| Component | Max | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|
| Overall | 100 | 35 | 45 | 56 | 67 |
| Internal assessment | 24 | 11 | 14 | 17 | 20 |
| Paper 1A (multiple choice) | 40 | 19 | 23 | 26 | 30 |
| Paper 1B (data analysis) | 20 | 7 | 9 | 12 | 14 |
| Paper 2 | 90 | 24 | 33 | 43 | 52 |
| Component | Max | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|
| Overall | 100 | 32 | 42 | 53 | 63 |
| Internal assessment | 24 | 11 | 14 | 17 | 20 |
| Paper 1A (multiple choice) | 25 | 11 | 13 | 14 | 16 |
| Paper 1B (data analysis) | 20 | 7 | 9 | 12 | 14 |
| Paper 2 | 50 | 12 | 17 | 23 | 28 |
Paper 1A
Most schools found it fair; calculators were allowed and a few items needed them. A slight rise in blanks near the end hinted at time pressure from the shared Paper 1 time limit.
Found difficult
- buoyancy
- kinetic theory of gases
- SI base units
- diffraction grating
- gravitational potential
- Compton scattering
- Doppler effect
- time management
Well prepared
- stellar parallax
| Q | Topic | How it went | Where marks were lost |
|---|---|---|---|
| SL1 / HL1 | instantaneous versus average velocity | Mixed | confused instantaneous with average velocity |
| SL2 / HL2 | motion with varying acceleration | Mixed | treated an instantaneous acceleration as constantTip: Use constant-acceleration equations only when acceleration really is constant. |
| SL4 / HL4 | buoyant force on two spheres | Most struggled | thought buoyancy depends on the object's densityTip: Buoyant force depends on fluid density and displaced volume, not object density. |
| SL6 / HL6 | kinetic energy from impulse | Answered well | Nothing specific reported.Tip: Impulse equals change in momentum; then use kinetic energy p squared over 2m. |
| SL9 / HL12 | cause of increased molecular speed | Most struggled | picked a true statement that was not the causeTip: When asked for a cause, choose the option that explains the change, not just a true fact. |
| SL10 / HL14 | ordering resistances of networks | Answered well | Nothing specific reported.Tip: Compare networks with simple series and parallel limits instead of computing each. |
| SL13 / HL17 | mass oscillating between two springs | Mixed | Nothing specific reported. |
| SL15 / HL20 | refraction angle (calculator) | Mixed | used 50 degrees instead of the 40 degree incidence angleTip: Measure angles of incidence from the normal. |
| SL17 / HL24 | g on another planet from mass and diameter | Mixed | used diameter ratio as if it were radius |
| SL18 / HL26 | units in fundamental SI form | Most struggled | chose a correct unit not reduced to base unitsTip: Reduce derived units fully to kg, m, s, A, K, mol. |
| SL20 / HL29 | induced current direction in a rotating coil | Mixed | confused coil rotation with current direction |
| SL23 / HL38 | materials in a nuclear reactor | Mixed | Nothing specific reported.Tip: Know suitable materials for moderator, control rods and shielding. |
| SL24 / HL39 | neutron balance in a steady chain reaction | Mixed | Nothing specific reported. |
| SL24 / HL39 (second item so labelled) | distance from parallax angle | Answered well | Nothing specific reported. |
| HL 5 | calculation (calculator) | Answered well | Nothing specific reported. |
| HL 7 | kinematics | Mixed | dropped the factor 2 in a kinematics equation |
| HL 9 | relativistic velocity addition | Mixed | Nothing specific reported.Tip: Eliminate options faster than light before calculating. |
| HL 16 | resistance after changing length and area | Mixed | assumed the two changes cancel |
| HL 19 | speed at a given displacement in SHM | Most struggled | wrong fractions of amplitude |
| HL 21 | double-slit and single-slit spacing | Mixed | Nothing specific reported.Tip: Slit separation always exceeds slit width; use that to eliminate options. |
| HL 22 | harmonics in a half-open pipe | Mixed | two numbering conventions; both accepted |
| HL 23 | number of maxima from a diffraction grating | Most struggled | forgot maxima on both sides of centreTip: At normal incidence the total number of maxima is odd. |
| HL 25 | gravitational potential against distance | Most struggled | chose a graph not following 1/r |
| HL 30 | discovery of charge quantization | Most struggled | credited Coulomb instead of Millikan |
| HL 33 | nuclear graph | Mixed | chose a curve resembling binding energy per nucleon |
| HL 34 | expression with consistent units | Answered well | Nothing specific reported. |
| HL 35 | Compton scattering wavelength and speed | Most struggled | did not see wavelength increases while speed is unchanged |
| SL 5 | elastic energy stored in a spring | Mixed | Nothing specific reported.Tip: Elastic energy scales with extension squared. |
| SL 12 | simple multiplication of data | Answered well | Nothing specific reported. |
| SL 16 | Doppler shift of a decelerating source | Most struggled | Nothing specific reported.Tip: Check the sign of the frequency shift at start and end of the motion. |
What to practise
- Practise combined Paper 1A and 1B under one shared time limit.
- Learn which items need a calculator and which are faster by reasoning.
