Measured on 282 real questions
What actually comes up in ESAT Physics
Topic-by-topic and formula-by-formula frequency, measured on 282 real past-paper questions rather than guessed from the specification.
Mechanics and electricity between them account for two thirds of the 193 questions we tagged formula by formula. Magnetism is the smallest of the six chapters.
The ESAT specification lists what could be examined. It does not tell you what usually is, and the two are very different documents. Because no live ESAT paper has ever been published, most physics revision plans are built from the specification alone, which quietly implies every topic is equally likely.
So we measured it. We took the ESAT’s direct predecessor papers, ENGAA and NSAA Section 1 from 2016 to 2023, filtered every question against the current ESAT specification, and tagged the 282 that survived. A subset of 193 was then tagged a second time at the level of individual formulae, by two independent taggers who had to quote verbatim evidence from the worked solution before a tag counted.
The result is the table below: not what the board says it may ask, but what it actually asked, question by question.
Topic frequency
Every ESAT Physics topic, by how often it actually appeared.
282 questions, 11 topics. Each question carries exactly one topic tag, so these shares add to 100% and can be read as shares of a paper. The 95% confidence interval is the range the true share plausibly sits in given this sample size.
| # | Topic | Questions | Share | 95% CI |
|---|---|---|---|---|
| 1 | Electricity and circuits | 42 / 282 | 14.9% | 11.2-19.5% |
| 2 | Waves | 40 / 282 | 14.2% | 10.6-18.7% |
| 3 | Energy, work and power | 38 / 282 | 13.5% | 10.0-18.0% |
| 4 | Nuclear and radioactivity | 27 / 282 | 9.6% | 6.7-13.6% |
| 5 | Forces and dynamics | 24 / 282 | 8.5% | 5.8-12.4% |
| 6 | Materials, density, pressure and springs | 23 / 282 | 8.2% | 5.5-11.9% |
| 7 | Thermal physics | 23 / 282 | 8.2% | 5.5-11.9% |
| 8 | Momentum | 22 / 282 | 7.8% | 5.2-11.5% |
| 9 | Kinematics | 19 / 282 | 6.7% | 4.4-10.3% |
| 10 | Electromagnetism | 15 / 282 | 5.3% | 3.2-8.6% |
| 11 | Gases and matter | 9 / 282 | 3.2% | 1.7-6.0% |
Evidence base: ENGAA and NSAA Section 1, 2016-2023, filtered to the current ESAT specification.
Formula frequency
Which formulae the questions could not be solved without.
A second, deeper tagging pass over 193 of the 282 questions. Unlike the topic table, these percentages do not add up: one question often requires several formulae, so the rows overlap by design. Read each as “this share of questions needed this relationship”.
| # | Formula or rule | Chapter | Needed in | 95% CI |
|---|---|---|---|---|
| 1 | Ohm's law | Electricity | 14.5%28 of 193 | 10.2-20.2% |
| 2 | Newton's second law | Mechanics | 9.8%19 of 193 | 6.4-14.9% |
| 3 | Weight from mass | Mechanics | 8.8%17 of 193 | 5.6-13.7% |
| 4 | Electrical power from current and pd | Electricity | 8.3%16 of 193 | 5.2-13.0% |
| 5 | Wave equation | Waves | 8.3%16 of 193 | 5.2-13.0% |
| 6 | Resistors in series add | Electricity | 6.2%12 of 193 | 3.6-10.6% |
| 7 | Current as rate of flow of charge | Electricity | 4.7%9 of 193 | 2.5-8.6% |
| 8 | Equation of motion | Mechanics | 4.1%8 of 193 | 2.1-8.0% |
| 9 | Parallel branches share the same pdrule | Electricity | 4.1%8 of 193 | 2.1-8.0% |
| 10 | Resistive heating from current and resistance | Electricity | 4.1%8 of 193 | 2.1-8.0% |
| 11 | Work done by a force | Mechanics | 3.6%7 of 193 | 1.8-7.3% |
| 12 | Acceleration as rate of change of velocity | Mechanics | 3.6%7 of 193 | 1.8-7.3% |
| 13 | Boyle's law for a fixed mass of gas | Matter | 3.6%7 of 193 | 1.8-7.3% |
| 14 | Elastic energy stored in a stretched spring | Mechanics | 3.6%7 of 193 | 1.8-7.3% |
| 15 | Density | Matter | 3.6%7 of 193 | 1.8-7.3% |
| 16 | Power from pd and resistance | Electricity | 3.1%6 of 193 | 1.4-6.6% |
| 17 | Conservation of linear momentum in one dimension | Mechanics | 3.1%6 of 193 | 1.4-6.6% |
| 18 | Momentum | Mechanics | 2.6%5 of 193 | 1.1-5.9% |
| 19 | Echo and ultrasound timing: the pulse travels out and backtechnique | Waves | 2.6%5 of 193 | 1.1-5.9% |
| 20 | Newton's third lawrule | Mechanics | 2.6%5 of 193 | 1.1-5.9% |
By chapter
- Mechanics39.4%76 of 193
- Electricity26.9%52 of 193
- Waves15.5%30 of 193
- Matter8.8%17 of 193
- Thermal physics4.7%9 of 193
- Magnetism and electromagnetism4.1%8 of 193
How much of the sheet is dead weight
Across the 193 tagged questions, 66 catalogue entries were required at least once and 44 were never required at all. Knowing which group a formula belongs to is worth more than another pass over all of them.
