Practical circuits
10.1What the syllabus asks of you
- recall and use the circuit symbols shown in section 6 of this syllabus
- draw and interpret circuit diagrams containing the circuit symbols shown in section 6 of this syllabus
- define and use the electromotive force (e.m.f.) of a source as energy transferred per unit charge in driving charge around a complete circuit
- distinguish between e.m.f. and potential difference (p.d.) in terms of energy considerations
- understand the effects of the internal resistance of a source of e.m.f. on the terminal potential difference
Read the notes first
Chapter 10: Practical circuits
Drill this topic
Every question on Practical 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.
87 questions
1May / June 2026 · Paper 12 · Q34Show mark scheme →
AIt is the energy transferred per unit charge in driving charge through a connecting wire.
BIt is the energy transferred per unit charge in driving charge through the complete circuit.
CIt is the energy transferred per unit charge in driving charge through the external resistor.
DIt is the energy transferred per unit charge in driving charge through the internal resistance.
Mark scheme
2May / June 2026 · Paper 12 · Q35Show mark scheme →
A6.0 V
B9.0 V
C12 V
D24 V
Mark scheme
3May / June 2026 · Paper 13 · Q37Show mark scheme →
Agalvanometer
Bgenerator
Cmicrophone
Doscilloscope
Mark scheme
4May / June 2026 · Paper 14 · Q36Show mark scheme →
AThe difference between the electromotive force (e.m.f.) and the terminal p.d. of the power supply is equal to the total energy dissipated inside the power supply due to its internal resistance.
BThe terminal p.d. of the power supply is equal to the e.m.f. when there is no current in the supply.
CThe terminal p.d. of the power supply is the energy transferred in moving a unit charge around the complete circuit.
DThe terminal p.d. of the power supply is always more than the e.m.f. due to the internal resistance of the supply.
Mark scheme
5Oct / Nov 2025 · Paper 11 · Q35Show mark scheme →
Adecreases / decreases
Bdecreases / increases
Cincreases / decreases
Dincreases / increases
Mark scheme
6Oct / Nov 2025 · Paper 12 · Q34Show mark scheme →
AThe energy dissipated in the external circuit is EQ.
BThe energy dissipated within the cell is EQ.
CThe external resistance is EQ.
DThe total energy dissipated in the cell and the external circuit is EQ.
Mark scheme
7Oct / Nov 2025 · Paper 13 · Q35Show mark scheme →
Adecreases / decreases
Bdecreases / increases
Cincreases / decreases
Dincreases / increases
Mark scheme
8Oct / Nov 2025 · Paper 14 · Q33Show mark scheme →
ACircuit with ammeter in series with parallel combination of fixed resistor and LDR (LDR symbol with arrows)
BCircuit with ammeter in series with parallel combination of fixed resistor and thermistor
CCircuit with ammeter in series with parallel combination of fixed resistor and thermistor (ammeter in different position)
DCircuit with ammeter in series with parallel combination of fixed resistor and LDR (ammeter in different position)
Mark scheme
9Oct / Nov 2025 · Paper 14 · Q37Show mark scheme →
Acurrent in battery: increases; reading on voltmeter: decreases
Bcurrent in battery: increases; reading on voltmeter: remains the same
Ccurrent in battery: remains the same; reading on voltmeter: decreases
Dcurrent in battery: remains the same; reading on voltmeter: remains the same
Mark scheme
10May / June 2025 · Paper 11 · Q37Show mark scheme →
A0.050 Ω
B1.6 Ω
C20 Ω
D23 Ω
Mark scheme
11May / June 2025 · Paper 12 · Q35Show mark scheme →
Acurrent 0.50I₁, terminal p.d. 1.0V₁
Bcurrent 0.50I₁, terminal p.d. 1.2V₁
Ccurrent 0.60I₁, terminal p.d. 1.0V₁
Dcurrent 0.60I₁, terminal p.d. 1.2V₁
Mark scheme
12May / June 2025 · Paper 13 · Q36Show mark scheme →
AThe e.m.f. E decreases.
BThe internal resistance r increases.
CThe p.d. across r increases.
DThe resistance of the variable resistor increases.
