Question

A radioactive material has a half-life of $10$ days. What fraction of the material would remain after $30$ days?

• A. $0.5$
• B. $0.25$
• C. $0.125$
• D. $0.33$

Answer 1

The correct option is C $0.125$

The half life period is 10 days.
30 days $=\frac{30}{10}=$ 3 half life periods.
The fraction of the material would remain after 30 days is
${\left(\frac{1}{2}\right)}^3=\frac{1}{8}=0.125$