Approximately How Many Radioactive Atoms Are Present in a Tritium

question 24

Multiple Choice

Approximately how many radioactive atoms are present in a tritium sample with an activity of 0.20 × 10−⁶ Ci and a half-life of 12.3 years? (1 Ci = 3.7 × 10¹⁰ decays/s)

• A)1.3E+5
• B)1.1E+2
• C)3.5E-6
• D)4.1E+12
• E)​2.9E+12