The pie chart shows the sources of the background radiation and the radiation doses that the average person in the UK is exposed to in one year.
Radiation dose is measured in millisieverts (mSv).
2 (a) (i) What is the radiation dose that the average person in the UK receives from radon gas?
Radiation dose from radon gas = ........................................ mSv
2 (a) (ii) A person may receive a higher than average dose of radiation from background sources.
Suggest two reasons why.
2 (b) Exposure to radon gas can cause lung cancer.
A recent study has compared the risk of getting lung cancer, by the age of 75 years, for cigarette smokers and non-smokers.
The people in the study had been exposed throughout their lives to different levels of radon gas.
A summary of the data produced from the study is given in the table.
2 (b) (i) Why were people that have had no exposure to radon gas included in the study?
2 (b) (ii) Using information from the table, what conclusions can be made about exposure to radon gas and the risk of getting lung cancer?
2 (c) At the moment, the regulations designed to protect people from over-exposure to radiation are based on a model called the ‘linear no-threshold’ (LNT) model.
Some scientists believe that the LNT model is too simple. These scientists believe that at low radiation levels a process called ‘radiation hormesis’ happens.
The graphs show that each model suggests a link between the risk of developing a cancer and exposure to low levels of radiation.
The link between the risk of developing cancer and exposure to low levels of radiation suggested by each of the models is different.
2 (d) Scientists have conducted experiments in which mice have been exposed to different levels of radiation. The number of mice developing a cancer has then been measured.
Discuss whether it is ethical to use animals in scientific experiments.
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From Q2 P2 AQA January 2012 (Higher)