Question

A radioactive cloud may contain Iodine-131, which has a half-life of 8 days. If the waste must decay to a concentration of less than 0.1% to be considered safe, it will take approximately ___ days to reach safe levels.

Answer 1

100/2 ➙ 50/2 ➙ 25/2 ➙ 12.5/2 ➙ 6.25/2 ➙ 3.13/2 ➙ 1.56/2 ➙ 0.78/2 ➙ 0.39/2 ➙ 0.195/2 ➙ 0.0975

10 half lives x 8 days/half live = 80 days

Step-by-step explanation: