After six half-lives have gone by, what fraction of a sample of a radioactive isotope remains?

Question

? · Answer

First half life ....... 1/2  remaining
Second half life .. 1/4  remaining
Third half life ...... 1/8  remaining
Fourth half life .... 1/16 remaining
Fifth half life ....... 1/32 remaining
Sixth half life ...... 1/64 remaining

? · Answer

(1/2)^6  =  1/64   
that's a fraction so you're down

After six half-lives have gone by, what fraction of a sample of a radioactive isotope remains?

2 Answers