⁹⁰Sr Is an Isotope Produced from Atmospheric Testing of Nuclear

question 5

Multiple Choice

⁹⁰Sr is an isotope produced from atmospheric testing of nuclear bombs. If nuclear testing was stopped in 1960, what percentage of radioactivity due to ⁹⁰Sr remained in 2000? The half-life of ⁹⁰Sr is 28.5 years.

• A) 62.2 %
• B) 37.8 %
• C) 12.3 %
• D) 0.85 %
• E) virtually 0 %

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