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
50 g
b
75 g
c
100 g
d
25 g
The half-life of an element is the amount of time it takes for half of a sample to decay. In this case, the half-life for element X is 5 days. After 5 days, half of the 100-gram sample will remain, which is 50 grams.
Since another 5 days have passed, another half-life has occurred. After the second half-life, half of the 50-gram sample will remain, which is 25 grams.
Therefore, the correct answer is d) 25 g.