SI units
1.2What the syllabus asks of you
- recall the following SI base quantities and their units: mass (kg), length (m), time (s), current (A), temperature (K)
- express derived units as products or quotients of the SI base units and use the derived units for quantities listed in this syllabus as appropriate
- use SI base units to check the homogeneity of physical equations
- recall and use the following prefixes and their symbols to indicate decimal submultiples or multiples of both base and derived units: pico (p), nano (n), micro (μ), milli (m), centi (c), deci (d), kilo (k), mega (M), giga (G), tera (T)
Read the notes first
Chapter 1: SI units
Drill this topic
Every question on SI units, untimed, marked as you go.
Make a worksheet
Choose the years and how many questions, then print it with the answers on separate pages.
96 questions
1May / June 2026 · Paper 11 · Q1Show mark scheme →
Aampere
Bcharge
Ccoulomb
Dcurrent
Mark scheme
2May / June 2026 · Paper 11 · Q16Show mark scheme →
AN m^-3
Bg mm^-1
Ckg cm^-2
Dµg mm^-3
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3May / June 2026 · Paper 12 · Q2Show mark scheme →
Akg s^{-3}
Bkg s
Ckg m^{2} s^{-3}
Dkg m^{4} s^{-3}
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4May / June 2026 · Paper 14 · Q4Show mark scheme →
Am² s⁻² K⁻³
Bm² s⁻² K⁻⁴
Ckg m² s⁻² K⁻³
Dkg m² s⁻² K⁻⁴
Mark scheme
5Oct / Nov 2025 · Paper 11 · Q3Show mark scheme →
AJ s⁻¹
Bkg m² s⁻³
Ckg m² s⁻¹
DN m s⁻¹
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6Oct / Nov 2025 · Paper 11 · Q22Show mark scheme →
Akg m s–2
Bkg m–1 s–2
Ckg m–2 s–2
Dkg m–3 s–2
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7Oct / Nov 2025 · Paper 12 · Q3Show mark scheme →
Aacceleration
Bforce
Cmass
Dmomentum
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8Oct / Nov 2025 · Paper 13 · Q3Show mark scheme →
AJ s⁻¹
Bkg m² s⁻³
Ckg m² s⁻¹
DN m s⁻¹
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9Oct / Nov 2025 · Paper 13 · Q22Show mark scheme →
Akg m s–2
Bkg m–1 s–2
Ckg m–2 s–2
Dkg m–3 s–2
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10May / June 2025 · Paper 12 · Q2Show mark scheme →
A0.00025 N m⁻²
B0.25 N m⁻²
C250 000 N m⁻²
D250 000 000 N m⁻²
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11May / June 2025 · Paper 12 · Q4Show mark scheme →
A–2
B–1/2
C1/2
D2
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12May / June 2025 · Paper 13 · Q4Show mark scheme →
Akg m s⁻³ °C⁻¹
Bkg m s⁻³ K⁻¹
Ckg m s⁻¹ °C⁻¹
Dkg m s⁻¹ K⁻¹
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13May / June 2025 · Paper 14 · Q2Show mark scheme →
AN m
BV C
CW s
Dkg m s^{-2}
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14Oct / Nov 2024 · Paper 11 · Q1Show mark scheme →
Akg m⁻¹ s²
Bkg s⁻²
Ckg m s⁻²
Dkg m² s⁻²
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15Oct / Nov 2024 · Paper 12 · Q19Show mark scheme →
