Understanding the physics is only part of what determines your IB grade. The other part is exam strategy — knowing how each paper is structured, how marks are awarded, and how to present your answers in the way examiners want to see them.
This guide covers each paper in the IB Physics assessment, the strategic approach I recommend to my students, and the most common mistakes that are entirely preventable.
Overview of the IB Physics Assessment
| Paper | Format | Duration (SL) | Duration (HL) | Weighting |
|---|---|---|---|---|
| Paper 1 | Multiple Choice (30/40 questions) | 45 min | 60 min | 20% |
| Paper 2 | Short & Extended Response | 75 min | 135 min | 40% |
| Paper 3 | Data Analysis + Option Topic | 60 min | 75 min | 20% |
| IA | Individual Investigation | Internal | 20% | |
Paper 1: Multiple Choice Strategy
Paper 1 is deceptively difficult. The questions are carefully written with plausible distractors that target specific misconceptions. You cannot coast through it on intuition.
Read every option before answering
This sounds obvious but many students stop at the first answer that looks right. The IB often writes two options that both appear correct until you read them carefully — one will have a subtle error in units, sign, or magnitude.
Draw a diagram or write an equation
Even for MCQ, jotting a quick FBD or equation on your paper grounds your thinking. Students who try to reason through everything in their head make significantly more errors. Take 20 seconds to write it down.
Use process of elimination
If you can eliminate two options confidently, you've turned a 25% guess into a 50/50. Rule out any option with the wrong unit, the wrong sign (especially in direction problems), or an impossibly large or small magnitude.
Flag and move on
If a question takes more than 90 seconds, mark it and return later. One hard question isn't worth losing time on easier ones that come after it.
Watch for questions asking for displacement vs distance, speed vs velocity, or "which of the following is NOT true." These negation questions catch students who skim. Underline the word NOT when you see it.
Paper 2: Extended Response Strategy
Paper 2 is where your understanding depth is tested. Questions are multi-part and often build — a mistake early can cascade, but examiners use "error carried forward" (ECF) to award marks for correct method applied to a wrong earlier result.
Show every step of working
Even if the answer is wrong, a correct method earns marks. Write: what formula you're using, substitution with values and units, the result with units. Never skip steps for marks worth 2 or more.
Give answers to the correct significant figures
The rule: give the same number of significant figures as the least precise data in the question — usually 3 sig figs. An answer with too many or too few sig figs loses 1 mark. This is a free mark for students who are careful.
Units, units, units
Every numerical answer must include units. "6.2" is incomplete. "6.2 m s⁻¹" is correct. Losing unit marks on a Paper 2 question is one of the easiest ways to drop marks — and one of the most preventable.
Descriptive and "explain" questions
Questions that say "explain" require a mechanism, not just a statement. "The temperature increases" is a statement. "The internal energy of the gas increases because the molecules move faster on average, raising the temperature" is an explanation. Use the command term to calibrate the depth required.
Paper 3: Data Analysis and Option Topic
Paper 3 begins with a data analysis section that most students underperform on — not because the physics is hard, but because data analysis skills aren't practised enough.
Uncertainty and error analysis
Know how to calculate absolute and percentage uncertainty, propagate uncertainties through calculations, and decide whether a discrepancy is within experimental error. If the accepted value falls within your range of experimental error, your result is consistent with theory — say that explicitly.
Graph drawing and analysis
When asked to draw a line of best fit, draw a smooth curve or straight line that minimises total distance from points — not a dot-to-dot. If asked for gradient, draw a large triangle and show it. For linearisation: if y vs x² gives a straight line, state that the relationship is y ∝ x² and identify the gradient's physical meaning.
Option topic revision
Treat the option topic as a separate mini-exam. Astrophysics, relativity, and engineering physics each require specific vocabulary and a small number of key derivations. Past papers from your option are the most efficient revision tool.
General Exam Habits That Make a Difference
- Read the question twice. Many marks are lost because students answer a question that wasn't asked. The number of marks next to a question tells you how many distinct points are expected.
- Sketch a diagram for any force or field problem. Even a rough sketch clarifies direction and relationships before you start calculating.
- Check answers are physically reasonable. A kinetic energy of 10⁵⁰ J for a book falling off a desk is impossible — recognising this and finding the error is part of scientific thinking.
- Practise under timed conditions. Knowing the physics is not the same as being able to apply it in 90 seconds per question. Regular timed past paper practice is non-negotiable.
Working with an IB Physics HL tutor online gives you targeted feedback on your exam technique — not just content review. Many of my students make significant gains from understanding how to present their answers, not just what to write.
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