A radioactive substance has a half-life of 60 minutes. After 3 hours, the fraction of atoms that have decayed, would be :
(a) 87.5%
(b) 25.1%
(c) 8.5%
(d) 12.5%
Correct option (a) 87.5%
Explanation:
The amount of substance left after time t is
Therefore, amount decayed after 3 hours