Akg m⁻¹ s⁻²
Bkg m⁻² s⁻²
CN m⁻¹
DN m
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16Oct / Nov 2024 · Paper 13 · Q3Show mark scheme →
Akg s^-2 K^-4
Bkg s^-3 K^-4
Ckg m^-1 s^-2 K^-4
Dkg m^-1 s^-3 K^-4
Mark scheme
17May / June 2024 · Paper 11 · Q1Show mark scheme →
Aampere
Bcoulomb
Cdegree Celsius
Dgram
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18May / June 2024 · Paper 11 · Q2Show mark scheme →
A\frac{energy}{distance}
B\frac{energy}{time}
Cmomentum \times distance
Dmomentum \times time
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19May / June 2024 · Paper 11 · Q8Show mark scheme →
A2.2 m s⁻¹
B2.2 × 10⁷ μm s⁻¹
C2.2 × 10¹¹ nm s⁻¹
D2.2 × 10⁶ mm s⁻¹
Mark scheme
20May / June 2024 · Paper 13 · Q1Show mark scheme →
A5 mJ
B5 MJ
C5 μJ
D5 nJ
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21May / June 2024 · Paper 13 · Q16Show mark scheme →
AJ C⁻¹
BJ m⁻¹
CJ N⁻¹
DJ s⁻¹
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22Feb / March 2024 · Paper 12 · Q1Show mark scheme →
Acurrent A
Bforce N
Cmass g
Dtemperature °C
Mark scheme
23Feb / March 2024 · Paper 12 · Q3Show mark scheme →
AT = 2π(k/m)
BT = 2π(m/k)
CT = 2π√(k/m)
DT = 2π√(m/k)
Mark scheme
24Oct / Nov 2023 · Paper 11 · Q2Show mark scheme →
Acharge
Bmass
Ctemperature
Dtime
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25Oct / Nov 2023 · Paper 12 · Q2Show mark scheme →
Aforce
Bnewton
Csecond
Dtime
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26Oct / Nov 2023 · Paper 13 · Q2Show mark scheme →
A500
B5000
C500 000
D5 000 000
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27May / June 2023 · Paper 11 · Q1Show mark scheme →
AA
Bkg
CC
Ds
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28May / June 2023 · Paper 12 · Q2Show mark scheme →
Alargest unit: Gm; smallest unit: μm
Blargest unit: Gm; smallest unit: pm
Clargest unit: Tm; smallest unit: μm
Dlargest unit: Tm; smallest unit: pm
Mark scheme
29May / June 2023 · Paper 13 · Q2Show mark scheme →
Akg m² s⁻³ A⁻²
Bkg⁻¹ m⁻² s³ A²
CJ C⁻¹ A⁻¹
DW A⁻²
Mark scheme
30Feb / March 2023 · Paper 12 · Q2Show mark scheme →
Aunit of b: m s, unit of c: s
Bunit of b: m s^-1, unit of c: s^-1
Cunit of b: m^-1 s, unit of c: s
Dunit of b: m^-1 s^-1, unit of c: s^-1
Mark scheme
31Oct / Nov 2022 · Paper 12 · Q2Show mark scheme →
A3.7 × 10⁻³ kW
B3.7 × 10⁻³ KW
C3.7 × 10³ kW
D3.7 × 10³ KW
Mark scheme
32Oct / Nov 2022 · Paper 13 · Q2Show mark scheme →
Akg m² s⁻¹ A⁻¹
Bkg m² s⁻³ A⁻¹
Ckg m² s⁻¹ A
Dkg m s⁻³ A⁻¹
Mark scheme
33May / June 2022 · Paper 11 · Q2Show mark scheme →
AJ C⁻¹ and kg m² A⁻¹ s⁻²
BJ s and kg m² s⁻¹
CN m and kg m³ s⁻²
DN s and kg m s⁻³
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34May / June 2022 · Paper 12 · Q2Show mark scheme →
AC
BK
C°C
D°K
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35May / June 2022 · Paper 13 · Q2Show mark scheme →
