The half-life of a radioactive element is $10 \mathrm{~h}$. The fraction of initial radioactivity of the…

The half-life of a radioactive element is $10 \mathrm{~h}$. The fraction of initial radioactivity of the element that will remain after $40 \mathrm{~h}$ is
  1. $\frac{1}{2}$
  2. $\frac{1}{16}$
  3. $\frac{1}{8}$
  4. $\frac{1}{4}$

Solution

After 4 half-lifes $\frac{N_0}{2^4}=\frac{N_0}{16}$

Asked in: AP EAMCET 2012

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