Mark scheme
13Feb / March 2025 · Paper 12 · Q34Show mark scheme →
ASymbol A: microphone symbol
BSymbol B: battery symbol
CSymbol C: loudspeaker symbol
DSymbol D: loudspeaker symbol
Mark scheme
14Feb / March 2025 · Paper 12 · Q36Show mark scheme →
AV increases because there is a p.d. across R.
BV decreases because there is a p.d. across r.
CV remains the same because the decrease of p.d. across r is balanced by the increase of p.d. across R.
DV remains the same because the sum of the p.d.s across r and R is still equal to E.
Mark scheme
15Oct / Nov 2024 · Paper 11 · Q34Show mark scheme →
Athe charge moving through the cell per unit time
Bthe energy transferred to the fixed resistor per unit charge
Cthe intensity of the light incident on the LDR
Dthe terminal potential difference across the cell
Mark scheme
16Oct / Nov 2024 · Paper 11 · Q35Show mark scheme →
Adecreases decreases
Bdecreases increases
Cno change decreases
Dno change increases
Mark scheme
17Oct / Nov 2024 · Paper 12 · Q37Show mark scheme →
A0.04 Ω
B0.20 Ω
C0.39 Ω
D0.77 Ω
Mark scheme
18Oct / Nov 2024 · Paper 13 · Q36Show mark scheme →
AElectromotive force is the energy transferred per unit charge.
BEnergy is transferred from chemical potential energy in the cell to other forms when the switch is closed.
CThe electromotive force of the cell is greater than the terminal potential difference when the switch is closed.
DWhen the switch is open, the voltmeter measures the electromotive force of the cell.
Mark scheme
19Oct / Nov 2024 · Paper 13 · Q37Show mark scheme →
A\frac{E - 4.0}{1.6}
B\frac{E - 4.0}{0.80}
C\frac{E - 2.0}{1.6}
D\frac{E - 2.0}{0.80}
Mark scheme
20May / June 2024 · Paper 11 · Q35Show mark scheme →
Acurrent I decreases, terminal p.d. across cell decreases
Bcurrent I decreases, terminal p.d. across cell increases
Ccurrent I increases, terminal p.d. across cell decreases
Dcurrent I increases, terminal p.d. across cell increases
Mark scheme
21May / June 2024 · Paper 13 · Q35Show mark scheme →
AI1 decreases, I2 decreases
BI1 decreases, I2 stays the same
CI1 increases, I2 decreases
DI1 increases, I2 stays the same
Mark scheme
22Feb / March 2024 · Paper 12 · Q32Show mark scheme →
Ap.d. = W/q, e.m.f. = W/q
Bp.d. = W/q, e.m.f. = Wq
Cp.d. = Wq, e.m.f. = W/q
Dp.d. = Wq, e.m.f. = Wq
Mark scheme
23Feb / March 2024 · Paper 12 · Q35Show mark scheme →
AV decreases, I decreases
BV decreases, I increases
CV increases, I decreases
DV increases, I increases
Mark scheme
24Oct / Nov 2023 · Paper 11 · Q34Show mark scheme →
AThe e.m.f. is the energy converted from electrical to other forms in the cell.
BThe e.m.f. is the energy provided by the cell per unit charge passing through it.
CThe e.m.f. is the potential difference across the internal resistance of the cell.
DThe e.m.f. is the potential difference across the terminals of the cell.
Mark scheme
25Oct / Nov 2023 · Paper 11 · Q36Show mark scheme →
AE – Ir = IR
BE = Ir – IR
CE + Ir = IR
DE = IR
Mark scheme
26Oct / Nov 2023 · Paper 12 · Q34Show mark scheme →
AThe e.m.f. across each resistor equals the potential difference across the battery.
BThe potential difference across each resistor equals the e.m.f. E of the battery.
CThe sum of the e.m.f.s across the resistors equals the potential difference across the battery.
DThe sum of the potential differences across the resistors equals the e.m.f. E of the battery.
