Use the graph in the figure below to find the half-life of isotope A.
A grid has a horizontal axis labeled Time (days) and a vertical axis labeled Grams of radionuclide. Two curves are drawn on the graph. All points given are approximate.
Curve A begins at (0,40), curves down and to the right with a slope that becomes increasingly less steep, and ends at (43,10). The curve passes through the following points:
(10,30), (22,20), and (38,12).
Curve B begins at (0,32), curves down and to the right with a slope that becomes increasingly less steep, and ends at (40,0). The curve passes through the following points:
(3,24), (8,16), and (16,8).
To find the half-life of isotope A, we need to determine the time it takes for the quantity of isotope A to decrease by half.
From the graph, we can see that isotope A starts at 40 grams and decreases to 20 grams at approximately 22 days. This is a decrease of 20 grams in 22 days, which means it took 22 days for the quantity of isotope A to decrease by half.
Therefore, the half-life of isotope A is approximately 22 days.