Source: https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-3-3-convection-currents [Revision notes](https://senecalearning.com/en-gb/revision-notes.md) › [IGCSE](https://senecalearning.com/en-gb/revision-notes/igcse.md) › [Physics](https://senecalearning.com/en-gb/revision-notes/igcse/physics.md) › [Cambridge International](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international.md) › [Higher](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher.md) › Convection Currents # Convection Currents Physics: Cambridge International GCSE Supplement, topic 2.3.3 ## Convection Liquids and gases are called fluids because they can flow. They do not conduct heat well, but they can transfer heat energy using convection currents. Convection currents are created by areas of different densities in a fluid. They work like this: ### Stage 1 ![Stage 1](https://image-v2.cdn.app.senecalearning.com/courseImages/physics/2.3.1%20%20Thermal%20Processes/warm-air-rising-min.jpg) - When part of a fluid is heated, the particles in this area gain kinetic energy. - When the particles gain kinetic energy they move away from each other, so the area that has been heated becomes less dense and the warm fluid particles rise. ### Stage 2 ![Stage 2](https://image-v2.cdn.app.senecalearning.com/courseImages/physics/2.3.1%20%20Thermal%20Processes/sinking-ship-min.jpg) - The warm fluid rises and transfers some thermal energy to nearby fluid. - As a consequence the warm fluid becomes less dense and starts to sink. ### Stage 3 ![Stage 3](https://image-v2.cdn.app.senecalearning.com/courseImages/physics/2.3.1%20%20Thermal%20Processes/warm-air-rising-min.jpg) - At the bottom, colder parts of the fluid that hasn’t been heated yet will replace the warm fluid that has risen. - These colder particles are then heated. They move apart and start to rise. ### Stage 4 ![Stage 4](https://image-v2.cdn.app.senecalearning.com/courseImages/physics/2.3.1%20%20Thermal%20Processes/2.3.2%20-%20Convection%20current%20(s1)-min.jpg) - This cycle creates convection currents. Convection currents are the result of different densities in the fluid. These different densities are created by heating. ## Convection Currents - Examples Convection currents are used in: ### Radiators ![Radiators](https://image-v2.cdn.app.senecalearning.com/courseImages/physics/2.3.1%20%20Thermal%20Processes/radiator.jpg) - In colder countries, most homes have heaters (called radiators) fixed at around floor level. - They heat rooms using convection currents. The warm air rises and pushes cold air down to floor level, where it is heated up by the radiator. ### Air Conditioning ![Air Conditioning](https://image-v2.cdn.app.senecalearning.com/courseImages/physics/2.3.1%20%20Thermal%20Processes/air-conditioner.jpg) - In hot countries, most homes have air conditioning (AC) units fixed at the top of the wall. - Hot air rises up to where the AC unit is fixed. It is cooled down and falls, pushing up more hot air to be cooled by the air conditioning unit. ### Weather ![Weather](https://image-v2.cdn.app.senecalearning.com/courseImages/physics/2.1.1%20-%20Matter/windy-day%20-%20Edited-min-min.jpg) - Convection currents can create wind, clouds and other more extreme weather in the atmosphere. ## Test yourself on Convection Currents - Which of the following are true of convection currents in a kettle? - What causes convection currents? - Convection Currents - What can cause extreme weather events? - Suggest how hot air balloons work. [Practise this topic for free](https://app.senecalearning.com/classroom/course/800680e0-d9b4-11e7-8664-d19507716171/section/2ef26940-1b12-11e8-8ccb-ad70f70751b3/session) - Previous topic: [2.3.2 Molecular Conduction](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-3-2-molecular-conduction.md) - Next topic: [2.3.4 Radiation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-3-4-radiation.md) ## Physics: Cambridge International GCSE Supplement contents ### 1 Motion, Forces & Energy - 1.1 Physical Quantities & Measurement Techniques - [1.1.1 Measuring Length](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-1-1-measuring-length.md) - [1.1.2 Measuring Volume](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-1-2-measuring-volume.md) - [1.1.3 Measuring Time](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-1-3-measuring-time.md) - [1.1.4 Scalar & Vector Quantities](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-1-4-scalar-and-vector-quantities.md) - [1.1.5 Adding Vectors](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-1-5-adding-vectors.md) - 1.2 Motion - [1.2.1 Average Speed](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-2-1-average-speed.md) - [1.2.2 Calculating Average Speed](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-2-2-calculating-average-speed.md) - [1.2.3 