4 (a) Radioactive tracers can be used when scanning a person's kidneys - Edexcel - GCSE Physics - Question 4 - 2022 - Paper 1
Question 4
4 (a) Radioactive tracers can be used when scanning a person's kidneys.
A radioactive isotope is injected into a person's blood stream.
The isotope emits radiation... show full transcript
Worked Solution & Example Answer:4 (a) Radioactive tracers can be used when scanning a person's kidneys - Edexcel - GCSE Physics - Question 4 - 2022 - Paper 1
Step 1
What type of radiation travels from the kidney to the scanner?
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Answer
The type of radiation that travels from the kidney to the scanner is gamma radiation (D), as it can pass through and out of the body, making it detectable.
Step 2
State why an isotope with a half-life of about 6 minutes is not suitable.
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An isotope with a half-life of about 6 minutes decays too quickly to provide stable readings during the 30-minute scan duration.
Step 3
State why an isotope with a half-life of about 6 days is not suitable.
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An isotope with a half-life of about 6 days would not decay sufficiently during the scan, leading to prolonged exposure and potential harm.
Step 4
State two ways of reducing the radiation risks to the technician.
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Use of protective clothing such as lead aprons or gloves.
Implement distance limiting measures, allowing the technician to remain at a safe distance from the source.
Step 5
Explain how pushing the control rods further into the reactor slows down the nuclear chain reaction.
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Pushing the control rods further into the reactor absorbs more neutrons, reducing their availability to sustain the chain reaction. This decreases the overall rate of fission events.
Step 6
Calculate the average speed of the slow neutrons as a percentage of the average speed of the fast neutrons.
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The average speed of fast neutrons is 3.0 × 10^7 m/s, and the average speed of slow neutrons is 4.0 × 10^5 m/s. To find the percentage:
[ \left( \frac{4.0 \times 10^5}{3.0 \times 10^7} \right) \times 100 = \frac{4.0}{30} \approx 1.33% ]
The average speed of the slow neutrons is approximately 1.33% of the speed of the fast neutrons.
Step 7
Describe how energy is transferred from the nuclear reaction to the next stage in the process.
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Energy from the nuclear reaction is primarily in the form of heat generated during the fission process. This heat is transferred to a coolant, which circulates through the reactor and carries the thermal energy away to a steam generator, where it can be used to convert water into steam for driving turbines.
