SOLUTION: The half-life of a radioactive element is 5 days. How long will it a 1000 g sample to decay to 62.5 g?
15 days
20 days
2.5 days
5 days
10 days
Algebra ->
Test
-> SOLUTION: The half-life of a radioactive element is 5 days. How long will it a 1000 g sample to decay to 62.5 g?
15 days
20 days
2.5 days
5 days
10 days
Log On
= 500 g after 5 days (one half-life period);
= 250 g after 10 days (two half-life periods);
= 125 g after 15 days (three half-life periods);
= 62.5 g after 20 days (four half-life periods).
ANSWER. 20 days, or 4 (four) half-life periods.
From my post, you see that the answer can be obtained MENTALLY.