Mark scheme
27Oct / Nov 2023 · Paper 13 · Q34Show mark scheme →
AGraph of V/V against I/A: straight line from (0, 0.50) to (6.0, 0)
BGraph of V/V against I/A: straight line from (0, 3.0) to (0.5, 0)
CGraph of V/V against I/A: straight line from (0, 3.0) to (6.0, 0)
DGraph of V/V against I/A: straight line from (0, 6.0) to (3.0, 0)
Mark scheme
28May / June 2023 · Paper 11 · Q34Show mark scheme →
Acircuit symbol A
Bcircuit symbol B
Ccircuit symbol C
Dcircuit symbol D
Mark scheme
29May / June 2023 · Paper 11 · Q35Show mark scheme →
Aammeter reading decreases, voltmeter reading decreases
Bammeter reading decreases, voltmeter reading stays the same
Cammeter reading stays the same, voltmeter reading decreases
Dammeter reading stays the same, voltmeter reading stays the same
Mark scheme
30May / June 2023 · Paper 12 · Q34Show mark scheme →
Alamp 1 off; lamp 2 off
Blamp 1 on; lamp 2 off
Clamp 1 off; lamp 2 on
Dlamp 1 on; lamp 2 on
Mark scheme
31May / June 2023 · Paper 13 · Q34Show mark scheme →
Avoltmeter reading decreases, ammeter reading increases
Bvoltmeter reading decreases, ammeter reading decreases
Cvoltmeter reading increases, ammeter reading increases
Dvoltmeter reading increases, ammeter reading decreases
Mark scheme
32Feb / March 2023 · Paper 12 · Q34Show mark scheme →
AThe terminal p.d. is decreased because more work is done moving unit charge through the internal resistance of the cell.
BThe terminal p.d. is decreased because the current in the variable resistor is decreased.
CThe terminal p.d. is increased because more work is done moving unit charge through the variable resistor.
DThe terminal p.d. is increased because the current in the variable resistor is increased.
Mark scheme
33Feb / March 2023 · Paper 12 · Q36Show mark scheme →
Ar = 3.0 Ω, R = 14 Ω
Br = 3.0 Ω, R = 20 Ω
Cr = 5.8 Ω, R = 14 Ω
Dr = 5.8 Ω, R = 20 Ω
Mark scheme
34Oct / Nov 2022 · Paper 11 · Q35Show mark scheme →
Acharge per unit energy transferred
Bcharge per unit time
Cenergy transferred per unit charge
Denergy transferred per unit time
Mark scheme
35Oct / Nov 2022 · Paper 12 · Q35Show mark scheme →
A0.22 W
B0.43 W
C0.64 W
D1.0 W
Mark scheme
36Oct / Nov 2022 · Paper 13 · Q31Show mark scheme →
Aenergy / J: 30, e.m.f. / V: 2.5
Benergy / J: 30, e.m.f. / V: 7.5
Cenergy / J: 24, e.m.f. / V: 10.0
Denergy / J: 24, e.m.f. / V: 12.5
Mark scheme
37Oct / Nov 2022 · Paper 13 · Q34Show mark scheme →
A0.244 Ω
B0.250 Ω
C10.8 Ω
D11.3 Ω
Mark scheme
38May / June 2022 · Paper 11 · Q35Show mark scheme →
A0.5 V
B2 V
C3 V
D6 V
Mark scheme
39May / June 2022 · Paper 12 · Q35Show mark scheme →
Aa decrease in the charge of each charge carrier
Ba decrease in the potential difference measured across the cell
Can increase in the energy dissipated per unit time in the fixed resistor
Dan increase in the number of charge carriers leaving the cell per unit time
Mark scheme
40May / June 2022 · Paper 13 · Q36Show mark scheme →
Abuzzer
Belectric bell
Cloudspeaker
Dmicrophone
Mark scheme
41Feb / March 2022 · Paper 12 · Q33Show mark scheme →
A8 V
B9 V
C12 V
D15 V
Mark scheme
42Feb / March 2022 · Paper 12 · Q34Show mark scheme →
Agraph A
Bgraph B
Cgraph C
Dgraph D
Mark scheme
43Oct / Nov 2021 · Paper 11 · Q33Show mark scheme →
A3.0 V
B6.0 V
C9.0 V
D15 V
Mark scheme
44Oct / Nov 2021 · Paper 11 · Q36Show mark scheme →
Asymbol A
Bsymbol B
Csymbol C
Dsymbol D
Mark scheme
45Oct / Nov 2021 · Paper 11 · Q37Show mark scheme →
A0
B$E$
C$2E$
D$3E$
Mark scheme
46Oct / Nov 2021 · Paper 12 · Q34Show mark scheme →
AThe current in the circuit increases.
