The half-life of a radioactive substance is 10 years. How much of a 100 g sample remains after 30 years?
Q1. The half-life of a radioactive substance is 10 years. How much of a 100 g sample remains after 30 years?
Answer: 12.5 g
Explanation: After 30 years (3 half-lives), 100 g -> 50 g -> 25 g -> 12.5 g remains. Option C is after 1 half-life.