How many half-lives have passed in a sample that originally contained 5000 parent isotopes but now has only 625?

Peter Lenkefi asked Feb 20, 2023

413,528 views

34 votes

Peter Lenkefi asked Feb 20, 2023

2.8k points

Your comment on this question:

Email me at this address if a comment is added after mine:Email me if a comment is added after mine

Privacy: Your email address will only be used for sending these notifications.

Email me at this address if my answer is selected or commented on:Email me if my answer is selected or commented on

Privacy: Your email address will only be used for sending these notifications.

20 votes

Answer:

3 half lives

Step-by-step explanation:

5000 * (1/2)^n = 625 where n = number of half lives

log ( 625/5000) / log(1/2) = n = 3

5000 2500 1250 625

Dan Bolser answered Feb 27, 2023

3.1k points

Email me at this address if a comment is added after mine:Email me if a comment is added after mine

Privacy: Your email address will only be used for sending these notifications.

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

1.6m questions

2.0m answers