Some Good Resources for Your IGCSE Physics Revision

1. Grade Gorilla – Some good quizzes to test your knowledge.

2. Revision Video – Very good revision video to help your prepare

3. Edexcel – The official Edexcel website proved you with real past papers to practice. Practicing and then marking your papers is the best way you can revise.

Revision Video on Unit 3 Waves

4.15 and 4.17 energy transfer in generating electricity and advantages and disadvantages of the method

Wind

Kinetic energy from wind is harnessed by a turbine. The turbine spins a generator turning this into electricity.

• +Renewable
• +No greenhouse gases produced

• -danger to wildlife
• -Noise
• -Depends on wind
• -Takes a lot of space and produces very less energy

Water (hydropower)

Kinetic energy from moving water is harnessed by a turbine which spins a generator and turns that into electrical energy

• +Renewable
• +No greenhouse gases produced

• -Causes hindrance in fish migration (dams) and damages their habitat
• -Depends on water
• -Limited locations

Geothermal sources

Heat energy from earth's core is used to rapidly heat up water which turns into high pressure steam with kinetic energy. This used to turn a turbine which turns a generator and turns kinetic energy into electrical energy.

• +Renewable
• +No greenhouse gases produced

• -Emits harmful gases – sulfur dioxide
• -Limited locations

Solar heating system

Heat energy from sun is used to rapidly heat up water and turn into high pressure steam. The steam turns a turbine which turns a generator which converts kinetic energy into electrical energy.

• +Renewable
• +No greenhouse gases produced

• -Limited location
• -Depends on sun (day time/clear sky only)

Solar cells

Light energy from the sun is converted into electrical energy in the solar cell.

• +Renewable
• +No greenhouse gases

• -Depends on sun
• -Limited locations
• -Low energy production

Fossil fuels

Chemical energy stored in fossil fuels is converted into heat energy by combustion. The heat energy is used to rapidly vaporize water and turn a turbine which turns this heat energy into kinetic energy, the turbine spins a generator which converts kinetic energy into electrical energy.

• +Any location
• +High energy production with less space
• +Easy to setup

• -Non renewable
• -Greenhouse gases and soot is produced
• -Needs fossil fuels

Nuclear power

Nuclear energy stored in radioactive materials is converted into thermal energy by the process of nuclear fission. The thermal energy is used to heat up water and turn it into high pressure steam. A turbine converts thermal energy into kinetic energy. The kinetic energy is converted into electrical energy by a generator.

• +No greenhouse gases
• +High energy production

• -Nuclear waste

• -Non renewable

• -Complicated to set up

7.5 Properties of alpha, beta particles and gamma radiation

Alpha (α)

• Made up of 2 protons and 2 neutron
• Strongly ionizing
• Low penetrating power – can be stopped by paper or several cm of air.

Beta (β)

• Fast moving electron
• Moderately ionizing
• Moderately penetrating – can be stopped by 1 m of air or several cm of aluminium
• Emitted when a neutron turns into a proton and releases an electron

Gamma (γ)

• Very high frequency electromagnetic waves
• Weekly ionizing
• Strongly penetrating – can be stopped by several cm of lead or 1 m of concrete

7.4 Alpha, beta and gamma rays

Ionisation is when an atom loses or gains an electron. This effectively damages the atoms by making ions.

Alpha, beta and gamma rays are 3 types of ionizing radiation.