AQA GCSE Combined Science: Trilogy Physics Paper 1 (Higher), 2024: Question 1

✅ Correct answers

• Kinetic energy of the beater or food
• Internal energy / thermal energy of the surroundings, whisk or food

💡 Key knowledge

• The beater starts moving, so its kinetic energy increases.
• Some electrical energy is wasted as heat, so internal energy increases.
• The mark scheme ignores sound, so do not use sound energy here.

🧠 Exam technique

• Give two different energy stores.
• Use the exact GCSE language: kinetic and internal/thermal.
• “Energy is transferred to…” is fine, but name the store clearly for the mark.

❌ Common errors

• Writing sound energy instead of internal energy.
• Saying only “energy increases” without naming the store.
• Repeating the same store in two different words.

✅ Correct answer

power = work done / time

P = W / t

💡 Key knowledge

• Power is the rate of energy transfer or work done.
• Unit check: power is in W , work done in J , time in s .

🧠 Exam technique

• You can write the words or symbols.
• If using symbols, make sure the letter is correct: P , W , t .

📐 Calculations: step-by-step

1. Start with P = W / t
2. Substitute the values: 92 = 23 000 / t
3. Rearrange: t = 23 000 / 92
4. Calculate: t = 250 s

Final answer: 250 s

🧠 Exam technique

• Write the equation first to secure method marks.
• Show the rearrangement, not just the final number.
• Use the correct unit: s .

❌ Common calculation traps

• Using t = P / W by mistake.
• Forgetting to rearrange the equation before substituting.
• Writing the answer without units.
• Using 23 000 as 23.0 or 2300 by accident.

✅ Correct answer

P = I²R

💡 Key knowledge

• This is the standard electrical power equation for a component.
• It shows power depends on current squared and resistance.

❌ Common errors

• Choosing a wrong rearrangement, such as P = I / R .
• Mixing up this equation with V = IR .

📐 Calculations: step-by-step

1. Convert the current: 500 mA = 0.500 A
2. Use the equation: P = I²R
3. Substitute: P = 0.500² × 640
4. Calculate: P = 160 W

Final answer: 160 W

🧠 Exam technique

• Convert mA to A before calculating.
• Square the current first: 0.500² , not the resistance.
• Include units in the final answer.
• The mark scheme allows correct working even if the current is not converted, but the safest method is to convert first.

❌ Common calculation traps

• Using 500 instead of 0.500 .
• Using P = I R or P = V I incorrectly.
• Forgetting the square on the current.
• Giving the answer with no unit or the wrong unit.

✅ Correct answer

230 V

💡 Key knowledge

• The UK mains electricity supply is 230 V .
• This is the potential difference between live and neutral.

❌ Common errors

• Writing a different value from memory.
• Writing the unit incorrectly or forgetting it.

✅ Correct answer

decreases

💡 Key knowledge

• At a fixed mains potential difference, if current increases, resistance must decrease.
• This links to P = I²R : more current means more power.

🧠 Exam technique

• Read the sentence carefully and complete it with one physics word.
• The mark is for the correct direction of change.

❌ Common errors

• Writing increases.
• Trying to explain too much and accidentally contradicting the answer.

💡 What top answers did well

• Used the exact required energy stores in 01.1.
• Wrote the correct equation before working out the answer in calculations.
• Converted mA to A correctly.
• Kept units attached to final answers.

🧠 Best strategy in the exam

• For recall questions, give the standard GCSE phrasing.
• For calculations, always write the equation first.
• Check whether the question wants a value, a unit, or a completed sentence.