AQA GCSE Physics Physics Paper 1 (Higher), June 2022: Question 11

9 marks · Standard Demand difficulty · Short Answer

Analyze hair straighteners circuits by drawing an LED symbol, explaining switch function, calculating operating time from energy and power, and explaining the effect of closing switches on power output.

Practise this question

Question

The question presents a series of sub-questions about hair straighteners containing heating elements and circuits. Part 1.1 asks to draw the circuit symbol for an LED in a provided box. Part 1.2 refers to a circuit diagram in Figure 13 showing three parallel branches with resistors and switches S1, S2, and S3, asking why the straighteners do not turn on when only switch S2 is closed. Part 1.3 asks to calculate the time taken for the hair straighteners to reach operating temperature given a power output of 120 W and energy transferred of 3.6 kJ. Part 1.4 shows Figure 14 with switch S1 closed, and asks to explain what happens to the power output of the power supply when switches S2 and S3 are also closed.
Question text

11 Figure 12 shows some hair straighteners.

Hair straighteners contain heating elements.

Figure 12

11.1 When the hair straighteners reach normal operating temperature, an LED turns on.

Draw the circuit symbol for an LED in the box.

[1 mark]

Figure 13 shows the circuit diagram for the hair straighteners.

Each resistor represents a heating element.

The power output of the hair straighteners can be changed by closing different

switches.

Figure 13

11.2 Why do the hair straighteners not turn on when only switch S2 is closed?

[1 mark]

11.3 The hair straighteners have a maximum power output of 120 W.

The energy transferred to the hair straighteners to reach normal operating

temperature is 3.6 kJ.

Calculate the time taken for the hair straighteners to reach normal operating

temperature when operating at maximum power.

Use the Physics Equations Sheet.

[4 marks]

*31* 33

Time = seconds

11.4 Figure 14 shows the hair straighteners circuit with switch S1 closed.

Figure 14

Switch S2 and switch S3 are then closed at the same time.

Explain what happens to the power output of the power supply.

[3 marks]

Mark scheme

Show the mark scheme The mark scheme provides answers for questions 11.1 through 11.4. Question 11.1 shows the standard LED symbol. Question 11.2 accepts answers stating there is a gap or S1 needs to be closed. Question 11.3 outlines the calculation steps for energy = power x time, resulting in 30 seconds. Question 11.4 accepts that total resistance decreases, current increases, and power output increases.

AO /

Question Answers Extra information Mark

Spec. Ref.

11.1 allow: 1 AO1

4.2.1.1

AO /

Spec. Ref.

11.2 there is a gap in the circuit 1 AO1

or 4.2.2

S1 needs to be closed to

complete the circuit

or

S1 needs to be closed to turn the

hair straighteners on

AO /

Spec. Ref.

11.3 E = 3600 (J) 1 AO2

4.2.4.2

3600 = 120 × t this mark may score if E is 1

incorrectly / not converted

3600 this mark may score if E is 1

t = incorrectly / not converted

t = 30 (s) allow an answer consistent with 1

their value of–E HYSICS – –

AO /

Spec. Ref.

24 11.4 the total resistance of the circuit 1 AO1

decreases 4.2.4.1

4.2.2

so the current increases 1

which increases the power 1

output

Total Question 11 9

How to answer it

GCSE Physics Study Guide: Electric Circuits & Power

What this question tests

This question assesses your knowledge of standard circuit symbols, series and parallel switching logic, rearranging energy-power equations, and explaining the electrical effects of adding parallel branches to a circuit.

Question Part 1.1

Drawing an LED Circuit Symbol

✅ Correct Answer

A diode symbol (triangle pointing right inside a circle, with a vertical line at the tip) accompanied by two outward-pointing arrows originating from the diode.

💡 Key Knowledge

Recall standard component symbols. A regular diode allows current in one direction; an LED (Light Emitting Diode) emits light when current flows, represented by the two arrows pointing diagonally away from it.

❌ Common Errors

Forgetting the arrows entirely (which just draws a standard semiconductor diode) or pointing the arrows inwards towards the diode.

🎯 1 mark available for correct recall and precision drawing of the symbol.
Question Part 1.2

Switching Logic in Circuits

✅ Correct Answer

"There is a gap in the circuit" OR "Switch S₁ needs to be closed to complete the circuit."

🧠 Exam Technique

Look at the position of the switches in Figure 13. Switch S₁ is on the main live/supply line. Even if S₂ is closed, the main loop remains incomplete because S₁ is open.

🎯 1 mark available for recognising that a complete closed loop is required for current to flow.
Question Part 1.3

Calculating Time from Energy and Power

📐 Step-by-Step Calculation

  1. Identify the formula: Energy transferred = Power × time ( E = P × t )
  2. Convert units: Energy = 3.6 kJ = 3600 J (multiply by 1000). Power = 120 W .
  3. Rearrange the equation: t = E / P
  4. Substitute and solve: t = 3600 / 120 = 30 seconds .

❌ Common Calculation Traps

Forgetting to convert kilojoules (kJ) into joules (J). Writing 3.6 instead of 3600 will throw your final answer off by a factor of a thousand!

🎯 4 marks available: 1 for correct energy conversion, 1 for correct equation substitution, 1 for correct rearrangement, and 1 for the final unit-accurate answer ( 30 s ).
Question Part 1.4

Explaining Power Changes in Parallel Branches

✅ Correct Answer

  1. The total resistance of the circuit decreases.
  2. So the current increases.
  3. Which increases the power output.

💡 Key Knowledge

Adding resistors in parallel decreases overall circuit resistance because more alternative pathways are opened up for charge to flow. Since P = I²R or P = V²/R , lowering resistance at a constant voltage increases current and power output.

🧠 Exam Technique

This is a classic 3-mark causal chain question. Make sure you link the steps logically in order: Resistance down → Current up → Power up. Do not skip intermediate links!

🎯 3 marks available (1 mark for each correct step in the logical sequence of resistance, current, and power).

Topics

Physics · 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.