Velocity](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-2-3-velocity.md) - [1.2.4 Acceleration](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-2-4-acceleration.md) - [1.2.5 Distance-Time Graphs](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-2-5-distance-time-graphs.md) - [1.2.6 Speed-Time Graphs](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-2-6-speed-time-graphs.md) - [1.2.7 More Speed-Time Graphs](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-2-7-more-speed-time-graphs.md) - [1.2.8 Calculating Uniform Acceleration](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-2-8-calculating-uniform-acceleration.md) - [1.2.9 Gravity](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-2-9-gravity.md) - [1.2.10 Free Fall - Distance-Time & Speed-Time Graphs](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-2-10-free-fall-distance-time-and-speed-time-graphs.md) - [1.2.11 Air Resistance](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-2-11-air-resistance.md) - [1.2.12 Air Resistance - Graphs](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-2-12-air-resistance-graphs.md) - [1.2.13 Optional: Calculating Acceleration](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-2-13-optional-calculating-acceleration.md) - 1.3 Mass & Weight - [1.3.1 Mass](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-3-1-mass.md) - [1.3.2 Weight](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-3-2-weight.md) - [1.3.3 Gravity Calculations](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-3-3-gravity-calculations.md) - 1.4 Density - [1.4.1 Density](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-4-1-density.md) - [1.4.2 Equation for Density](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-4-2-equation-for-density.md) - [1.4.3 Density - Experiments](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-4-3-density-experiments.md) - [1.4.4 Density - Calculations](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-4-4-density-calculations.md) - 1.5 Forces: Effects of Forces - [1.5.1 Spring Constant](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-5-1-spring-constant.md) - [1.5.2 Spring Constant Equation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-5-2-spring-constant-equation.md) - [1.5.3 Force & Acceleration](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-5-3-force-and-acceleration.md) - [1.5.4 Friction](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-5-4-friction.md) - 1.6 Forces: Turning Effects of Forces - [1.6.1 Circular Motion](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-6-1-circular-motion.md) - [1.6.2 Turning Effect](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-6-2-turning-effect.md) - [1.6.3 Moments](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-6-3-moments.md) - [1.6.4 Calculating Moments](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-6-4-calculating-moments.md) - 1.7 Forces: Centre of Gravity - [1.7.1 Equilibrium](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-7-1-equilibrium.md) - [1.7.2 Centre of Gravity](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-7-2-centre-of-gravity.md) - [1.7.3 Centre of Gravity Experiment](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-7-3-centre-of-gravity-experiment.md) - 1.8 Momentum - [1.8.1 Momentum](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-8-1-momentum.md) - 1.9 Energy, Work, & Power: Energy - [1.9.1 Energy Changes](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-9-1-energy-changes.md) - [1.9.2 Energy Conversion](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-9-2-energy-conversion.md) - [1.9.3 Kinetic Energy Stored](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-9-3-kinetic-energy-stored.md) - [1.9.4 Calculating Changes in Kinetic Energy](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-9-4-calculating-changes-in-kinetic-energy.md) - [1.9.5 Gravitational Potential Energy Stored](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-9-5-gravitational-potential-energy-stored.md) - [1.9.6 Calculating Changes in GPE](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-9-6-calculating-changes-in-gpe.md) - [1.9.7 Elastic Potential Energy Stored](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-9-7-elastic-potential-energy-stored.md) - [1.9.8 Calculating Changes in EPE](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-9-8-calculating-changes-in-epe.md) - 1.10 Energy, Work & Power: Work - [1.10.1 Mechanical Work](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-10-1-mechanical-work.md) - [1.10.2 Calculating Mechanical Work](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-10-2-calculating-mechanical-work.md) - [1.10.3 Calculating Electrical Work Done](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-10-3-calculating-electrical-work-done.md) - 1.11 Energy, Work & Power: Energy Resources - [1.11.1 Energy