revision
- Created by: tegan.xx0
- Created on: 03-03-15 09:59
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- Photo Cells
- Produces DC current
- Can Operate in remote locations.
- Transfers light energy into electricity
- The amount of power you make depends on the surface area of light.
- How photos cells work:
- 1. Energy is absorbed by silicon atoms(light)
- 2. Electrons- knocked off silicon atoms
- 3. Electrons can flow
- Solar Cell
- Uses the suns thermal energy to heat water
- Wind Turbines
- Mirrors reflect the light
- Advantages
- Renewable energy resource
- Don't produce waste
- Disadvantages
- Spoils the landscape
- Dynamo Effect
- Ways to increase the dynamo effect
- 1. Increase the size of the magnet
- Increase the number of coils
- Increase the speed you move the magnet
- Efficiency= useful energy output (x100) / total energy output
- Efficiency will not be over 100%
- Ways to increase the dynamo effect
- Greenhouse Effect
- 1. Electromagnetic radiation from the sun enters the earths atmosphere.
- 2. but when they travel out into space, some radiations are to weak to escape.
- 3. so they are kept in the earths atmosphere. These then keep warming up the sun.
- 4. The earths atmosphere gets thicker because of dust and other man mad sources.
- Natural Green house gases:
- Decomposing plant material.
- Evaporations from oceans lakes and rivers.
- Respiration by plants and animals, forest fires and volcanoes.
- Man Made Greenhouse Gases:
- Rice paddy fields, cattle and coal mines.
- Burning hydrocarbon fuels.
- Making cement, burning fuels.
- Chosing the right fuel:
- Toxicity
- Energy Value
- Availability
- Cost
- Useability
- Pollution
- Storage
- Ionising Radiation
- Alpha
- Least Penetrating, can be stopped by a piece of paper.
- Used in smoke detectors.
- Very dangerous, easily absorbed by cells.
- Gammma
- Most penetrating, can be stopped by lead.
- Used to sterilise surgical instruments, kills harmful bacteria in food.
- Not as dangerous, less likely to be absorbed by a cell.
- Kills cancer cells.
- Beta
- Is slightly more penetrating than Alpha. Stopped by a thin sheet of Aluminium
- Used for tracing and monitoring the thickness of materials.
- less likely to be absorbed by a cell
- Alpha
- Photo Cells
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