Series and parallel circuits
4.3.2What the syllabus asks of you
- Recall and use in calculations, the fact that: (a) the current at every point in a series circuit is the same (b) the sum of the currents entering a junction in a parallel circuit is equal to the sum of the currents that leave the junction (c) the total p.d. across the components in a series circuit is equal to the sum of the individual p.d.s across each component (d) the p.d. across an arrangement of parallel resistances is the same as the p.d. across one branch in the arrangement of the parallel resistances
- Calculate the combined resistance of two or more resistors in series
- Calculate the combined resistance of two resistors in parallel
- Calculate current, voltage and resistance in parts of a circuit or in the whole circuit
Read the notes first
Chapter 4: Series and parallel circuits
Drill this topic
Every question on Series and parallel circuits, untimed, marked as you go.
Make a worksheet
Choose the years and how many questions, then print it with the answers on separate pages.
35 questions
1May / June 2026 · Paper 11 · Q33Show mark scheme →
Areading $I_1$/A = 3.0; reading $I_2$/A = 3.0
Breading $I_1$/A = 3.0; reading $I_2$/A = 9.0
Creading $I_1$/A = 6.0; reading $I_2$/A = 3.0
Dreading $I_1$/A = 9.0; reading $I_2$/A = 12.0
Mark scheme
2May / June 2026 · Paper 11 · Q34Show mark scheme →
A2.0 V
B3.3 V
C5.0 V
D8.0 V
Mark scheme
3May / June 2026 · Paper 12 · Q32Show mark scheme →
AX closed, Y closed, Z closed
BX closed, Y closed, Z open
CX open, Y closed, Z closed
DX open, Y open, Z closed
Mark scheme
4Oct / Nov 2025 · Paper 11 · Q29Show mark scheme →
Acircuit A
Bcircuit B
Ccircuit C
Dcircuit D
Mark scheme
5Oct / Nov 2025 · Paper 12 · Q33Show mark scheme →
Aa 0.75 Ω resistor and a 6.0 Ω resistor in parallel
Ba 0.75 Ω resistor and a 6.0 Ω resistor in series
Ca 20 Ω resistor and a 30 Ω resistor in parallel
Da 20 Ω resistor and a 30 Ω resistor in series
Mark scheme
6Oct / Nov 2025 · Paper 12 · Q34Show mark scheme →
AIt increases from 0 to $\frac{1}{3}E$.
BIt increases from 0 to $\frac{1}{2}E$.
CIt increases from 0 to $\frac{2}{3}E$.
DIt increases from 0 to $E$.
Mark scheme
7May / June 2025 · Paper 11 · Q31Show mark scheme →
A2.0 Ω
B4.0 Ω
C9.0 Ω
D18 Ω
Mark scheme
8May / June 2025 · Paper 12 · Q29Show mark scheme →
A1.0 V
B3.0 V
C4.5 V
D6.0 V
Mark scheme
9Oct / Nov 2024 · Paper 11 · Q34Show mark scheme →
AI0 is equal to I1; V0 is equal to V2
BI0 is equal to I2; V0 is equal to the sum of V1 and V2
CI0 is equal to the sum of I1 and I2; V0 is equal to V1
DI0 is equal to the sum of I1 and I2; V0 is equal to the sum of V1 and V2
Mark scheme
10Oct / Nov 2024 · Paper 12 · Q28Show mark scheme →
A\frac{E}{4R} \quad \frac{E}{4R} \quad \frac{E}{4R} \quad \frac{E}{4R}
B\frac{E}{4R} \quad \frac{E}{3R} \quad \frac{E}{2R} \quad \frac{E}{R}
C\frac{E}{R} \quad \frac{E}{2R} \quad \frac{E}{3R} \quad \frac{E}{4R}
D\frac{E}{R} \quad \frac{E}{R} \quad \frac{E}{R} \quad \frac{E}{R}
Mark scheme
11May / June 2024 · Paper 12 · Q29Show mark scheme →
A1, 2, 3 and 5
B1, 2, 4 and 5
C1, 3, 4 and 5
D2, 3, 4 and 5
Mark scheme
12Oct / Nov 2023 · Paper 11 · Q26Show mark scheme →
Aresistance of circuit P: R, resistance of circuit Q: R/2
Bresistance of circuit P: R, resistance of circuit Q: 2R
Cresistance of circuit P: 2R, resistance of circuit Q: R/2
Dresistance of circuit P: 2R, resistance of circuit Q: 2R
Mark scheme
13Oct / Nov 2023 · Paper 12 · Q34Show mark scheme →
A0.25
B0.50
C2.0
D4.0
Mark scheme
14May / June 2023 · Paper 12 · Q29Show mark scheme →
Aminimum resistance / Ω: 5.0; maximum resistance / Ω: 15
Bminimum resistance / Ω: 5.0; maximum resistance / Ω: 45
Cminimum resistance / Ω: 15; maximum resistance / Ω: 30
Dminimum resistance / Ω: 15; maximum resistance / Ω: 45
Mark scheme
15Oct / Nov 2022 · Paper 11 · Q29Show mark scheme →
Acircuit diagram A
Bcircuit diagram B
Ccircuit diagram C
Dcircuit diagram D
Mark scheme
16Oct / Nov 2022 · Paper 11 · Q30Show mark scheme →
AThe current in the lamp increases.