Acenti, deci, milli
Bdeci, milli, centi
Cpico, kilo, milli
Dkilo, milli, pico
Mark scheme
36May / June 2022 · Paper 13 · Q3Show mark scheme →
A1
B2
C3
D4
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37May / June 2022 · Paper 13 · Q16Show mark scheme →
A8.35 × 10² kg m⁻³
B1.20 × 10³ kg m⁻³
C8.35 × 10⁵ kg m⁻³
D1.20 × 10⁶ kg m⁻³
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38Feb / March 2022 · Paper 12 · Q1Show mark scheme →
A10 K
B11 J N⁻¹ m⁻¹
C17 Pa m³ N⁻¹
D25 T m
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39Feb / March 2022 · Paper 12 · Q2Show mark scheme →
A1.28 × 10⁸ B
B1.28 × 10¹¹ B
C1.28 × 10¹⁴ B
D1.28 × 10¹⁷ B
Mark scheme
40Feb / March 2022 · Paper 12 · Q14Show mark scheme →
AN m⁻³
Bg mm⁻¹
Ckg cm⁻²
Dμg mm⁻³
Mark scheme
41Oct / Nov 2021 · Paper 11 · Q2Show mark scheme →
AA kg⁻¹
BA s² kg⁻¹
CA s kg⁻¹
DA s⁻² kg⁻¹
Mark scheme
42Oct / Nov 2021 · Paper 12 · Q2Show mark scheme →
A4.3 × 10³ mJ
B4.3 × 10³ MJ
C4.3 × 10⁻³ mJ
D4.3 × 10⁻³ MJ
Mark scheme
43Oct / Nov 2021 · Paper 13 · Q2Show mark scheme →
Akg⁻¹ m⁻² s A²
Bkg⁻¹ m⁻² s³ A²
Ckg m² s⁻¹ A⁻²
Dkg m² s⁻³ A⁻²
Mark scheme
44May / June 2021 · Paper 11 · Q2Show mark scheme →
Anewton per second (N s⁻¹)
Bnewton second (N s)
Cnewton metre (N m)
Dnewton metre per second (N m s⁻¹)
Mark scheme
45May / June 2021 · Paper 11 · Q32Show mark scheme →
Aampere and second
Bampere and volt
Cvolt and ohm
Dvolt and second
Mark scheme
46May / June 2021 · Paper 12 · Q2Show mark scheme →
Aacceleration
Bcharge
Ccurrent
Dresistance
Mark scheme
47May / June 2021 · Paper 13 · Q2Show mark scheme →
Akg m s⁻²
BN s⁻¹
CN s
Dkg s m⁻¹
Mark scheme
48Feb / March 2021 · Paper 12 · Q2Show mark scheme →
Aacceleration
Bforce
Cmass
Dmomentum
Mark scheme
49Oct / Nov 2020 · Paper 11 · Q2Show mark scheme →
A0.05 ms
B50 ns
C500 000 ps
D0.5 µs
Mark scheme
50Oct / Nov 2020 · Paper 12 · Q2Show mark scheme →
Ap = -1/2, q = -1/2
Bp = -1/2, q = 1/2
Cp = 1/2, q = -1/2
Dp = 1/2, q = 1/2
Mark scheme
51Oct / Nov 2020 · Paper 13 · Q2Show mark scheme →
Acoulomb
Bkelvin
Ckilogram
Dsecond
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52May / June 2020 · Paper 11 · Q2Show mark scheme →
Ap = −1/2, q = −1/2
Bp = −1/2, q = 1/2
Cp = 1/2, q = −1/2
Dp = 1/2, q = 1/2
Mark scheme
53Feb / March 2020 · Paper 12 · Q2Show mark scheme →
A1 × 10^9
B8 × 10^9
C1 × 10^12
D8 × 10^12
Mark scheme
54Oct / Nov 2019 · Paper 11 · Q2Show mark scheme →
Av = \sqrt{\frac{gL}{2\pi}}
Bv = \frac{gL}{4\pi^2}
Cv = 2\pi\sqrt{\frac{g}{L}}
Dv = \frac{2\pi g}{L}
Mark scheme
55Oct / Nov 2019 · Paper 11 · Q32Show mark scheme →
AA Ω
BN m⁻¹ C⁻¹
CW A⁻¹
D(Ω W)^(1/2)
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56Oct / Nov 2019 · Paper 12 · Q2Show mark scheme →
Acharge per unit time
Bforce per unit area
Cmass per unit volume
Dwork done per unit distance
