AQA A-LEVEL PHYSICS · 7408
Paper 2
Revision Notes
Thermal physics · Fields · Capacitors · Magnetism and induction
· Nuclear physics
Thermal physics Gravitational fields Electric fields
Capacitors Magnetic fields and induction Nuclear physics
Built from the AQA 7408 specification. Includes worked examples, quick-check
questions with answers, required practicals, an equation list and an exam checklist.
,Contents
Using this pack and data 3
Thermal physics
Thermal energy transfer 4
Worked examples: thermal energy 5
Ideal gases 6
Kinetic theory of gases 7
Worked examples: gases 8
Quick-check questions: thermal physics 9
Gravitational fields
Gravitational fields 10
Orbits of planets and satellites 11
Worked examples: gravitational fields 12
Quick-check questions: gravitational fields 13
Electric fields
Electric fields 14
Gravitational and electric fields compared 15
Worked examples: electric fields 16
Quick-check questions: electric fields 17
Capacitors
Capacitance and energy storage 18
Capacitor charge and discharge 19
Worked examples: capacitors 20
Quick-check questions: capacitors 21
Magnetic fields and induction
Forces in magnetic fields 22
Flux, induction and Faraday’s law 23
Alternating current and transformers 24
Worked examples: magnetism and induction 25
Worked example 6 and quick-check: magnetism 26
Nuclear physics
Radiation and the nucleus 27
Radioactive decay 28
Nuclear instability and size 29
Mass, energy, fission and fusion 30
Worked examples: nuclear physics 31
Worked examples: binding energy, density, fission 32
Quick-check questions: nuclear physics 33
Reference
Required practicals in Paper 2 34
Equations for Paper 2 35
Exam checklist 36
Paper 2 revision notes · 2
,REFERENCE
Using this pack and data
How the pack works
Paper 2 assesses AQA 7408 sections 3.6.2 Thermal physics, 3.7 Fields
and their consequences and 3.8 Nuclear physics, with assumed
knowledge from sections 3.1 to 3.6.1. Written paper, 2 hours, 85 marks
(60 marks of short and long answer questions plus 25 multiple choice
questions).
Each topic has colour-coded notes, worked examples with every step
shown, and a quick-check page with answers.
The last pages hold the required practicals, an equation list and an
exam checklist.
Constants used in the examples
Gravitational constant G 6.67 × 10⁻¹¹ N m² kg⁻²
Permittivity of free space ε₀ 8.85 × 10⁻¹² F m⁻¹
Elementary charge e 1.60 × 10⁻¹⁹ C
Electron mass me 9.11 × 10⁻³¹ kg
Proton mass mp 1.67 × 10⁻²⁷ kg
Boltzmann constant k 1.38 × 10⁻²³ J K⁻¹
Molar gas constant R 8.31 J mol⁻¹ K⁻¹
Avogadro constant NA 6.02 × 10²³ mol⁻¹
Speed of light c 3.00 × 10⁸ m s⁻¹
Atomic mass unit u 1.66 × 10⁻²⁷ kg ≡ 931.5 MeV
Earth mass and radius 5.98 × 10²⁴ kg, 6.37 × 10⁶ m
Rounding
Carry full calculator values through a calculation and round only the final
answer to the same number of significant figures as the data (usually 2 or
3).
Paper 2 revision notes · 3
, THERMAL PHYSICS
Thermal energy transfer
Internal energy
Internal energy is the sum of the randomly distributed kinetic and
potential energies of all the particles in a body.
Heating a system, or doing work on it, increases its internal energy.
Losing energy by heating, or doing work on surroundings, decreases it.
Qualitative first law: change in internal energy = energy transferred by
heating + work done on the system.
During a change of state the potential energies of the particles change
but the kinetic energies do not, so the temperature stays constant.
While temperature changes within one state, the mean kinetic energy
of the particles changes.
Specific heat capacity
Energy needed to raise the temperature of 1 kg of a substance by 1 K (or
1 °C).
Q = m c Δθ (J = kg × J kg⁻¹ K⁻¹ × K)
Specific latent heat
Energy needed to change the state of 1 kg of a substance with no change
in temperature.
Q=ml (lf fusion: solid ↔ liquid, lv vaporisation: liquid ↔
gas)
Continuous flow
For a fluid heated as it flows past a heater, use the mass flowing per
second.
P = (m/t) c Δθ
Exam tip
Heating curves: flat sections are changes of state (potential energy
changing); sloping sections are temperature rising (kinetic energy rising).
A steeper slope means a smaller specific heat capacity for equal power
and mass.
