Electric current
9.1What the syllabus asks of you
- understand that an electric current is a flow of charge carriers
- understand that the charge on charge carriers is quantised
- recall and use Q = It
- use, for a current-carrying conductor, the expression I = Anvq, where n is the number density of charge carriers
Read the notes first
Chapter 9: Electric current
Drill this topic
Every question on Electric current, untimed, marked as you go.
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Choose the years and how many questions, then print it with the answers on separate pages.
79 questions
1May / June 2026 · Paper 11 · Q34Show mark scheme →
A0.5 C
B5 C
C500 C
D5000 C
Mark scheme
2May / June 2026 · Paper 11 · Q38Show mark scheme →
Aα-particles
Bβ⁻ particles
Cneutrons
Dprotons
Mark scheme
3May / June 2026 · Paper 12 · Q31Show mark scheme →
AI = nqabc
BI = \frac{nqV}{t}
CI = \frac{nqbc}{t}
DI = nqaV
Mark scheme
4May / June 2026 · Paper 13 · Q32Show mark scheme →
A1.2 × 10⁻¹⁵
B7.2 × 10³
C1.3 × 10¹⁹
D4.5 × 10²²
Mark scheme
5May / June 2026 · Paper 13 · Q34Show mark scheme →
A3.3 × 10⁻⁸ m
B2.0 × 10⁻⁵ m
C8.0 × 10⁻⁵ m
D2.5 × 10⁻⁴ m
Mark scheme
6May / June 2026 · Paper 14 · Q33Show mark scheme →
A1.25 × 10¹²
B6.25 × 10¹²
C1.25 × 10¹⁵
D6.25 × 10¹⁵
Mark scheme
7Oct / Nov 2025 · Paper 11 · Q32Show mark scheme →
A6.40 × 10⁻²⁰ C
B4.00 × 10⁻¹⁹ C
C1.12 × 10⁻¹⁸ C
D9.11 × 10⁻¹⁸ C
Mark scheme
8Oct / Nov 2025 · Paper 13 · Q32Show mark scheme →
A6.40 × 10⁻²⁰ C
B4.00 × 10⁻¹⁹ C
C1.12 × 10⁻¹⁸ C
D9.11 × 10⁻¹⁸ C
Mark scheme
9Oct / Nov 2025 · Paper 14 · Q35Show mark scheme →
A1.8 × 10^18
B2.2 × 10^19
C3.5 × 10^19
D7.0 × 10^20
Mark scheme
10May / June 2025 · Paper 12 · Q34Show mark scheme →
A3.13 × 10^16
B1.25 × 10^17
C5.00 × 10^17
D1.25 × 10^21
Mark scheme
11May / June 2025 · Paper 13 · Q32Show mark scheme →
Adensity of conduction electrons
Bnumber of conduction electrons per unit time
Cnumber of conduction electrons per unit volume
Dvolume of conduction electrons
Mark scheme
12May / June 2025 · Paper 13 · Q33Show mark scheme →
A–4.8 × 10⁻¹⁹ C
B–3.2 × 10⁻¹⁹ C
C–2.4 × 10⁻¹⁹ C
D+3.2 × 10⁻¹⁹ C
Mark scheme
13May / June 2025 · Paper 14 · Q29Show mark scheme →
A5.2 × 10⁴
B9.0 × 10¹⁹
C5.4 × 10²¹
D3.2 × 10²³
Mark scheme
14Feb / March 2025 · Paper 12 · Q30Show mark scheme →
AY greater than X | Y greater than X
BY same as X | Y same as X
CY greater than X | Y same as X
DY same as X | Y greater than X
Mark scheme
15Feb / March 2025 · Paper 12 · Q33Show mark scheme →
A6.0 × 10²⁰
B1.0 × 10¹⁹
C6.0 × 10¹⁷
D1.0 × 10¹⁶
Mark scheme
16Feb / March 2025 · Paper 12 · Q35Show mark scheme →
A0.4 C
B2 C
C10 C
D20 C
Mark scheme
17Oct / Nov 2024 · Paper 12 · Q32Show mark scheme →
AIt can take any value.
