IB Physics Paper 2 is where many students lose marks—not because they don’t know physics, but because they make avoidable exam mistakes.
If you’ve ever walked out of Paper 2 thinking “I knew this, but my answer didn’t come out right”, you’re not alone. This paper tests more than formulas. It tests understanding, structure, explanations, and exam technique.
In this guide on IB Physics Paper 2: Common Mistakes and How to Avoid Them, we break down the most frequent errors students make, explain why they happen, and show you simple, practical ways to fix them before exam day.
This article is written for students, parents, and teachers who want clear explanations—not confusing jargon.
Before fixing mistakes, you need to understand what Paper 2 is really testing.
IB Physics Paper 2:
Is structured response
Requires full working and explanations
Tests depth of understanding, not speed
Unlike Paper 1, you cannot guess. Every mark depends on:
Correct method
Logical steps
Clear physics reasoning
This is why small mistakes add up quickly.
This is one of the most common mistakes in IB Physics Paper 2.
Many students see a keyword like velocity or force and immediately write a formula—without fully reading the question.
You may use the wrong equation
You may miss hidden conditions
Your answer may not match what the examiner asked
If the question says:
“Calculate the maximum speed…”
But you calculate the average speed, you lose marks even if your math is correct.
Read the question twice
Underline key words (maximum, explain, compare, derive)
Ask yourself: What exactly is being asked?
In Paper 2, words matter almost as much as calculations.
Many students can calculate correctly but lose marks on explain, describe, or justify questions.
Writing one vague sentence
Using everyday language instead of physics terms
Not linking cause and effect
Weak answer:
“The current increases.”
Strong answer:
“The current increases because the potential difference across the resistor increases, according to Ohm’s law.”
Use physics vocabulary
Always explain why, not just what
Link ideas using words like because, therefore, as a result
IB examiners love clear diagrams. Many students either:
Skip diagrams completely
Draw messy, unclear sketches
Both can cost marks.
Some marks are awarded only for diagrams
A good diagram can save time and clarify thinking
It shows understanding, not guessing
In electric fields, ray diagrams, or forces:
Missing arrows
No labels
Incorrect directions
Draw simple, neat diagrams
Label all important quantities
Use arrows for direction (forces, fields, motion)
This sounds small—but it’s a huge mark loser.
IB Physics marking schemes are strict about units.
Forgetting units completely
Using incorrect SI units
Mixing symbols (m instead of m/s)
Writing:
v = 20
Instead of:
v = 20 m s⁻¹
Always write units next to final answers
Learn common SI units by heart
Check dimensional consistency
Many physics answers are correct in principle but wrong due to math errors.
Rearranging equations incorrectly
Rounding too early
Sign errors (especially with vectors)
A single minus sign mistake can:
Reverse direction
Change interpretation
Lose multiple marks
Rearrange equations symbolically first
Substitute numbers at the end
Check if your answer makes physical sense
In IB Physics Paper 2, working earns marks.
Even if your final answer is wrong, you can still earn method marks.
Writing only:
Final answer
With no steps.
One small mistake = zero marks
Examiner cannot award partial credit
Always show:
Formula used
Substitution
Final answer
Even rough working can earn marks.
Physics has many concepts that sound similar but are not the same.
Speed vs velocity
Energy vs power
Force vs momentum
Electric field vs electric force
Saying:
“The object has more force”
When force depends on interaction, not the object alone.
Learn definitions properly
Practice explaining differences in words
Create a comparison table during revision
Graphs appear frequently in Paper 2, and many students misread them.
Confusing gradient with area
Not identifying key points
Ignoring units on axes
Gradient of velocity–time graph = acceleration
Area under curve = displacement
Mixing these up costs easy marks.
Practice graph questions regularly
Always check axes and units
State what the gradient or area represents
Many students run out of time and leave questions unfinished.
Spending too long on one question
Trying to perfect every answer
Panicking midway through the paper
Know how many marks each question carries
Spend time proportionally
Move on if stuck—come back later
This is a big reason students struggle in IB Physics Paper 2.
IB questions are rarely copied directly from textbooks.
Questions are applied in new contexts
You must adapt knowledge
Rote learning breaks under pressure
Ask “why” when learning formulas
Practice applying concepts in different situations
Explain answers in your own words
If exams are close and time is limited, focus on these three priorities:
Improve explanations using correct physics terms
Practice structured answers with full working
Learn common command terms (explain, calculate, describe)
These changes alone can raise your Paper 2 score significantly.
IB Physics Paper 2 is challenging—but most lost marks come from common, fixable mistakes, not lack of intelligence.
By improving how you read questions, explain ideas, show working, and manage time, you can turn average answers into high-scoring ones.
Start fixing these mistakes now, practice with purpose, and you’ll walk into the exam far more confident.
If you need extra guidance, working with an IB Physics specialist can make a huge difference.
Because it tests explanations, reasoning, and full working—not just final answers.
A significant portion. Weak explanations can cost multiple marks even if calculations are correct.
Yes. Showing correct steps can earn marks even if the final answer is wrong.
Yes, as long as ideas are clear and logically connected.
Very important. Some marks are awarded specifically for correct diagrams.
Past paper questions with markscheme analysis and focused feedback.
Yes—especially an IB-trained tutor who understands examiner expectations.
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