Question

Amount of ${}_{53}{I}^{128}(t_{\frac{1}{2}}=25min)left$ after 75 minutes is

• A. $\frac{1}{6}$
• B. $\frac{1}{4}$
• C. $\frac{1}{8}$
• D. $\frac{1}{9}$

Answer 1

The correct option is C $\frac{1}{8}$

$\frac{N}{N_0}={\left(\frac{1}{2}\right)}^{\frac{T}{t_{\frac{1}{2}}}}$
$\frac{N}{N_0}={\left(\frac{1}{2}\right)}^{\frac{75}{25}};\frac{N}{N_0}={\left(\frac{1}{2}\right)}^3=\frac{1}{8}$