Living for the Future

Oliver Wood
Mind Map by , created over 5 years ago

AS Level Physics (P2: Living for the Future) Mind Map on Living for the Future, created by Oliver Wood on 02/05/2014.

Oliver Wood
Created by Oliver Wood over 5 years ago
Physics P2
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P2.1 Forces And Their Effects
Alex Maraio
Living for the Future
1 Solar Energy
1.1 Photocells
1.1.1 Robust, little maintainance
1.1.2 Solar fuel, no long cables
1.1.3 No pollituon
1.1.4 P-N silicon junction P-type has absence of free electrons N-type has excess free electrons Photons excite electrons Electric current produced
1.1.5 (-) No energy when dark/cloudy
1.1.6 Output: Light intensity Surface area Distance from light source
1.1.7 DRAW OUT
1.2 Passive heating
1.2.1 Glass lets in shorter IR radiation IR absorbed by walls and floor, heat up IR re-emitted at longer wavelength Glass reflects longer wavelength IR inside
1.3 Wind energy
1.3.1 Windspeed dependent Will not work in too little/too much wind
1.3.2 No CO2
1.3.3 Noisy. take space, "NIMBY"
2 Generating Electricity
2.1 The Dynamo effect
2.1.1 Wire coil in a magnetic field = Current Induced current
2.1.2 Increasing the effect: Faster moving magnet More wire coils Stronger magnet
2.1.3 To reverse current: Rotate magnet in opp. direction Reverse magnet polarity
2.1.4 Either the coil OR the magnets can move
2.1.5 Always AC
2.1.6 DRAW OUT
2.2 Power Stations
2.2.1 Water boils to steam High-pressure steam drives turbine Turbine drives Generator
2.3 Energy Efficiency
2.3.1 Energy lost at each stage
2.3.2 Efficiency = Useful output / Total input
3 Global Warming
3.1 Most electromagnetic waves pass through atmosphere
3.1.1 IR absorbed at short wavelengths by Earth Re-emitted at long wavelengths Long wavelengths trapped CO2 Volcanic eruptions Forest fires Organic decay Oceans emit it Respiration
3.2 Greenhouse Gases
3.2.1 Methane Decay lacking oxygen Wetlands, oceans
3.2.2 CO2
3.2.3 Water vapour = Most potent Occurs naturally
3.3 Dust : Two effects
3.3.1 Factory smoke traps IR Temp. Increases
3.3.2 Volcanic ash reflects IR Temp. falls
4 Fuels for Power
4.1 Measuring power
4.1.1 Appliances use a certain amount of power per second
4.1.2 Power = Voltage x Current Watts
4.1.3 Energy supplied = Power x Time Kilowatt Hours (kWh)
4.2 Cost of Energy
4.2.1 Cost = Energy used x Cost per kWh
4.2.2 Often lower rates at night (off-peak)
4.3 Choices of Sources
4.3.1 Availability
4.3.2 Ease of extraction
4.3.3 Environmental effect
4.3.4 Risks associated
4.4 The National Grid
4.4.1 Transformers step up VOLTAGE to 400,000v Transport electricity in powerlines Transformers step down energy for consumer
4.4.2 High current heats up wires Heat = Energy loss Transformers allow higher [Voltage] and lower [Ampage] Lowers energy lost Keeps cost down "When a transformer increases voltage, the ampage is reduced - Wires don't heat up, and therefore less energy is lost to the environment (sink)."