Two independent taggers, Cohen’s kappa 0.838 on 97.7% raw agreement. Cohen's kappa on the essential/absent binary over (question x offered-entry) cells. 0.81-1.00 is conventionally "almost perfect" agreement.
Where the data disagrees with the revision guides
The magnetism trap
F = BIL feels like a signature ESAT physics formula and it is drilled hard in most preparation. In the tagged set it was essential to 2.1% of questions, four out of 193. The chapter it belongs to, magnetism and electromagnetism, came bottom of six at 4.1%, and the independent topic tagging agreed at 5.3%. Two separate tagging passes reaching the same conclusion is what makes this worth acting on: it is a real feature of the papers, not an artefact of one method. Learn it, but do not let it displace circuits.
- Force on a wire in a magnetic field
- 2.1% · 4 of 193 · rank 2595% CI 0.8-5.2%
What this means for your revision
Four things the numbers say about ESAT Physics.
- 01
Electricity and circuits (14.9%), waves (14.2%) and energy, work and power (13.5%) are the three biggest topics and are within a whisker of each other. None of them is optional.
- 02
Grouped by chapter, mechanics is 39.4% of the 193 formula-tagged questions and electricity 26.9%. Those two chapters are where marginal revision hours pay.
- 03
Ohm’s law is needed in 14.5% of tagged questions, more than any other single relationship. Newton’s second law follows at 9.8%.
- 04
Of the 110 physics entries on our recall sheet, 44 were never required by a single one of the 193 tagged questions. Knowing which 66 do the work is most of the battle.
Free resource
The recall sheet these numbers came from.
Neither the ESAT nor the TMUA gives you a formulae booklet or a calculator, so everything on the specification is a memorisation liability. Our recall sheet lists every formula, rule and technique for all seven modules, each one tied to the spec clause that requires it, with the measured frequency beside it. It is free.
Get the free ESAT recall sheetMethod and coverage
How this was measured, and what it does not cover.
The corpus is 1,250 real past-paper questions across all seven modules, of which 282 are ESAT Physics - and every percentage on this page is out of that 282, not out of the full corpus.
Not one question we wrote ourselves is counted. Our own question bank is excluded on purpose: treating questions we authored as evidence of what Cambridge asks would be circular.
Two independent taggers on Haiku 4.5 read each question's worked solution and chose required formulae from a closed per-question shortlist, quoting verbatim evidence. Every tag was verified mechanically before counting.
What the corpus holds
| Paper | Years | Published | Held |
|---|---|---|---|
| ENGAA | 2016-2023 | 362 | 315 |
| NSAA | 2016-2023 | 680 | 575 |
| TMUA | 2016-2023 + early specimen | - | 360 |
What it does not hold
A frequency table is a claim about a denominator, so a gap in the denominator biases every percentage above. These are the gaps, audited 2026-08-17. The first two matter to a candidate; the rest are recorded for completeness.
TMUA 2024 onwards
TMUA figures cover the 2016-2023 sittings and the early specimen. The 2024 and later sittings are not held.
This is the one gap that touches a LIVE test. TMUA percentages describe the Cambridge-era papers, which are the closest available evidence but are not the most recent sittings a current candidate will have seen.
ESAT, all years
No live ESAT paper has ever been released. Only the 2024 specimen and sample exist, and the sample has no answer key.
This is the whole reason ENGAA and NSAA stand in as the evidence base: they are ESAT's direct predecessors, filtered to the current ESAT specification.
NSAA 2016-2019 · 72 questions
NSAA Section 1 had a fifth part (E, Advanced Maths and Physics) in 2016-2019 which this corpus does not carry.
NSAA papers contain 680 questions. 608 are held here, and 575 of those fall inside the current ESAT specification - 575 is the number every ESAT percentage on this page is drawn from. Because Part E is out of ESAT scope, excluding it makes the ESAT-relevant percentages MORE accurate, not less: it would otherwise dilute every count with material ESAT never tests.
ENGAA and NSAA, all years
Only Section 1 papers are held. Neither test's Section 2 is in the corpus.
No effect on ESAT-relevant frequency: the format being measured does not exist in ESAT.