Modern Physics 3 Question 9
9. Half-life of a radioactive substance $A$ is 4 days. The probability that a nucleus will decay in two half-lives is
(a) $\frac{1}{4}$
(b) $\frac{3}{4}$
(c) $\frac{1}{2}$
(d) 1
(2006, 3M)
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Solution:
- After two half lives $\frac{1}{4}$ th fraction of nuclei will remain undecayed. Or, $\frac{3}{4}$ th fraction will decay. Hence, the probability that a nucleus decays in two half lives is $\frac{3}{4}$.