BThe potential difference across the load resistor increases.
CThe power dissipated in the internal resistance of the battery increases.
DThe total power dissipated in the circuit increases.
Mark scheme
47Oct / Nov 2021 · Paper 12 · Q36Show mark scheme →
AThe e.m.f. is the energy transferred from chemical energy to electrical energy in the cell and the p.d. is the energy transferred from electrical energy to thermal energy in the resistor.
BThe p.d. is the energy transferred from chemical energy to electrical energy in the cell and the e.m.f. is the energy transferred from electrical energy to thermal energy in the resistor.
CThe e.m.f. is the energy transferred per unit charge from chemical energy to electrical energy in the cell and the p.d. is the energy transferred per unit charge from electrical energy to thermal energy in the resistor.
DThe p.d. is the energy transferred per unit charge from chemical energy to electrical energy in the cell and the e.m.f. is the energy transferred per unit charge from electrical energy to thermal energy in the resistor.
Mark scheme
48Oct / Nov 2021 · Paper 13 · Q34Show mark scheme →
A0.5P
BP
C2P
D4P
Mark scheme
49May / June 2021 · Paper 11 · Q35Show mark scheme →
A1 coulomb of charge always dissipates 6 J of energy in the internal resistance of the cell.
B1 electron gains 6 J of energy when passing through the cell.
CThere is a potential difference of 6 V applied across any external circuit connected to the cell.
DWhen 1 coulomb of charge passes through the cell, 6 J of chemical energy is transformed.
Mark scheme
50May / June 2021 · Paper 12 · Q36Show mark scheme →
AThe voltmeter reading decreases because the current through the cell decreases.
BThe voltmeter reading decreases because the current through the cell increases.
CThe voltmeter reading increases because the current through the cell decreases.
DThe voltmeter reading increases because the current through the cell increases.
Mark scheme
51May / June 2021 · Paper 13 · Q34Show mark scheme →
AEach coulomb of charge from the battery supplies 9.0 J of electrical energy to the whole circuit.
BThe battery supplies 9.0 J of electrical energy to an external circuit for each coulomb of charge.
CThe potential difference across any component connected to the battery will be 9.0 V.
DThere will always be a potential difference of 9.0 V across the battery terminals.
Mark scheme
52May / June 2021 · Paper 13 · Q36Show mark scheme →
Aammeter reading decreases, voltmeter reading decreases
Bammeter reading decreases, voltmeter reading stays the same
Cammeter reading increases, voltmeter reading decreases
Dammeter reading increases, voltmeter reading stays the same
Mark scheme
53Feb / March 2021 · Paper 12 · Q36Show mark scheme →
A1.0 Ω
B2.0 Ω
C4.0 Ω
D8.0 Ω
Mark scheme
54Oct / Nov 2020 · Paper 12 · Q36Show mark scheme →
A0 V
B4 V
C8 V
D12 V
Mark scheme
55Oct / Nov 2020 · Paper 13 · Q36Show mark scheme →
Ae.m.f. decreases, power dissipated decreases
Be.m.f. decreases, power dissipated no change
Ce.m.f. no change, power dissipated decreases
De.m.f. no change, power dissipated no change
Mark scheme
56May / June 2020 · Paper 11 · Q36Show mark scheme →
A$R\sqrt{\dfrac{P}{(R-r)}}$
B$R\sqrt{\dfrac{P}{(R+r)}}$
C$(R-r)\sqrt{\dfrac{P}{R}}$
D$(R+r)\sqrt{\dfrac{P}{R}}$
Mark scheme
57May / June 2020 · Paper 12 · Q36Show mark scheme →
A1.4 V
B1.5 V
C1.7 V
D2.9 V
Mark scheme
58May / June 2020 · Paper 13 · Q37Show mark scheme →
Athe current in the circuit
Bthe electromotive force of the cell
Cthe potential difference across the internal resistance
Dthe terminal potential difference across the cell
Mark scheme
59Feb / March 2020 · Paper 12 · Q35Show mark scheme →
Ae.m.f. 3 V, internal resistance 0.2 Ω
Be.m.f. 3 V, internal resistance 0.4 Ω
Ce.m.f. 21 V, internal resistance 0.2 Ω
De.m.f. 21 V, internal resistance 0.4 Ω
Mark scheme
60Feb / March 2020 · Paper 12 · Q36Show mark scheme →
A0.3 V
B5.7 V
C6.0 V
D6.3 V
Mark scheme
61Oct / Nov 2019 · Paper 11 · Q35Show mark scheme →
AElectromotive force is the energy transferred per unit charge.