BIt is an integer multiple of the elementary charge.
CIt is the elementary charge.
DIt is the rate of flow of the current.
Mark scheme
18Oct / Nov 2024 · Paper 12 · Q34Show mark scheme →
A1.3 × 10¹⁶
B5.3 × 10²²
C1.5 × 10²³
D4.3 × 10²³
Mark scheme
19Oct / Nov 2024 · Paper 13 · Q31Show mark scheme →
Aa flow of charge carriers
Ba flow of energy
Can electron
Dthe charge on a particle
Mark scheme
20Oct / Nov 2024 · Paper 13 · Q32Show mark scheme →
A0.75I
B1.5I
C6I
D12I
Mark scheme
21May / June 2024 · Paper 12 · Q32Show mark scheme →
A0.5I
BI
C2I
D4I
Mark scheme
22May / June 2024 · Paper 12 · Q33Show mark scheme →
A–4.8 × 10–19 C
B–2.4 × 10–19 C
C+1.6 × 10–19 C
D+3.2 × 10–19 C
Mark scheme
23Feb / March 2024 · Paper 12 · Q36Show mark scheme →
A4.7 × 10⁹
B9.4 × 10⁹
C1.4 × 10¹⁰
D2.8 × 10¹⁰
Mark scheme
24Feb / March 2024 · Paper 12 · Q37Show mark scheme →
AThe magnitude of the charge increases with the potential difference across the wire.
BThe magnitude of the charge is zero unless there is a potential difference across the wire.
CThe sign and magnitude of the charge do not depend on the potential difference across the wire.
DThe sign of the charge depends on the potential difference across the wire.
Mark scheme
25Oct / Nov 2023 · Paper 11 · Q30Show mark scheme →
Acharge carried per charge carrier
Bnumber of charge carriers per unit area
Cnumber of charge carriers per unit volume
Dtotal mass of charge carriers per unit volume
Mark scheme
26Oct / Nov 2023 · Paper 12 · Q30Show mark scheme →
Azero
B1.0 × 10⁻¹⁹ C
C4.8 × 10⁻¹⁹ C
D8.0 × 10⁻¹⁹ C
Mark scheme
27Oct / Nov 2023 · Paper 13 · Q30Show mark scheme →
Aalpha-particles
Bbeta-particles
Cneutrons
Dprotons
Mark scheme
28May / June 2023 · Paper 11 · Q30Show mark scheme →
A2.5 × 10¹⁷
B2.5 × 10²⁰
C9.0 × 10²⁰
D9.0 × 10²³
Mark scheme
29May / June 2023 · Paper 12 · Q30Show mark scheme →
A1.1 × 10⁻¹⁹ C
B4.0 × 10⁻¹⁹ C
C4.8 × 10⁻¹⁹ C
D9.1 × 10⁻¹⁹ C
Mark scheme
30May / June 2023 · Paper 13 · Q30Show mark scheme →
ANegatively charged electrons in the wire move from the negative terminal to the positive terminal.
BNegatively charged nuclei in the wire move from the negative terminal to the positive terminal.
CPositively charged electrons in the wire move from the positive terminal to the negative terminal.
DPositively charged nuclei in the wire move from the positive terminal to the negative terminal.
Mark scheme
31Oct / Nov 2022 · Paper 11 · Q31Show mark scheme →
AQ/8
BQ/4
CQ/2
DQ
Mark scheme
32Oct / Nov 2022 · Paper 12 · Q31Show mark scheme →
A9.8 × 10⁻⁷ m s⁻¹
B3.9 × 10⁻⁶ m s⁻¹
C6.1 × 10⁻⁶ m s⁻¹
D2.5 × 10⁻⁵ m s⁻¹
Mark scheme
33Oct / Nov 2022 · Paper 13 · Q30Show mark scheme →
AIt is nearly 3 × 10^8 m s–1.
