Question

. The half-life of iodine-131 is 8.07 days. If 0.25 g are left after 45.7 days, how many gramswere in the original sample?

Answer 1

Given data

*The half-life of iodine-131 is t = 8.07 days

*The mass left is N = 0.25 g

*The number of days is T = 45.7 days

The expression for the radioactive decay equation is given as

$N=N_0(\frac{1}{2})^{\frac{T}{t}}$

Substitute the values in the above expression as

$\begin{gathered} 0.25=N_0(\frac{1}{2})^{\frac{45.7}{8.07}} \\ N=12.66 \end{gathered}$