Resources](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-11-1-energy-resources.md) - [1.11.2 Fossil Fuels](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-11-2-fossil-fuels.md) - [1.11.3 Geothermal Energy](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-11-3-geothermal-energy.md) - [1.11.4 Wind Energy](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-11-4-wind-energy.md) - [1.11.5 Water Energy](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-11-5-water-energy.md) - [1.11.6 Tidal Energy](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-11-6-tidal-energy.md) - [1.11.7 Nuclear Energy](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-11-7-nuclear-energy.md) - [1.11.8 Solar Energy](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-11-8-solar-energy.md) - [1.11.9 Original Source of Energy](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-11-9-original-source-of-energy.md) - [1.11.10 Fusion](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-11-10-fusion.md) - [1.11.11 Efficiency](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-11-11-efficiency.md) - [1.11.12 Calculating Efficiency](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-11-12-calculating-efficiency.md) - [1.11.13 Energy Wastage](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-11-13-energy-wastage.md) - 1.12 Energy, Work & Power: Power - [1.12.1 Power](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-12-1-power.md) - 1.13 Pressure - [1.13.1 Pressure](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-13-1-pressure.md) - [1.13.2 Atmospheric Pressure](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-13-2-atmospheric-pressure.md) - [1.13.3 Calculating Pressure](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-13-3-calculating-pressure.md) - [1.13.4 Liquid Pressure](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-13-4-liquid-pressure.md) - [1.13.5 Manometer](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-13-5-manometer.md) - [1.13.6 Calculating Liquid Pressure](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/1-13-6-calculating-liquid-pressure.md) ### 2 Thermal Physics - 2.1 Kinetic Particle Model of Matter - [2.1.1 Kinetic Particle Model of Matter](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-1-1-kinetic-particle-model-of-matter.md) - [2.1.2 States of Matter](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-1-2-states-of-matter.md) - [2.1.3 Properties of Gases](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-1-3-properties-of-gases.md) - 2.2 Thermal Properties & Temperature - [2.2.1 Thermal Expansion](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-2-1-thermal-expansion.md) - [2.2.2 Changes in Internal Energy](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-2-2-changes-in-internal-energy.md) - [2.2.3 Heat Capacities](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-2-3-heat-capacities.md) - [2.2.4 Heat Capacities Experiment](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-2-4-heat-capacities-experiment.md) - [2.2.5 Internal Energy](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-2-5-internal-energy.md) - [2.2.6 Calculating Internal Energy](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-2-6-calculating-internal-energy.md) - [2.2.7 End of Topic Test - Thermal Physics](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-2-7-end-of-topic-test-thermal-physics.md) - [2.2.8 Changes of State](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-2-8-changes-of-state.md) - [2.2.9 Evaporation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-2-9-evaporation.md) - [2.2.10 Factors Affecting Evaporation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-2-10-factors-affecting-evaporation.md) - [2.2.11 Examples of Evaporation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-2-11-examples-of-evaporation.md) - 2.3 Transfer of Thermal Energy - [2.3.1 Conduction](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-3-1-conduction.md) - [2.3.2 Molecular Conduction](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-3-2-molecular-conduction.md) - [2.3.3 Convection Currents](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-3-3-convection-currents.md) - [2.3.4 Radiation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-3-4-radiation.md) - [2.3.5 Surface Colour](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-3-5-surface-colour.md) - [2.3.6 Emitting Radiation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-3-6-emitting-radiation.md) - [2.3.7 Leslie's Cube & Other Radiation Experiments](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-3-7-leslies-cube-and-other-radiation-experiments.md) - [2.3.8 Uses of Energy Transfer](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/2-3-8-uses-of-energy-transfer.md) ### 3 Waves - 3.1 General Properties of Waves - [3.1.1 Wave