly restricted to short multiple-choice questions in this session.