Paper 2 revision notes · 4
Paper 2
Revision Notes
Thermal physics · Fields · Capacitors · Magnetism and induction
· Nuclear physics
Thermal physics Gravitational fields Electric fields
Capacitors Magnetic fields and induction Nuclear physics
Built from the AQA 7408 specification. Includes worked examples, quick-check
questions with answers, required practicals, an equation list and an exam checklist.
,Contents
Using this pack and data 3
Thermal physics
Thermal energy transfer 4
Worked examples: thermal energy 5
Ideal gases 6
Kinetic theory of gases 7
Worked examples: gases 8
Quick-check questions: thermal physics 9
Gravitational fields
Gravitational fields 10
Orbits of planets and satellites 11
Worked examples: gravitational fields 12
Quick-check questions: gravitational fields 13
Electric fields
Electric fields 14
Gravitational and electric fields compared 15
Worked examples: electric fields 16
Quick-check questions: electric fields 17
Capacitors
Capacitance and energy storage 18
Capacitor charge and discharge 19
Worked examples: capacitors 20
Quick-check questions: capacitors 21
Magnetic fields and induction
Forces in magnetic fields 22
Flux, induction and Faraday’s law 23
Alternating current and transformers 24
Worked examples: magnetism and induction 25
Worked example 6 and quick-check: magnetism 26
Nuclear physics
Radiation and the nucleus 27
Radioactive decay 28
Nuclear instability and size 29
Mass, energy, fission and fusion 30
Worked examples: nuclear physics 31
Worked examples: binding energy, density, fission 32
Quick-check questions: nuclear physics 33
Reference
Required practicals in Paper 2 34
Equations for Paper 2 35
Exam checklist 36
Paper 2 revision notes · 2
,REFERENCE
Using this pack and data
How the pack works
Paper 2 assesses AQA 7408 sections 3.6.2 Thermal physics, 3.7 Fields
and their consequences and 3.8 Nuclear physics, with assumed
knowledge from sections 3.1 to 3.6.1. Written paper, 2 hours, 85 marks
(60 marks of short and long answer questions plus 25 multiple choice
questions).
Each topic has colour-coded notes, worked examples with every step
shown, and a quick-check page with answers.
The last pages hold the required practicals, an equation list and an
exam checklist.
Constants used in the examples
Gravitational constant G 6.67 × 10⁻¹¹ N m² kg⁻²
Permittivity of free space ε₀ 8.85 × 10⁻¹² F m⁻¹
Elementary charge e 1.60 × 10⁻¹⁹ C
Electron mass me 9.11 × 10⁻³¹ kg
Proton mass mp 1.67 × 10⁻²⁷ kg
Boltzmann constant k 1.38 × 10⁻²³ J K⁻¹
Molar gas constant R 8.31 J mol⁻¹ K⁻¹
Avogadro constant NA 6.02 × 10²³ mol⁻¹
Speed of light c 3.00 × 10⁸ m s⁻¹
Atomic mass unit u 1.66 × 10⁻²⁷ kg ≡ 931.5 MeV
Earth mass and radius 5.98 × 10²⁴ kg, 6.37 × 10⁶ m
Rounding
Carry full calculator values through a calculation and round only the final
answer to the same number of significant figures as the data (usually 2 or
3).
Paper 2 revision notes · 3
, THERMAL PHYSICS
Thermal energy transfer
Internal energy
Internal energy is the sum of the randomly distributed kinetic and
potential energies of all the particles in a body.
Heating a system, or doing work on it, increases its internal energy.
Losing energy by heating, or doing work on surroundings, decreases it.
Qualitative first law: change in internal energy = energy transferred by
heating + work done on the system.
During a change of state the potential energies of the particles change
but the kinetic energies do not, so the temperature stays constant.
While temperature changes within one state, the mean kinetic energy
of the particles changes.
Specific heat capacity
Energy needed to raise the temperature of 1 kg of a substance by 1 K (or
1 °C).
Q = m c Δθ (J = kg × J kg⁻¹ K⁻¹ × K)
Specific latent heat
Energy needed to change the state of 1 kg of a substance with no change
in temperature.
Q=ml (lf fusion: solid ↔ liquid, lv vaporisation: liquid ↔
gas)
Continuous flow
For a fluid heated as it flows past a heater, use the mass flowing per
second.
P = (m/t) c Δθ
Exam tip
Heating curves: flat sections are changes of state (potential energy
changing); sloping sections are temperature rising (kinetic energy rising).
A steeper slope means a smaller specific heat capacity for equal power
and mass.
Paper 2 revision notes · 4
