A Radioactive Source Has a Half-Life of 2 Min $\times$ 10⁶
B)1

question 70

Multiple Choice

A radioactive source has a half-life of 2 min.At time t = 0 it is placed near a detector and the counting rate is observed to be 3000 counts/s.If the detection efficiency is 25%,how many radioactive nuclei are there at time t = 2 min?

• A)1.04 \(\times\) 10⁶
• B)1.67 \(\times\) 10⁶
• C)2.08 \(\times\) 10⁶
• D)3.41 \(\times\) 10⁶
• E)3.79 \(\times\) 10⁶

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