AQA GCSE Physics Physics Paper 1 (Foundation), June 2025: Question 8

✅ Model Answer

• Renewable: An energy resource that is replenished as it is used (or replaced naturally). [1 mark]
• Non-renewable: An energy resource that is finite (limited supply and will eventually run out). [1 mark]

🧠 Exam Technique

• Always define both terms clearly when asked to describe the difference.
• Use the exact examiner buzzwords: "replenished as it is used" and "finite".

❌ Common Errors to Avoid

• Vague everyday phrases like "can be reused" or "recycled" — energy itself cannot be recycled!
• Saying renewable means "it will never run out" or "infinite supply" (examiners explicitly ignore this phrasing).

💡 Key Knowledge

Renewable examples: Solar, wind, tides, hydroelectric, geothermal, biomass, waves.

Non-renewable examples: Coal, crude oil, natural gas, nuclear (uranium/plutonium).

✅ Model Answer

density = mass / volume

or using standard symbols: ρ = m / V [1 mark]

🧠 Exam Technique

Make sure your letter symbols are correct: density is represented by the Greek letter rho ( ρ ), not d or p . If unsure of the symbol, write the words in full to be safe!

📐 Step-by-Step Calculation

Step 1: Identify given quantities

• Mass ( m ) = 824 000 kg
• Density ( ρ ) = 1030 kg/m³

Step 2: Substitute values into formula

1030 = 824 000 / V

Step 3: Rearrange to make V the subject

V = 824 000 / 1030

Step 4: Calculate final numerical value

V = 800 m³

❌ Common Calculation Traps

• Rearrangement errors: Incorrectly multiplying mass by density ( 824 000 × 1030 = 848 720 000 ). Remember: V = m / ρ .
• Missing substitution step: Always write the formula with numbers plugged in before rearranging. That secures your first method mark even if your final arithmetic fails!

✅ Model Answer (Give ANY TWO)

• At very low flow speeds (below ~0.25 m/s) there is no power output / output is zero. [1 mark]
• For any given flow speed (above 0.25 m/s), tidal power output is always greater than wind power output. [1 mark]
• A small change in flow speed produces a much bigger increase in tidal power than in wind power. [1 mark]
• The relationship between flow speed and power output is non-linear / increases at an increasing rate. [1 mark]
• Wind power needs a much higher flow speed to generate the same power as a tidal turbine. [1 mark]

🧠 Reading the Graph Accurately

• Look at thresholds: Both curves start at flat zero until around 0.2–0.3 m/s.
• Compare identical X values: At flow speed = 1.0 m/s, tidal generates ~15 kW, but wind generates only ~2 kW.
• Describe curve shape: The lines curve upward sharply; do not describe them as directly proportional!

💡 Structure of a Level 2 (3–4 Marks) Answer

To reach the top band, points must be identified with reasons/causes and logically linked to form a clear comparative account discussing both turbines:

• Visual Impact: Wind turbine has a 100 m diameter and towers over the landscape/house, creating significant visual pollution. In contrast, the tidal turbine (10 m) is completely submerged underwater, causing no visual impact.
• Noise Pollution: Wind turbines produce audible hums/whirring blades that disturb local residents nearby. The tidal turbine operates underwater, so sound does not travel into homes on land.
• Wildlife & Habitats: Rotating wind blades pose a collision hazard to birds and bats. Tidal turbine blades can disturb marine habitats and risk striking fish or sea mammals.
• Materials & Land Footprint: The wind turbine is 10 times larger in diameter and requires far more raw materials (concrete, steel, composite polymers) to construct than a single tidal turbine.

🧠 Examiner Insights & Marking Tips

• Use Figure 16 explicitly: Notice the scale! The wind turbine is 100 m across and taller than the house; the tidal turbine is only 10 m and under the water surface.
• Always compare directly: Use comparative words such as "whereas", "in contrast", or "compared to".
• Avoid generic statements: Writing just "wind turbines cause pollution" earns zero. You must qualify it: "visual pollution because they are visible above the landscape".