P2- radiation and life
- Created by: willbrewin1
- Created on: 19-04-15 12:31
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- P2- radiation and life
- radiation is just the transfer of energy
- visible light is the radiation our eyes can see: ROYGBIV
- EM radiation is emitted from a source and can go through a vacuum, so will travel until it hits matter
- EM spectrum (starting with lowest energy and frequency)
- radio waves, micro waves, infra red, visible light, ultra violet, x-rays and gamma
- energy is delivered as photons by all radiation
- higher frequency means more energy in photons
- frequency of thermal radiation increases with temperature
- what happens when radiation reaches something
- transmission (light through glass)
- reflection (light on a mirror)
- absorption (uv on a sunbather)
- when radiation is absorbed photons transfer their energy
- ionising radiation eg gamma- photons collide with atoms, and an electron is pushed out
- if happens in nucleus can as random DNA changes and mutation, CANCER causing
- protection from radiation- UV: clothes or sunblock, X-rays: lead shields or concrete blocks
- uses of EM radiation
- microwaves- vibrate water particles heating it
- health risks- some absorbed by body, heat particles ad damage them
- normal ovens- infra red to heat food
- microwaves- vibrate water particles heating it
- atmosphere- absorbs some radiation (keeps planet warm) some pass through eg visible light
- ozone- O^3, formed when uv radiation splits an O^2 molecule and an O atom joins with an O^2 molecule forming ozone
- carbon cycle
- into atmosphere- respiration, combustion, bacteria and fungi breaking down matter
- human activity is unbalancing carbon cycle
- global warming- sea levels up, lan loss, extreme weather, food production change
- human activity is unbalancing carbon cycle
- out of atmosphere- photosynthesi-s
- into atmosphere- respiration, combustion, bacteria and fungi breaking down matter
- EM communication: infra red- tv remote, radio waves- radio, micro wave- mobiles
- radio and micro- good long distance, no interference
- low frequency
- infra red and light are used in fibres, reflect of a wires plastic tube
- radio and micro- good long distance, no interference
- info can be changed to an electrical signal, then sent long distance or superimposed onto a EM carrier wave
- analogue- wave, every value between two points, so when amplified the interference means original signal can be hard to determine
- digital- only transmits two values, so when amplified the original signal can be seen- better quality
- radiation is just the transfer of energy
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