BThe current in the variable resistor decreases.
CThe e.m.f. of the battery decreases.
DThe total resistance in the circuit increases.
Mark scheme
17Oct / Nov 2022 · Paper 11 · Q31Show mark scheme →
ACircuit A
BCircuit B
CCircuit C
DCircuit D
Mark scheme
18May / June 2022 · Paper 11 · Q34Show mark scheme →
ACircuit A
BCircuit B
CCircuit C
DCircuit D
Mark scheme
19May / June 2022 · Paper 12 · Q34Show mark scheme →
A
B
C
D
Mark scheme
20May / June 2022 · Paper 12 · Q36Show mark scheme →
AL1 only
BL3 only
CL1 and L2 only
DL1, L2 and L3
Mark scheme
21Oct / Nov 2021 · Paper 11 · Q31Show mark scheme →
APQ
BPR
CQS
DRS
Mark scheme
22May / June 2021 · Paper 12 · Q32Show mark scheme →
A0–1 mA
B0–10 mA
C0–1.0 A
D0–10 A
Mark scheme
23Oct / Nov 2020 · Paper 11 · Q35Show mark scheme →
A2.0 V
B5.0 V
C6.0 V
D8.0 V
Mark scheme
24Oct / Nov 2020 · Paper 11 · Q36Show mark scheme →
A1.0 Ω
B4.0 Ω
C8.0 Ω
D16 Ω
Mark scheme
25Oct / Nov 2020 · Paper 12 · Q31Also set in Oct / Nov 2020 Paper 11Show mark scheme →
AI1 = I2 = I3
BI1 > I2 and I2 = I3
CI1 > I3 > I2
DI1 > I2 > I3
Mark scheme
26May / June 2020 · Paper 12 · Q38Show mark scheme →
Areading on ammeter X decreases, reading on ammeter Y decreases
Breading on ammeter X decreases, reading on ammeter Y increases
Creading on ammeter X increases, reading on ammeter Y decreases
Dreading on ammeter X increases, reading on ammeter Y increases
Mark scheme
27Oct / Nov 2019 · Paper 12 · Q33Also set in Oct / Nov 2019 Paper 11, Oct / Nov 2016 Paper 12Show mark scheme →
AThe current is the same in all resistors connected in parallel.
BThe current is the same in all resistors connected in series.
CThe voltage across each resistor is different for all resistors connected in parallel.
DThe voltage across each resistor is the same for all resistors connected in series.
Mark scheme
28Oct / Nov 2019 · Paper 12 · Q34Also set in Oct / Nov 2019 Paper 11Show mark scheme →
A2 Ω in parallel with 4 Ω in parallel with 4 Ω
B2 Ω in parallel with 4 Ω, in series with 4 Ω
C4 Ω in parallel with 4 Ω, in series with 2 Ω
D2 Ω in series with 4 Ω in series with 4 Ω
Mark scheme
29May / June 2019 · Paper 12 · Q33Show mark scheme →
AThe lamps are dimmer and the motor rotates more quickly.
BThe lamps are dimmer and the motor rotates more slowly.
CThe lamps have the same brightness and the motor rotates more quickly.
DThe lamps have the same brightness and the motor rotates more slowly.
Mark scheme
30May / June 2019 · Paper 12 · Q38Also set in May / June 2019 Paper 11Show mark scheme →
Athe voltage supplied to lamp Y decreases; the power supplied to lamp Y decreases
Bthe voltage supplied to lamp Y decreases; the power supplied to lamp Y stays the same
Cthe voltage supplied to lamp Y increases; the power supplied to lamp Y increases
Dthe voltage supplied to lamp Y increases; the power supplied to lamp Y stays the same
Mark scheme
31Oct / Nov 2018 · Paper 11 · Q30Show mark scheme →
Areading on P / V: 4.0, e.m.f. of cell / V: 8.0
Breading on P / V: 4.0, e.m.f. of cell / V: 12
Creading on P / V: 8.0, e.m.f. of cell / V: 8.0
Dreading on P / V: 8.0, e.m.f. of cell / V: 12
Mark scheme
32Oct / Nov 2018 · Paper 12 · Q30Show mark scheme →
A7.0 Ω
B9.0 Ω
C12 Ω
D16 Ω
Mark scheme
33Oct / Nov 2017 · Paper 12 · Q29Show mark scheme →
Areading on voltmeter 2 / V: 2.0; reading on voltmeter 3 / V: 4.0
Breading on voltmeter 2 / V: 2.0; reading on voltmeter 3 / V: 8.0
Creading on voltmeter 2 / V: 4.0; reading on voltmeter 3 / V: 4.0
Dreading on voltmeter 2 / V: 4.0; reading on voltmeter 3 / V: 8.0
Mark scheme
34May / June 2016 · Paper 11 · Q31Show mark scheme →
ACircuit A
BCircuit B
CCircuit C
DCircuit D
Mark scheme
35May / June 2016 · Paper 12 · Q29Show mark scheme →
A
B
C
D
Mark scheme