BEnergy is transferred from chemical potential energy in the cell to other forms when the switch is closed.
CThe electromotive force of the cell is greater than the terminal potential difference when the switch is closed.
DWhen the switch is open, the voltmeter measures the electromotive force of the cell.
Mark scheme
62Oct / Nov 2019 · Paper 12 · Q34Show mark scheme →
A$\dfrac{E_2 r_1 - E_1 r_2}{E_1}$
B$\dfrac{E_2 r_1 - E_1 r_2}{E_2}$
C$\dfrac{E_1 r_2 - E_2 r_1}{E_1}$
D$\dfrac{E_1 r_2 - E_2 r_1}{E_2}$
Mark scheme
63Oct / Nov 2019 · Paper 12 · Q35Show mark scheme →
AThe e.m.f. $E$ decreases.
BThe internal resistance $r$ increases.
CThe p.d. across $r$ increases.
DThe resistance of the variable resistor increases.
Mark scheme
64Oct / Nov 2019 · Paper 13 · Q36Show mark scheme →
AThe current in the circuit will halve.
BThe e.m.f. of the cell will remain constant.
CThe power dissipated by the fixed resistor will decrease.
DThe terminal p.d. of the cell will increase.
Mark scheme
65May / June 2019 · Paper 11 · Q35Show mark scheme →
Aterminal potential difference decreases; output power decreases
Bterminal potential difference decreases; output power unchanged
Cterminal potential difference unchanged; output power decreases
Dterminal potential difference unchanged; output power unchanged
Mark scheme
66May / June 2019 · Paper 11 · Q36Show mark scheme →
AE = 0.113 V, r = 3.11 Ω
BE = 3.04 V, r = 0.0358 Ω
CE = 3.11 V, r = 0.113 Ω
DE = 9.34 V, r = 6.34 Ω
Mark scheme
67May / June 2019 · Paper 12 · Q35Show mark scheme →
Acurrent I decreases; terminal potential difference across cell decreases
Bcurrent I decreases; terminal potential difference across cell increases
Ccurrent I increases; terminal potential difference across cell decreases
Dcurrent I increases; terminal potential difference across cell increases
Mark scheme
68May / June 2019 · Paper 13 · Q34Show mark scheme →
AX₁ to Y₁ X₂ to Y₂
BX₁ to Y₁ X₂ to Z₂
CX₁ to Z₁ X₂ to Y₂
DX₁ to Z₁ X₂ to Z₂
Mark scheme
69Feb / March 2019 · Paper 12 · Q36Show mark scheme →
AGraph of I against r: curve starting high on the I-axis and decreasing, approaching zero as r increases.
BGraph of I against r: curve starting at a finite value on the I-axis and decreasing towards zero as r increases.
CGraph of I against r: straight line with negative gradient starting from a finite value on the I-axis.
DGraph of I against r: horizontal straight line at constant I.