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57Oct / Nov 2019 · Paper 13 · Q1Show mark scheme →
Aacceleration of a bicycle = 1.4 m s⁻¹
Belectric current in a lamp = 0.25 A s⁻¹
Celectric potential difference across a battery = 8.0 J C⁻¹
Dkinetic energy of a car = 4500 N m⁻¹
Mark scheme
58Oct / Nov 2019 · Paper 13 · Q2Show mark scheme →
AN m and kg m² s⁻²
BN s and kg m s⁻¹
CJ s⁻¹ and kg m² s⁻³
DPa and kg m s⁻²
Mark scheme
59May / June 2019 · Paper 11 · Q1Show mark scheme →
Ajoule
Bnewton
Cpascal
Dwatt
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60May / June 2019 · Paper 11 · Q2Show mark scheme →
Akg m² s⁻¹
Bkg m² s⁻²
Ckg m² s⁻³
Dkg m² s⁻⁴
Mark scheme
61May / June 2019 · Paper 12 · Q1Show mark scheme →
A2 µJ C⁻¹
B2 mV
C2 pV
D2000 mV
Mark scheme
62May / June 2019 · Paper 12 · Q2Show mark scheme →
Aelectric field strength: 3, power: 3
Belectric field strength: 3, power: 2
Celectric field strength: 4, power: 2
Delectric field strength: 4, power: 3
Mark scheme
63May / June 2019 · Paper 12 · Q3Show mark scheme →
Ah = DE/v where D is distance, E is energy and v is velocity
Bh = v/D where v is velocity and D is distance
Ch = 1/(4πE) where E is electric field strength
Dh = Fr²/m where F is force, r is radius and m is mass
Mark scheme
64May / June 2019 · Paper 13 · Q1Show mark scheme →
Acurrent
Bgram
Ckelvin
Dvolt
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65May / June 2019 · Paper 13 · Q2Show mark scheme →
A2.3 × 10⁴ μg cm⁻³
B2.3 × 10⁴ g cm⁻³
C2.3 kg cm⁻³
D2.3 × 10⁻² kg cm⁻³
Mark scheme
66May / June 2019 · Paper 13 · Q5Show mark scheme →
AµA 1600
BµA 160
CmA 16.0
DA 1.60
Mark scheme
67Feb / March 2019 · Paper 12 · Q2Show mark scheme →
Am^2 s^-2 K^-3
Bm^2 s^-2 K^-4
Ckg m^2 s^-2 K^-3
Dkg m^2 s^-2 K^-4
Mark scheme
68Oct / Nov 2018 · Paper 11 · Q2Show mark scheme →
Akg m⁻² s⁻¹
Bkg m² s⁻³
Ckg s⁻²
Dkg s⁻³
Mark scheme
69Oct / Nov 2018 · Paper 12 · Q2Show mark scheme →
Akg m² s⁻² A⁻¹
Bkg m² s⁻³ A⁻²
Ckg m s⁻² A⁻¹
Dkg m s⁻³ A⁻¹
Mark scheme
70Oct / Nov 2018 · Paper 12 · Q33Show mark scheme →
Aampere and second
Bampere and volt
Cvolt and ohm
Dvolt and second
Mark scheme
71Oct / Nov 2018 · Paper 13 · Q2Show mark scheme →
Aenergy / distance
Bforce
Cpower × time
Drate of change of momentum
Mark scheme
72Oct / Nov 2018 · Paper 13 · Q14Show mark scheme →
AN m⁻³
Bg mm⁻¹
Ckg cm⁻²
Dµg mm⁻³
Mark scheme
73May / June 2018 · Paper 11 · Q1Show mark scheme →
Akg m⁻¹ s⁻²
Bkg m⁻² s⁻²
CN m⁻¹
DN m
Mark scheme
74May / June 2018 · Paper 12 · Q2Show mark scheme →
A1
B2
C3
D4
Mark scheme
75Feb / March 2018 · Paper 12 · Q1Show mark scheme →
Aampere per second
Bjoule per volt
Cwatt per ampere
Dwatt per volt
Mark scheme
76Feb / March 2018 · Paper 12 · Q2Show mark scheme →
Aefficiency — no unit
Bmoment of force — N m–1
Cmomentum — N s
Dwork done — J
Mark scheme
77Oct / Nov 2017 · Paper 11 · Q1Show mark scheme →
Aunit of force, kg m s⁻²
