Answering 6-Mark Extended Response Questions

Six-mark questions are the highest-tariff questions on the Edexcel GCSE Physics (1PH0) papers. They require a structured, detailed response and are marked differently from other questions. This lesson teaches you exactly how to approach them.

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How 6-Mark Questions Are Marked

Unlike other questions where each mark corresponds to a specific point, 6-mark questions use levels-based marking. Your answer is assessed holistically and placed into one of three levels:

Level	Marks	Description
Level 3	5–6	A comprehensive, logically structured answer with correct scientific terminology. Covers all key points. Clear and coherent.
Level 2	3–4	A reasonable answer that covers most key points. May lack some detail or structure. Mostly correct science.
Level 1	1–2	A basic answer with limited relevant points. May contain errors. Poorly structured or incomplete.
No level	0	No relevant content.

What This Means for You

• You do not need to make exactly 6 separate points for 6 marks.
• The quality of your answer matters as much as the quantity.
• Structure and scientific vocabulary can push you from Level 2 to Level 3.
• A well-organised answer with 4 strong points can score higher than a disorganised answer with 6 weak points.

Exam Tip: Quality of written communication is assessed in 6-mark questions. Use correct spelling of scientific terms, write in complete sentences, and organise your answer logically.

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The Planning Method

Before writing your answer, spend 60–90 seconds planning. Use this four-step approach:

Step 1: Identify the Command Word

Is the question asking you to describe, explain, evaluate, or compare? This determines the type of answer required (see Lesson 2).

Step 2: Jot Down 3–5 Key Points

In the margin or on rough paper, write brief notes of the key physics points you want to include.

Step 3: Order Your Points Logically

Number your points in a logical sequence — chronological, cause-and-effect, or by category.

Step 4: Write Your Answer

Using your plan, write a structured response. Use paragraphs, connective words, and scientific vocabulary.

graph LR
    A["Read question<br/>Identify command word"] --> B["Jot 3–5<br/>key points"]
    B --> C["Order points<br/>logically"]
    C --> D["Write structured<br/>answer"]

    style A fill:#2980b9,color:#fff
    style B fill:#27ae60,color:#fff
    style C fill:#e67e22,color:#fff
    style D fill:#8e44ad,color:#fff

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Worked Example 1: Describe and Explain Terminal Velocity

Question: A skydiver jumps from a plane. Describe and explain how the forces acting on the skydiver change from the moment she jumps until she reaches terminal velocity. [6 marks]

Planning Notes

1. Initially: weight > air resistance → accelerates
2. Speed increases → air resistance increases
3. Resultant force decreases → acceleration decreases
4. Eventually: weight = air resistance → resultant force = 0 → terminal velocity

Model Answer

When the skydiver first jumps from the plane, the only significant force acting on her is her weight (the force of gravity pulling her downwards). Air resistance is very small at this point because her speed is low. The resultant force is large and acts downwards, so she accelerates.

As her speed increases, the air resistance (drag force) acting upwards on her also increases. This is because air resistance depends on speed — the faster an object moves, the greater the drag. The resultant downward force therefore decreases, which means her acceleration decreases, although she is still getting faster.

Eventually, the air resistance becomes equal to her weight. At this point, the resultant force is zero and she stops accelerating. She continues to fall at a constant velocity — this is called terminal velocity.

Exam Tip: This answer earns Level 3 because it: (1) follows a logical sequence, (2) uses correct scientific terminology (resultant force, drag, terminal velocity), (3) explains the cause-and-effect relationship between forces and motion, and (4) is well-structured with clear paragraphs.

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Worked Example 2: Evaluate Renewable vs Non-Renewable Energy Sources

Question: Evaluate the use of renewable and non-renewable energy sources for generating electricity. [6 marks]

Planning Notes

• Renewable: no fuel costs, no CO₂, but unreliable, low power, high start-up cost
• Non-renewable: reliable, high power, but CO₂ emissions, fuel will run out, pollution
• Conclusion needed

Model Answer

Renewable energy sources such as wind, solar, and hydroelectric do not produce greenhouse gas emissions during operation, which helps to reduce climate change. They use resources that will not run out, making them sustainable in the long term. However, many renewable sources are unreliable — for example, wind turbines only generate electricity when the wind blows, and solar panels are ineffective at night. They also tend to have lower power output compared to fossil fuel power stations.

Non-renewable energy sources such as coal, oil, natural gas, and nuclear fuels can generate electricity reliably and on demand, with a high power output that can meet large-scale energy needs. However, burning fossil fuels releases carbon dioxide, contributing to global warming, and also produces pollutants such as sulfur dioxide (which causes acid rain). Fossil fuels are finite resources that will eventually run out. Nuclear power does not produce CO₂ during operation but creates radioactive waste that is difficult to dispose of safely.

In conclusion, a mix of both renewable and non-renewable sources is currently needed. Renewable sources should be prioritised to reduce emissions, but non-renewable sources (particularly nuclear) are still needed to provide reliable base-load electricity until energy storage technology improves.

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Worked Example 3: Explain How a Transformer Works

Question: Explain how a step-up transformer increases the potential difference of an alternating current supply. [6 marks]

Model Answer

A step-up transformer consists of a primary coil and a secondary coil wound around a soft iron core. The secondary coil has more turns than the primary coil.

When an alternating current (AC) flows through the primary coil, it creates a changing magnetic field around the coil. The soft iron core is easily magnetised and channels this changing magnetic field through to the secondary coil.

The changing magnetic field passes through the secondary coil and induces an alternating potential difference across it. This is an example of electromagnetic induction. Because the secondary coil has more turns than the primary coil, the induced potential difference is greater than the input potential difference — the voltage has been "stepped up".

The relationship is given by: V_p / V_s = N_p / N_s, where V is the potential difference and N is the number of turns. Since N_s > N_p in a step-up transformer, V_s > V_p.