How to Answer Extended Response Questions in IGCSE Physics

Extended response questions are worth 6 marks and are marked using levels. Your answer must be detailed, accurate and well-organised to reach Level 3.

The levels

• Level 3 (5-6 marks): A detailed and coherent answer. All or most key points are covered. The answer follows a logical structure.
• Level 2 (3-4 marks): A reasonable answer with some correct physics. Some key points may be missing or the answer may lack structure.
• Level 1 (1-2 marks): A basic answer with limited correct physics. The answer may be disorganised or contain significant errors.

How to plan your answer

Before writing, spend 2 minutes listing the key physics points. Then arrange them in a logical order.

Structure options

Process description: Follow the time sequence. Start with the initial conditions, describe each stage, end with the final outcome.

Comparison: Use a point-by-point structure. For each aspect (e.g., cost, efficiency, environmental impact), state how each option performs.

Argument: State the claim, present evidence for and against, reach a conclusion.

Writing tips

• Use correct physics vocabulary (not everyday language).
• Be specific: “the kinetic energy of the particles increases” is better than “they have more energy.”
• Link cause to effect: “because… therefore… this means that…”
• Do not repeat the same point in different words.
• Write in full sentences, not bullet points (unless the question allows it).

Example (6 marks)

Question: Describe and explain how a hydroelectric power station generates electricity.

Level 3 answer:

Water is stored in a reservoir at height, giving it gravitational potential energy. When the sluice gate opens, water flows downhill through pipes, and its gravitational potential energy is transferred to kinetic energy. The moving water strikes the blades of a turbine, causing the turbine to rotate. The turbine is connected to a generator, which contains a coil of wire that rotates in a magnetic field (or magnets that rotate around a coil). As the coil rotates, the magnetic flux through the coil changes, inducing an EMF in the coil by electromagnetic induction. This generates an alternating current, which is transmitted to the grid through a step-up transformer that increases the voltage to reduce energy losses in the transmission cables.