BIt is proportional to the cross-sectional area of the wire.
CIt is proportional to the length of the wire.
DIt is proportional to the magnitude of the current.
Mark scheme
34May / June 2022 · Paper 11 · Q31Show mark scheme →
A3.3 × 10⁻⁸ m
B2.0 × 10⁻⁵ m
C8.0 × 10⁻⁵ m
D2.5 × 10⁻⁴ m
Mark scheme
35May / June 2022 · Paper 12 · Q31Show mark scheme →
AI = nqabc
BI = \frac{nqV}{t}
CI = \frac{nqbc}{t}
DI = nqaV
Mark scheme
36May / June 2022 · Paper 13 · Q32Show mark scheme →
A$\dfrac{1}{4}$
B$\dfrac{1}{2}$
C$\dfrac{2}{1}$
D$\dfrac{4}{1}$
Mark scheme
37Feb / March 2022 · Paper 12 · Q29Show mark scheme →
Athe number of charge carriers in the wire
Bthe number of charge carriers multiplied by the volume of the wire
Cthe number of charge carriers per unit length of the wire
Dthe number of charge carriers per unit volume of the wire
Mark scheme
38Feb / March 2022 · Paper 12 · Q30Show mark scheme →
A6.3 pA
B1.1 A
C67 A
D4.0 kA
Mark scheme
39Oct / Nov 2021 · Paper 11 · Q32Show mark scheme →
Acharge = current × time
Bdistance = speed × time
Cnumber = number density × area
Dvolume = length × area
Mark scheme
40Oct / Nov 2021 · Paper 12 · Q33Show mark scheme →
Athe electric charge of one electron
Bthe electric charge transferred by a current of one ampere in one second
Cthe kinetic energy gained by an electron accelerated through a potential difference of one volt
Dthe kinetic energy of an electron moving at a speed of one metre per second
Mark scheme
41Oct / Nov 2021 · Paper 13 · Q33Show mark scheme →
A0.5 mA
B0.5 A
C500 A
D500 kA
Mark scheme
42May / June 2021 · Paper 12 · Q32Show mark scheme →
AGraph A: v decreasing curve from maximum at x=0 to minimum at x=L
BGraph B: v increasing curve from minimum at x=0 to maximum at x=L
CGraph C: v decreasing linearly from maximum at x=0 to zero at x=L
DGraph D: v increasing linearly from zero at x=0 to maximum at x=L
Mark scheme
43May / June 2021 · Paper 13 · Q33Show mark scheme →
A0.0027 A
B0.0039 A
C0.27 A
D0.39 A
Mark scheme
44Feb / March 2021 · Paper 12 · Q32Show mark scheme →
Athe number of charge carriers in the wire
Bthe number of charge carriers per unit cross-sectional area of the wire
Cthe number of charge carriers per unit length of the wire
Dthe number of charge carriers per unit volume of the wire
Mark scheme
45Oct / Nov 2020 · Paper 11 · Q32Show mark scheme →
A4.7 × 10⁻³ m s⁻¹
B9.3 × 10⁻³ m s⁻¹
C1.1 × 10⁻² m s⁻¹
D1.9 × 10⁻² m s⁻¹
Mark scheme
46Oct / Nov 2020 · Paper 12 · Q33Show mark scheme →
A4Qn
B\frac{4Q}{n}
C8\pi rQn
D\frac{2Qn}{\pi r}
Mark scheme
47Oct / Nov 2020 · Paper 13 · Q33Show mark scheme →
A3/2
B3/4
C1/6
D1/12
Mark scheme
48May / June 2020 · Paper 11 · Q33Show mark scheme →
AX to Y, 2.0 × 10^16
BX to Y, 5.1 × 10^-22
CY to X, 2.0 × 10^16
DY to X, 5.1 × 10^-22
Mark scheme
49May / June 2020 · Paper 12 · Q33Show mark scheme →
A8.0 × 10^–11 m s^–1
B3.2 × 10^–10 m s^–1
C8.0 × 10^–5 m s^–1
D3.2 × 10^–4 m s^–1
Mark scheme
50May / June 2020 · Paper 13 · Q33Show mark scheme →
Athe charge passing a point in 1 second when a current produces 1 joule of work
Bthe charge passing a point in 1 second when a current produces 1 watt of power
Cthe charge passing a point in 1 second when there is a current of 1 ampere
Dthe charge passing a point in 1 second when there is 1 ohm of resistance
Mark scheme
51May / June 2020 · Paper 13 · Q34Show mark scheme →
A\frac{1}{4}
B\frac{1}{2}
C2
D4
Mark scheme
52Feb / March 2020 · Paper 12 · Q32Show mark scheme →
A1.4 × 10^4
B1.5 × 10^15
C1.8 × 10^16
D9.0 × 10^16
Mark scheme
53Oct / Nov 2019 · Paper 11 · Q30Show mark scheme →
AThe average drift speed of the conduction electrons decreases as they move from right to left through the plate.
