Source: https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/9-3-1-doppler-effect

[Revision notes](https://senecalearning.com/en-gb/revision-notes.md) › [A Level](https://senecalearning.com/en-gb/revision-notes/a-level.md) › [Physics](https://senecalearning.com/en-gb/revision-notes/a-level/physics.md) › [AQA](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa.md) › Doppler Effect

# Doppler Effect

Physics: AQA A Level, topic 9.3.1

## Doppler Effect

The Doppler effect, applied to electromagnetic radiation, is very useful in astrophysics and cosmology.

### Formula

![Formula](https://image-v2.cdn.app.senecalearning.com/2018-09/20334b5d-1b76-4e02-ba69-a21455d2e814/trigonometry-calculator-maths-.jpg)

- For electromagnetic radiation, the following formula holds providing that the velocity of the source of the radiation is significantly lower than the speed of light.
 - $$\frac{\Delta f}{f} \approx \frac{v}{c}$$ 
- Where f is the frequency of light, and v is the speed of the emitting source.

### Moving star

![Moving star](https://image-v2.cdn.app.senecalearning.com/courseImages/physics/AQA%20New%20Modules/8.1.1/large%20star.jpg)

- For a single star moving away from the Earth at a constant speed, the light from the star decreases in frequency.
- If the star is moving away at 0.01c (one hundredth of the speed of light), then the frequency of any given wavelength (typically one of the hydrogen lines) will be lower by 1%.

## Binary Stars

Binary stars are systems where two similar stars orbit around their combined centre of gravity.

### Spectral line splitting

![Spectral line splitting](https://image-v2.cdn.app.senecalearning.com/2018-10/b022d107-906f-4e07-9385-4367bc0e6812/binary-star-system.png)

- In a binary system, in which two stars orbit around a common centre of gravity, then the spectral line splits into two.

### Explanation

![Explanation](https://image-v2.cdn.app.senecalearning.com/2018-04/245c7596-7d84-4f2a-bee6-80961a1e1291/shutterstock_276228476.jpg)

- This is explained by one star moving away from the Earth slightly less quickly and the other star moving away from the Earth slightly more quickly than in the single star case.

### Orbital velocity

![Orbital velocity](https://image-v2.cdn.app.senecalearning.com/2018-09/76cfa754-9e3b-480a-b91c-7dcd82fdd16c/solar-system-earth-sun-orbit-.jpg)

- The orbital velocity can be found by finding the recession speeds of the two stars (the speed the stars are moving away from us) and finding the difference.
- Half of that difference is the orbital speed of the star (assuming the two stars to be identical).

## Galaxies and Quasars

Galaxies are vast collections of stars in space.  Quasars are very massive, high energy objects found in deep space.

### Cosmological redshift

![Cosmological redshift](https://image-v2.cdn.app.senecalearning.com/2018-03/a382cdac-83a5-44fe-892a-cfe863058f79/shutterstock_557777728.jpg)

- For galaxies and quasars, there is also a cosmological redshift, z, which is due to the expansion of the Universe itself. 
- For low velocities:
 - $$ z = \frac{v}{c}$$

### Very distant objects

![Very distant objects](https://image-v2.cdn.app.senecalearning.com/2018-08/260e9340-96bc-4757-a576-f1c670fd8afc/andromeda-galaxy-755442_1280.jpg)

- Very distant galaxies and quasars can have enormous z-values which can only really be explained by general relativity calculations.

## Test yourself on Doppler Effect

- What is the formula for the Doppler shift?
- If two stars in a binary system are identical what is the orbital speed?
- Which of these statements are true about binary stars?
- What is a binary star system?
- What is the equation for the expansion factor due to cosmological redshift?

[Practise this topic for free](https://app.senecalearning.com/classroom/course/890da800-6a58-11e8-973c-cb81832c8407/section/75ee4c10-765e-4bed-bfea-9b8cfb215512/session)

- Previous topic: [9.2.6 Astronomical Objects](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/9-2-6-astronomical-objects.md)
- Next topic: [9.3.2 Hubble's Law](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/9-3-2-hubbles-law.md)

