If 80% of a radioactive element remains radioactive after 250 years, what percent remains radioactive after 600 years? What is the half life of the element?
If 80% of a radioactive element remains radioactive after 250 years, what percent remains radioactive after 600 years? What is the half life of the element?
we use the formula
where is the amount remaining after time , is the initial amount, and is the decay constant.
say , then when , we have
use that equation to find .
after that, you can answer the other questions (the half-life is easy, it is )