BThe average drift speed of the conduction electrons increases as they move from right to left through the plate.
CThe number density of the conduction electrons decreases from right to left through the plate.
DThe number density of the conduction electrons increases from right to left through the plate.
Mark scheme
54Oct / Nov 2019 · Paper 11 · Q31Show mark scheme →
Aenvx²
Benvxy
Cenvx³y²
Denvx⁴y
Mark scheme
55Oct / Nov 2019 · Paper 12 · Q31Show mark scheme →
A7.2 × 10⁻⁷ ; 1.2 × 10²⁸
B7.2 × 10⁻⁷ ; 5.9 × 10²⁸
C2.3 × 10⁻⁶ ; 7.3 × 10²⁶
D2.3 × 10⁻⁶ ; 3.7 × 10²⁷
Mark scheme
56Oct / Nov 2019 · Paper 13 · Q33Show mark scheme →
A6.0 × 10²⁰
B1.0 × 10¹⁹
C6.0 × 10¹⁷
D1.0 × 10¹⁶
Mark scheme
57May / June 2019 · Paper 11 · Q32Show mark scheme →
A– 4.8 × 10⁻¹⁹ C
B+1.6 × 10⁻¹⁹ C
C+3.2 × 10⁻¹⁹ C
D+4.0 × 10⁻¹⁹ C
Mark scheme
58May / June 2019 · Paper 12 · Q33Show mark scheme →
A1/2 Q
BQ
CQ√2
D2Q
Mark scheme
59Feb / March 2019 · Paper 12 · Q32Show mark scheme →
An is the number of charge carriers per unit volume of the wire.
BnA is the number of charge carriers per unit length of the wire.
Cq is the charge of each charge carrier.
Dv is the velocity of each charge carrier.
Mark scheme
60Oct / Nov 2018 · Paper 11 · Q33Show mark scheme →
A4.0 × 10⁻⁴ m s⁻¹
B8.0 × 10⁻⁴ m s⁻¹
C1.6 × 10⁻³ m s⁻¹
D3.2 × 10⁻³ m s⁻¹
Mark scheme
61Oct / Nov 2018 · Paper 13 · Q32Show mark scheme →
Athe average drift velocity of the charge carriers
Bthe instantaneous velocity of the charge carriers
Cthe voltage applied across the wire
Dthe volume of the wire
Mark scheme
62May / June 2018 · Paper 11 · Q30Show mark scheme →
Athe number of atoms per unit volume of the metal
Bthe number of free electrons per atom in the metal
Cthe number of free electrons per unit volume of the metal
Dthe total number of electrons per unit volume of the metal
Mark scheme
63May / June 2018 · Paper 13 · Q29Show mark scheme →
A6.40 × 10⁻²⁰ C
B4.00 × 10⁻¹⁹ C
C1.12 × 10⁻¹⁸ C
D9.11 × 10⁻¹⁸ C
Mark scheme
64May / June 2018 · Paper 13 · Q30Show mark scheme →
A0.18 m s⁻¹
B18 m s⁻¹
C180 m s⁻¹
D1800 m s⁻¹
Mark scheme
65Feb / March 2018 · Paper 12 · Q35Show mark scheme →
Acurrent per unit of cross-sectional area
Bpotential difference per unit of length
Cresistance and cross-sectional area
Dresistivity and length
Mark scheme
66Oct / Nov 2017 · Paper 11 · Q33Show mark scheme →
AX to Y, 2.0 × 10^16
BX to Y, 5.1 × 10^-22
CY to X, 2.0 × 10^16
DY to X, 5.1 × 10^-22
Mark scheme
