Small Traces of Radioactive Substances Are Present in the Human

Multiple Choice

Small traces of radioactive substances are present in the human body.The most abundant radioisotope in the body is potassium-40.A person weighing 70 kg contains about 150 g of potassium, and about 0.01% of this amount is potassium-40.The half-life of potassium-40 is 1.25 x109 years.Estimate the rate at which radiation is produced by the decay of potassium-40 in the body.

A) 4,000 decays/s
B) 40,000 decays/s
C) 400,000 decays/s
D) 400 decays/s
E) 4 decays/s