Basics](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-1-1-wave-basics.md) - [3.1.2 Transverse Wave](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-1-2-transverse-wave.md) - [3.1.3 Longitudinal Wave](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-1-3-longitudinal-wave.md) - [3.1.4 Ripple Tank](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-1-4-ripple-tank.md) - [3.1.5 Wave Speed](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-1-5-wave-speed.md) - [3.1.6 Wave Speed Formula](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-1-6-wave-speed-formula.md) - [3.1.7 Calculating Wave Speed](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-1-7-calculating-wave-speed.md) - [3.1.8 Wave Frequency](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-1-8-wave-frequency.md) - [3.1.9 Calculating Wave Frequency](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-1-9-calculating-wave-frequency.md) - [3.1.10 Wavelength](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-1-10-wavelength.md) - [3.1.11 Diffraction](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-1-11-diffraction.md) - 3.2 Light: Reflection & Refraction - [3.2.1 Reflection](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-2-1-reflection.md) - [3.2.2 Internal Reflection](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-2-2-internal-reflection.md) - [3.2.3 Refraction](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-2-3-refraction.md) - [3.2.4 More Refraction](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-2-4-more-refraction.md) - [3.2.5 Refractive Index Equation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-2-5-refractive-index-equation.md) - [3.2.6 Refractive Index](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-2-6-refractive-index.md) - [3.2.7 Critical Angle](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-2-7-critical-angle.md) - [3.2.8 Optical Fibres](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-2-8-optical-fibres.md) - [3.2.9 Optical Fibres in Communications](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-2-9-optical-fibres-in-communications.md) - [3.2.10 Medical Applications of Optical Fibres](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-2-10-medical-applications-of-optical-fibres.md) - 3.3 Light: Thin Lenses - [3.3.1 Thin Converging Lenses 1](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-3-1-thin-converging-lenses-1.md) - [3.3.2 Thin Converging Lens 2](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-3-2-thin-converging-lens-2.md) - [3.3.3 Thin Converging Lens 3](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-3-3-thin-converging-lens-3.md) - [3.3.4 Thin Converging Lens 4](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-3-4-thin-converging-lens-4.md) - [3.3.5 Calculating Lenses](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-3-5-calculating-lenses.md) - 3.4 Light: Dispersion of Light - [3.4.1 Dispersion of Light](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-4-1-dispersion-of-light.md) - [3.4.2 Triangular Prisms 1](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-4-2-triangular-prisms-1.md) - [3.4.3 Triangular Prisms 2](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-4-3-triangular-prisms-2.md) - 3.5 Electromagnetic Spectrum - [3.5.1 Properties of Electromagnetic Waves](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-5-1-properties-of-electromagnetic-waves.md) - [3.5.2 Gamma Rays](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-5-2-gamma-rays.md) - [3.5.3 X-Rays](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-5-3-x-rays.md) - [3.5.4 UV Light](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-5-4-uv-light.md) - [3.5.5 Visible Light](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-5-5-visible-light.md) - [3.5.6 Infrared Radiation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-5-6-infrared-radiation.md) - [3.5.7 Microwaves](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-5-7-microwaves.md) - [3.5.8 Radio Waves](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-5-8-radio-waves.md) - [3.5.9 Other Uses of EM Waves](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-5-9-other-uses-of-em-waves.md) - [3.5.10 Analogue & Digital Signals](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-5-10-analogue-and-digital-signals.md) - 3.6 Sound - [3.6.1 Sound Waves](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-6-1-sound-waves.md) - [3.6.2 Ears](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-6-2-ears.md) - [3.6.3 Speed of Sound](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-6-3-speed-of-sound.md) - [3.6.4 Measuring Sound Waves](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-6-4-measuring-sound-waves.md) - [3.6.5 Oscilloscope Traces](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-6-5-oscilloscope-traces.md) - [3.6.6 Sound