Atoms And Nuclei Question 394
A sample of radioactive substance has $ 10^{6} $ nuclei. If half-life is 20 seconds, the number of nuclei left in the sample after 10 seconds is
Options:
A) $ 10^{4} $
B) $ 2\times 10^{5} $
C) $ 7\times 10^{5} $
D) $ 11\times 10^{5} $
Show Answer
Answer:
Correct Answer: C
Solution:
$ N=N_{0}{{e}^{-\lambda t}}=10^{6}{{e}^{-[ \frac{\ln2}{20}\times 10 ]}} $ $ =10^{6}{{e}^{-\ln\sqrt{2}}}=\frac{10^{6}}{\sqrt{2}}=\approx 7.07\times 10^{5} $
BETA
