posted by Heena on .
Draw a graph to show the decay of 32g of plutonium-241. Use the graph to find the mass of plutonium-241 after 20 years.
We don't draw graphs for students here. I suggest you use semilogarithmic graph paper, with a logarithmic mass scale, and a linear scale for time. The decay curve will then be a straight line.
The half life of Pu-241 is 13 years.
M = 32*(2)^-(t/13)
LogM = Log32 -(t/13)*Log2
= 1.505 - 0.02316 t
(using log to base 10)
= 1.042 when t = 20 years
M = 11 g
About 1/3 will remain after 20 years.