Waves Experiment](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/3-6-6-sound-waves-experiment.md) ### 4 Electricity & Magnetism - 4.1 Simple Phenomena of Magnetism - [4.1.1 Magnets](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-1-1-magnets.md) - [4.1.2 Magnetic Forces](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-1-2-magnetic-forces.md) - [4.1.3 Magnetic Materials](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-1-3-magnetic-materials.md) - [4.1.4 Induced Magnetism](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-1-4-induced-magnetism.md) - [4.1.5 Temporary & Permanent Magnets](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-1-5-temporary-and-permanent-magnets.md) - [4.1.6 Electromagnets](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-1-6-electromagnets.md) - [4.1.7 Magnetic Field Lines](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-1-7-magnetic-field-lines.md) - 4.2 Electrical Quantities: Electric Charge - [4.2.1 Electrical Charge](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-2-1-electrical-charge.md) - [4.2.2 Charged Objects](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-2-2-charged-objects.md) - [4.2.3 Static Electricity Experiments](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-2-3-static-electricity-experiments.md) - [4.2.4 Charging by Induction](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-2-4-charging-by-induction.md) - [4.2.5 Electric Fields](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-2-5-electric-fields.md) - [4.2.6 Electric Field Patterns](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-2-6-electric-field-patterns.md) - [4.2.7 Conductors](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-2-7-conductors.md) - [4.2.8 Electrical Conductors - Electrons](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-2-8-electrical-conductors-electrons.md) - 4.3 Electrical Quantities: Electric Current - [4.3.1 Current](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-3-1-current.md) - [4.3.2 Conventional Current](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-3-2-conventional-current.md) - [4.3.3 Current Equation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-3-3-current-equation.md) - [4.3.4 Calculating Current](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-3-4-calculating-current.md) - [4.3.5 AC/DC](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-3-5-acdc.md) - 4.4 Electromotive Force & Potential Difference - [4.4.1 Electromotive Force](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-4-1-electromotive-force.md) - [4.4.2 Potential Difference](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-4-2-potential-difference.md) - [4.4.3 Potential Difference Equation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-4-3-potential-difference-equation.md) - [4.4.4 Calculating Voltage](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-4-4-calculating-voltage.md) - 4.5 Electrical Quantities: Resistance - [4.5.1 Circuit Measurements](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-5-1-circuit-measurements.md) - [4.5.2 Resistance](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-5-2-resistance.md) - [4.5.3 Equation for Resistance](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-5-3-equation-for-resistance.md) - [4.5.4 Measuring Resistance](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-5-4-measuring-resistance.md) - [4.5.5 Calculating Resistance & Ohm's Law](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-5-5-calculating-resistance-and-ohms-law.md) - [4.5.6 Variable Resistance](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-5-6-variable-resistance.md) - [4.5.7 Resistance Graph](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-5-7-resistance-graph.md) - 4.6 Electrical Energy & Electrical Power - [4.6.1 Electrical Work](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-6-1-electrical-work.md) - [4.6.2 Electrical Power](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-6-2-electrical-power.md) - [4.6.3 Calculating Electrical Work](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-6-3-calculating-electrical-work.md) - 4.7 Electric Circuits: Circuit Diagrams & Components - [4.7.1 Circuit Diagrams](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-7-1-circuit-diagrams.md) - [4.7.2 Circuit Symbols](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-7-2-circuit-symbols.md) - [4.7.3 More Circuit Symbols](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-7-3-more-circuit-symbols.md) - [4.7.4 Diodes](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-7-4-diodes.md) - [4.7.5 LDRs & Thermistors](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-7-5-ldrs-and-thermistors.md) - 4.8 Electric Circuits: Series & Parallel Circuits - [4.8.1 Series Circuits](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-8-1-series-circuits.md) - [4.8.2 