The half-life for a 100-gram sample of radioactive element X is 5 days. How much of element X remains after 10 days have passed?
a. 25 g
b. 50 g
c. 75 g
d. 100 g
The half-life of 5 days means that after each 5-day period, half of the original sample amount will remain.
After 5 days, half of the 100-gram sample will remain, which is 50 grams.
After another 5 days (a total of 10 days), half of the remaining 50 grams will remain, which is 25 grams.
Therefore, the answer is 25 grams.
The correct option is: a. 25 g