Electromotive force and potential difference
4.2.3What the syllabus asks of you
- Define e.m.f. (electromotive force) as the electrical work done by a source in moving a unit charge around a complete circuit; recall and use the equation e.m.f. = work done (by a source) / charge E = W / Q
- Define p.d. (potential difference) as the work done by a unit charge passing through a component; recall and use the equation p.d. = work done (on a component) / charge V = W / Q
- Know that e.m.f. and p.d. are measured in volts and that the volt is given by joule per coulomb ( J / C)
- Describe the use of voltmeters (analogue and digital) with different ranges
- Calculate the total e.m.f. where several sources are arranged in series
- State that the e.m.f of identical sources connected in parallel is equal to the e.m.f. of one of the sources
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Chapter 4: Electromotive force and potential difference
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19 questions
1May / June 2025 · Paper 12 · Q28Show mark scheme →
Aelectromotive force, N
Belectromotive force, V
Cpotential difference, N
Dpotential difference, V
Mark scheme
2Oct / Nov 2024 · Paper 11 · Q32Show mark scheme →
Apower
Bpotential difference
Celectromotive force
Denergy
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3Oct / Nov 2024 · Paper 11 · Q33Show mark scheme →
A0 V
B1.5 V
C3.0 V
D4.5 V
Mark scheme
4Oct / Nov 2024 · Paper 12 · Q29Also set in May / June 2016 Paper 11, May / June 2016 Paper 12Show mark scheme →
Aone coulomb per ampere
Bone coulomb per joule
Cone joule per ampere
Done joule per coulomb
Mark scheme
5May / June 2024 · Paper 12 · Q28Show mark scheme →
Ap.d. = voltage × current
Bp.d. = energy / time
Cp.d. = work done / charge
Dp.d. = current / resistance
Mark scheme
6May / June 2023 · Paper 11 · Q29Also set in May / June 2016 Paper 12Show mark scheme →
AThe battery can supply a current for a longer time than a single 1.5 V cell.
BThe battery can supply any e.m.f. between 0 V and 4.5 V.
CThe battery supplies more energy to each coulomb of charge than a single 1.5 V cell.
DThe e.m.f. of the battery is 4.5 V.
Mark scheme
7May / June 2023 · Paper 12 · Q28Show mark scheme →
AEach cell produces more energy.
BEach cell supplies more charge.
CEach cell takes longer to discharge.
DThe e.m.f. is greater than that of a single cell.
Mark scheme
8Oct / Nov 2022 · Paper 11 · Q28Show mark scheme →
Awork done × time
Bwork done × charge
Cwork done / time
Dwork done / charge
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9May / June 2022 · Paper 11 · Q33Show mark scheme →
Aunit: ampere, instrument: ammeter
Bunit: ampere, instrument: voltmeter
Cunit: volt, instrument: ammeter
Dunit: volt, instrument: voltmeter
Mark scheme
10May / June 2022 · Paper 12 · Q33Show mark scheme →
A0.020 V
B0.040 V
C25 V
D50 V
Mark scheme
11Oct / Nov 2021 · Paper 11 · Q29Show mark scheme →
Aelectrical resistance
Belectric current
Celectrical power
Delectromotive force
Mark scheme
12Oct / Nov 2021 · Paper 12 · Q33Show mark scheme →
AX: electromotive force, Y: potential difference, Z: coulomb
BX: electromotive force, Y: potential difference, Z: volt
CX: potential difference, Y: electromotive force, Z: coulomb
DX: potential difference, Y: electromotive force, Z: volt
Mark scheme
13May / June 2020 · Paper 11 · Q36Show mark scheme →
AJ / C; the sum of the e.m.f.s of the three cells
BJ / C; the e.m.f. of one of the cells
CN / V; the sum of the e.m.f.s of the three cells
DN / V; the e.m.f. of one of the cells
Mark scheme
14May / June 2019 · Paper 11 · Q32Show mark scheme →
Aampere / ohm
Bampere / watt
Cohm / ampere
Dwatt / ampere
Mark scheme
15May / June 2019 · Paper 12 · Q34Show mark scheme →
AThe current I is 2 A.
BThe e.m.f. E is 12 J.
CThe p.d. V (across the resistor) is 10 V.
DThe resistance R is 5 Ω.
Mark scheme
16Oct / Nov 2018 · Paper 11 · Q29Show mark scheme →
A0.20 J
B2.0 J
C5.0 J
D20 J
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17Oct / Nov 2017 · Paper 11 · Q29Show mark scheme →
A\frac{\text{work done}}{\text{charge}}
B\frac{\text{charge}}{\text{time}}
C\frac{\text{work done}}{\text{charge}}
D\frac{\text{work done}}{\text{time}}
Mark scheme
18Oct / Nov 2017 · Paper 12 · Q31Also set in Oct / Nov 2017 Paper 11Show mark scheme →
AI1 > I2, 2.0
BI1 > I2, 4.0
CI1 = I2, 2.0
DI1 = I2, 4.0
Mark scheme
19May / June 2017 · Paper 11 · Q37Show mark scheme →
AThe battery has a greater e.m.f. than a single cell on its own.
BThe battery has a lower e.m.f. than a single cell on its own.
CThe battery lasts longer than a single cell on its own.
DThe battery supplies a smaller current than a single cell on its own.
Mark scheme