## Physics: AQA A Level contents

### 1 Measurements & Errors
- 1.1 Measurements & Errors
  - [1.1.1 SI Base Units](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/1-1-1-si-base-units.md)
  - [1.1.2 Combining SI Units](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/1-1-2-combining-si-units.md)
  - [1.1.3 Prefixes of Units](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/1-1-3-prefixes-of-units.md)
  - [1.1.4 Standard Form](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/1-1-4-standard-form.md)
  - [1.1.5 Converting Units](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/1-1-5-converting-units.md)
  - [1.1.6 End of Topic Test - Units & Prefixes](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/1-1-6-end-of-topic-test-units-and-prefixes.md)
  - [1.1.7 Limitation of Physical Measurements](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/1-1-7-limitation-of-physical-measurements.md)
  - [1.1.8 Uncertainty](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/1-1-8-uncertainty.md)
  - [1.1.9 Estimation](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/1-1-9-estimation.md)
  - [1.1.10 End of Topic Test - Measurements & Errors](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/1-1-10-end-of-topic-test-measurements-and-errors.md)
  - [1.1.11 Diagnostic Misconceptions - Converting between SI](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/1-1-11-diagnostic-misconceptions-converting-between-si.md)
  - [1.1.12 Diagnostic Misconceptions - SI & Area/Volume](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/1-1-12-diagnostic-misconceptions-si-and-areavolume.md)

### 2 Particles & Radiation
- 2.1 Particles
  - [2.1.1 Atomic Model](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-1-1-atomic-model.md)
  - [2.1.2 Specific Charge, Protons & Neutron Numbers](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-1-2-specific-charge-protons-and-neutron-numbers.md)
  - [2.1.3 End of Topic Test - Atomic Model](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-1-3-end-of-topic-test-atomic-model.md)
  - [2.1.4 Isotopes](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-1-4-isotopes.md)
  - [2.1.5 Stable & Unstable Nuclei](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-1-5-stable-and-unstable-nuclei.md)
  - [2.1.6 End of Topic Test - Isotopes & Nuclei](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-1-6-end-of-topic-test-isotopes-and-nuclei.md)
  - [2.1.7 A-A* (AO3/4) - Stable & Unstable Nuclei](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-1-7-a-a-ao34-stable-and-unstable-nuclei.md)
  - [2.1.8 Particles, Antiparticles & Photons](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-1-8-particles-antiparticles-and-photons.md)
  - [2.1.9 Particle Interactions](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-1-9-particle-interactions.md)
  - [2.1.10 Classification of Particles](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-1-10-classification-of-particles.md)
  - [2.1.11 End of Topic Test - Particles & Interactions](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-1-11-end-of-topic-test-particles-and-interactions.md)
  - [2.1.12 Quarks & Antiquarks](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-1-12-quarks-and-antiquarks.md)
  - [2.1.13 Application of Conservation Laws](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-1-13-application-of-conservation-laws.md)
  - [2.1.14 End of Topic Test - Leptons & Quarks](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-1-14-end-of-topic-test-leptons-and-quarks.md)
  - [2.1.15 Exam-Style Question -  Radioactive Decay](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-1-15-exam-style-question-radioactive-decay.md)
- 2.2 Electromagnetic Radiation & Quantum Phenomena
  - [2.2.1 The Photoelectric Effect](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-2-1-the-photoelectric-effect.md)
  - [2.2.2 The Photoelectric Effect Explanation](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-2-2-the-photoelectric-effect-explanation.md)
  - [2.2.3 End of Topic Test - The Photoelectric Effect](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-2-3-end-of-topic-test-the-photoelectric-effect.md)
  - [2.2.4 Collisions of Electrons with Atoms](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-2-4-collisions-of-electrons-with-atoms.md)
  - [2.2.5 Energy Levels & Photon Emission](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-2-5-energy-levels-and-photon-emission.md)
  - [2.2.6 Wave-Particle Duality](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-2-6-wave-particle-duality.md)
  - [2.2.7 End of Topic Test - Absorption & Emission](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-2-7-end-of-topic-test-absorption-and-emission.md)
  - [2.2.8 Diagnostic Misconceptions - Electron Volts](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-2-8-diagnostic-misconceptions-electron-volts.md)
  - [2.2.9 Diagnostic Misconceptions - Converting eV & Joules](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/2-2-9-diagnostic-misconceptions-converting-ev-and-joules.md)

