Question

If 0.78% of a radioactive substance remains, then how many half-lives have passed?

3

7

6

4

Answer 1

7

Step-by-step explanation:

Just took the quiz on k12.

Nuclear Chemistry

Answer 2

The answer would be 7 because of this solution:

You divide (1|2) and then divide it by 7.

The answer should be 0.78% of the remaining half-lives after 7. Because of the remaining radioactive substance that happens during that 0.78 percentage.