A Sphere Made of a Radioactive Isotope Initially Has a Mass

question 55

Multiple Choice

A sphere made of a radioactive isotope initially has a mass of 6.88 kg.The half-life of this isotope is 1.34 h,and it decays by β^- emission.At the end of 2.68 h,what is the mass of this sphere?

• A) 6.88 kg
• B) 3.44 kg
• C) 1.72 kg
• D) 2.53 kg

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