- Use units, extreme values and sketches to eliminate options.
- Know the conditions behind data booklet equations, e.g. in-phase sources for interference.
- For cause-type questions, pick the statement that explains the change.
Paper 1B
First Paper 1B, common to both levels; familiar density and refraction experiments went well, but the unfamiliar magnetic field context in Q3 was the hardest part.
Found difficult
- analysing unfamiliar data
- unit conversion
- vector components
Well prepared
- graph analysis
| Q | Topic | How it went | Where marks were lost |
|---|---|---|---|
| 1a | improving a single measurement | Mixed | suggested repeats instead of improving one readingTip: Answer the method asked for, not a generic repeat-and-average. |
| 1bi, 1bii | density with propagated uncertainty | Mixed | added absolute uncertainties; forgot to convert the uncertainty with the units; uncertainty to more than one significant figureTip: Quote uncertainty to one significant figure and match the value's precision to it. |
| 1c | comparing results with reference water data | Most struggled | treated the given curve as experimental; ignored uncertainty rangeTip: Use the uncertainties from earlier parts when comparing with a reference. |
| 2a, 2b | refraction experiment | Answered well | Nothing specific reported. |
| 2ci | gradient of best-fit line | Answered well | used table points instead of points on the lineTip: Take gradient points from the best-fit line, not the data table. |
| 2cii | drawing a maximum gradient line | Mixed | drew a parallel line; left blankTip: Draw the steepest line still passing through all error bars. |
| 2ciii | uncertainty in refractive index from gradient | Most struggled | used data-point uncertainty instead of gradient uncertainty; gave a value without working |
| 3a | comparing graphs in an unfamiliar magnetic experiment | Most struggled | Nothing specific reported. |
| 3b | field direction of coils | Mixed | repeated the stem without a reason |
| 3c | resolving into perpendicular components | Mixed | wrong trigonometric ratioTip: Attempt every part; later parts can be easier than earlier ones. |
What to practise
- Revise IA skills: propagating uncertainties and comparing results with expected graphs.
- Use clues from earlier parts, e.g. uncertainty needed in a later answer.
- Practise analysing data from unfamiliar experiments and finding the relationship.
HL Paper 2
Considered harder by most respondents but with no time problems; answers were well set out, though SHM energies, the greenhouse mechanism and reasoning about entropy were weak.
Found difficult
- simple harmonic motion
- greenhouse effect
- spacetime diagrams
Well prepared
- motion graphs
- Doppler effect
- SI base units
- orbital motion
| Q | Topic | How it went | Where marks were lost |
|---|---|---|---|
| 1ai | quantity given by area under a graph (work done) | Answered well | Nothing specific reported. |
| 1aii | non-uniform acceleration | Answered well | assumed constant acceleration |
| 1b | constant and its base units | Mixed | did not break newtons into base units |
| 2a | orbital calculation | Mixed | errors with powers |
| 2b | finding a mass from orbital data | Answered well | Nothing specific reported. |
| 2c | orbital motion | Answered well | Nothing specific reported. |
| 3ai | deviation from Rutherford scattering | Mixed | read deviation as deflection of the path |
| 3aii | distance of closest approach | Mixed | Nothing specific reported. |
| 3bi | decay constant | Answered well | half-life not in seconds |
| 3bii | mass of daughter product | Mixed | stopped at undecayed parent massTip: Finish by finding the daughter mass from the decayed parent. |
| 3c | nuclear energy levels | Most struggled | described electron transitions |
| 4a | microstates of two configurations | Mixed | described energy without linking to microstates |
| 4b | second law and entropy | Mixed | Nothing specific reported. |
| 5a | Doppler effect | Answered well | wrong sign or moving-source formula |
| 5bi | wave calculation | Answered well | Nothing specific reported. |
| 5bii | destructive interference path difference | Mixed | generic answer without the given values; path difference stated as 0.70 mTip: Use the numbers in the question to show the path difference. |
| 5c | refraction of sound into water | Mixed | wrong incidence angle; claim not backed by calculation |
| 6a | uniform electric field | Mixed | used point-charge field formula |
| 6b | force on an electron | Answered well | Nothing specific reported. |
| 6c | electron path in a field | Mixed | mixed horizontal and vertical motion in one equationTip: Treat horizontal and vertical motion separately. |
| 6d | electron motion | Answered well | Nothing specific reported. |
| 7ai | speed from a spacetime diagram | Mixed | omitted the negative sign |
| 7aii | invariant quantity | Mixed | did not mention reference frames |
| 7b | spacetime diagram | Answered well | Nothing specific reported. |
| 8a | solar intensity received | Mixed | omitted intensity reaching Earth |
| 8bi | greenhouse mechanism | Most struggled | restated re-radiation from the stem |
| 8bii | energy balance show-that | Mixed | invented an emissivity to force the answer |
| 8biii | energy balance | Mixed | stopped after first step |
| 8c | calculation | Answered well | Nothing specific reported. |
| 8d | fusion in the Sun and spectral evidence | Mixed | thought fusion products can be collected; omitted electronsTip: Evidence for helium in stars comes from absorption spectra. |
| 8e | stellar evolution and fusion | Mixed | no mention of rate, conditions or location |
| 9a | SHM item | Answered well | Nothing specific reported. |
| 9bi | direction of force in SHM | Mixed | incomplete link between energy and extension |
| 9bii-9ciii | energy changes in a vertical spring system | Most struggled | only considered elastic and kinetic energy; took max elastic energy as totalTip: Include gravitational energy for vertical oscillations. |
| 9di | factors affecting induced emf | Mixed | gave magnet speed, which varies; restated the formula |
| 9dii | electromagnetic damping | Mixed | Nothing specific reported. |
What to practise
- Show working so examiners can award error carried forward.
