Question

the half -life of a radioactive isotope is the time it takes for a quantity of the isotope to be reduced to half its initial mass. starting with 155 gramsbof a radioactive isotope, how much will be left after 3 half-lives?​

Answer 1

after 3 half lives the amount should be reduced to 19.375g

Explanation:

after the first half life , amount left =

155÷2

= 77.5g

2nd half life

77.5÷2

=38.75g

3rd Half life

38.75÷2

=19.375g