Common Mistakes in Paper 2 (Structured Response Questions)

Why Paper 2 Is the Most Important Exam

Paper 2 is the most heavily weighted external assessment in IB Physics and often has the greatest influence on a student’s final grade.

Standard Level (SL)

• 50 marks
• 1 hour 30 minutes

Higher Level (HL)

• 90 marks
• 2 hours 30 minutes

Unlike Paper 1A and Paper 1B, Paper 2 assesses a wide range of skills:

• Conceptual understanding
• Problem solving
• Mathematical reasoning
• Scientific explanations
• Data interpretation
• Application of knowledge in unfamiliar situations

The biggest challenge is not usually physics knowledge—it is converting that knowledge into marks.

The 10 Most Common Mistakes

1. Not Showing Enough Working

Many students perform calculations correctly but write only the final answer.

This is one of the fastest ways to lose marks.

Paper 2 frequently awards marks for:

• Selecting the correct equation
• Rearranging correctly
• Substituting correctly
• Applying the correct principle

How to Overcome It

Always write:

Equation
↓
Substitution
↓
Calculation
↓
Answer with units

Even if your final answer is incorrect, method marks can still be awarded.

2. Ignoring the Command Term

Many students answer a different question from the one being asked.

Common command terms include:

How to Overcome It

Before writing:

Ask yourself:

What exactly is the examiner asking me to do?

The command term tells you how to answer.

3. Writing Weak Explanations

Students often write statements rather than explanations.

Example:

Weak answer:

The current decreases because resistance increases.

Strong answer:

As temperature increases, lattice ions vibrate more strongly, increasing collisions with charge carriers. This increases resistance and therefore decreases current for a constant potential difference.

How to Overcome It

Use the Physics Explanation Formula:

Cause → Physics Principle → Effect

Every explanation should include all three components.

4. Forgetting Units

Students often lose easy marks by writing:

v = 24

instead of

v = 24 m s⁻¹

How to Overcome It

Every numerical answer should contain:

• Value
• Unit

Before moving on, quickly check:

Does my answer have a unit?

5. Not Using the Data Booklet Effectively

Many students waste time trying to remember equations that are already provided.

Others use the wrong equation because they do not know where to find the correct one.

How to Overcome It

During revision:

Practice using the Data Booklet.

You should know:

• Where major equations are located
• Common constants
• Unit conversions

The Data Booklet should feel familiar before exam day.

6. Giving Up on Multi-Step Questions

Paper 2 often contains linked questions.

Example:

(a) Calculate acceleration.

(b) Use the acceleration to calculate force.

(c) Explain the result.

Students sometimes leave later parts blank if part (a) was incorrect.

How to Overcome It

Continue using your previous answer.

IB examiners often award:

• Follow-through marks
• Method marks

One mistake should not cost marks in every subsequent part.

7. Poor Time Management

Many students spend too long on difficult questions.

Consequences:

• Rushed final questions
• Incomplete responses
• Missed easy marks

How to Overcome It

Use mark allocation as a guide.

Approximate target:

• 1.7–1.8 minutes per mark

Examples:

Move on if progress stops.

Return later.

8. Not Using Physics Before Mathematics

Students often search for equations before understanding the situation.

This frequently leads to:

• Incorrect equations
• Unnecessary calculations
• Lost marks

How to Overcome It

Before calculating:

Ask:

• What principle applies?
• Is energy conserved?
• Is momentum conserved?
• Is this a wave phenomenon?
• Is this electric field behaviour?

Physics should guide mathematics.

9. Misinterpreting Graphs and Diagrams

Graphs appear regularly in Paper 2.

Students commonly:

• Ignore scales
• Misread values
• Use data points instead of best-fit lines
• Forget units

How to Overcome It

Before answering:

1. Read axis labels.
2. Check units.
3. Check scale.
4. Identify gradients and intercepts.

Never assume a graph is straightforward.

10. Leaving Questions Blank

A blank response earns zero marks.

Many students believe:

I don’t know the answer.

However, partial understanding can still earn marks.

How to Overcome It

Even if uncertain:

• Write the relevant equation.
• State the governing principle.
• Draw a diagram.
• Identify known variables.

Always attempt something.

Common Mistakes in Extended Response Questions

Questions worth 6–8 marks often require structured answers.

Many students lose marks because they write ideas randomly.

How to Overcome It

Use this structure:

Step 1: State the Principle

Introduce the relevant physics concept.

Step 2: Apply the Principle

Connect it to the situation.

Step 3: Explain the Outcome

Describe the effect or result.

Step 4: Conclude

Answer the question directly.

A logical structure helps examiners award marks efficiently.

Common Mistakes in Calculations

Rounding Too Early

Rounding intermediate values introduces errors.

Solution

Keep extra significant figures throughout the calculation.

Round only at the end.

Incorrect Significant Figures

Students often report:

3.14159265 J

when the data was given to two significant figures.

Solution

Match the precision of the question.

Missing Rearrangement Steps

Jumping directly to an answer makes it difficult to earn method marks.

Solution

Show the algebra whenever possible.

Examiner-Recommended Strategy

First Pass

Complete all straightforward questions.

Collect easy marks quickly.

Second Pass

Work through longer calculations and explanations.

Final Review

Check:

• Units
• Significant figures
• Missing responses
• Calculator entries
• Graph readings

Many students recover several marks during the final review.

Quick Self-Check Before the Exam

• Do I always show working?
• Do I understand command terms?
• Do I include units in final answers?
• Can I structure physics explanations logically?
• Do I use the Data Booklet efficiently?
• Do I continue questions even after making a mistake?
• Do I manage time according to marks available?
• Do I check significant figures before moving on?

Final Thought

Most marks lost in Paper 2 are not due to difficult physics.

They are lost through:

• Missing units
• Poor explanations
• Incomplete working
• Misreading questions
• Weak time management

Students who consistently achieve a 7 approach Paper 2 systematically.

They show their reasoning, communicate clearly, and make it easy for the examiner to award marks.

Remember:

In Paper 2, your job is not only to know the physics—it is to show the examiner that you know it.