Section: Math 0 Likes
The graph models the mass y, in nanograms, of cobalt-60 (Co-60) (May 2023 U.S.)
The graph models the mass y, in nanograms, of cobalt-60 (Co-60) remaining in a sample after x half-lives. The half-life of Co-60 is 5.27 years.
What is the mass, in nanograms, of Co-60 remaining in the sample after 10.54 years?
A. 0.47
B. 1.25
C. 2.00
D. 2.64
Solution
Correct answer: B. 1.25.
The graph shows the exponential decay of cobalt-60 (Co-60) over time, specifically after each half-life. The half-life of Co-60 is 5.27 years. To determine the mass remaining after 10.54 years, we first calculate how many half-lives have passed in that time period.
Number of half-lives = Total Time/Half-life = 10.54 years/5.27 years / half-life = 2
From the graph, after 2 half-lives, the mass remaining is approximately 1.25 nanograms.
So, the mass of Co-60 remaining in the sample after 10.54 years is 1.25 nanograms.
Exam Edition: May 2023 U.S.
Exam Year: 2023
Related topics: Graph Interpretation, Exponential Decay