Mark scheme
70Oct / Nov 2018 · Paper 11 · Q36Show mark scheme →
Avoltmeter reading decreases, ammeter reading increases
Bvoltmeter reading decreases, ammeter reading decreases
Cvoltmeter reading increases, ammeter reading increases
Dvoltmeter reading increases, ammeter reading decreases
Mark scheme
71Oct / Nov 2018 · Paper 13 · Q35Show mark scheme →
A2.4 W
B2.7 W
C3.6 W
D5.6 W
Mark scheme
72May / June 2018 · Paper 12 · Q35Show mark scheme →
AV decreases, I decreases
BV decreases, I increases
CV increases, I decreases
DV increases, I increases
Mark scheme
73May / June 2018 · Paper 13 · Q31Show mark scheme →
A\frac{E^2(R+r)}{R^2}
B\frac{E^2R}{(R+r)^2}
C\frac{E^2(R+r)}{r^2}
D\frac{E^2r}{(R+r)^2}
Mark scheme
74Feb / March 2018 · Paper 12 · Q32Show mark scheme →
AWhen switch S is closed, the e.m.f. of the battery falls because work is done against the internal resistance of the battery.
BWhen switch S is closed, the e.m.f. of the battery falls because work is done against the resistance of R.
CWhen switch S is closed, the potential difference across the battery falls because work is done against the internal resistance of the battery.
DWhen switch S is closed, the potential difference across the battery falls because work is done against the resistance of R.
Mark scheme
75Oct / Nov 2017 · Paper 12 · Q36Show mark scheme →
A4.8 V
B4.9 V
C5.0 V
D5.1 V
Mark scheme
76Oct / Nov 2017 · Paper 13 · Q34Show mark scheme →
A$P$ is independent of both $r$ and $R$.
B$P$ depends on $r$ but not on $R$.
C$P$ depends on $R$ but not on $r$.
D$P$ depends on both $r$ and $R$.
Mark scheme
77Oct / Nov 2017 · Paper 13 · Q35Show mark scheme →
Aforward biased: 1 V; reverse biased: 3 V
Bforward biased: 2 V; reverse biased: 0 V
Cforward biased: 2 V; reverse biased: 3 V
Dforward biased: 3 V; reverse biased: 0 V
Mark scheme
78Oct / Nov 2017 · Paper 13 · Q36Show mark scheme →
A0
Br1 - r2
Cr1 + r2
D\frac{r_1 r_2}{r_1 + r_2}
Mark scheme
79May / June 2017 · Paper 11 · Q35Show mark scheme →
Aammeter reading decreases, voltmeter reading decreases
Bammeter reading decreases, voltmeter reading stays the same
Cammeter reading increases, voltmeter reading decreases
Dammeter reading increases, voltmeter reading stays the same
Mark scheme
80May / June 2017 · Paper 12 · Q35Show mark scheme →
AThe terminal p.d. is decreased because more work is done moving unit charge through the internal resistance of the cell.
BThe terminal p.d. is decreased because the current in the variable resistor is decreased.
CThe terminal p.d. is increased because more work is done moving unit charge through the variable resistor.
DThe terminal p.d. is increased because the current in the variable resistor is increased.
Mark scheme
81May / June 2017 · Paper 13 · Q34Show mark scheme →
Agraph with lower V intercept and steeper gradient than original
Bgraph with lower V intercept and same gradient as original
Cgraph with same V intercept and steeper gradient than original
Dgraph with lower V intercept and shallower gradient than original
Mark scheme
82Feb / March 2017 · Paper 12 · Q35Show mark scheme →
A0.60 A
B1.2 A
C1.8 A
D3.0 A
Mark scheme
83Oct / Nov 2016 · Paper 12 · Q34Show mark scheme →
A\frac{1}{4}
B\frac{1}{2}
C2
D4
Mark scheme
84Oct / Nov 2016 · Paper 12 · Q36Show mark scheme →
Apotential difference: 1 and 3; electromotive force: 2 and 4
Bpotential difference: 1 and 4; electromotive force: 2 and 3
Cpotential difference: 2 and 3; electromotive force: 1 and 4
Dpotential difference: 2 and 4; electromotive force: 1 and 3
Mark scheme
85May / June 2016 · Paper 11 · Q37Show mark scheme →
Acircuit A
Bcircuit B
Ccircuit C
Dcircuit D
Mark scheme
86May / June 2016 · Paper 13 · Q37Show mark scheme →
A1.0 Ω
B2.0 Ω
C4.0 Ω
D6.5 Ω
Mark scheme
87Feb / March 2016 · Paper 12 · Q37Show mark scheme →
A50 A
B70 A
C120 A
D190 A
Mark scheme