AQA GCSE Combined Science: Trilogy Physics Paper 1 (Foundation), 2024: Question 1
11 marks · Low Demand difficulty · Short Answer
Analyze a series circuit to determine current, potential difference, power, resistance, and charge flow, and explain the effects of temperature and circuit breaks.
Practise this questionQuestion
Question text
01 Figure 1 shows a circuit diagram. The circuit contains a battery and two lamps,
X and Y.
Figure 1
01.1 How does the current in lamp X compare with the current in lamp Y?
[1 mark]
Tick ( ) one box.
The current in lamp X is smaller.
The current in both lamps is the same.
The current in lamp X is greater.
01.2 Lamp X and lamp Y are not identical.
The potential difference across the battery is 4.5 V.
The potential difference across lamp X is 1.5 V.
Calculate the potential difference across lamp Y.
[1 mark]
Potential difference across lamp Y = V
The current in lamp X is 1.2 A.
The potential difference across lamp X is 1.5 V.
01.3 Calculate the power of lamp X.
Use the equation:
power = potential difference × current
[2 marks]
Power = W
01.4 Calculate the resistance of lamp X.
Use the equation:
potential difference
resistance =
current
[2 marks]
4 Resistance = Ω
01.5 The current in lamp X is 1.2 A.
Calculate the charge flow through lamp X in 40 seconds.
Use the equation:
charge flow = current × time
[2 marks]
Charge flow = C
01.6 The switch can be used to turn the lamps on and off.
Immediately after the lamps are switched on, the resistance of each lamp increases.
Why does the resistance of each lamp increase?
[1 mark]
Tick ( ) one box.
The current in the battery decreases.
The potential difference across each lamp decreases.
The power of the battery increases.
The temperature of each lamp increases.5
Figure 1 is repeated below.
Figure 1
01.7 Lamp Y breaks.
What happens to lamp X?
Give a reason for your answer.
[2 marks]
Tick ( ) one box.
Lamp X gets brighter.
Lamp X stays the same brightness.
Lamp X no longer emits light.
Reason
Mark scheme
Show the mark scheme
Question 1
AO /
Question Answers Extra information Mark
Spec. Ref.
01.1 the current in both lamps is the 1 AO1
same 6.2.2
AO /
Spec. Ref.
01.2 (4.5 – 1.5 =) 3 (V) allow (4.5 – 1.5 =) 3.0 (V) 1 AO2
6.2.2
AO /
Spec. Ref.
01.3 P = 1.5 × 1.2 1 AO2
6.2.4.1
1.8 (W) 1
AO /
Spec. Ref.
01.4 1.5 1 AO2
R =
1.2 6.2.1.3
1.25 (Ω) allow 1.3 (Ω) 1
AO /
Spec. Ref.
01.5 Q = 1.2 × 40 1 AO2
6.2.1.2
48 (C) 1
AO /
Spec. Ref.
01.6 the temperature of each lamp 1 AO1
increases – – – 6.2.1.4
AO / 7
Spec. Ref.
01.7 lamp X no longer emits light 1 AO3
6.2.2
because the circuit is no longer dependent on MP1 1
complete
allow because there is no
current
Total Question 1 11
How to answer it
Series Circuits and Electrical Calculations
What this question tests
This question assesses your understanding of series circuits. You need to recall the rules for current and potential difference in a single loop, perform basic calculations using provided equations (Power, Resistance, and Charge), and explain how temperature affects resistance in a filament lamp.
Current in a Series Circuit
Key Knowledge
In a series circuit (a single loop), the current is the same at any point. It does not get "used up" as it goes through components.
Correct Answer
Tick: The current in both lamps is the same.
Potential Difference in Series
Key Knowledge
In a series circuit, the total potential difference (voltage) of the power supply is shared between the components.
Calculation
Total PD = PD across X + PD across Y
4.5 V = 1.5 V + PD across Y
4.5 - 1.5 = 3.0 V
Power and Resistance Calculations
Using Lamp X data: Current = 1.2 A, PD = 1.5 V
01.3 Calculate Power
1. Power = PD × Current
2. Power = 1.5 × 1.2
3. Power = 1.8 W
01.4 Calculate Resistance
1. Resistance = PD / Current
2. Resistance = 1.5 / 1.2
3. Resistance = 1.25 Ω (or 1.3 Ω)
Exam Technique: Substitution
Even if you find the math easy, always show the substitution (the numbers you put into the equation). If you make a calculator error but show the correct numbers, you still get 1 mark!
Charge Flow
Step-by-Step
1. Charge flow = current × time
2. Q = 1.2 A × 40 s
3. Q = 48 C
Common Trap
Always check the time unit. Here it is in seconds, which is correct. If it were in minutes, you would have to multiply by 60 first!
Resistance and Temperature
Key Knowledge
As current flows through a lamp filament, it gets hot. The atoms in the metal vibrate more, making it harder for electrons to flow through.
Correct Answer
Tick: The temperature of each lamp increases.
Circuit Failure
Examiner Insight
This is a two-part answer. The "Reason" mark is dependent on the first mark. If you get the observation wrong, you cannot get the reason mark.
Correct Answer
Observation: Lamp X no longer emits light.
Reason: The circuit is no longer complete (or there is no current).
Common Error
Students often think the other bulb stays on or gets brighter. This only happens in parallel circuits. In series, if one component breaks, the whole loop is broken and everything stops working.
Topics
Physics · P2: Electricity
Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Physics Paper 1 (Foundation), 2024. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.