Marks-weighted analysis of 198 questions across 570 marks from 18 IB Physics SL papers. The headline finding: 51.9% of all marks come from questions that fuse two or more topics — the redesigned exams reward students who connect the themes, not those who revise them in isolation.
Share of total marks across the five IB Physics themes. Theme A (Space, time & motion) and Theme B (Particulate nature of matter) alone account for over half of every exam.
Mechanics (A) leads at 27.6%, but the marks are spread more evenly across all five themes than students expect — no theme can be safely skipped.
All 19 examined sub-topics ranked by % of total marks, colour-coded by theme. This is the chart that matters most for revision planning.
Marks per theme split across the three papers. Paper 2 (extended response) carries the heaviest load in every theme — and, as the next section shows, that is where the topics get fused together.
Paper 1A = multiple choice · Paper 1B = data-based / experimental · Paper 2 = extended response. Values are marks attributed to each theme after multi-topic questions are split among their tags.
The redesigned 2025 exams were built to blend themes inside a single question. A Paper 2 part now routinely asks you to move from mechanics into fields, from matter into nuclear, from waves into thermal — all in one train of reasoning. Revising each topic in a silo is no longer enough: over half of all marks depend on connecting two or more topics together.
| Themes fused | Times seen | What that means in a question |
|---|---|---|
| B + E Matter + Nuclear & quantum | 8 | Thermal, gas-law and atomic-structure ideas fused with radioactive decay, nuclear energy release and quantum behaviour. |
| A + D Motion + Fields | 6 | Momentum, kinematics and energy analysis fused with gravitational, electric and magnetic fields (charged particles, orbits, projectiles in a field). |
| B + C Matter + Waves | 4 | Thermal / particle physics fused with wave behaviour — standing waves in rods and gas columns, sound travelling through materials. |
| A + E Motion + Nuclear & quantum | 2 | Momentum and energy conservation applied to nuclear decay products and particle collisions. |
| A + C Motion + Waves | 2 | Kinematics and simple harmonic motion fused with oscillation and wave behaviour. |
| C + E Waves + Nuclear & quantum | 2 | Wave phenomena fused with atomic spectra and quantum ideas. |
Mass defect & energy release, then momentum conservation to share the kinetic energy between decay products, then Geiger–Marsden atomic structure — one question, three connected steps.
Buoyancy / floating equilibrium of a cork, its SHM when pushed down, a collision analysed by momentum, then thermal conduction, heat capacity and latent heat — plus the density anomaly of water.
Stellar luminosity from black-body radiation, then apparent brightness via the inverse-square law — astrophysics linking radiation and geometry.
SHM used as a timebase, feeding into uniform-acceleration kinematics, then resolving the component of g and friction on an incline.
Free-body force analysis, circular motion held by friction, then kinetic energy compared with the work done by drag.
Moles and atomic spacing, latent heat and internal energy, then longitudinal standing waves set up in a rod — matter physics into wave physics.
Acceleration of a charge in an electric field, kinematics of its flight, then a magnetic velocity selector — a fields-and-motion chain.
Stellar fusion and mass–energy release, Wien's law for peak wavelength, Doppler shift from rotation, and gravitational equilibrium — five ideas in one astrophysics question.
How the 198 questions break down by accessibility. Most of the paper is genuinely attemptable — but the multi-topic questions above are where the "hard" band clusters.
Almost a quarter of questions are accessible marks — recall, single-step substitution and reading data. These are non-negotiable and should be banked in full.
The core of every paper. Two- and three-step reasoning within a topic — reliable marks for students who have drilled past papers.
The demanding band, dominated by the cross-topic synthesis questions. This is exactly where connecting themes earns the grade.
Official grade boundaries for the new 2025 Physics syllabus.
With only three new-syllabus sittings (2025 specimen, May 2025, November 2025) so far, we are gathering the official IB grade boundary documents before publishing a table. We will not print estimated or fabricated numbers here — as soon as verified boundaries are available for the redesigned Physics SL course, they will appear in this section.
Full IB-style predicted papers for the new Physics SL syllabus are in development — modelled directly on the cross-topic patterns you see above.
Because the syllabus is new, we are writing Physics SL predicted papers from scratch — Paper 1A, 1B and 2 in exam style, deliberately built around the multi-topic synthesis that defines the redesigned course. They are not published yet. In the meantime, our tutors work through real new-syllabus questions with students and drill the exact theme pairings that carry the marks.