AQA GCSE Physics Physics Paper 1 (Higher), June 2022: Question 3
8 marks · Standard Demand difficulty · Short Answer
Recall power equations relating current, potential difference, and efficiency, and calculate current and useful power output in energy transfer contexts
Practise this questionQuestion
Question text
03 An engineering company has invented pavement tiles that generate electricity as
people walk on them.
Figure 3 shows someone walking on the pavement tiles.
Figure 3
Use the Physics Equations Sheet to answer questions 03.1 and 03.2.
03.1 What equation links current (I), potential difference (V) and power (P)?
[1 mark]
Tick ( ) one box.
V
P =
I
P = V × I
I = P × V
V = I × P 9
03.2 When a person walks on a tile, a potential difference of 40 V is induced across the tile.
The power output of the tile is 4.4 W.
Calculate the current in the tile.
[3 marks]
Current = A
Use the Physics Equations Sheet to answer questions 03.3 and 03.4.
03.3 What equation links efficiency, total power input and useful power output?
[1 mark]
Tick ( ) one box.
useful power output
Efficiency =
total power input
total power input
Efficiency =
useful power output
Efficiency = useful power output × total power input
03.4 The tiles are used to power LED lights in the pavement.
An LED light has a total power input of 4.0 W.
The efficiency of the LED light is 0.85
Calculate the useful power output of the LED light.
[3 marks]
Useful power output = W
Mark scheme
Show the mark scheme
AO /
Question Answers Extra information Mark
Spec. Ref.
03.1 P = V × I 1 AO1
4.2.4.1
AO /
Spec. Ref.
03.2 4.4 = 40 × I 1 AO2
4.2.4.1
4.4 1
I =
I = 0.11 (A) 1
AO /
Spec. Ref.
03.3 useful power output 1 AO1
efficiency = 4.1.2.2
total power input
AO /
Spec. Ref.
03.4 P AO2
0.85 = 1 4.1.2.2
4.0
P = 0.85 × 4.0 1
P = 3.4 (W) 1
– HYSICS – –
Total Question 3 8
Question 4
How to answer it
Electricity Generating Pavement Tiles Study Guide
What this question tests
This question tests your recall of standard physics equations (power, current, potential difference, and efficiency), your ability to rearrange these formulas, and your skill in substituting numerical values to calculate unknown quantities with correct units.
Power, Current, and Potential Difference Equation
✅ Correct Answer
Tick the box for: P = V × I
💡 Key Knowledge
- P = Power measured in watts (W)
- V = Potential difference measured in volts (V)
- I = Current measured in amperes (A)
Calculating Current from Power and Potential Difference
📐 Step-by-Step Calculation
- State the formula: P = V × I
- Substitute the values: 4.4 = 40 × I
- Rearrange and solve: I = 4.4 / 40
- Final Answer: I = 0.11 A
❌ Common Errors
- Dividing potential difference by power (40 / 4.4) instead of power by potential difference.
- Forgetting to include the unit (A) in the final answer line, though the mark scheme accepts the numerical value if the unit is pre-printed.
Efficiency Equation
✅ Correct Answer
Tick the box for: Efficiency = useful power output / total power input
🧠 Exam Technique
Remember that efficiency is a ratio of "what you want" (useful output) divided by "what you paid for/put in" (total input). Efficiency can never be greater than 1 (or 100%), so the larger number (total input) must always be on the bottom!
Calculating Useful Power Output
📐 Step-by-Step Calculation
- State the formula: Efficiency = useful power output / total power input
- Substitute the values: 0.85 = P / 4.0
- Rearrange: P = 0.85 × 4.0
- Final Answer: P = 3.4 W
🧠 Exam Technique
Always show your working out line by line. Even if you make a calculator slip on the final multiplication, showing the correct substitution ( 0.85 = P / 4.0 ) often secures method marks.
Topics
Physics · P1: Energy · P2: Electricity
Question and mark scheme from the AQA GCSE Physics examination, Physics Paper 1 (Higher), June 2022. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.