### 3 Waves
- 3.1 Progressive & Stationary Waves
  - [3.1.1 Progressive Waves](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-1-1-progressive-waves.md)
  - [3.1.2 Wave Speed & Phase Difference](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-1-2-wave-speed-and-phase-difference.md)
  - [3.1.3 Longitudinal & Transverse Waves](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-1-3-longitudinal-and-transverse-waves.md)
  - [3.1.4 End of Topic Test - Progressive Waves](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-1-4-end-of-topic-test-progressive-waves.md)
  - [3.1.5 Polarisation](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-1-5-polarisation.md)
  - [3.1.6 Stationary Waves](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-1-6-stationary-waves.md)
  - [3.1.7 Stationary Waves 2](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-1-7-stationary-waves-2.md)
  - [3.1.8 End of Topic Test - Polarisation & Stationary Wave](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-1-8-end-of-topic-test-polarisation-and-stationary-wave.md)
  - [3.1.9 A-A* (AO3/4) - Stationary Waves](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-1-9-a-a-ao34-stationary-waves.md)
- 3.2 Refraction, Diffraction & Interference
  - [3.2.1 Interference](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-2-1-interference.md)
  - [3.2.2 Interference 2](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-2-2-interference-2.md)
  - [3.2.3 End of Topic Test - Interference](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-2-3-end-of-topic-test-interference.md)
  - [3.2.4 Diffraction](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-2-4-diffraction.md)
  - [3.2.5 Diffraction Gratings](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-2-5-diffraction-gratings.md)
  - [3.2.6 End of Topic Test - Diffraction](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-2-6-end-of-topic-test-diffraction.md)
  - [3.2.7 Refraction at a Plane Surface](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-2-7-refraction-at-a-plane-surface.md)
  - [3.2.8 Internal Reflection & Fibre Optics](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-2-8-internal-reflection-and-fibre-optics.md)
  - [3.2.9 End of Topic Test - Refraction](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-2-9-end-of-topic-test-refraction.md)
  - [3.2.10 Exam-Style Question - Waves](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/3-2-10-exam-style-question-waves.md)

### 4 Mechanics & Materials
- 4.1 Force, Energy & Momentum
  - [4.1.1 Scalars & Vectors](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-1-scalars-and-vectors.md)
  - [4.1.2 Vector Problems](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-2-vector-problems.md)
  - [4.1.3 End of Topic Test - Scalars & Vectors](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-3-end-of-topic-test-scalars-and-vectors.md)
  - [4.1.4 Moments](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-4-moments.md)
  - [4.1.5 Centre of Mass](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-5-centre-of-mass.md)
  - [4.1.6 End of Topic Test - Moments & Centre of Mass](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-6-end-of-topic-test-moments-and-centre-of-mass.md)
  - [4.1.7 Motion in a Straight Line](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-7-motion-in-a-straight-line.md)
  - [4.1.8 Graphs of Motion](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-8-graphs-of-motion.md)
  - [4.1.9 Bouncing Ball Example](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-9-bouncing-ball-example.md)
  - [4.1.10 End of Topic Test - Motion in a Straight Line](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-10-end-of-topic-test-motion-in-a-straight-line.md)
  - [4.1.11 Acceleration Due to Gravity](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-11-acceleration-due-to-gravity.md)
  - [4.1.12 Projectile Motion](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-12-projectile-motion.md)
  - [4.1.13 Friction](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-13-friction.md)
  - [4.1.14 Terminal Speed](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-14-terminal-speed.md)
  - [4.1.15 End of Topic Test - Acceleration Due to Gravity](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-15-end-of-topic-test-acceleration-due-to-gravity.md)
  - [4.1.16 Newton's Laws](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-16-newtons-laws.md)
  - [4.1.17 Momentum](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-17-momentum.md)
  - [4.1.18 Momentum 2](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-18-momentum-2.md)
  - [4.1.19 End of Topic Test - Newton's Laws & Momentum](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-19-end-of-topic-test-newtons-laws-and-momentum.md)
  - [4.1.20 A-A* (AO3/4) - Newton's Third Law](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-20-a-a-ao34-newtons-third-law.md)
  - [4.1.21 Work & Energy](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-21-work-and-energy.md)
  - [4.1.22 Power & Efficiency](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-22-power-and-efficiency.md)
  - [4.1.23 Conservation of Energy](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-23-conservation-of-energy.md)
  - [4.1.24 End of Topic Test - Work, Energy & Power](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-24-end-of-topic-test-work-energy-and-power.md)
  - [4.1.25 Exam-Style Question - Forces](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-25-exam-style-question-forces.md)
  - [4.1.26 Diagnostic Misconceptions - Perpendicular Vectors](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-26-diagnostic-misconceptions-perpendicular-vectors.md)
  - [4.1.27 Diagnostic Misconceptions - Weight Acts Downwards](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-27-diagnostic-misconceptions-weight-acts-downwards.md)
  - [4.1.28 Diagnostic Misconceptions - Acceleration Direction](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-28-diagnostic-misconceptions-acceleration-direction.md)
  - [4.1.29 Diagnostic Misconceptions - Stationary Objects](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-29-diagnostic-misconceptions-stationary-objects.md)
  - [4.1.30 Diagnostic Misconceptions - Action & Reaction](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-30-diagnostic-misconceptions-action-and-reaction.md)
  - [4.1.31 Diagnostic Misconceptions - RF Direction](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-31-diagnostic-misconceptions-rf-direction.md)
  - [4.1.32 Diagnostic Misconceptions - RF Acceleration](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-32-diagnostic-misconceptions-rf-acceleration.md)
  - [4.1.33 Diagnostic Misconceptions - Change in Momentum](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-1-33-diagnostic-misconceptions-change-in-momentum.md)
- 4.2 Materials
  - [4.2.1 Density](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-2-1-density.md)
  - [4.2.2 Bulk Properties of Solids](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-2-2-bulk-properties-of-solids.md)
  - [4.2.3 Energy in Materials](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-2-3-energy-in-materials.md)
  - [4.2.4 Young Modulus](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-2-4-young-modulus.md)
  - [4.2.5 End of Topic Test - Materials](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/4-2-5-end-of-topic-test-materials.md)

