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Americium-241 is used in smoke detectors. It undergoes alpha decay with a half life of 432 years. The alpha particles ionize some of the air
Question
Americium-241 is used in smoke detectors. It undergoes alpha decay with a half life of 432 years. The alpha particles ionize some of the air near the americium-241 source, and these charged ions are collected on a metal plate that has a small voltage applied to it. The collected particles cause a small electric current to flow in the detector. If smoke particles get in between the americium-241 source and the detector and reduce the current, the alarm is triggered. A typical smoke detector experiences 370000 alpha decays each second. How much time is needed for the number of decays to reduce to 93000 decays per second?
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Physics
3 years
2021-09-03T10:50:48+00:00
2021-09-03T10:50:48+00:00 1 Answers
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Answers ( )
Answer:
860.6 years.
Explanation:
The parameters given are;
Initial detector activity = 370000 alpha decays per second
Final detector activity = 93000 alpha decays per second
Formula for time to change in activity is given by the following relation;
t₉₃₀₀₀ = 2.72 × 10¹⁰ seconds = 860.6 years.