C2,P2

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Electromagnetic radiation comes in tiny ‘packets’ called photons.

The photons deliver different quantities of energy, with radio photons delivering the smallest amount, and gamma photons delivering the greatest amount of energy.

A higher frequency of electromagnetic radiation means more energy is transferred by each photon.

If the photons have enough energy, they can break molecules into bits called ions. This is called ionisation. These types of radiation are called ionising radiation. This radiation can remove electrons from atoms in its path.

In the electromagnetic spectrum only the three types of radiation, which have the photons with most energy, are ionising. These are ultravioletX-rays and gamma rays.

Ultaviolet, x-rays and gamma rays all can cause cancer because they can damage cells.

Some greenhouse gases absorb infrared radiation one of these are carbon dixiode although there is a small amount of it in our atmosphere it absorbs infrared radation well.

The carbon cycle

Processes which remove carbon dioxide from the air:

Photosynthesis 

Dissoving in the oceans.

Processes which release carbon dioxide back into the air:

Respiration from microbes, animals and plants.

Combustion burning e.g. burning wood and fossil fuels such as coal, oil and gas

Decomposers such as microbes and fungi break down the remains of dead animals and plants and release carbon dioxide into the air from the process of respiration.

Global warming can cause climate change which can affect our environment especially animals habitat for example the ice caps melting in antartica which could make polar bears extinct.

Climate change can stop growing of crops and can cause rising in sea-levels.

Infrared, radio waves and micro waves are all used for signals such as tv, computer and telephone calls.

Microwaves pass through the atmosphere and radio waves reflect from a charged layer of the upper atmosphere.

Analogue signals

Noise adds extra random information to analogue signals. Each time the signal is amplified the noise is also amplified. Gradually, the signal becomes less and less like the original signal. Eventually, it may be impossible to make out the music in a radio broadcast from the background noise, for example.

Digital signals

Noise also adds extra random information to digital signals. However, this noise is usually lower in amplitude than the 'on' states of the digital signal. As a result, the electronics in the amplifiers can ignore the noise and it does not get passed along. This means that the quality of the signal is maintained. This is…

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