67Oct / Nov 2017 · Paper 12 · Q33Show mark scheme →
A$\dfrac{1}{4}$
B$\dfrac{1}{2}$
C2
D4
Mark scheme
68Oct / Nov 2017 · Paper 13 · Q33Show mark scheme →
A$8.0 \times 10^{-11}\,\mathrm{m\,s^{-1}}$
B$3.2 \times 10^{-10}\,\mathrm{m\,s^{-1}}$
C$8.0 \times 10^{-5}\,\mathrm{m\,s^{-1}}$
D$3.2 \times 10^{-4}\,\mathrm{m\,s^{-1}}$
Mark scheme
69May / June 2017 · Paper 11 · Q32Show mark scheme →
Athe charge flowing past a point in the wire per unit time
Bthe number of electrons flowing past a point in the wire per unit time
Cthe number of positive ions flowing past a point in the wire per unit time
Dthe number of protons flowing past a point in the wire per unit time
Mark scheme
70May / June 2017 · Paper 12 · Q32Show mark scheme →
A1.25 × 10¹³
B1.25 × 10¹⁶
C1.25 × 10¹⁹
D1.25 × 10²⁵
Mark scheme
71May / June 2017 · Paper 13 · Q31Show mark scheme →
A3.2 × 10^–26 A
B8.0 × 10^–13 A
C1.6 × 10^–12 A
D2.0 × 10^–7 A
Mark scheme
72Feb / March 2017 · Paper 12 · Q32Show mark scheme →
AA: area of cross-section; n: number of free electrons; v: voltage; q: charge of each molecule
BA: area of cross-section; n: number of free electrons per unit volume; v: average drift speed of electrons; q: charge of each electron
CA: current; n: number of free electrons; v: average drift speed of electrons; q: charge of each molecule
DA: current; n: number of free electrons per unit volume; v: voltage; q: charge of each electron
Mark scheme
73Oct / Nov 2016 · Paper 11 · Q34Show mark scheme →
Athe charge passing a point per unit time
Bthe drift speed of the electrons
Cthe number density of the free electrons
Dthe number of free electrons passing a point per unit time
Mark scheme
74Oct / Nov 2016 · Paper 12 · Q32Show mark scheme →
A0.4 C
B2 C
C10 C
D20 C
Mark scheme
75Oct / Nov 2016 · Paper 12 · Q33Show mark scheme →
A1.2 × 10⁻¹⁵
B7.2 × 10³
C1.3 × 10¹⁹
D4.5 × 10²²
Mark scheme
76Oct / Nov 2016 · Paper 13 · Q34Show mark scheme →
Athe charge passing a point per unit time
Bthe drift speed of the electrons
Cthe number density of the free electrons
Dthe number of free electrons passing a point per unit time
Mark scheme
77May / June 2016 · Paper 12 · Q35Show mark scheme →
A21
B25
C42
D250
Mark scheme
78May / June 2016 · Paper 13 · Q31Show mark scheme →
A– 4.8 × 10^–19 C
B+1.6 × 10^–19 C
C+3.2 × 10^–19 C
D+4.0 × 10^–19 C
Mark scheme
79Feb / March 2016 · Paper 12 · Q30Show mark scheme →
A6.0 × 10²⁰
B1.0 × 10¹⁹
C6.0 × 10¹⁷
D1.0 × 10¹⁶
Mark scheme