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P2 ­ Radiation and Life - Revision Notes

Light is a type of electromagnetic (EM) radiation, radiation is just a transfer of energy. For example,
sunlight is a transfer of energy from the sun to the earth. Visible light (the colours of the rainbow,
can be written as red visible…

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2. When a photon hits a molecule or atom, it sometimes has enough energy to remove an
electron and change the atom or molecule.
3. This process is called ionisation.
4. The changed atoms or molecules can go on to initiate (start) other chemical reactions.
5. It takes lots of…

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1. Microwaves are used to send signals between mobile phones and mobile phone masts.
2. When someone makes a call on a mobile, the phone emits microwave radiation. Some of
this radiation is absorbed by their body, this causes heating of body -=tissues (which all
contain water).
3. There are…

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complex organisms. So the ozone layer is very important ­ it protects us from too much UV
radiation.

Two of the greenhouse gases which keep the earth warm are carbon dioxide (CO) and methane
(CH). There's a small amount of CO and just trace amounts of methane, both of these…

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1. People's lifestyles have changed, all this needs energy, which we get mainly from burning
fossil fuels, which releases more CO.
2. The population is on the rise, so more land is needed to build houses and grow food, this
space is sometimes made by chopping down and burning trees,…

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Global warming has changed weather patterns in many parts of the world. It's thought that
many regions will suffer from more extreme weather because of this. Hurricanes form over
water that's warmer than 27°C, so more hurricanes are expected.
The extra heat in the atmosphere will also increase convection (stronger…

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2. Digital signals can only take one of a small number of discrete values (usually 2), e.g. 0 or 1,
True or False, Off or On.
3. The information is carried by switching the EM carrier on or off.
4. This creates pulses, shorts bursts of waves.
5. A digital…

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