The half-life for a 100-gram sample of radioactive element X is 10 days. How much of element X remains after 30 days have passed?
a
25 g
b
50 g
c
75 g
d
12.5 g
The half-life for element X is 10 days, which means that after 10 days, half of the sample will remain.
After 30 days, which is equivalent to 3 half-lives, we can calculate how much of the sample remains as follows:
Initial amount: 100 grams
After 1st half-life: 100/2 = 50 grams
After 2nd half-life: 50/2 = 25 grams
After 3rd half-life: 25/2 = 12.5 grams
Therefore, the answer is option d) 12.5 grams.