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
12.5 g
c
50 g
d
10o g - no change
The half-life of element X is 5 days, which means that after each 5-day period, half of the sample decays.
After 5 days, half of the sample would remain, which is 100 g/2 = 50 g.
After another 5 days (10 days in total), again half of the remaining sample would decay.
So, half of the 50 g would remain, which is 50 g/2 = 25 g.
Therefore, the correct answer is option a) 25 g.