Question

How much of a 1500. mg sample of potassium-42 is left after 48 hours if its half-life is 12.4hours?

Answer 1

Given data

*The initial quantity of potassium-42 is 1500 mg

*The given time is t = 48 hours

*The half-life of Potassium - 42 is T = 12.4 hours

The expression for the radioactive decay is given as

$A(t)=A_0(\frac{1}{2})^{\frac{t}{T_{}_{}_{}}}$

Substitute the values in the above expression as

$\begin{gathered} A(48)=1500(\frac{1}{2})^{\frac{48}{12.4}} \\ =102.59\text{ mg} \end{gathered}$