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After the release of radioactive material into the atmosphere from a nuclear power plant in a country in 1982, the hay in that country was contaminated by a radioactive
isotope (half-life 5 days). If it is safe to feed the hay to cows when 9% of the radioactive isotope remains, how long did the farmers need to wait to use this hay?
The farmers needed to wait approximately
(Round to one decimal place as needed.)
days for it to be safe to feed the hay to the cows.
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martin58853 martin58853 · Answer 1 · 2020-08-07T02:37:22+02:00

Answer:

17.5 days

Step-by-step explanation:

The half life of this element is five days.

For the first five days it will decrease to 100*0.5=50%.

For the second five days it will decrease to 50*0.5= 25%

For the third five days it will decrease to 25*0.5 = 12.25%

It means in each day in the five days it reduce 0.1 of the it's remaining amount.

12.5 - 9 = 3.5 %

0.5 of 12.5 = 6.25%

It's going to be 15 days + 2.5 days= 17.5 days