- Know the data booklet symbols.
- Give answers as decimals, not fractions or surds.
- Tie descriptive answers to the context, not generic statements.
SL Paper 2
SL candidates handled motion graphs, I-V characteristics and basic waves well, but the greenhouse mechanism, energy balance and stellar fusion were weak.
Found difficult
- greenhouse effect
- energy balance
- stellar fusion
Well prepared
- motion graphs
- I-V characteristics
- wave properties
| Q | Topic | How it went | Where marks were lost |
|---|---|---|---|
| 1ai | quantity given by area under a graph (work done) | Answered well | Nothing specific reported. |
| 1aii | non-uniform acceleration | Answered well | assumed constant acceleration |
| 1b | constant and its base units | Mixed | did not break newtons into base units |
| 2a | orbital calculation | Mixed | errors with powers |
| 2b | finding a mass from orbital data | Answered well | Nothing specific reported. |
| 3a | reading an I-V graph | Answered well | power of ten error |
| 3b | resistance of a non-ohmic component | Answered well | Nothing specific reported. |
| 3c | current from an I-V curve | Mixed | used the wrong component's resistance |
| 3d | emf with two resistors in series | Mixed | ignored the second series resistor |
| 4a | sound versus EM waves | Mixed | Nothing specific reported. |
| 4bi | wave calculation | Answered well | Nothing specific reported. |
| 4bii | destructive interference path difference | Mixed | generic answer without given values |
| 4c | refraction of sound into water | Mixed | wrong incidence angle |
| 5a | force on an electron | Answered well | Nothing specific reported. |
| 5b | electron path in a field | Mixed | mixed horizontal and vertical motion in one equation |
| 5c | electron motion | Answered well | Nothing specific reported. |
| 6a | solar intensity received | Mixed | omitted intensity reaching Earth |
| 6b | greenhouse mechanism and energy balance | Most struggled | invented an emissivity; stopped after first step |
| 6c | calculation | Answered well | Nothing specific reported. |
| 6d | fusion in the Sun and spectral evidence | Mixed | thought fusion products can be collected |
| 6e | stellar evolution and fusion | Mixed | named red giant or white dwarf wrongly |
What to practise
- Show clear working.
- Give decimal answers.
- Answer descriptive questions in context.
Internal assessment
What moderators raised about the scientific investigation this session, criterion by criterion.
- Research design. background derives data booklet equations or recounts history instead of focusing on the research question
- Research design. method lacks the precision needed to detect the expected change
- Research design. unneeded personal engagement section or pretending not to know a textbook relationship
- Data analysis. meaningless significant figures, linear confused with proportional, forced linear fits
- Data analysis. max/min gradients from first and last error bars only
- Conclusion. no justified comparison with a reliable accepted value or range
- Evaluation. generic error lists and improvements not tied to the actual method
- Evaluation. strengths listed, which are not assessed
About this summary
After every session the IB sends schools a subject report: how candidates did on each paper and question, and what teachers should work on. This page is my reading of the Physics report for May 2025 TZ1, in my own words. No text from the report or from the exam questions is reproduced, and it is not endorsed by the International Baccalaureate.
Session codes: TZ is the time zone variant of the papers. Other variants of the same session:
Frequently asked questions
Which questions were hardest in Physics May 2025 TZ1?
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The questions most candidates struggled with were on buoyant force on two spheres, cause of increased molecular speed, units in fundamental SI form and speed at a given displacement in SHM. The tables above list every question discussed in the report, paper by paper.
What did candidates find difficult in May 2025 TZ1?
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Across the papers the examiners listed buoyancy, kinetic theory of gases, SI base units, diffraction grating, gravitational potential, Compton scattering, Doppler effect and time management, among others.
What were the grade boundaries for Physics May 2025 TZ1?
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Physics HL: a 7 from 67 out of 100 overall in May 2025 TZ1. Physics SL: a 7 from 63 out of 100 overall in May 2025 TZ1. The component boundaries are in the table on this page.
Is this the official IB subject report?
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No. It is my summary of the report the IB issues to schools after each session, rewritten in my own words with a teacher's reading of it. No text from the report or from exam questions is reproduced. Your school's IB coordinator can access the original.
Related
IB examiner reports: every session, Maths and Physics IB Physics November 2024: the previous report IB Physics November 2025 TZ1: the next report IB Physics HL grade boundaries, every session IB Physics SL grade boundaries, every session IB Physics revision notes IB Maths and Physics topic tests, with markschemes