GCSE Physics Edexcel P2 Topic 6

These are revision notes I made myself. I got A* in the Physics GCSE exam and 80 UMS (full marks) in the P2 exam using only these notes.

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P2 Topic 6: Benefits and drawbacks of using radioactive materials
Henri Becquerel (1852-1908) investigated how Uranium phosphoresces (emits light) after being exposed to
sunlight.
He observed that `invisible rays' also emitted by Uranium could expose (darken) photographic plates. During
a day with cloud weather in 1896, he stored the uranium away with a photographic plate. The plate became
unexpectedly exposed; He discovered Uranium didn't need an external energy source.
He had discovered radioactivity.
Becquerel also found that radiation could ionise gases. Marie Curie and her husband burned their hands
handling radium, like Becquerel. They discovered some materials emitted much more radiation than others.
Ionising radiation is linked with cancer and other health problems. Large amounts of it cause tissue damage
such as radiation burns and other effects that cannot be seen. Radiation sickness may also occur as a lot of
body cells get battered at once.
Smaller exposure over a long period of time can damage cells, not kill them, and cause mutations in their
DNA. This may cause some cells to malfunction and lead to cancer.
Handling radioactive sources
The risk of harm decreases with distance from the source so they are always handled with tongs. Sources
should also not be pointed at people. All but the most penetrating radiation can be stopped by a few
millimetres of lead so sources are kept in a lead-lined container.
Industrial nuclear workers wear full protective suits to prevent tiny radioactive particles being inhaled or
lodging on the skin. Lead-lined suits, lead/concrete barriers and thick lead screens are used to prevent
exposure to gamma rays.
Nuclear waste
There are three kinds of nuclear waste:
o High level waste.
o Intermediate level waste.
o Low level waste.
High level waste
This produces high amounts of ionising radiation for about 50 years.
The fission products from the Uranium fuel used in nuclear power is very radioactive; this is High level waste.
HLW is transported in thick concrete and steel containers which absorb the radiation. As well as this, it is
sealed in glass to stop the radioactive material escaping and stored in canisters until the waste is less
radioactive.
Intermediate level waste
This is moderately radioactive and stays so for tens of thousands of years. ILW also includes the metal
cylinders used to contain the Uranium fuel. The fuel made the metal container itself radioactive.
It is currently stored in concrete and steel containers and none has been disposed of yet.
Lower level waste
This is only slightly radioactive and remains so for tens of thousands of years, similar to ILW. This includes the
clothing and cleaning materials from the nuclear power stations. Hospitals also have LLW due to the
radioactive isotopes used in radiotherapy.
LLW is compacted and buried in special landfill sites as there is a possibility of radioactive material leaking
into soil or water.

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Method of disposal Problems
Firing into space Launch vehicle could fall back to Earth, spreading
radioactive material over a wide area.
Dumping barrels in sea Barrels could corrode and release radioactive materials
which could enter food chains.
Storage underground Site has to be geologically stable i.e. very low risk of
earthquakes.
Pros and Cons of Nuclear power
PROS CONS
No CO2 produced so carbon free. Radioactive waste is produced which is highly
More electricity produced than other renewable dangerous.…read more

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The activity of a radioisotope is 640 Bq. Two hours later it has fallen to 40 Bq. Find the half life of the sample.
Initial count: 640
After ONE half life: 320
After TWO half lives: 160
After THREE half lives: 80
After FOUR half lives: 40
Four half lives taken. Two hours represents four half lives so the half life is 30 minutes.…read more

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Background radiation is the low-level radiation that's around us all the time. Background radiation comes
from:
o Radioactivity of naturally occurring unstable isotopes which are all around us ­ in the air, food,
building materials and rocks.
o Radiation comes from space in the form of cosmic rays. Fortunately, the Earth's atmosphere protects
us from much of this radiation and its magnetic field deflects cosmic rays away from us.…read more

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When the amount of detected radiation changes, it means the paper is coming out too thick or too thin so the
control unit adjusts the rollers to give the correct thickness.
It needs to be a Beta source because then the paper will partly block the radiation. If Gamma or Alpha
particles were used, it would either all go through or none of it at all so the reading wouldn't change.…read more

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