Question Detail
Question
A sample of radioactive substance has a half-life of 20 hours. What fraction of the original radioactive nuclei will remain after 100 hours?
Correct Answer
Option A is the correct answer.
Detailed Explanation
100 hours is 5 half-lives (since half-life is 20 hours). Fraction remaining = (1/2)^5 = 1/32.
Hint
Fraction remaining = (1/2)^n, where n is the number of half-lives.