Using the graph shown above, find out how many half-lives does it take for 3/4 of the daughter products to form.
A) 1
B) 2
C) 3
D) 4

Question

Using the graph shown above, find out how many half-lives does it take for 3/4 of the daughter products to form.
A) 1 
B) 2 
C) 3 
D) 4

Quizplus · Accepted Answer

At the start, there is no daughter product formed. As we move from left to right on the graph, the daughter product is formed at the expense of the parent product. When half of the parent product has decayed, we have one half-life. At this point, 50% of the parent product remains and 50% has decayed to daughter product. When two half-lives have passed, 25% of the parent product remains and 75% has decayed to daughter product. Therefore, it takes two half-lives for 3/4 (or 75%) of the daughter product to form.

Using the Graph Shown Above, Find Out How Many Half-Lives