AQA GCSE Physics
AQA GCSE Physics 4.2.2 Series and Parallel Circuits Exam Questions
Free AQA GCSE Physics exam questions for 4.2.2 Series and Parallel Circuits, with a mark scheme for every pack. Covers rules for current, potential difference and resistance in series and parallel circuits, total resistance and solving circuit calculations.
4.2.2 Series and Parallel Circuits exam questions
2 question packs of real past exam questions, each with its mark scheme. Do not stop after a few: answer as many as you can without notes, then mark every answer with the mark scheme. The more questions you do, the more quickly you will spot how examiners ask about each idea.
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About AQA GCSE Physics 4.2.2 Series and Parallel Circuits
This AQA GCSE Physics section is about how current, potential difference and resistance behave when components are connected in series or in parallel. You need the rules for each type, the equation for total resistance of resistors in series, and an explanation of why adding resistors in parallel lowers the total resistance. It is examined on Paper 1 and builds on V = I R from 4.2.1. Examiners often give a circuit diagram with some meter readings and ask you to find the missing values in several steps.
What you need to know
- Series circuits The current is the same through each component. The total potential difference of the supply is shared between the components.
- Series resistance The total resistance of two components in series is the sum of the resistance of each: R total = R1 + R2.
- Parallel circuits The potential difference across each branch is the same as the supply. The total current through the whole circuit is the sum of the currents through the separate branches.
- Parallel resistance The total resistance of two resistors in parallel is less than the resistance of the smallest individual resistor. You must explain this qualitatively: adding a branch gives charge another path, so total current increases for the same p.d. You do not need to calculate it.
- Solving circuits Use V = I R for individual components and for the whole circuit, applying the series and parallel rules to find unknown values step by step.
Common mistakes in 4.2.2 Series and Parallel Circuits
- Saying current is shared in a series circuit. Current is the same everywhere in series; potential difference is shared.
- Adding resistances in parallel as if they were in series. In parallel the total resistance is less than the smallest resistor.
- Using the supply p.d. with a single resistor's resistance in a series circuit. Use the p.d. across that component, or the total resistance with the supply p.d.
- Explaining lower parallel resistance with 'there is more space'. Say the extra branch provides another path, so total current increases for the same potential difference.
Try three 4.2.2 Series and Parallel Circuits exam-style questions
1. A 4.0 Ω and a 8.0 Ω resistor are connected in series to a 6.0 V battery. Calculate the current and the potential difference across the 8.0 Ω resistor. (4 marks)
Show the mark scheme answer
R total = 12 Ω; I = 6.0 / 12 = 0.50 A; V = I R = 0.50 x 8.0; = 4.0 V.
2. Two lamps are connected in parallel to a 12 V supply. The currents through the lamps are 0.4 A and 0.6 A. State the reading on an ammeter in the main circuit and the p.d. across each lamp. (2 marks)
Show the mark scheme answer
1.0 A; 12 V across each lamp.
3. Explain why adding a resistor in parallel with another resistor decreases the total resistance of the circuit. (2 marks)
Show the mark scheme answer
The extra branch provides another path for the charge (current); so the total current from the supply increases for the same potential difference, meaning total resistance decreases.
4.2.2 Series and Parallel Circuits FAQs
What does AQA GCSE Physics 4.2.2 Series and parallel circuits cover?
It covers the rules for current, potential difference and resistance in series and parallel circuits and using them with V = I R to solve circuit problems.
Do I need to calculate resistance in parallel?
No. At GCSE you only calculate total resistance for series circuits (R1 + R2) and explain why parallel resistance is lower than the smallest individual resistor.
How do I remember the rules?
Series: same current, shared p.d., resistances add. Parallel: same p.d., currents add, total resistance goes down. Practise multi-step questions where you apply both.