Series Circuits - Resistors](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-8-2-series-circuits-resistors.md) - [4.8.3 Series Circuits - Cells](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-8-3-series-circuits-cells.md) - [4.8.4 Series Circuits - Potential Difference](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-8-4-series-circuits-potential-difference.md) - [4.8.5 Calculating Series Circuits](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-8-5-calculating-series-circuits.md) - [4.8.6 Parallel Circuits](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-8-6-parallel-circuits.md) - [4.8.7 Parallel Circuits - Current](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-8-7-parallel-circuits-current.md) - [4.8.8 Parallel Circuits - Resistance](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-8-8-parallel-circuits-resistance.md) - [4.8.9 Parallel Circuits in Practice](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-8-9-parallel-circuits-in-practice.md) - 4.9 Electric Circuits: Action & Use - [4.9.1 Potentiometer](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-9-1-potentiometer.md) - [4.9.2 Potential Divider Equation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-9-2-potential-divider-equation.md) - 4.10 Electrical Safety - [4.10.1 Dangers of Electricity](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-10-1-dangers-of-electricity.md) - [4.10.2 Live & Neutral Wires](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-10-2-live-and-neutral-wires.md) - [4.10.3 Earthing Metal Cases](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-10-3-earthing-metal-cases.md) - [4.10.4 Fuses & Trip Switches](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-10-4-fuses-and-trip-switches.md) - [4.10.5 Fuse Ratings](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-10-5-fuse-ratings.md) - 4.11 Electromagnetic Effects: Electromagnetic Induction - [4.11.1 Electromagnetic Induction](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-11-1-electromagnetic-induction.md) - [4.11.2 Size of e.m.f](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-11-2-size-of-emf.md) - [4.11.3 Forces Between Electricity & Magnets](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-11-3-forces-between-electricity-and-magnets.md) - [4.11.4 Rotation of Coil & Induced e.m.f](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-11-4-rotation-of-coil-and-induced-emf.md) - 4.12 Electromagnetic Effects: The A.C. Generator - [4.12.1 The Rotating-Coil Generator](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-12-1-the-rotating-coil-generator.md) - [4.12.2 Features of a Rotating-Coil Generator](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-12-2-features-of-a-rotating-coil-generator.md) - 4.13 Magnetic Effect of a Current - [4.13.1 Magnetic Effect of a Current](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-13-1-magnetic-effect-of-a-current.md) - [4.13.2 Solenoid Field](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-13-2-solenoid-field.md) - [4.13.3 Relays](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-13-3-relays.md) - 4.14 Force on a Current-Carrying Conductor - [4.14.1 Magnetic Field Strength](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-14-1-magnetic-field-strength.md) - [4.14.2 Uses of Magnets & Currents](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-14-2-uses-of-magnets-and-currents.md) - [4.14.3 Catapult Experiment](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-14-3-catapult-experiment.md) - [4.14.4 Beam Force Experiment](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-14-4-beam-force-experiment.md) - 4.15 Electromagnetic Effects: The D.C. Motor - [4.15.1 Motor Effect](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-15-1-motor-effect.md) - [4.15.2 Direction of Motor Effect](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-15-2-direction-of-motor-effect.md) - [4.15.3 DC Motors](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-15-3-dc-motors.md) - [4.15.4 Coil of Wire in a Magnetic Field](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-15-4-coil-of-wire-in-a-magnetic-field.md) - 4.16 Electromagnetic Effects: The Transformer - [4.16.1 Transformers](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-16-1-transformers.md) - [4.16.2 Transformers Equation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-16-2-transformers-equation.md) - [4.16.3 Types of Transformer](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-16-3-types-of-transformer.md) - [4.16.4 Principles of Transformer Operation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-16-4-principles-of-transformer-operation.md) - [4.16.5 Energy in Transformers](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/4-16-5-energy-in-transformers.md) ### 5 Nuclear Physics - 5.1 The Nuclear