### 5 Electricity
- 5.1 Current Electricity
  - [5.1.1 Basics of Electricity](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/5-1-1-basics-of-electricity.md)
  - [5.1.2 Current-Voltage Characteristics](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/5-1-2-current-voltage-characteristics.md)
  - [5.1.3 End of Topic Test - Basics of Electricity](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/5-1-3-end-of-topic-test-basics-of-electricity.md)
  - [5.1.4 Resistivity](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/5-1-4-resistivity.md)
  - [5.1.5 Superconductivity](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/5-1-5-superconductivity.md)
  - [5.1.6 A-A* (AO3/4) - Superconductivity](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/5-1-6-a-a-ao34-superconductivity.md)
  - [5.1.7 End of Topic Test - Resistivity & Superconductors](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/5-1-7-end-of-topic-test-resistivity-and-superconductors.md)
  - [5.1.8 Circuits](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/5-1-8-circuits.md)
  - [5.1.9 Power and Conservation](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/5-1-9-power-and-conservation.md)
  - [5.1.10 Potential Divider](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/5-1-10-potential-divider.md)
  - [5.1.11 Emf & Internal Resistance](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/5-1-11-emf-and-internal-resistance.md)
  - [5.1.12 End of Topic Test - Power & Potential](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/5-1-12-end-of-topic-test-power-and-potential.md)
  - [5.1.13 Exam-Style Question - Resistance](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/5-1-13-exam-style-question-resistance.md)
  - [5.1.14 Diagnostic Misconceptions - Constant Current](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/5-1-14-diagnostic-misconceptions-constant-current.md)
  - [5.1.15 Diagnostic Misconceptions - Potential Difference](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/5-1-15-diagnostic-misconceptions-potential-difference.md)