Bunit of momentum, kg m s⁻¹
Cunit of pressure, kg m⁻² s⁻²
Dunit of work, kg m² s⁻²
Mark scheme
78Oct / Nov 2017 · Paper 12 · Q1Show mark scheme →
Am s⁻² and N kg⁻¹
BN s and kg m s⁻¹
CPa and N m⁻²
DV m⁻² and N C⁻¹
Mark scheme
79Oct / Nov 2017 · Paper 12 · Q3Show mark scheme →
Am s⁻² K⁻¹
Bm s⁻¹ K⁻¹
Cm² s⁻² K⁻¹
Dm² s⁻¹ K⁻¹
Mark scheme
80Oct / Nov 2017 · Paper 13 · Q1Show mark scheme →
A$10^3$
B$10^6$
C$10^9$
D$10^{12}$
Mark scheme
81Oct / Nov 2017 · Paper 13 · Q2Show mark scheme →
A1
B2
C3
D4
Mark scheme
82May / June 2017 · Paper 11 · Q3Show mark scheme →
A1/2
B1
C3/2
D2
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83May / June 2017 · Paper 12 · Q3Show mark scheme →
AA Ω
BW A–1
Ckg m2 s–1 A–1
Dkg m2 s–3 A–1
Mark scheme
84May / June 2017 · Paper 12 · Q13Show mark scheme →
As$^{-2}$
Bkg$^2$ s$^{-2}$
Ckg$^2$ m$^2$ s$^{-2}$
Dm$^2$ s$^{-2}$
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85May / June 2017 · Paper 13 · Q3Show mark scheme →
Akg m² s⁻¹ A⁻¹
Bkg m s⁻² A
Ckg m² s⁻¹ A
Dkg m² s⁻³ A⁻¹
Mark scheme
86Feb / March 2017 · Paper 12 · Q1Show mark scheme →
A\frac{\text{force}}{\text{length} \times \text{speed}}
B\frac{\text{force}}{\text{length} \times \text{time}}
C\frac{\text{mass}}{\text{length} \times (\text{time})^2}
D\frac{\text{mass} \times (\text{time})^2}{\text{length}}
Mark scheme
87Oct / Nov 2016 · Paper 11 · Q2Show mark scheme →
Akg m^3 s^{-4} A^2
Bkg m^3 s^{-4} A^{-2}
Ckg m^3 A^2
Dkg m^3 A^{-2}
Mark scheme
88Oct / Nov 2016 · Paper 12 · Q2Show mark scheme →
Am⁻¹ s
Bm³ s⁻³
Cm⁻⁴ s⁻⁴
Dno units
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89Oct / Nov 2016 · Paper 13 · Q2Show mark scheme →
Akg m^3 s^{-4} A^2
Bkg m^3 s^{-4} A^{-2}
Ckg m^3 A^2
Dkg m^3 A^{-2}
Mark scheme
90May / June 2016 · Paper 11 · Q2Show mark scheme →
Aelectromotive force and electric potential difference
Bpressure and stress
Cspring constant and moment of a force
Dtorque and work
Mark scheme
91May / June 2016 · Paper 12 · Q1Show mark scheme →
Aacceleration of a bicycle = 1.4 m s⁻¹
Belectric current in a lamp = 0.25 A s⁻¹
Celectric potential difference across a battery = 8.0 J C⁻¹
Dkinetic energy of a car = 4500 N m⁻¹
Mark scheme
92May / June 2016 · Paper 12 · Q2Show mark scheme →
Akg m² s⁻¹
Bkg m² s⁻²
Ckg m² s⁻³
Dkg m² s⁻⁴
Mark scheme
93May / June 2016 · Paper 13 · Q1Show mark scheme →
Aampere, kelvin, joule, gram
Bkilogram, newton, metre, ampere
Cmetre, coulomb, second, kelvin
Dsecond, kelvin, ampere, kilogram
Mark scheme
94May / June 2016 · Paper 13 · Q2Show mark scheme →
Akg m s⁻²
Bkg s⁻²
Ckg m s⁻¹
Dkg s⁻¹
Mark scheme
95Feb / March 2016 · Paper 12 · Q1Show mark scheme →
An 10⁻⁶, µ 10⁻⁹, p 10⁻¹²
Bn 10⁻⁶, µ 10⁻¹², p 10⁻⁹
Cn 10⁻⁹, µ 10⁻⁶, p 10⁻¹²
Dn 10⁻¹², µ 10⁻⁹, p 10⁻⁶
Mark scheme
96Feb / March 2016 · Paper 12 · Q3Show mark scheme →
Am s⁻² K⁻¹
Bkg m s⁻¹ K⁻¹
Cm² s⁻² K⁻¹
Dkg m² s⁻¹ K⁻¹
Mark scheme