Model of the Atom - [5.1.1 Atomic Model](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-1-1-atomic-model.md) - [5.1.2 Scattering of Alpha Particles](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-1-2-scattering-of-alpha-particles.md) - [5.1.3 Subatomic Particles](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-1-3-subatomic-particles.md) - [5.1.4 Proton & Nucleon Numbers](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-1-4-proton-and-nucleon-numbers.md) - [5.1.5 Calculating Number of Neutrons](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-1-5-calculating-number-of-neutrons.md) - [5.1.6 Isotopes](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-1-6-isotopes.md) - [5.1.7 More Isotopes](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-1-7-more-isotopes.md) - [5.1.8 Carbon Nuclides](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-1-8-carbon-nuclides.md) - [5.1.9 Nuclear Fusion](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-1-9-nuclear-fusion.md) - [5.1.10 Nuclear Fission](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-1-10-nuclear-fission.md) - [5.1.11 More Nuclear Fission](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-1-11-more-nuclear-fission.md) - 5.2 Radioactivity: Detection of Radioactivity - [5.2.1 Radioactivity](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-2-1-radioactivity.md) - [5.2.2 Types of Radiation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-2-2-types-of-radiation.md) - [5.2.3 Detection of Radioactivity](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-2-3-detection-of-radioactivity.md) - [5.2.4 Background Radiation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-2-4-background-radiation.md) - 5.3 Radioactivity: The Three Types of Nuclear Emission - [5.3.1 Three Types of Emission](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-3-1-three-types-of-emission.md) - [5.3.2 Relative Ionising Effects](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-3-2-relative-ionising-effects.md) - [5.3.3 Electric Fields](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-3-3-electric-fields.md) - [5.3.4 Magnetic Fields Radiation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-3-4-magnetic-fields-radiation.md) - 5.4 Radioactive Decay - [5.4.1 Radioactive Decay](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-4-1-radioactive-decay.md) - [5.4.2 Decay Equations](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-4-2-decay-equations.md) - [5.4.3 Half Life](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-4-3-half-life.md) - [5.4.4 Measuring Half-Life](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-4-4-measuring-half-life.md) - [5.4.5 Practical Applications of Radiation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-4-5-practical-applications-of-radiation.md) - [5.4.6 Ionising Radiation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-4-6-ionising-radiation.md) - [5.4.7 Safety Precautions](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/5-4-7-safety-precautions.md) ### 6 Space Physics - 6.1 The Earth & the Solar System - [6.1.1 The Earth](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/6-1-1-the-earth.md) - [6.1.2 The Moon](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/6-1-2-the-moon.md) - [6.1.3 The Solar System & The Accretion Model](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/6-1-3-the-solar-system-and-the-accretion-model.md) - [6.1.4 Gravitational Field & Speed of Light](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/6-1-4-gravitational-field-and-speed-of-light.md) - [6.1.5 The Sun's Gravitational Field](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/6-1-5-the-suns-gravitational-field.md) - 6.2 Stars & the Universe - [6.2.1 The Sun as a Star](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/6-2-1-the-sun-as-a-star.md) - [6.2.2 Galaxies](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/6-2-2-galaxies.md) - [6.2.3 Life Cycle of a Star like the Sun](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/6-2-3-life-cycle-of-a-star-like-the-sun.md) - [6.2.4 Life Cycle of a Star Much Bigger than the Sun](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/6-2-4-life-cycle-of-a-star-much-bigger-than-the-sun.md) - [6.2.5 Creation of Elements](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/6-2-5-creation-of-elements.md) - [6.2.6 Red-shift](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/6-2-6-red-shift.md) - [6.2.7 The Big Bang](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/6-2-7-the-big-bang.md) - [6.2.8 Cosmic Microwave Background Radiation](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/6-2-8-cosmic-microwave-background-radiation.md) - [6.2.9 The Hubble Constant](https://senecalearning.com/en-gb/revision-notes/igcse/physics/cambridge-international/higher/6-2-9-the-hubble-constant.md)