### 6 Further Mechanics & Thermal Physics (A2 only)
- 6.1 Periodic Motion (A2 only)
  - [6.1.1 Circular Motion](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-1-1-circular-motion.md)
  - [6.1.2 Circular Motion 2](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-1-2-circular-motion-2.md)
  - [6.1.3 End of Topic Test - Circular Motion](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-1-3-end-of-topic-test-circular-motion.md)
  - [6.1.4 Simple Harmonic Motion](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-1-4-simple-harmonic-motion.md)
  - [6.1.5 Simple Harmonic Systems](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-1-5-simple-harmonic-systems.md)
  - [6.1.6 Energy in Simple Harmonic Motion](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-1-6-energy-in-simple-harmonic-motion.md)
  - [6.1.7 Resonance](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-1-7-resonance.md)
  - [6.1.8 End of Topic Test - Simple Harmonic Motion](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-1-8-end-of-topic-test-simple-harmonic-motion.md)
  - [6.1.9 A-A* (AO3/4) - Simple Harmonic Motion](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-1-9-a-a-ao34-simple-harmonic-motion.md)
- 6.2 Thermal Physics (A2 only)
  - [6.2.1 Thermal Energy Transfer](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-2-1-thermal-energy-transfer.md)
  - [6.2.2 Thermal Energy Transfer Experiments](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-2-2-thermal-energy-transfer-experiments.md)
  - [6.2.3 Ideal Gases](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-2-3-ideal-gases.md)
  - [6.2.4 Ideal Gases 2](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-2-4-ideal-gases-2.md)
  - [6.2.5 Boyle's Law & Charles' Law](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-2-5-boyles-law-and-charles-law.md)
  - [6.2.6 Molecular Kinetic Theory Model](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-2-6-molecular-kinetic-theory-model.md)
  - [6.2.7 Molecular Kinetic Theory Model 2](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-2-7-molecular-kinetic-theory-model-2.md)
  - [6.2.8 End of Topic Test - Thermal Energy & Ideal Gases](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-2-8-end-of-topic-test-thermal-energy-and-ideal-gases.md)
  - [6.2.9 Exam-Style Question - Ideal Gases](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-2-9-exam-style-question-ideal-gases.md)
  - [6.2.10 Diagnostic Misconceptions - Material & Mass](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-2-10-diagnostic-misconceptions-material-and-mass.md)
  - [6.2.11 Diagnostic Misconceptions - No Energy](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/6-2-11-diagnostic-misconceptions-no-energy.md)

### 7 Fields & Their Consequences (A2 only)
- 7.1 Fields (A2 only)
  - [7.1.1 Fields](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-1-1-fields.md)
- 7.2 Gravitational Fields (A2 only)
  - [7.2.1 Newton's Law](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-2-1-newtons-law.md)
  - [7.2.2 Gravitational Field Strength](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-2-2-gravitational-field-strength.md)
  - [7.2.3 Gravitational Potential](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-2-3-gravitational-potential.md)
  - [7.2.4 Orbits of Planets & Satellites](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-2-4-orbits-of-planets-and-satellites.md)
  - [7.2.5 Escape Velocity & Synchronous Orbits](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-2-5-escape-velocity-and-synchronous-orbits.md)
  - [7.2.6 End of Topic Test - Gravitational Fields](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-2-6-end-of-topic-test-gravitational-fields.md)
- 7.3 Electric Fields (A2 only)
  - [7.3.1 Coulomb's Law](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-3-1-coulombs-law.md)
  - [7.3.2 Electric Field Strength](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-3-2-electric-field-strength.md)
  - [7.3.3 Electric Field Strength 2](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-3-3-electric-field-strength-2.md)
  - [7.3.4 Electric Potential](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-3-4-electric-potential.md)
  - [7.3.5 End of Topic Test - Electric Fields](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-3-5-end-of-topic-test-electric-fields.md)
  - [7.3.6 A-A* (AO3/4) - Electric and Gravitational Field](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-3-6-a-a-ao34-electric-and-gravitational-field.md)
- 7.4 Capacitance (A2 only)
  - [7.4.1 Capacitance](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-4-1-capacitance.md)
  - [7.4.2 Parallel Plate Capacitor](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-4-2-parallel-plate-capacitor.md)
  - [7.4.3 Energy Stored by a Capacitor](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-4-3-energy-stored-by-a-capacitor.md)
  - [7.4.4 Capacitor Discharge](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-4-4-capacitor-discharge.md)
  - [7.4.5 Capacitor Charge](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-4-5-capacitor-charge.md)
- 7.5 Magnetic Fields (A2 only)
  - [7.5.1 Magnetic Flux Density](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-5-1-magnetic-flux-density.md)
  - [7.5.2 End of Topic Test - Capacitance & Flux Density](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-5-2-end-of-topic-test-capacitance-and-flux-density.md)
  - [7.5.3 Moving Charges in a Magnetic Field](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-5-3-moving-charges-in-a-magnetic-field.md)
  - [7.5.4 Magnetic Flux & Flux Linkage](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-5-4-magnetic-flux-and-flux-linkage.md)
  - [7.5.5 Electromagnetic Induction](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-5-5-electromagnetic-induction.md)
  - [7.5.6 Electromagnetic Induction 2](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-5-6-electromagnetic-induction-2.md)
  - [7.5.7 Alternating Currents](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-5-7-alternating-currents.md)
  - [7.5.8 Operation of a Transformer](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-5-8-operation-of-a-transformer.md)
  - [7.5.9 Magnetic Flux Density](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-5-9-magnetic-flux-density.md)
  - [7.5.10 End of Topic Test - Electromagnetic Induction](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/7-5-10-end-of-topic-test-electromagnetic-induction.md)

