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
75 g
c
100 g
d
50 g
The half-life for a radioactive substance is the amount of time it takes for half of the substance to decay. In this case, the half-life is 5 days. After 5 days, half of the 100 grams of element X will remain, which is 50 grams. After another 5 days (10 days total), half of the remaining 50 grams will decay, leaving 25 grams remaining.
Therefore, the correct answer is:
b) 25 g