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9 (a) Sometimes food can become contaminated with radioactive substances - Edexcel - GCSE Physics - Question 9 - 2021 - Paper 1
Question 9
9 (a) Sometimes food can become contaminated with radioactive substances. Describe the harmful effects of eating food contaminated with radioactive substances. (b) ... show full transcript
Worked Solution & Example Answer:9 (a) Sometimes food can become contaminated with radioactive substances - Edexcel - GCSE Physics - Question 9 - 2021 - Paper 1
Step 1
Describe the harmful effects of eating food contaminated with radioactive substances.
Answer
Eating food contaminated with radioactive substances can lead to significant health issues, including:
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Radiation Sickness: Exposure to high levels of radiation can cause acute radiation syndrome, characterized by symptoms such as nausea, vomiting, and fatigue.
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Cancer Risk: Long-term exposure to radioactive materials can lead to an increased risk of developing various cancers, particularly thyroid cancer due to iodine isotopes.
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Genetic Damage: Radiation can cause mutations in DNA, potentially leading to hereditary effects in future generations.
Step 2
Explain why some food is irradiated with gamma radiation.
Answer
Food is irradiated with gamma radiation for several reasons:
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Preservation: Gamma radiation helps in extending the shelf life of food by destroying bacteria, parasites, and other pathogens that cause spoilage.
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Safety: Irradiation reduces the risk of foodborne illnesses by eliminating harmful microorganisms, thus ensuring food safety for consumers.
Step 3
State how the nucleus does change when it emits a gamma ray.
Answer
When an atom emits a gamma ray, the nucleus undergoes a change in energy level. Although the number of protons and neutrons remains unchanged, the nucleus transitions to a lower energy state, which is often associated with a different configuration of the energy levels of its constituent particles.
Step 4
Compare the processes of alpha decay and beta decay.
Answer
Alpha decay and beta decay are two distinct processes of radioactive decay that affect the original nucleus in different ways:
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Alpha Decay:
- An alpha particle, which is composed of 2 protons and 2 neutrons (essentially a helium nucleus), is emitted from the nucleus.
- This results in the atomic number decreasing by 2 and the mass number decreasing by 4.
- The nucleus becomes more stable as a heavier nucleus transforms into a lighter one.
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Beta Decay:
- In beta decay, a neutron in the nucleus is transformed into a proton and an electron (the beta particle). The electron is emitted from the nucleus.
- This process increases the atomic number by 1 while the mass number remains unchanged, resulting in the formation of a new element that is one place higher in the periodic table.
In summary, alpha decay reduces both the mass and atomic number of the nucleus, while beta decay increases the atomic number but leaves the mass number unaffected.