Nuclear radiations Flashcards
Why are atoms neutral?
They have the same number of protons and electrons.
What does ionisation involve?
Gaining or loosing electrons.
- When the atoms gain electrons, it becomes negatively charged.
- When the atoms loses electrons, it becomes positively charged.
What can the formation of ions cause?
Chemical reactions.
- Such reactions may disrupt the normal behaviour of molecules inside the body e.g. they may cause strands of DNA to break or change;
- protein molecules may change their shapes and these effects are potentially harmful.
Where does α, β, and γ radiation come from?
The nucleus.
Which type of radiation causes the most and least ionisation?
- α radiation cause the most ionisation.
- γ radiation cause the least ionisation.
What are the ranges of the different types of radiation and what absorbs them?
- α radiation is short ranged (a few centimetres) and easily absorbed by a sheet of paper or card.
- β radiation has a range of about 1 m and is absorbed by a few millimetres of aluminium.
- γ radiation is more penetrating and, although a few centimetres of lead will stop most of the radiation, some can pass through several metres of lead or concrete.
Experiments can be done to find out the penetrating power of radiation. What should be taken into account?
Background radiation should always taken to account.
How is α radiation used in a smoke detecter?
- The radiation ionises the oxygen and nitrogen in air which causes a very small electric current that is detected by the smoke alarm.
- When smoke fills the detector in the alarm during a fire, the air is not ionised, the current is less and the alarm sounds.
How is β radiation and a detector used in paper mills?
The amount of radiation passing through the sheet is monitored and the pressure on the rollers is adjusted accordingly.
What can γ radiation be used for?
- To kill microbes and bacteria so it it can be used for steralising medical equipment.
- To check for leaks in pipes and welds.
What can β or γ sources be used for?
To trace the passage of blood and other substances around the body.
What is plutonium?
Plutonium is a waste product from nuclear reactors which can be used to make nuclear bombs.
How is high and low level radioactive waste disposed of?
- Some low level waste can be buried in landfill sites.
- High level waste is encased in glass and buried deep underground or reprocessed.
Radioactive Waste…
Can remain radioactive for thousands of years. It must be stored where it cannot leak into natural underground water supplies and hence into lakes and rivers. It is not suitable for making nuclear bombs, but it could be used by terrorists to contaminate water supplies or areas of lands.
Advantages and disadvantages of nuclear power stations.
- The advantages are that fossil fuel reserves are not used and no greenhouse gases are discharged into the atmosphere.
- The disadvantages are its very high maintenance and decommissioning costs, and the risk of accidents similar to the one at Chernobyl.
