Overview
For the IB Diploma Programme, start with the single most important rule: never leave a blank on Paper 1. The multiple-choice section — Paper 1A under the 2025 syllabus — has no negative marking, so a wrong answer scores exactly the same as an empty box: zero. Every unanswered question is a guaranteed miss, while every guess carries at least a one-in-four chance of a mark. That turns the paper into a decision-making game where good technique quietly harvests marks pure recall would leave behind.
What Paper 1 multiple choice is
Paper 1A is the multiple-choice component of IB Physics: a short stem and four options (A–D), and you pick one. Typical papers run to around 30 questions at SL and 40 at HL, though counts, timing and whether the data booklet is provided for this section vary — always confirm the figures against the current specification before exam day. Our free [IB Physics SL course](/ib/courses/physics-sl) and [HL course](/ib/courses/physics-hl) track the live syllabus.
The defining feature is worth repeating: there is no negative marking. Right scores one mark; wrong and blank both score nothing. No working is credited — only your chosen letter counts.
Why you answer every question
Because blanks and wrong answers cost the same, leaving anything empty is pure lost value. Guessing the questions you don't know, after eliminating an option or two, returns marks for free on plausible odds — and over a whole paper that can be the difference between grade boundaries.
So the discipline is absolute: an answer goes in every box. If you run short on time, spend the final thirty seconds filling every blank with a letter — a rushed guess beats a pristine blank every time.
Reading the question — qualifiers and traps
For the IB Diploma Programme, many avoidable Paper 1 errors happen before any physics does — in misreading the stem, where one word can flip the answer.
- Underline the qualifier. Words like NOT, EXCEPT, LEAST and INCORRECT invert what you are looking for. "Which is NOT a vector?" rewards the odd one out. They are often capitalised for a reason — treat that as a warning light.
- Watch the units in the stem. A quantity given in milliseconds, kilometres or MeV must be converted before it meets an equation — distractors are frequently built from candidates who forgot to.
- Note what is actually asked. "Change in momentum" is not "momentum." "Power" is not "energy." Answer the question on the page, not the one you expected.
Elimination strategy
For the IB Diploma Programme, multiple choice hands you the answer — it is among the four options, and your job is to remove the impostors. Elimination is usually faster and safer than solving from scratch, especially when you are unsure.
Cross off any option that breaks physics: a negative value for a quantity that must be positive, a unit that doesn't match, a magnitude wildly too large or small. Often two options fall away instantly, turning a one-in-four guess into a coin flip. Even eliminating a single option improves your odds — never guess blind when thirty seconds of ruling-out is available.
Calculation MCQs — unit and order-of-magnitude checks
For the IB Diploma Programme, for questions that need a number, two fast checks catch most mistakes without redoing the calculation.
- Unit check. Track the units through your working. If you are after a force and your arithmetic yields metres per second, you have used the wrong relationship — stop and rethink.
- Order-of-magnitude check. Estimate the answer's size first. Should this be roughly 10³ or 10⁻³? A power-of-ten estimate rules out options that are off by orders of magnitude — exactly how many distractors are built.
The wrong options are rarely random — they are engineered from a common slip, so a predictable mistake lands neatly on a "wrong" letter. The usual culprits:
- Factor-of-two errors — forgetting the ½ in ½mv² or ½at², or doubling a radius that should stay a diameter.
- Unit-prefix traps — treating milli as kilo, or missing a 10³, so the answer is off by a clean power of ten.
- Radians versus degrees — a calculator in the wrong mode wrecks anything with sin, cos or angular quantities.
So if your answer matches an option exactly, that is reassuring but not proof — trap answers are built to look right to someone who made the intended slip. Sanity-check before you commit.
Using physical intuition to sanity-check
Before you lock in a letter, ask: is this answer physically reasonable? A car that "accelerates" to 4,000 m s⁻¹, or a wavelength longer than a football pitch for visible light, signals a slip somewhere. Intuition won't hand you the answer, but paired with an order-of-magnitude estimate it filters out options that cannot possibly be correct.
Timing and flag-and-return
For the IB Diploma Programme, with roughly one to one-and-a-half minutes per question, Paper 1A rewards steady momentum over perfectionism. The trap is sinking five minutes into one stubborn question while easy marks wait untouched later.
Work front to back and flag anything that doesn't yield in about ninety seconds, putting down your best guess so the box is never blank. Return to flagged questions at the end with fresh eyes — a later question sometimes jogs the idea you needed. In the final minute, sweep for any empty box and fill it. Finishing with blanks left is the one outcome you can always prevent.
How to revise for multiple choice
For the IB Diploma Programme, multiple choice is a trainable skill, and the fastest improver is timed practice on real question styles — working under the clock builds the pattern-recognition that spots a factor-of-two trap or a prefix slip on sight.
- Do sets of real-style MCQs against a timer so pacing becomes automatic.
- Review every wrong answer and name the mistake — misread qualifier, unit slip, wrong equation, calculator mode. The patterns that emerge are your revision priorities.
- Practise with the data booklet the way the real section allows, so finding a formula is instant.
Common mistakes
For the IB Diploma Programme, none of these require more physics — they are technique leaks that drain marks from candidates who already know the material.
- Leaving questions blank — the only guaranteed way to score nothing.
- Missing a qualifier like NOT or EXCEPT and answering the opposite question.
- Skipping unit conversions in the stem before calculating.
- Falling for factor-of-two, prefix or radian/degree distractors without a sanity check.
- Not eliminating before guessing, throwing away better odds.
- Over-investing in one hard question and running out of time for easy marks.
How MarkScheme helps
MarkScheme is built for this kind of deliberate practice: work through timed sets, then review where you went wrong and why. For written follow-up, [get an answer marked](/mark) against the criteria to see exactly what an examiner would credit. Pair that with the [IB Physics Paper 2 guide](/blog/ib-physics-paper-2-guide) for the structured paper, the [how to get a 7 in IB Physics](/blog/ib-physics-how-to-get-a-7) strategy, the [SL past papers](/blog/ib-physics-sl-past-papers-guide) guide for timed sets, and the [IB guides hub](/guides/ib) for everything else.
Frequently asked questions
This section covers Frequently asked questions — what IB examiners reward most often in past papers and coursework.
Is there negative marking in IB Physics Paper 1?
No. Under the current syllabus the multiple-choice section has no negative marking, so a wrong answer scores the same as a blank: zero. Confirm the details against the current specification, but this no-penalty principle is exactly why guessing is worthwhile.
Should I guess on IB Physics Paper 1?
Yes — but guess smartly. Eliminate any options that break physics or fail a unit or order-of-magnitude check first, then choose from what remains. Even removing one option improves your odds, and with no negative marking a guess can only help you.
How much time should I spend per question?
Roughly one to one-and-a-half minutes on average. Flag anything that resists in about ninety seconds, put down a provisional answer, and return to it after banking the easier marks.
How do I avoid the trap answers?
Mark qualifiers like NOT or EXCEPT, convert all units before calculating, and check your calculator's angle mode. On calculations, run a quick unit and order-of-magnitude estimate — most wrong options come from a common slip such as a missing factor of two or a prefix error.
What is the best way to revise for the multiple-choice section?
Timed practice on real question styles, followed by honest review of every mistake. Naming why each wrong answer was wrong turns practice into targeted improvement far faster than re-reading notes.