Copper-64 (Cu-64) has a half-life of approximately 12.7 hours. After one half-life (12.7 hours), half of the original sample would remain. Therefore, from a 2 mg sample, after 12 hours, approximately 1 mg of Cu-64 would remain, as it has not yet fully completed one full half-life.
1mg
0.25
1 mg
1 mg
This would depend on the specific sample and its stability. Without additional information, it is not possible to determine how much of the sample would remain unchanged after two hours.
After 132 hours, 1/4 of the initial sample of 10 Ci of Mo-99 would remain. Since the half-life is 66 hours, after 66 hours half of the sample would remain (5 Ci), and after another 66 hours (totaling 132 hours), half of that remaining amount would be left.
Copper-64 (Cu-64) has a half-life of approximately 12.7 hours. After one half-life (12.7 hours), half of the original sample would remain. Therefore, from a 2 mg sample, after 12 hours, approximately 1 mg of Cu-64 would remain, as it has not yet fully completed one full half-life.
1 mg
1mg
If the substance has a half-life of 10 years, there would be 10 half-lives in a 100-year span. Each half-life reduces the amount by half, so after 100 years, 1/2^10 = 1/1024 grams of the sample would remain.
0.25
1 mg
0.5 mg
0.25 mg
1 mg
.25 mg