Question

Curium-243 has a half-life of 285 days. In a sample of 5.6 grams of curium-243. how many grams will remain after 12 days?

Answer 1

approximately 5.4g

Explanation:

You can use the formula:

`N(t)=N_"0"*(1/2)^(t/T_"1/2"`

Where N is the amount of radioactive isotopes left to the time "t" (in this case t is measured in days). In this case measured in grams. `T_"1/2"` is the half-life period. In this case 285 days.
`N_"0"` is the starting amout of radioactive isotopes, in this case 5.6 grams
Insert the numbers to get:

`N(12)=5.6`g`*(1/2)^(12/285)~~5.4`g

As a side note, I'm pretty sure Cm-243 has a lot longer half-life than that :P