P2 - Radiation & Life
- Created by: eloisa_braith
- Created on: 18-05-15 16:40
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- P2 - Radiation & Life
- Electromagnetic Radiation
- Radiation = transfer of energy
- Energy is delivered as photons
- Photon = tiny 'packet' of energy
- Amount of energy carried by photon depends on frequency of the radiation
- Total energy = no. photons x energy per photon
- Intensity = how much energy hits each square metre of surface per second (W/m2)
- If light is absorbed the energy is passed on to the object
- Amount of energy carried by photon depends on frequency of the radiation
- Amount of energy carried by photon depends on frequency of the radiation
- Total energy = no. photons x energy per photon
- Intensity = how much energy hits each square metre of surface per second (W/m2)
- Photon = tiny 'packet' of energy
- Energy is delivered as photons
- EM Spectrum
- Radio waves, microwaves, infra red, visible light, ultra violet, x-rays, gamma rays
- All travels at the same speed
- An object that emits radiation is called a source
- Transmitted = passes through things (eg. glass)
- Reflected = bounces back (eg. mirror)
- Absorbed = light taken in (eg. sunbather) - detector
- Radiation = transfer of energy
- Ionisation
- Photons sometimes have enough energy to remove an electron from an atom
- Can only be done by radiation with high energy
- Can cause DNA to mutate when the cells divide over & over again - this is cancer
- Protection
- UV - clothes, suncream
- X-rays - lead shields, lead aprons, concrete
- Can kill cells
- Uses of EM radiation
- Cooking food
- Infra red - toasters, grills
- Microwaves - microwaves
- Make particles vibrate, making them heat up
- Strongly absorbed by water molecules
- Strongly absorbed by water molecules
- High power = high intensity so less cooking time
- Make particles vibrate, making them heat up
- Cooking food
- EM waves & communication
- Radio waves & microwaves used
- Not absorbed by earth's atmosphere much
- Satellites for TV & phones
- Not absorbed by earth's atmosphere much
- Radio waves & microwaves used
- Global warming
- Rise of carbon dioxide causing global warming by increasing greenhouse effect
- Rise in sea level due to melting ice
- Extra heatin atmosphere causes strong winds
- Drought & floods
- EM radiation & the atmosphere
- Energy from sun is absorbed by earth
- Earth radiates some of this hear
- Energy is absorbed by greenhouse gases
- Energy is re-radiated in all directions
- Energy is absorbed by greenhouse gases
- Earth radiates some of this hear
- Part of the atmosphere is called ozone = absorbs UV
- UV splits a normal O2 molecule and adds the single O to another O2 molecule
- This creates O3 which is ozone
- Loss of ozone makes holes in the ozone layer
- More UV gets to us
- UV splits a normal O2 molecule and adds the single O to another O2 molecule
- Energy from sun is absorbed by earth
- Analogue & Digital Sounds
- All info is converted into electrical signals before it's transmitted
- Both signals weaken as they travel so have to be amplified
- Pick up noise/ interference en route
- Digital = either on or off
- Much higher quality
- Analogue = take any value in a particular range
- Electromagnetic Radiation
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