### 8 Nuclear Physics (A2 only)
- 8.1 Radioactivity (A2 only)
  - [8.1.1 Rutherford Scattering](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/8-1-1-rutherford-scattering.md)
  - [8.1.2 Alpha & Beta Radiation](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/8-1-2-alpha-and-beta-radiation.md)
  - [8.1.3 Gamma Radiation](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/8-1-3-gamma-radiation.md)
  - [8.1.4 Radioactive Decay](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/8-1-4-radioactive-decay.md)
  - [8.1.5 Half Life](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/8-1-5-half-life.md)
  - [8.1.6 End of Topic Test - Radioactivity](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/8-1-6-end-of-topic-test-radioactivity.md)
  - [8.1.7 Nuclear Instability](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/8-1-7-nuclear-instability.md)
  - [8.1.8 Nuclear Radius](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/8-1-8-nuclear-radius.md)
  - [8.1.9 Mass & Energy](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/8-1-9-mass-and-energy.md)
  - [8.1.10 Binding Energy](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/8-1-10-binding-energy.md)
  - [8.1.11 Induced Fission](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/8-1-11-induced-fission.md)
  - [8.1.12 Safety Aspects of Nuclear Reactors](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/8-1-12-safety-aspects-of-nuclear-reactors.md)
  - [8.1.13 End of Topic Test - Nuclear Physics](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/8-1-13-end-of-topic-test-nuclear-physics.md)
  - [8.1.14 A-A* (AO3/4) - Nuclear Fusion](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/8-1-14-a-a-ao34-nuclear-fusion.md)

### 9 Option: Astrophysics (A2 only)
- 9.1 Telescopes (A2 only)
  - [9.1.1 Astronomical Telescopes](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/9-1-1-astronomical-telescopes.md)
  - [9.1.2 Reflecting Telescopes](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/9-1-2-reflecting-telescopes.md)
  - [9.1.3 Single Dish Radio Telescopes](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/9-1-3-single-dish-radio-telescopes.md)
  - [9.1.4 Large Diameter Telescopes](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/9-1-4-large-diameter-telescopes.md)
- 9.2 Classification of Stars (A2 only)
  - [9.2.1 Classification by Luminosity](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/9-2-1-classification-by-luminosity.md)
  - [9.2.2 Absolute Magnitude](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/9-2-2-absolute-magnitude.md)
  - [9.2.3 Black Body Radiation](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/9-2-3-black-body-radiation.md)
  - [9.2.4 Stellar Spectral Classes](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/9-2-4-stellar-spectral-classes.md)
  - [9.2.5 Hertzsprung-Russell Diagrams](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/9-2-5-hertzsprung-russell-diagrams.md)
  - [9.2.6 Astronomical Objects](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/9-2-6-astronomical-objects.md)
- 9.3 Cosmology (A2 only)
  - [9.3.1 Doppler Effect](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/9-3-1-doppler-effect.md)
  - [9.3.2 Hubble's Law](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/9-3-2-hubbles-law.md)
  - [9.3.3 Quasars](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/9-3-3-quasars.md)
  - [9.3.4 Detecting Exoplanets](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/9-3-4-detecting-exoplanets.md)

