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7. (a) Use words from the box to complete the sentences about nuclear fission of uranium-235 (U-235) - Edexcel - GCSE Physics - Question 7 - 2020 - Paper 1
Question 7
7. (a) Use words from the box to complete the sentences about nuclear fission of uranium-235 (U-235). A neutron hits a nucleus of U-235 and causes the nucleus to __... show full transcript
Worked Solution & Example Answer:7. (a) Use words from the box to complete the sentences about nuclear fission of uranium-235 (U-235) - Edexcel - GCSE Physics - Question 7 - 2020 - Paper 1
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b) Calculate the mass of oil needed to generate the same amount of electricity as 1 kg of natural uranium.
Answer
Since 1 kg of uranium generates 45,000 units, and 1 kg of oil generates only 5 units, the mass of oil needed can be calculated using the formula:
ext{mass of oil} = rac{ ext{45,000 units (from uranium)}}{ ext{5 units (from oil)}} = 9,000 ext{ kg}.Step 4
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d) Explain why americium-241 is the best of these three sources to use in this smoke detector.
Answer
Americium-241 is the best choice for smoke detectors because:
- Americium emits alpha particles, which are more effective in ionizing air compared to the gamma radiation emitted from other sources. This ionization is crucial for detecting smoke.
- Alpha radiation has a very short range, meaning it doesn't escape the detector, allowing it to provide a precise reading based on smoke levels.
- Its half-life of 433 years means it can be used effectively over a long period without replacement, ensuring consistent performance in smoke detection.