### 10 Option: Medical Physics (A2 only)
- 10.1 Physics of the Eye (A2 only)
  - [10.1.1 Physics of Vision](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-1-1-physics-of-vision.md)
  - [10.1.2 Defects of Vision](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-1-2-defects-of-vision.md)
  - [10.1.3 Lenses](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-1-3-lenses.md)
  - [10.1.4 Correcting Defects of Vision](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-1-4-correcting-defects-of-vision.md)
- 10.2 Physics of the Ear (A2 only)
  - [10.2.1 Structure of the Ear](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-2-1-structure-of-the-ear.md)
  - [10.2.2 Sensitivity of the Ear](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-2-2-sensitivity-of-the-ear.md)
  - [10.2.3 Hearing Defects](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-2-3-hearing-defects.md)
- 10.3 Biological Measurement (A2 only)
  - [10.3.1 Electrocardiography (ECG)](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-3-1-electrocardiography-ecg.md)
- 10.4 Non-Ionising Imaging (A2 only)
  - [10.4.1 Ultrasound Imaging](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-4-1-ultrasound-imaging.md)
  - [10.4.2 Ultrasound Imaging 2](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-4-2-ultrasound-imaging-2.md)
  - [10.4.3 Fibre Optics & Endoscopy](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-4-3-fibre-optics-and-endoscopy.md)
  - [10.4.4 Magnetic Resonance Scanning](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-4-4-magnetic-resonance-scanning.md)
- 10.5 X-Ray Imaging (A2 only)
  - [10.5.1 Diagnostic X-Rays](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-5-1-diagnostic-x-rays.md)
  - [10.5.2 X-Ray Image Processing](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-5-2-x-ray-image-processing.md)
  - [10.5.3 Absorption of X-Rays](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-5-3-absorption-of-x-rays.md)
  - [10.5.4 CT Scanners](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-5-4-ct-scanners.md)
- 10.6 Radionuclide Imaging & Therapy (A2 only)
  - [10.6.1 Imaging Techniques](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-6-1-imaging-techniques.md)
  - [10.6.2 Half Life](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-6-2-half-life.md)
  - [10.6.3 Gamma Camera](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-6-3-gamma-camera.md)
  - [10.6.4 High Energy X-Rays](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-6-4-high-energy-x-rays.md)
  - [10.6.5 Radioactive Implants](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-6-5-radioactive-implants.md)
  - [10.6.6 Imaging Comparisons](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/10-6-6-imaging-comparisons.md)

### 11 Option: Engineering Physics (A2 only)
- 11.1 Rotational Dynamics (A2 only)
  - [11.1.1 Moment of Inertia](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/11-1-1-moment-of-inertia.md)
  - [11.1.2 Rotational Kinetic Energy](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/11-1-2-rotational-kinetic-energy.md)
  - [11.1.3 Rotational Motion](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/11-1-3-rotational-motion.md)
  - [11.1.4 Torque & Angular Acceleration](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/11-1-4-torque-and-angular-acceleration.md)
  - [11.1.5 Angular Momentum](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/11-1-5-angular-momentum.md)
  - [11.1.6 Angular Work & Power](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/11-1-6-angular-work-and-power.md)
- 11.2 Thermodynamics & Engines (A2 only)
  - [11.2.1 First Law of Thermodynamics](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/11-2-1-first-law-of-thermodynamics.md)
  - [11.2.2 Non-Flow Processes](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/11-2-2-non-flow-processes.md)
  - [11.2.3 p-V Diagrams](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/11-2-3-p-v-diagrams.md)
  - [11.2.4 Engine Cycles](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/11-2-4-engine-cycles.md)
  - [11.2.5 Second Law & Engines](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/11-2-5-second-law-and-engines.md)
  - [11.2.6 Reversed Heat Engines](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/11-2-6-reversed-heat-engines.md)

### 12 Option: Turning Points in Physics (A2 only)
- 12.1 Discovery of the Electron (A2 only)
  - [12.1.1 Cathode Rays](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/12-1-1-cathode-rays.md)
  - [12.1.2 Thermionic Electron Emission](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/12-1-2-thermionic-electron-emission.md)
  - [12.1.3 Electron Specific Charge](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/12-1-3-electron-specific-charge.md)
  - [12.1.4 Millikan's Experiment](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/12-1-4-millikans-experiment.md)
- 12.2 Wave-Particle Duality (A2 only)
  - [12.2.1 Newton's & Huygen's Theories of Light](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/12-2-1-newtons-and-huygens-theories-of-light.md)
  - [12.2.2 Electromagnetic Waves](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/12-2-2-electromagnetic-waves.md)
  - [12.2.3 Photoelectricity](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/12-2-3-photoelectricity.md)
  - [12.2.4 Wave-Particle Duality](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/12-2-4-wave-particle-duality.md)
  - [12.2.5 Electron Microscopes](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/12-2-5-electron-microscopes.md)
- 12.3 Special Relativity (A2 only)
  - [12.3.1 Michelson-Morley Experiment](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/12-3-1-michelson-morley-experiment.md)
  - [12.3.2 Einstein's Theory of Special Relativity](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/12-3-2-einsteins-theory-of-special-relativity.md)
  - [12.3.3 Time Dilation](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/12-3-3-time-dilation.md)
  - [12.3.4 Length Contraction](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/12-3-4-length-contraction.md)
  - [12.3.5 Mass & Energy](https://senecalearning.com/en-gb/revision-notes/a-level/physics/aqa/12-3-5-mass-and-energy.md)